Nanomedicine: Nanotechnology, Biology and Medicine - Articles in Press

Synthesis, characterization and evaluation of antimicrobial and cytotoxic effect of silver and titanium nanoparticles - Accepted Manuscript

2010-03-08

Abstract: Microbial resistance represents a challenge for the scientific community to develop new bioactive compounds. Nosocomial infections represent an enormous emerging problem, especially in patients with ambulatory treatment, which are required to carry medical devices for an extended period of time. In this work, an evaluation of the antimicrobial activity of both silver and titanium nanoparticles against a panel of selected pathogenic and opportunistic microorganisms some of them commonly associated to device-associated infections was carried out. Cytotoxicity assay monitoring DNA damage and cell viability were evaluated using human-derived monocyte cell lines. We show that silver-coated nanoparticles having a size of 20-25 nm were the most effective amid all the nanoparticles assayed against the tested microorganisms. In addition, these nanoparticles showed no significant cytotoxicity, suggesting their use as antimicrobial additives in the process of fabrication of ambulatory and non-ambulatory medical devices.

Cerium Oxide Nanoparticles Protect GastroIntestinal Epithelium from Radiation-Induced Damage by Reduction of ROS and Upregulation of Super Oxide Dismutase-2 - Accepted Manuscript

2010-02-22

Abstract: The ability of rare earth cerium oxide (CeO2) nanoparticles to confer radioprotection against gastrointestinal epithelium was examined. The pre-treatment of normal human colon cells (CRL 1541) with varying concentrations of CeO2 nanoparticles 24 hours prior to single dose radiation exposure conferred protection from radiation-induced cell death by reducing the amount of reactive oxygen species (ROS) produced and increasing the expression of Super Oxide Dismutase-2 (SOD-2), in a dose-dependent manner. In subsequent experiments, athymic nude mice were pretreated with intraperitoneal injections of CeO2 nanoparticles prior to a single dose of radiation to the abdominal area. Immunohistochemical analysis show a decrease in TUNEL and Caspase-3-positive cells in the colonic crypt, 4 hours post radiation. In sharp contrast, a significant increase in SOD-2 expression was observed. In the end, these studies suggest that CeO2 nanoparticles protect the gastrointestinal epithelium against radiation-induced damage by 1) acting as free radical scavengers and 2) increasing the production of SOD-2 before radiation insult.

Discriminated effects of thiolated chitosan coated-pMMA Paclitaxel-loaded nanoparticles on different normal and cancer cell lines - Accepted Manuscript

Seyedeh Parinaz Akhlaghi, Seyed Nasser Ostad, Rassoul Dinarvand, Fatemeh Atyabi — 2010-02-22

Abstract: The aim of the present work was to prepare and characterize poly (methyl methacrylate) nanoparticles coated by chitosan-glutathione conjugate in order to encapsulate insoluble anticancer drugs. Nanoparticles were synthesized through radical polymerization of methyl methacrylate initiated by Cerium (IV) ammonium nitrate. Paclitaxel, a model anticancer drug, was encapsulated in nanoparticles with a maximal encapsulation efficiency of 98.27%. These nanoparticles showed sustained in vitro release of the incorporated PTX (75% of the loaded dose was released in 10 days). All nanoparticles had positive charge and were spherical with a size range of about 130-250 nm. The PTX-loaded nanoparticles showed cytotoxicity for 3T3 and T47D breast carcinoma cells, along with no cytotoxicity for two colon cell lines (HT29, Caco2).

In Vitro Evaluation of Novel Polymer-Coated Magnetic Nanoparticles for Controlled Drug Delivery - Accepted Manuscript

2010-02-22

Abstract: Novel poly(N-isopropylacrylamide-acrylamide-allylamine)-coated magnetic nanoparticles (MNPs) were synthesized using silane-coated MNPs as a template for radical polymerization of N-isopropylacrylamide, acrylamide, and allylamine. Properties of these nanoparticles such as size, biocompatibility, drug loading efficiency and drug release kinetics were evaluated in vitro for targeted and controlled drug delivery. Spherical core-shell nanoparticles with 100 nm in diameter showed significantly lower toxicity compared to bare MNPs, doxorubicin encapsulation efficiency of 72%, and significantly higher doxorubicin release at 41°C compared to 37°C, which demonstrates their temperature sensitivity. Released drugs were also active in destroying prostate cancer cells (JHU31). Furthermore, the nanoparticle uptake by JHU31 was dose and incubation time-dependent, reaching saturation at 500 μg/mL and 4 hours, respectively. In addition, magnetic resonance imaging capabilities of the particles were observed using agarose platforms containing cells incubated with nanoparticles. Future work includes investigation of targeting capability and effectiveness of these nanoparticles in vivo using animal models.

Landscape Phage Fusion Protein-mediated Targeting of Nanomedicines Enhances their Prostate Tumor Cell Association and Cytotoxic Efficiency - Accepted Manuscript

2010-02-05

Abstract: Tumor-specific cytotoxicity of drugs can be enhanced by targeting them to tumor receptors using tumor-specific ligands. Phage display offers a high-throughput approach to screen for the targeting ligands. We have successfully isolated phage fusion peptides selective and specific for PC3 prostate cancer cells. Also, we have demonstrated a novel approach of targeting liposomes through tumor-specific phage fusion coat proteins, exploiting the intrinsic properties of the phage coat protein as an integral membrane protein. Here we describe the production of Rhodamine-labeled liposomes as well as doxorubicin-loaded long circulating liposomes targeted to PC3 prostate tumor cells via PC-specific phage peptides, as an extension of our previous studies. Targeting of labeled liposomes was demonstrated using fluorescence microscopy as well as flow cytometry. Targeting of doxorubicin-loaded liposomes enhanced their cytotoxic effect against PC3 cells in vitro indicating a possible therapeutic advantage. The simplicity of the approach for generating targeted liposomes coupled with the ability to rapidly obtain tumor-specific phage fusion proteins via phage display may contribute to a combinatorial system for the production of targeted liposomal therapeutics for advanced stages of prostate tumor.

Accurate quantitation of glutathione in cell lysates through surface-assisted laser desorption/ionization mass spectrometry using gold nanoparticles - Accepted Manuscript

Cheng-Kang Chiang, Yang-Wei Lin, Wen-Tsen Chen, Huan-Tsung Chang — 2010-02-05

Abstract: We developed a method for the determination of three aminothiols-cysteine (Cys), glutathione (GSH), and homocysteine (HCys)-using surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) The analytes were first captured using the unmodified 14-nm Au NPs; N-2-mercaptopropionylglycine (MPG) modified Au NPs served as internal standard was sequentially added and then the sample was analyzed using SALDI-MS. This approach provided good quantitative linearity of the three analytes (R2= ca. 0.99), with good reproducibility (relative standard deviations:<10%), in the analyses of GSH in the lysates of human red blood cells and MCF-7 cancer breast cells in the presence and absence of the anti-inflammatory drug sulfasalazine. The internal standard SALDI-MS approach provides simplicity, accuracy, and precision to the determination of GSH in cells under drug invasion, to open an avenue for SALDI-MS to be used for the precise quantitative determination of a variety of analytes.

