Nanomedicine: Nanotechnology, Biology and Medicine - Articles in Press

Highly Stable, Ligand Clustered “Patchy” Micelle Nanocarriers for Systemic Tumor Targeting - Accepted Manuscript

Zhiyong Poon, Jung Ah Lee, Shenwen Huang, Richard J. Prevost, Paula T. Hammond — 2010-09-02

Abstract: A novel linear-dendritic block copolymer has been synthesized and evaluated for targeted delivery. The use of the dendron as the micellar exterior block in this architecture allows the presentation of a relatively small quantity of ligands in clusters for enhanced targeting, thus maintaining a long circulation time of these “patchy” micelles. The polypeptide linear hydrophobic block drives formation of micelles that carry core-loaded drugs, and their unique design gives them an extremely high level of stability in vivo. We have found that these systems lead to extended time periods of increased accumulation in the tumor (up to 5 days) compared to non-targeted vehicles. We also demonstrate a 4x increase in efficacy of paclitaxel when delivered in the targeted nanoparticle systems, while significantly decreasing in vivo toxicity of the chemotherapy treatment.

Preparation and Biological Evaluation of Multifunctional PLGA-Nanoparticles designed for Photoacoustic Imaging - Accepted Manuscript

2010-08-23

Abstract: Nanoparticulate contrast agents for molecular imaging have attracted widespread interest for diagnostic applications with high resolution in medicine. Here we introduce polymer-based multifunctional nanoparticles exhibiting a near infrared (NIR) absorption in the range of the Nd:YAG laser wavelength of 1064 nm as a novel resorbable photoacoustic contrast system and report about their biological evaluation.Submicron sized spherical nanoparticles with a high encapsulation efficiency> 87% were achieved by incorporation of NIR dyes (IR5 / IR26) in poly[(rac-lactide)-co-glycolide] (PLGA) with 50 mol% glycolide content via a specific spray drying process in good yield> 75%. By subsequent application of a centrifugation protocol two different size fractions with a diameter in the range of 445 to 540 nm and 253 to 305 nm were obtained, which were further used for investigation of photoacoustic properties and cytotoxic effects. The prepared PLGA nanoparticles exhibited photoacoustic properties using a Nd:YAG laser-based system. After exposure of particle concentrations up to 10 mg ml-1 for two days no effects on viability, mitochondrial activity and proliferation and cell death of human hepatocarcinoma cells (HepG2) and monkey kidney cells (Vero) were observed.The excellent photoacoustic properties in combination with the positive biological results qualify the dye-loaded PLGA particles as promising candidates for a resorbable photoacoustic contrast system.

Succinated chitosan as a gene carrier for improved chitosan solubility and gene transfection - Accepted Manuscript

Elsie Khai-Woon Toh, Hsing-Yin Chen, Yu-Lun Lo, Shih-Jer Huang, Li-Fang Wang — 2010-08-23

Abstract: Chitosan (CHI), a linear polysaccharide, has been intensely explored as a non-viral gene delivery vector. The low physiological solubility of CHI has limited its gene transfection efficiency. Here we report the synthesis of different substitution degrees of succinated chitosans (CHI-succ) to increase water solubility. From the 1H-NMR spectra, the degree of deacetylation of hydrolyzed CHI was roughly 88% and the degree of succinylation (DS) in three CHI-succ polymers were approximately 5, 10, and 20%. Various weight ratios of CHI/DNA and CHI-succ/DNA polyplexes were prepared for gel electrophoresis retardation, particle size, zeta-potential, and morphology studies. The results suggest that the plasmid DNA is readily entrapped at a CHI-succ/DNA weight ratio of 20, and the sizes and x-potentials were between 110~140 nm and ± 1~5 mV, and exhibited low cytotoxicity against HEK 293T cells. CHI-succ with 5 and 10% DS showed improved transfection efficiency as compared to nascent CHI.