Hepatoma-targeted gene delivery using a tumor cell-specific gene regulation system combined with a human liver cell-specific bionanocapsule - Accepted Manuscript

2010-02-05

Abstract: Hepatoma (hepatocellular carcinoma) is the most common type of malignant tumor originating in the liver and has a relatively low 5-year survival rate. The development of hepatoma-targeted therapy is needed to increase treatment efficiency and to reduce the incidence of undesirable side effects. In this study, we developed a novel hepatoma-targeted gene delivery system. The gene delivery system was prepared by combining a human liver cell-specific bionanocapsule (BNC) and a tumor cell-specific gene regulation polymer, which responds to hyperactivated protein kinase C (PKC)α in hepatoma cells. The complex of the polymer/DNA with BNC was delivered into cells and tissues. The developed system showed increased transfection efficiency and resulted in cell-specific gene expression in hepatoma cells and tissues (HuH-7), but no gene expression in normal human hepatocytes or human epidermoid tumor cells (A431). The combination of a tumor cell-specific gene regulation system responding to PKCα and BNC showed novel potential for the selective treatment of hepatomas. The system could be a useful method with applications in hepatoma-specific gene therapy and molecular imaging.

Uptake and distribution of fullerenes in human mast cells - Accepted Manuscript

2010-02-05

Abstract: Fullerenes are carbon cages of variable size that can be derivatized with various side chain moieties resulting in compounds that are being developed into nanomedicines. While fullerene use in several pre-clinical in vitro and in vivo models of disease has demonstrated their potential as diagnostic and therapeutic agents, little is known about how they enter cells, what organelles they target, and the time course for their cellular deposition. Fullerenes (C70) that have previously been shown to be potent inhibitors of mast cell (MC)-mediated allergic inflammation were conjugated with Texas Red (TR) and used in conjunction with confocal microscopy to determine mechanisms of uptake, the organelle localization, and the duration they can be detected in situ. We show C70-TR are non-specifically endocytosed into MC where they are shuttled throughout the cytoplasm, lysosomes, mitochondria, and into endoplasmic reticulum at different times. No nuclear or secretory granule localization was observed. The C70-TR remained detectable within cells at one week. These studies show MC endocytose fullerenes where they are shuttled to organelles involved with calcium and reactive oxygen species (ROS) production which may explain their efficacy as cellular inhibitors.

Nanotopographical modification: A regulator of cellular function through focal adhesions - Accepted Manuscript

M.J.P. Biggs, R.G. Richards, M.J. Dalby — 2010-02-05

Abstract: As materials technology and the field of biomedical engineering advances, the role of cellular mechanisms, in particular adhesive interactions with implantable devices, becomes more relevant in both research and clinical practice. A key tenet of medical device design revolves around the exquisite ability of biological systems to respond to topographic features or chemical stimuli, a process which has led to the development of next-generation biomaterials for a wide variety of clinical disorders. In vitro studies have identified nanoscale features as potent modulators of cellular behaviour and the onset of focal adhesion formation. The focus of this review is on the recent developments concerning the role of nanoscale structures on integrin mediated adhesion and cellular function with an emphasis on the generation of synthetic constructs for regenerative applications.

Cellular Prostheses: Functional Abiotic Nanosystems to Probe, Manipulate, and Endow Function in Live Cells - Accepted Manuscript

Siyuan Lu, Anupam Madhukar — 2010-01-29

Abstract: A class of nanoscale (~1-10nm) structures designed to probe, manipulate, or endow function by direct interfacing with live cells is considered. Such a concept of cellular level prostheses is illustrated via the example of light-activated nanoscale photodiodes capable of creating local electric fields that modulate existing voltage gated ion channels in excitable cells. The dynamics of the membrane potential modulation by such photovoltaic functional abiotic nanosystems (PV-FANs) is modeled through an appropriate equivalent circuit. The feasibility of exceeding the typical ~10mV depolarization threshold for activating the action potentials is examined. In view of the continuing advances in the ability to design, synthesize and characterize abiotic nanoscale systems that can provide desired function, several approaches to the implementation of PV-FANs are discussed. The FANs as “cellular prostheses” can provide a variety of functions in response to different stimuli and represent a paradigm changing opportunity at the frontiers of Nanomedicine.

Beta-Casein Based Nano-Vehicles for Oral Delivery of Chemotherapeutic Drugs: Drug-Protein Interactions and Mitoxantrone Loading Capacity - Accepted Manuscript

Alina Shapira, Gilad Markman, Yehuda G. Assaraf, Yoav D. Livney — 2010-01-25

Abstract: Beta-casein (β-CN), a major milk protein, is amphiphilic and self-associates into micelles in aqueous solutions. We have recently introduced (Shapira A. et al, Nanomedicine 2009 (in press)) a novel oral drug delivery system based on β-CN nanoparticles. The current research builds up and complements this work by studying the interactions of mitoxantrone (MX) and β-CN as they co-assemble into nanoparticles, using absorption and emission spectra, static and dynamic light scattering and by fluorescent emission of both MX and Trp-143 of β-CN. The optimal loading molar-ratio was 3.3 MX:β-CN at 1mg/ml β-CN and the association constant was (2.45±1.76)x105M-1 based on β-CN Trp143 fluorescence; independent MX fluorescence results provided supporting values. In these conditions a bimodal particle distribution was obtained (174.4 nm, 45.9%; 485.1 nm, 54.1%). The gastric digestibility of β-CN suggests possible targeting to stomach tumors. Hence, β-CN nanoparticles may serve as effective vehicles of hydrophobic drugs for oral-delivery preparations.

Enhanced transdermal delivery of an anti HIV agent via ethanolic liposomes - Accepted Manuscript

Vaibhav Dubey, Dinesh Mishra, Manoj Nahar, Vikas Jain, Narendra Kumar Jain — 2010-01-20

Abstract: Indinavir, a protease inhibitor depicts short biological half life, variable pH dependent oral absorption with extensive first pass metabolism thus presenting a challenge concerning its oral administration. The current work aims to formulate and characterize indinavir bearing ethanolic liposomes (ethosomes), and investigate their enhanced transdermal delivery potential. The prepared ethanolic liposomes were characterized to be spherical, unilamellar structures having low polydispersity (0.12±0.03), nanometric size range (147 ± 4.5 nm) and better entrapment efficiency (96.71±1.4%). Permeation studies of indinavir across human cadaver skin depicted enhanced transdermal flux of 27.2±4.2 µg/cm2/h from ethanolic liposomes which was significantly (P<0.05) greater than ethanolic drug solution (13.2±2.7 µg/cm2/h), conventional liposomes (6.3±1.5 µg/cm2/h) and plain drug solution (3.2±1.2 µg/cm2/h), respectively. Additionally, the ethanolic liposomes depicted shortest lag time (0.41 h) for indinavir, thus presenting a suitable approach for transdermal delivery of this protease inhibitor.