Modeling nanophotothermal therapy: Kinetics of thermal ablation of healthy and cancerous cell organelles and gold nanoparticles - Accepted Manuscript

Renat R. Letfullin, Christian B. Iversen, Thomas F. George — 2010-08-23

Abstract: Nanoparticles are being researched as a noninvasive method for selectively killing cancer cells. With particular antibody coatings on nanoparticles, they attach to the abnormal cells of interest (cancer or otherwise). Once attached, nanoparticles can be heated with UV/visible/IR or RF pulses, heating the surrounding area of the cell to its point of death. Researchers often use single-pulse or multipulse modes of laser heating when conducting nanoparticle ablation research. In this paper, time-dependent simulations and detailed analyses are carried out for different nonstationary pulsed laser-nanoparticle interaction modes, and the advantages and disadvantages of single-pulse and multipulse (set of short pulses) laser heating of nanoparticles are shown. Simulations are performed for the metal nanoparticles in the biological surrounding medium as well as for healthy and cancerous cell organelles.

Comparative structural and functional studies of nanoparticle formulations for DNA and siRNA delivery - Accepted Manuscript

Albert Kwok, Stephen L. Hart — 2010-08-11

Abstract: The transfection efficiencies of 25 kDa branched polyethylenimine (B-PEI) and 22 kDa linear PEI (L-PEI) with both DNA and siRNA were compared and correlated with their biophysical properties relating to complex formation, stability and disassembly. L-PEI DNA complexes transfected (5.18 × 108 RLU/mg) five-fold better than B-PEI DNA complexes (0.95 × 108 RLU/mg) while B-PEI siRNA complexes gave approximately 60% gene knockdown and L-PEI siRNA complexes were inactive. Both B-PEI and L-PEI packaged DNA and siRNA to form positively-charged nanoparticles; however, L-PEI nanoparticles were less stable than B-PEI nanoparticles, particularly with siRNA. The poor stability of L-PEI siRNA complexes appeared to be the major factor contributing to an observed lack of cellular uptake and hence poor transfection. The more stable B-PEI siRNA complexes; however, were bound, internalised and detectable in the cytoplasm. These results highlight the importance of particle stability for efficient siRNA and plasmid delivery, while retaining the ability to readily dissociate within the cell.

Polymer nanoparticles containing tumor lysates as antigen delivery vehicles for dendritic cell–based antitumor immunotherapy - Uncorrected Proof

2010-08-09

Abstract: Encapsulation of tumor-associated antigens in polymer nanoparticles (NP) is a promising approach to enhance efficiency of antigen delivery for anti-tumor vaccines. Head and neck squamous carcinoma (HNSCC) cell lines were initially used to generate tumor-associated antigens (TAA)-containing poly (lactic-co-glycolic acid) (PLGA) NP; encapsulation efficiency and release kinetics were profiled. Findings were adopted to entrap fresh tumor lysate from five patients with advanced HNSCC. To test the hypothesis that NP enhance antigen presentation, dendritic cell (DC) produced from patient blood monocyte precursors were loaded with either the un-encapsulated or NP-encapsulated versions of tumor lysates. These were used to stimulate freshly-isolated autologous CD8+ T cells. In four of five patients, anti-tumor CD8+ T cells showed significantly increased immunostimulatory IFN-γ (p=0.071) or decreased immmunoinhibitory IL-10 production (p=0.0004) associated with NP-mediated antigen delivery. The observations represent an enabling step in the production of clinically-translatable, inexpensive, highly-efficient, and personalized polymer-based immunotherapy for solid organ malignancies.Graphical Abstract: Scanning electron micrograph depicting dendritic cells with characteristic dendrites, taking up spherical tumor antigen containing nanoparticles.

Nanosuspension: a new vehicle for the improvement of the delivery of drugs to the ocular surface. Application to amphotericin B - Uncorrected Proof

Swarnali Das, Preeti K. Suresh — 2010-08-09

Abstract: Present limitations in the management of ophthalmic fungal infections include the inability to provide long-term extraocular drug delivery without compromising intraocular structures and/or systemic drug exposure. In the present study, the potential of Eudragit RS 100 nanoparticles (NPs) as a new vehicle for the improvement of the delivery of drugs to the ocular mucosa was investigated. Amphotericin B (AmB) was chosen as a model compound because of its potential usefulness for the treatment of fungal diseases. A solvent displacement technique was used to produce AmB-loaded Eudragit NPs. These NPs had a mean size range of 150–290 nm and a zeta potential of +19–28 mV. Even after 6 months of stability study, results were unchanged, indicating the good potential for ocular application. In vitro release studies revealed that a maximum amount of drug was released within 24 hours (60%). The results obtained from microbial assay showed that the antifungal activity of drug-loaded NPs was equal to or slightly lower than that of free-AmB solution. In vivo experiments showed that, following topical instillation of nanosuspension to a rabbit's eye there was no irritation. From these results we can conclude that Eudragit RS 100 nanosuspension may represent an efficacious vehicle to deliver the drug into the eye.Graphical Abstract: TEM image of nanoparticles.The NPs were successfully prepared by solvent displacement or nanoprecipitation method. The nonbiodegradable positively charged polymer Eudragit RS 100 was used, with varying ratios. The formulations were evaluated in terms of particle size, zeta potential, and differential scanning calorimetry measurements. Drug entrapment and release properties were also examined.