Nanotechnology-based manipulation of dendritic cells for enhanced immunotherapy strategies - Accepted Manuscript

Rebecca Klippstein, David Pozo — 2010-01-18

Abstract: Dendritic cells (DCs) are potent antigen presenting cells capable of initiating a primary immune response and possess the ability to activate T cells and stimulate the growth and differentiation of B cells. DCs provide a direct connection between innate and adaptive immune response and arise from bone marrow precursors that are present in immature forms in peripheral tissues where they are prepared to capture antigens. DCs migrate from the peripheral tissues to the closest lymph nodes through afferent lymphatic vessels to present the foreign antigens, stimulating T cell activation and initiating a cellular immune response. Moreover, it is known that DCs play an important role in various diseases and conditions where the immune system is involved, particularly in cancer and autoimmune disorders. For this reasons, targeting nanoparticles (NPs) to DCs provides a promising strategy for developing an efficient balanced and protective immune response. NPs can modulate the immune response and might be potentially useful as effective vaccine adjuvants for infectious disease and cancer therapy. The objective of this review is to present the latest advances in nanoparticle delivery methods targeting DCs, the mechanisms of action, potential effects, and therapeutic results of these systems and their future applications, such as improved vaccination strategies, cancer immunotherapy, and immunomodulatory treatments.

Poly(citric acid)-block-poly(ethylene glycol) Copolymers; New Candidates for Nanomedicine - Accepted Manuscript

Ashkan Tavakoli Naeini, Mohsen Adeli, Manouchehr Vossoughi — 2010-01-13

Abstract: Linear-dendritic ABA triblock copolymers containing poly(ethylene glycol) (PEG) as B block and hyperbranched poly(citric acid) (PCA) as A blocks were synthesized through polycondensation. The molecular self-assembly of synthesized PCA-PEG-PCA copolymers in water was led to nanoparticles and fibers in different sizes and shapes depend on the time and size of PCA blocks. Ten days after dissolving PCA-PEG-PCA copolymers in water, the size of fibers was reached to several millimeters. Mixing a water solution of fluorescein as a small guest molecule and PCA-PEG-PCA copolymers led to encapsulate fluorescein by products of molecular self-assembly. In order to investigate their potential application in nanomedicine and to understand the limitation and capability of these materials as nanoexcipients in biological systems, the different types of short-term in vitro cytotoxicity experiments on HT1080 cell line (human Fibrosarcoma) and hemocompatibility tests were performed.

Ag nanoparticles as a safe preservative for use in cosmetics - Accepted Manuscript

2010-01-08

Abstract: Concern is continuously raised regarding the safety of preservatives, which are crucial in most cosmetic preparations. The antimicrobial effects of silver (Ag) are well recognized; however, Ag has some limitations as a preservative, such as its interference with salts. In this study, we investigated the effects of recently synthesized Ag nanoparticles on microorganisms, the permeability of Ag nanoparticles in human skin, and the cytotoxicity of Ag nanoparticles in human keratinocytes under UVB-irradiation. Ag nanoparticles were found to be very stable, and they did not exhibit sedimentation for over one year. Ag nanoparticles showed sufficient preservation efficacy against mixed bacteria and mixed fungi, and did not penetrate normal human skin. At concentrations of 0.002 ppm~0.02 ppm, Ag nanoparticles had no effect on HaCaT keratinocytes, and did not enhance UVB-induced cell death. These results suggest that Ag nanoparticles are suitable for use as a preservative in cosmetics.

Delivery of amphotericin B nanosuspensions to the brain and determination of activity against Balamuthia mandrillaris amebas - Accepted Manuscript

A. Lemke, A.F. Kiderlen, B. Petri, O. Kayser — 2010-01-08

Abstract: Amphotericin B was formulated as nanosuspensions to develop a nanoparticulate brain delivery system. Nanosuspensions were produced with different surfactant solutions by high pressure homogenization, and characterized by laser diffractometry and photon correlation spectroscopy. Before in vitro and in vivo testing, all nanosuspensions were investigated for protein adsorption by 2-dimensional polyacrylamide gel electrophoresis to predict brain targeting capacities. Selected nanosuspensions were tested for amebicidal activity against Balamuthia mandrillaris, an agent of lethal encephalitis. Our results indicate that polysorbate 80 (Tween 80) / sodium cholate-coated nanosuspensions significantly increased drug brain delivery and inhibited the parasite in vitro, though less in vivo.

Time-Dependent Measure of a Nano-Scale Force-Pulse Driven by the Axonemal Dynein Motors in Individual Live Sperm Cells - Accepted Manuscript

Michael J. Allen, Robert E. Rudd, Mike W. McElfresh, Rod Balhorn — 2010-01-07

Abstract: Nano-scale mechanical forces generated by motor proteins are crucial to normal cellular and organismal functioning. The ability to measure and exploit such forces is important to developing motile biomimetic nanodevices powered by biological motors for Nanomedicine. Axonemal dynein motors positioned inside the sperm flagellum drive microtubule sliding and give rise to rhythmic beating. This force-generating action pushes the sperm cell through viscous media. Here we report new nano-scale information on how the propulsive force is generated by the sperm flagellum and how this force varies over time. Using a modified atomic force microscope, single cell recordings reveal discrete ~50 ms pulses oscillating with amplitude 9.8 +/- 2.6 nN independent of pulse frequency (3.5-19.5 Hz). The average work carried out by each cell is 4.6 x 10-16 J per pulse, equivalent to the hydrolysis of ~5,500 ATP molecules. The mechanochemical coupling at each active dynein head is ~2.2 pN/ATP, and ~3.9 pN per dynein arm.

Identification of deregulated genes by single wall carbon-nanotubes in human normal bronchial epithelial cells - Accepted Manuscript

2010-01-07

Abstract: In order to identify genes affected by single-wall carbon-nanotubes (SWCNTs) in human normal lung cells, we compared the gene expression profile of human normal bronchial epithelial (HNBE) cells with those SWCNTs-treated cells. A cDNA microarray analysis consisting of 54 675 human genes revealed significant changes in the expression of 14 294 genes, with 7 029 genes being up-regulated and 7 265 being down-regulated. This comprehensive list of genes included those associated with cell cycle, apoptosis, cell survival, cell adhesion and motility, signal transduction and transcription regulator. Additional analysis of 19 genes using reverse transcription (RT)-PCR supported the reliability of the microarray analysis. More specifically, our study demonstrates, for the first time, evidence that Rho GTPase-26, GTP binding protein-2, Protein phosphatase-1, Inhibin beta-E, Growth differentiation factor-15, Activating transcription factor-3 and Forkhead-a2 are up-regulated in the SWCNTs-treated HNBE cells compared to untreated cells; while Serpin peptidase inhibitor-4, Chemokine-11, Kinesins (14, 15 and 20A), Leupaxin, Repetin and Hyaluronan-mediated motility receptor are down-regulated in SWCNTs-treated HNBE cells in comparison with their control cells. These findings provide a large body of information regarding gene expression profiles associated with SWCNTs exposure in human lung bronchial epithelial cells, and also represent a source to investigate the mechanism of the effect of SWCNTs in human normal lung cells.

Doxorubicin-loaded solid lipid nanoparticles to overcome multidrug resistance in cancer therapy - Corrected Proof

2010-01-07

Abstract: In the present study we developed doxorubicin-loaded solid lipid nanoparticles (SLN-Dox) using biocompatible compounds, assessed the in vitro hemolytic effect, and examined their in vivo effects on drug retention and apoptosis intensity in P-glycoprotein-overexpressing MCF-7/ADR cells, a representative Dox-resistant breast cancer cell line. Our SLNs did not show hemolytic activity in human erythrocytes. In comparison with Dox, SLN-Dox efficiently enhanced apoptotic cell death through the higher accumulation of Dox in MCF-7/ADR cells. Therefore, SLN-Dox have potential to serve as a useful therapeutic approach to overcome the chemoresistance of adriamycin-resistant breast cancer.

Pharmacological and toxicological target organelles and safe use of single-walled carbon nanotubes as drug carriers in treating Alzheimer disease - Accepted Manuscript

Zhong Yang, Yingge Zhang, Yanlian Yang, Lan Sun, Dong Han, Hong Li, Chen Wang — 2010-01-06

Abstract: Identification of pharmacological and toxicological profiles is of critical importance for the use of nanoparticles as drug carriers in nanomedicine and for the bio-safety evaluation of environmental nanoparticles in nanotoxicology. Here we show that lysosomes are the pharmacological target organelles and mitochondria are the toxicological organelles of SWCNT. The gastrointestinally absorbed SWCNT were lysosomotropic but also entered mitochondria at large doses. III PI3K and LAMP-2A genes was involved in such an organelle preference. SWCNT resulted in collapse of mitochondrial membrane potentials, giving rise to overproduction of ROS, leading to damage of mitochondria, which was followed by lysosomal and cellular injury. Based on the dosage differences in target organelles, SWCNT were successfully used to deliver acetylcholine into brain for treatment of Alzheimer’s disease with rather high safety range by well controlling the doses, which ensures SWCNT only enter lysosomes, the pharmacological organelles, and no or less enter mitochondria, the toxicological organelles.

Dendrosome Based Delivery of siRNA Against E6/E7 Oncogenes in Cervical Cancer - Accepted Manuscript

Tathagata Dutta, Melinda Burgess, Nigel A.J. McMillan, Harendra S. Parekh — 2009-12-30

Abstract: While siRNA treatment holds great promise for the treatment of cancers the field has been held back by the availability of suitable delivery vehicles. For cervical cancer the E6 and E7 oncogenes are ideal siRNA targets for treatment. The purpose of the present study was to explore the potential of dendrosomes for the delivery of siRNA targeting E6 and E7 proteins of cervical cancer cells, in vitro. Optimization of dendrimer generation (G) and Nitrogen/Phosphate (N/P) ratio was carried out using dendrimer:FITC oligo complexes. The optimized N/P ratios were used in formulating dendrimer-siGFP complexes. While formulation 4D100 displayed the highest GFP knockdown, it was also found to be highly toxic to cells. In the final formulation 4D100 was encapsulated into dendrosomes, in order to mask these toxic effects. The optimized dendrosomal formulation (DF), DF3 was found to possess a siGFP-entrapment efficiency of 49.76 ± 1.62 %, vesicle size of 154 ± 1.73 nm, and zeta potential of +3.21 ± 0.07 mV. The GFP knockdown efficiency of DF3 (dendrosome) was found to be almost identical to that of 4D100 (dendrimer:siRNA complex), but the former was completely non-toxic to the cells. DF3 containing siRNA against E6/E7 was found to knockdown the target genes considerably, as compared to the other formulations trialed. Our results suggest that dendrosomes hold potential for the delivery of siRNA and a suitable targeting strategy could be useful for applications in vivo.

Singlet oxygen-induced apoptosis of cancer cells using upconversion fluorescent nanoparticles as a carrier of photosensitizer - Accepted Manuscript

Huichen Guo, Haisheng Qian, Niagara Muhammad Idris, Yong Zhang — 2009-12-30

Abstract: The photodynamic effect of upconversion nanoparticles loaded with a photosensitizer was studied on murine bladder cancer cells (MB49). Mesoporous silica was coated onto NaYF4 upconversion nanocrystals to form a core-shell structure and then loaded with the photosensitizer zinc (II)-phthalocyanine (ZnPc) into its porous silica. The nanoparticles displayed a uniform spherical shape with an average diameter of about 50 nm and showed good dispersibility in water. Intracellular uptake study in MB49 cells revealed a time- and concentration-dependent accumulation of these nanoparticles. Upon irradiation with 980 nm, their efficiency in activating the loaded ZnPc to generate singlet oxygen (1O2) molecules was confirmed in live cell. The cytotoxic effect of the released 1O2 from the nanoplatform was proven by cell viability assay, confocal microscopy, DNA agarose gel electrophoresis, cytochrome c releasing assay and prostate specific antigen-enzyme-linked immunosorbent assay (PSA-ELISA), all of which showed strong photodynamic effect of the nanoparticles on MB49 cells. This suggests the efficacy of NaYF4 upconversion nanoparticles as a carrier for photosensitizers and its use in photodynamic therapy of cancer and some other diseases.

Detection Sensitivity of Lymph Nodes of Various Sizes Using USPIO Nanoparticles in MRI - Accepted Manuscript

2009-12-30

Abstract: Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles based magnetic resonance imaging (MRI) has made a new promise for early detection of lymph nodes and their metastases. These nanoparticles are taken up by macrophages in normal lymph nodes and produce signal changes based on susceptibility artifact and dipolar relaxation. The effect of MR protocols and their parameters on artifact size and detection sensitivity has been studied before.In this study, USPIO nanoparticles were used as MRI contrast agent and their detection sensitivity in axillary lymph nodes were evaluated using previous defined pulse sequences. The minimum amount (dose) of USPIO which delineate lymph nodes of various sizes using susceptibility based gradient echo (GRE) pulse sequences was also determined. It was found that a dose administration of as low as 0.028 mgFe/kg for subcutaneous injection and 0.16 mgFe/kg for intravenous injection can be used to visualize axillary lymph nodes when a sensitive MR protocol is employed.

Release Dynamics of Ciprofloxacin (CFx) From Swellable Nanocarriers of Poly-(2-Hydroxyethyl methacrylate) (PHEMA): An In-Vitro Study - Accepted Manuscript

Raje Chouhan, A.K. Bajpai — 2009-12-30

Abstract: Swellable polymeric nanosystems have emerged as promising materials in drug release technologies. Such systems have shown potential in releasing antibiotic drug and even that in quite desirably controlled fashion. In the present investigation poly(2-hydroxyethyl methacrylate) (PHEMA) nanoparticles have been synthesized by suspension polymerization of HEMA and characterized by various techniques such as FTIR, scanning electron microscopy (SEM), particle size analysis and surface charge measurements. The synthesized nanoparticles were swellable in water and found to show promise to function as a swelling controlled release system. The release kinetics of drug-loaded particles was studied in PBS medium taking Ciprofloxacin (CFx) as a model antibacterial drug. The chemical stability of the pure and released drug was also assessed in phosphate buffer saline (PBS) (pH=7.4), acidic (pH 1.8), and alkaline (pH 8.6) solutions. The in vitro blood compatibility of nanoparticles was also investigated in terms of haemolysis tests. The drug loaded nanoparticles were also examined for their antibacterial and blood compatible behaviors.

Selective removal of ovarian cancer cells from human ascites fluid using magnetic nanoparticles - Accepted Manuscript

2009-12-07

Abstract: A majority of ovarian cancer metastases result from the shedding of malignant cells from the primary tumor into the abdominal cavity. Free-floating cancer cells in serous effusions of late-stage ovarian cancer patients may spread to internal organs making effective treatment extremely difficult. Selective removal of ovarian cancer cells from serous fluids may abate metastasis and improve long-term prognoses. We have previously shown that superparamagnetic nanoparticles conjugated to an ephrin-A1 mimetic peptide with a high affinity for the EphA2 receptor can be used to capture and remove cultured human ovarian cancer cells from the peritonea of experimental mice. Here we demonstrate the potential clinical utility of the methodology by in vitro capture and isolation of cancer cells from the ascites fluid of ovarian cancer patients.

Aquasomes: A promising carrier for peptides and protein delivery - Accepted Manuscript

M.S. Umashankar, R.K. Sachdeva, M. Gulati — 2009-11-20

Abstract: Aquasomes are one of the most recently developed delivery systems that are making a niche as the peptide/protein carriers. These are nanoparticulate carrier systems with three layered self-assembled structures. They comprise the central solid nanocrystalline core coated with polyhydroxy oligomers onto which biochemically active molecules are adsorbed. The solid core provides the structural stability. The carbohydrate coating acts as dehydroprotectant and stabilizes the biochemically active molecules. Due to this property of maintaining the conformational integrity of bioactive molecules, aquasomes are being proposed as a carrier system for delivery of peptide based pharmaceuticals. The delivery system has been successfully utilized for the delivery of insulin, hemoglobin and various antigens. Oral delivery of enzymes like serratiopeptidase has also been achieved. This article discusses the problems faced in the delivery of clinically important peptides and presents aquasomes as a reliable approach to troubleshoot them.

Radioactive gold nanoparticles in cancer therapy: therapeutic efficacy studies of GA-198AuNP nanoconstruct in prostate tumor–bearing mice - Corrected Proof

2009-11-16

Abstract: Biocompatibility studies and cancer therapeutic applications of nanoparticulate β-emitting gold-198 (198Au; βmax = 0.96 MeV; half-life of 2.7 days) are described. Gum arabic glycoprotein (GA)–functionalized gold nanoparticles (AuNPs) possess optimum sizes (12–18 nm core diameter and 85 nm hydrodynamic diameter) to target individual tumor cells and penetrate through tumor vasculature and pores. We report the results of detailed in vivo therapeutic investigations demonstrating the high tumor affinity of GA-198AuNPs in severely compromised immunodeficient (SCID) mice bearing human prostate tumor xenografts. Intratumoral administration of a single dose of β-emitting GA-198AuNPs (70 Gy) resulted in clinically significant tumor regression and effective control in the growth of prostate tumors over 30 days. Three weeks after administration of GA-198AuNPs, tumor volumes for the treated animals were 82% smaller as compared with tumor volume of control group. The treatment group showed only transitory weight loss in sharp contrast to the tumor-bearing control group, which underwent substantial weight loss. Pharmacokinetic studies have provided unequivocal evidence for the optimum retention of therapeutic payload of GA-198AuNPs within the tumor site throughout the treatment regimen with minimal or no leakage of radioactivity to various nontarget organs. The measurements of white and red blood cells, platelets, and lymphocytes within the treatment group resembled those of the normal SCID mice, thus providing further evidence on the therapeutic efficacy and concomitant in vivo tolerance and nontoxic features of GA-198AuNPs.

Novel cationic fullerenes as broad-spectrum light-activated antimicrobials - Accepted Manuscript

2009-11-16

Abstract: Photodynamic inactivation (PDI) is a rapidly developing antimicrobial technology which combines a non-toxic photoactivatable dye or photosensitizer (PS) in combination with harmless visible light of the correct wavelength to excite the dye to its reactive triplet state that will then generate reactive oxygen species (ROS) that are highly toxic to cells. Buckminsterfullerenes are closed-cage molecules entirely composed of sp2 hybridized carbon atoms and although their main absorption is in the UV, they also absorb visible light and have a long-lived triplet state. When C60 fullerene is derivatized with cationic functional groups it forms molecules that are more water-soluble and can mediate PDT efficiently upon illumination, and moreover cationic fullerenes can selectively bind to microbial cells. In this report we describe the synthesis and characterization of several new cationic fullerenes. Their relative effectiveness as broad-spectrum antimicrobial photosensitizers against Gram-positive, Gram-negative bacteria, and a fungal yeast was determined by quantitative structure function relationships.

Sparfloxacin-loaded PLGA nanoparticles for sustained ocular drug delivery - Corrected Proof

2009-10-26

Abstract: Poor ocular bioavailability of drugs (<1%) from conventional eye drops (ie, solution, suspension, and ointments) is mainly due to the physiologic barriers of the eye. In general, ocular efficacy is closely related to ocular drug bioavailability, which may be enhanced by increasing corneal drug penetration and prolonging precorneal drug residence time. In our current work, we develop and evaluate a new colloidal system, that is, poly(dl-lactide-co-glycolide) (PLGA) nanoparticles for sparfloxacin ophthalmic delivery, to improve precorneal residence time and ocular penetration. Nanoparticles were prepared by nanoprecipitation technique and characterized for various properties such as particle size, zeta potential, in vitro drug release, statistical model fitting, stability, and so forth. Microbiological assay was carried out against Pseudomonas aeruginosa using the cup-plate method. Precorneal residence time was studied in albino rabbits by gamma scintigraphy after radiolabeling of sparfloxacin by Tc-99m. Ocular tolerance of the developed nanosuspension was also studied by the Hen Egg Test-Chorioallantoic Membrane (HET-CAM) method. The developed nanosuspension showed a mean particle size in the range of 180 to 190 nm, suitable for ophthalmic application with zeta potential of –22 mV. In vitro release from the developed nanosuspension showed an extended release profile of sparfloxacin according to the Peppas model. Acquired gamma camera images showed good retention over the entire precorneal area for the developed nanosuspension compared with that of a marketed formulation. The marketed drug formulation cleared very rapidly from the corneal region and reached the systemic circulation through the nasolacrimal drainage system, as significant radioactivity was recorded in kidney and bladder after 6 hours of ocular administration, whereas the developed nanosuspension cleared at a very slow rate (P < .05) and remained at the corneal surface for longer duration, as no radioactivity was observed in the systemic circulation. HET-CAM assay with 0 score in 8 hours indicates the nonirritant property of the developed nanosuspension. The developed lyophilized nanosuspension was found to be stable for a longer duration of time than the conventional marketed formulation with a good shelf life.

Tumor-associated macrophages are predominant carriers of cyclodextrin-based nanoparticles into gliomas - Corrected Proof

Darya Alizadeh, Leying Zhang, Jungyeon- Hwang, Thomas Schluep, Behnam Badie — 2009-10-16

Abstract: The goal of this study was to evaluate the mechanism of cyclodextrin-based nanoparticle (CDP-NP) uptake into a murine glioma model. Using mixed in vitro culture systems, we demonstrated that CDP-NPs were preferentially taken up by BV2 and N9 microglia (MG) cells compared with GL261 glioma cells. Fluorescent microscopy and flow cytometry analysis of intracranial GL261 gliomas confirmed these findings and demonstrated a predominant CDP-NP uptake by macrophages (MPs) and MG within and around the tumor site. Notably, in mice bearing bilateral intracranial tumor, MG and MPs carrying CDP-NPs were able to migrate to the contralateral tumors. In conclusion, these studies better characterize the cellular distribution of CDP-NPs in intracranial tumors and demonstrate that MPs and MG could potentially be used as nanoparticle drug carriers into malignant brain tumors.

Chemical power for microscopic robots in capillaries - Corrected Proof

Tad Hogg, Robert A. Freitas — 2009-10-16

Abstract: The power available to microscopic robots (nanorobots) that oxidize bloodstream glucose while aggregated in circumferential rings on capillary walls is evaluated with a numerical model using axial symmetry and time-averaged release of oxygen from passing red blood cells. Robots about 1 μm in size can produce up to several tens of picowatts, in steady state, if they fully use oxygen reaching their surface from the blood plasma. Robots with pumps and tanks for onboard oxygen storage could collect oxygen to support burst power demands two to three orders of magnitude larger. We evaluate effects of oxygen depletion and local heating on surrounding tissue. These results give the power constraints when robots rely entirely on ambient available oxygen and identify aspects of the robot design significantly affecting available power. More generally, our numerical model provides an approach to evaluating robot design choices for nanomedicine treatments in and near capillaries.

Preparation and in vitro evaluation of actively targetable nanoparticles for SN-38 delivery against HT29 cell lines - Accepted Manuscript

2009-10-16

Abstract: SN-38 (7-ethyl-10-hydroxycamptothecin) is the active metabolite of irinotecan, which is 100-1000 folds more cytotoxic than irinotecan. Nonetheless extreme hydrophobicity of SN-38 has prevented its clinical use. One way of improving the solubility and stability of SN-38 is to formulate the drug into nanoparticles. Folic acid has been widely employed as a targeting moiety for various anti-cancer drugs. For folate-receptor-targeted anti-cancer therapy, SN-38 nanoparticles were produced employing poly-lactide-co-glycolide–polyethylene glycol–folate (PLGA-PEG-FOL) conjugate by emulsification/solvent evaporation method. The FOL-conjugated di-block copolymer was synthesized by coupling the PLGA-PEG-NH2 di-block copolymer with an activated folic acid. The conjugates were used for the formation of SN-38 NPs with an average size of 200 nm in diameter. The SN-38 targeted nanoparticles showed a greater cytotoxicity against HT-29 cancer cells than SN-38 non-targeted nanoparticles. These results suggested that folate-targeted nanoparticles could be a potentially useful delivery system for SN-38 as an anticancer agent.

Ligand-modified gene carriers increased uptake in target cells but reduced DNA release and transfection efficiency - Corrected Proof

Yen Cu, Cathy LeMoëllic, Michael J. Caplan, W. Mark Saltzman — 2009-10-05

Abstract: DNA delivery to cells can be improved by using particle carriers made from biodegradable polymers such as poly(lactic-co-glycolic)acid (PLGA). It is speculated that addition of targeting moieties to the particle surface to facilitate uptake can further enhance gene expression in specific cells or tissues. Taking advantage of well-known receptor/ligand interactions in intestinal and renal epithelial cells, we formulated PLGA particles with high density of surface-bound bovine serum albumin (BSA; ∼768 molecules/particle). BSA-coated particles exhibited significantly higher uptake by cells expressing the albumin receptor, megalin, and resisted degradation in low pH. However, gene expression from BSA-coated particles was 3- to 10-fold lower than that from unmodified particles; this reduction in transfection efficiency was probably due to the slower DNA release rate from modified particles. In this setting, addition of a targeting feature to particles reduced their effectiveness. Our study highlights the importance of the interplay between cell uptake and payload release in the design of polymer drug carriers.

Design of Eudragit RL 100 nanoparticles by nanoprecipitation method for ocular drug delivery - Corrected Proof

Swarnali Das, Preeti K. Suresh, Rohitas Desmukh — 2009-10-05

Abstract: The objective of the current study was to prepare positively charged amphotericin-B–loaded nanoparticles providing a controlled release formulation. The particles were prepared by solvent displacement or nanoprecipitation method. The non-biodegradable positively charged polymer Eudragit RL 100 was used to prepare the different formulations with varying ratios of drug and polymer. The formulations were evaluated in terms of particle size, zeta potential, and differential scanning calorimetry measurements. Drug entrapment and release properties were examined also. The antimicrobial activity against Fusarium solani was determined. In vivo eye irritation study was carried out by a modified Draize test. All the formulations remained within a size range of 130 to 300 nm in fresh preparation as well as after 2 months. The zeta potential was positive (+22 to +42 mV) for all the formulations and was suitable for ophthalmic application. A prolonged drug release was shown by all the formulations. The formulation possesses a good antifungal activity against Fusarium solani when tested by disk diffusion method, and no eye irritation on in vivo testing was found.

Self-assembled multifunctional Fe/MgO nanospheres for magnetic resonance imaging and hyperthermia - Corrected Proof

2009-10-05

Abstract: A one-step process for the production of nanoparticles presenting advanced magnetic properties can be achieved using vapor condensation. In this article, we report on the fabrication of Fe particles covered by a uniform MgO epitaxial shell. MgO has a lower surface energy than Fe, which results in a core-shell crystal formation. The particles satisfy a few of technical requirements for the practical use in real clinics, such as a high biocompatibility in living cells in-vitro, an injection through blood vessels without any clothing problems in murine model, a high absorption rate for magnetic hyperthermia at small particle concentration, and the potential to be used as contrast agent in the field of diagnostic magnetic imaging. They are also able to be used in drug delivery and magnetic-activated cell sorting.

Effect of endothelium mimicking self-assembled nanomatrices on cell adhesion and spreading of human endothelial cells and smooth muscle cells - Corrected Proof

2009-10-05

Abstract: The goal of this study is to develop unique native endothelium mimicking nanomatrices and evaluate their effects on adhesion and spreading of human umbilical vein endothelial cells (HUVECs) and aortic smooth muscle cells (AoSMCs). These nanomatrices were developed by self-assembly of peptide amphiphiles (PAs) through a solvent evaporation technique. Three PAs, one containing the Tyr-Ile-Gly-Ser-Arg (YIGSR) ligand, the second containing the Val-Ala-Pro-Gly (VAPG) ligand, and a third without cell adhesive ligands, were developed. Cell adhesion and spreading were evaluated by a PicoGreen-DNA assay and live/dead assay, respectively. Our results show that PA-YIGSR significantly enhances HUVEC adhesion (26,704 ± 2708), spreading (84 ± 8%), and proliferation (50 ± 2%) compared with that of other PAs. PA-VAPG and PA-YIGSR showed significantly greater AoSMC adhesion compared with that of PA-S. PA-VAPG also showed significantly greater spreading of AoSMCs (63 ± 11%) compared with that of other PAs. Also, all the PAs showed significantly reduced platelet adhesion compared with that of collagen I (control). These findings would facilitate the development of novel vascular grafts, heart valves, and cell-based therapies for cardiovascular diseases.

Cholesterol succinyl chitosan anchored liposomes: Preparation, characterization, physical stability and drug release behavior - Accepted Manuscript

Yinsong Wang, Shaoli Tu, Rongshan Li, Xiaoying Yang, Lingrong Liu, Qiqing Zhang — 2009-10-05

Abstract: The purpose of this study was to prepare cholesterol succinyl chitosan anchored liposomes (CAL) and to investigate their characterization, physical stability and drug release behavior in vitro. Three cholesterol succinyl chitosan (CHCS) conjugates with different substitution degrees (DS) of cholesterol moiety were synthesized and used as the anchoring materials to coating on the liposome surface by the incubation method. CALs were almost spherical in shape and had a classic shell-core structure. Compared with plain liposomes and chitosan coated liposomes (CCL), CALs had the larger sizes, the higher zeta potentials and the better physical stability by storage at 4°C ± 2°C and 25°C ± 2°C. Epirubicin, as a model drug, was effectively loaded into CALs, and exhibited sustained release behavior both in phosphate buffer solution (PBS, pH 7.4) and 1% (V/V) aqueous fetal bovine serum (FBS) compared to plain liposomes and CCL.

Pharmaceutical foams: are they the answer to the dilemma of topical nanoparticles? - Corrected Proof

Yanjun Zhao, Marc B. Brown, Stuart A. Jones — 2009-08-28

Abstract: Nanoparticulate systems have the potential to improve topical drug delivery because of their capacity to enhance drug loading and dissolution, protect chemically unstable therapeutic agents, and improve product aesthetics. However, the commercial use of nanoparticles in topical products is limited because the evidence that they penetrate intact skin is contradictory, and their ability to release active agents in traditional semisolid vehicles is poor. One way to overcome this problem is to formulate nanoparticles in a dynamic delivery system—that is, one that induces a change upon dose actuation so as to promote drug release. Pressurized pharmaceutical foams are one type of dynamic system that can drive a change of state and excipient concentration after dose actuation. This review summarizes the current status of topical products containing nanoparticles, discusses the recent scientific advances in foam production, and investigates the prospect of incorporating nanoparticles into dynamic topical foams. Recent literature suggests that dynamic foams have the potential to break down the nanoparticles loaded within them, improve drug release from nanoparticles, and enhance topical efficacy. Although the published data to support the use of dynamic systems are limited, it is clear that they provide a promising solution to enhance drug release from nanoparticles, and future research work should aim to investigate these systems in more detail.

Toxicity issues in the application of carbon nanotubes to biological systems - Corrected Proof

Constantine P. Firme, Prabhakar R. Bandaru — 2009-08-21

Abstract: Carbon nanotubes (CNTs) have recently emerged as a new option for possible use in methodologies of cancer treatment, bioengineering, and gene therapy. This review analyzes the potential, through possible toxicologic implications, of CNTs in nanomedicine. Generally, proven success in other fields may not translate to the use of CNTs in medicine for reasons including inconsistent data on cytotoxicity and limited control over functionalized-CNT behavior, both of which restrict predictability. Additionally, the lack of a centralized toxicity database limits comparison between research results. To better understand these problems, we seek insight from currently published toxicity studies, with data suggesting postexposure regeneration, resistance, and mechanisms of injury in cells, due to CNTs.

Visualization of liposomes carrying fibrinogen γ-chain dodecapeptide accumulated to sites of vascular injury using computed tomography - Corrected Proof

2009-08-21

Abstract: We have constructed liposomes with hemostatic activity as a platelet substitute using moderately thrombocytopenic rats. The liposomes were conjugated with the dodecapeptide (HHLGGAKQAGDV: H12), which is a fibrinogen γ-chain C-terminal sequence (γ 400–411). To visualize liposome accumulation at the site of vascular injury by in vivo computed tomography, a water-soluble contrast dye, N,N′-bis[2-hydroxy-1-(hydroxylmethyl)ethyl]-5-[(2S)-2-hydroxylpropanoylamino]-2,4,6-triiodoisophthalamide (iopamidol), was encapsulated into the H12-conjugated liposomes. We achieved direct visualization of specific accumulation of the H12-(iopamidol)liposomes at the jugular vein injured by ferric chloride and succeeded in semiquantitative analyses of the accumulated amount of H12-liposomes in the injured site. We therefore propose that H12-liposomes that are specifically recruited to, and exert their hemostatic activity at the site of vascular injury, have a significant potential as a carrier and/or as an ideal platelet substitute. Furthermore, the H12-(iopamidol)liposomes would also be clinically useful as diagnostic agents for pathological thrombus detection and as contrast dyes for hepatosplenography.

Characterization, in vitro cytotoxicity assessment, and in vivo visualization of multimodal, RITC-labeled, silica-coated magnetic nanoparticles for labeling human cord blood–derived mesenchymal stem cells - Corrected Proof

2009-08-21

Abstract: Live imaging is a powerful technique that can be used to characterize the fate and location of stem cells in animal models. Here we investigated the characteristics and in vitro cytotoxicity of human mesenchymal stem cells (MSCs) labeled with silica-coated magnetic nanoparticles incorporating rhodamine B isothiocyanate, MNPs@SiO2(RITC). We also conducted various in vivo–uptake tests with nanoparticle-labeled human MSCs. MNPs@SiO2(RITC) showed photostability against ultraviolet light exposure and were nontoxic to human MSCs, based on the MTT, apoptosis, and cell cycle arrest assays. In addition, MNPs@SiO2(RITC) did not affect the surface phenotype or morphology of human MSCs. We also demonstrated that MNPs@SiO2(RITC) have stable retention properties in MSCs in vitro. Furthermore, using optical and magnetic resonance imaging, we successfully detected a visible signal from labeled human MSCs that were transplanted into NOD.CB17-PrkdcSCID (NOD-SCID) mice. These results demonstrate that MNPs@SiO2(RITC) are biocompatible and useful tools for human MSC labeling and bioimaging.

Norcantharidin-associated galactosylated chitosan nanoparticles for hepatocyte-targeted delivery - Corrected Proof

2009-08-21

Abstract: In this study a new chitosan (CS) derivative, galactosylated chitosan (GC), was synthesized and used to prepare norcantharidin-associated GC nanoparticles (NCTD-GC NPs) by taking advantage of the ionic cross-linkage between the molecules of the anti-hepatocarcinoma medicine NCTD and of the GC as carrier. NCTD-GC NPs were obtained with average particle size of 118.68 ± 3.37 nm, entrapment efficiency of 57.92 ± 0.40%, and drug-loading amount of 10.38 ± 0.06%. Several important factors influencing the entrapment efficiency, drug-loading amount, and particle size of NCTD-GC NPs were studied. The characteristics of sustained and pH-sensitive release of NCTD from NCTD-GC NPs in vitro were studied. In addition, in vitro cellular uptake and cytotoxicity of nanoparticles to hepatoma cell lines SMMC-7721 and HepG2 were also investigated. In vitro, and compared to CS-based NCTD-CS NPs, NCTD-GC NPs demonstrated satisfactory compatibility with hepatoma cells and strong cytotoxicity against hepatocellular carcinoma cells. In vivo antitumor activity of NCTD-GC NPs was evaluated in mice bearing H22 liver tumors. NCTD-GC NPs displayed tumor inhibition effect in mice, better than either the free NCTD or the NCTD-CS NPs. As a hepatocyte-targeting carrier, GC NPs are potentially promising for clinical applications.

Cross-linked polyethylenimine-hexametaphosphate nanoparticles to deliver nucleic acids therapeutics - Corrected Proof

2009-08-21

Abstract: Branched polyethylenimine (PEI; 25 kDa) as a nonviral vector exhibits high transfection efficiency and is a potential candidate for efficient gene delivery. However, the cytotoxicity of PEI limits its application in vivo. PEI was ionically interacted with hexametaphosphate, a compact molecule with high anionic charge density, to obtain nanoparticles (PEI-HMP). Nanoparticles were assessed for their efficacy in protecting complexed DNA against nucleases. The intracellular trafficking of nanoparticles was monitored by confocal microscopy. The cytotoxicity and transfection efficiency of PEI-HMP nanoparticles were evaluated in vitro. In vitro transfection efficiency of PEI-HMP (7.7%) was ∼1.3- to 6.4-folds higher than that of the commercial reagents GenePORTER 2TM, FugeneTM, and SuperfectTM. Also, PEI-HMP (7.7%) delivered green fluorescent protein (GFP)-specific small interfering ribonucleic acid (siRNA) in culture cells leading to >80% suppression in GFP gene expression. PEI-HMP nanoparticles protected complexed DNA against DNase for at least 2 hours. A time-course uptake of PEI-HMP (7.7%) nanoparticles showed the internalization of nanoparticles inside the cell nucleus in 2 hours. Thus, PEI-HMP nanoparticles efficiently transfect cells with negligible cytotoxicity and show great promise as nonviral vectors for gene delivery.

Development of multiple-layer polymeric particles for targeted and controlled drug delivery - Corrected Proof

2009-08-21

Abstract: The purpose of this work was to develop multilayered particles consisting of a magnetic core and two encompassing shells made up of poly(N-isopropylacrylamide) (PNIPAAm) and poly(d,l-lactide-co-glycolide) (PLGA) for targeted and controlled drug delivery. Transmission electron microscopy confirmed that multilayered particles were obtained with PNIPAAm magnetic nanoparticles embedded within the PLGA shell. Factorial analysis studies also showed that the particle size was inversely proportional to the surfactant concentration and sonication power and directly proportional to the PLGA concentration. Drug-release results demonstrated that these multilayer particles produced an initial burst release and a subsequent sustained release of both bovine serum albumin (BSA) and curcumin loaded into the core and shell of the particle, respectively. BSA release was also affected by changes in temperature. In conclusion, our results indicate that the multilayered magnetic particles could be synthesized and used for targeted and controlled delivery of multiple drugs with different release mechanisms.

Interactions of single-wall carbon nanotubes with endothelial cells - Corrected Proof

2009-08-21

Abstract: Single-wall carbon nanotubes (SWCNTs) could be promising delivery vehicles for cancer therapy. These carriers are generally introduced intravenously, however, little is known of their interactions with endothelial cells, the cells lining vessels and mediating clearance of nanoparticles. Here we show that SWCNTs of 1 to 5 μm in length, both “pristine” and functionalized by oxidation, had limited toxicity for endothelial cells in vitro as determined by growth, migration morphogenesis, and survival assays. Endothelial cells transiently took up SWCNTs, and several lines of data indicated that they were associated with an enhanced acidic vesicle compartment within the endothelial cells. Our findings of SWCNT interactions with endothelial cells suggest these may be optimal vehicles for targeting the vasculature and potential carriers of anti-angiogenic drugs. The implications on their biological activity must be taken into account when considering the use of these nanoparticles for therapeutic delivery of drugs.

Novel optical nanosensors for probing and imaging live cells - Corrected Proof

Janina Kneipp, Harald Kneipp, Burghardt Wittig, Katrin Kneipp — 2009-08-21

Abstract: This review introduces multifunctional optical nanosensors based on surface-enhanced Raman scattering (SERS) and demonstrates their application in live cells. The novel nanosensors have the potential to improve our understanding of cellular processes on the molecular level. The hybrid sensor consists of gold or silver nanoparticles with an attached reporter species. The sensor can be detected and imaged based on the SERS signature of the reporter. This results in several advantages, such as high spectral specificity, multiplex capabilities, improved contrast, and photostability. SERS sensors not only highlight cellular structures, based on enhanced Raman spectra of intrinsic cellular molecules measured in the local optical fields of the gold nanoparticles, they also provide molecular structural information on their cellular environment. Moreover, the SERS signature of the reporter can deliver information on the local pH value inside a cell at subendosomal resolution. SERS sensors are suitable for one- and two-photon excitation.

Nanodelivery in airway diseases: Challenges and therapeutic applications - Corrected Proof

Indrajit Roy, Neeraj Vij — 2009-07-21

Abstract: This review describes the challenges and therapeutic applications of nanodelivery systems for treatment of airway diseases. Therapeutic applications of nanodelivery in airway diseases involve targeted delivery of DNA, short interfering RNA, drugs, or peptides to hematopoietic progenitor cells and pulmonary epithelium to control chronic pathophysiology of obstructive and conformational disorders. The major challenges to nanodelivery involve physiologic barriers such as mucus and alveolar fluid. It is necessary for the nanoparticles to be biodegradable and capable of providing sustained drug delivery to the selected cell type. Once inside the cell, the nanoparticle should be capable of escaping the endocytic degradation machinery. In addition, for effective gene delivery, nuclear entry and chromosomal integration are critical. The strategies to overcome these pathophysiologic barriers are discussed as an attempt to synchronize the efforts of pulmonary biologists, chemists, and clinicians to develop novel nanodelivery therapeutics for airway diseases.

Biological synthesis of metallic nanoparticles - Corrected Proof

Kaushik N. Thakkar, Snehit S. Mhatre, Rasesh Y. Parikh — 2009-07-21

Abstract: The synthesis of metallic nanoparticles is an active area of academic and, more importantly, “application research” in nanotechnology. A variety of chemical and physical procedures could be used for synthesis of metallic nanoparticles. However, these methods are fraught with many problems including use of toxic solvents, generation of hazardous by-products, and high energy consumption. Accordingly, there is an essential need to develop environmentally benign procedures for synthesis of metallic nanoparticles. A promising approach to achieve this objective is to exploit the array of biological resources in nature. Indeed, over the past several years, plants, algae, fungi, bacteria, and viruses have been used for production of low-cost, energy-efficient, and nontoxic metallic nanoparticles. In this review, we provide an overview of various reports of synthesis of metallic nanoparticles by biological means.