Emerging nanotechnology approaches in tissue engineering for peripheral nerve regeneration - Uncorrected Proof

Carla Cunha, Silvia Panseri, Stefania Antonini — 2010-08-09

Abstract: Effective nerve regeneration and functional recovery subsequent to peripheral nerve injury is still a clinical challenge. Autologous nerve graft transplantation is a feasible treatment in several clinical cases, but it is limited by donor site morbidity and insufficient donor tissue, impairing complete functional recovery. Tissue engineering has introduced innovative approaches to promote and guide peripheral nerve regeneration by using biomimetic conduits creating favorable microenvironments for nervous ingrowth, but despite the development of a plethora of nerve prostheses, few approaches have as yet entered the clinic. Promising strategies using nanotechnology have recently been proposed, such as the use of scaffolds with functionalized cell-binding domains, the use of guidance channels with cell-scale internally oriented fibers, and the possibility of sustained release of neurotrophic factors. This review addresses the fabrication, advantages, drawbacks, and results achieved by the most recent nanotechnology approaches in view of future solutions for peripheral nerve repair.

Shell cross-linked and hepatocyte-targeting nanoparticles containing doxorubicin via acid-cleavable linkage - Uncorrected Proof

Changhai Lu, Malcolm M.Q. Xing, Wen Zhong — 2010-07-21

Abstract: Hepatocyte-targeting and shell cross-linked nanoparticles with lactose moiety on the surface and doxorubicin (DOX) in the core were prepared from lactose-PEG-DOX conjugate. The process consists of the synthesis of a novel α-hydrazine-ω-propargyl poly(ethylene glycol) (PEG) with a double bond in the PEG backbone, followed by the bonding of a lactose molecule containing an azide group to the ω-end of PEG via “click” chemistry, and finally, the conjugation of DOX to the α-end of PEG via an acid-labile, hydrazone linkage. The resultant conjugate can be self-assembled into nanoparticles. Thiolated tri(ethylene glycol) was introduced into the shell of nanoparticles as a cross-linking agent. The release of DOX is more rapid from lactose-PEG-DOX at pH 5.0 than at pH 7.4. Fluorescent microscope studies suggest that the lactose-DOX nanoparticles are internalized by hepatoma cells through a lactose receptor–mediated mechanism, whereas the lactose-free nanoparticles are not endocytosed as rapidly as lactose-DOX nanoparticles. MTT assay also shows that lactose-DOX nanoparticles have a stronger inhibition against hepatoma cells than DOX nanoparticles and pure DOX.

A new thermography based early detection of cancer approach based on magnetic nanoparticles Theory simulation and in vitro validation - Accepted Manuscript

Arie Levy, Abraham Dayan, Moshe Ben-David, Israel Gannot — 2010-07-09

Abstract: This work offers the utilization of tumor-specific magnetic nanoparticles together with an alternating magnetic field as a means to thermally mark a tumor in order to detect it using thermal imaging system. Experiments were conducted using an in-vitro tissue model, an inductive heating system and an IR camera. The thermal images, recorded by the IR camera during the experiments, were analyzed using an algorithm, which was developed as part of this work. The results show that small tumor phantoms (diameter of 0.5mm) which were embedded under the surface of the tissue phantom (up to 14mm below the surface) can be detected and located, indicating that the proposed method could potentially offer considerable advantages over conventional thermography and other methods for cancer early detection. Nevertheless, several issues should be clarified in future researches before the method could be offered for clinical use.

Pulmonary toxicity by carbon nanotubes: A systematic report - Accepted Manuscript

Jitendra Kayat, Virendra Gajbhiye, Rakesh Kumar Tekade, Narendra Kumar Jain — 2010-07-09

Abstract: Carbon nanotubes (CNTs) are nanosized, cylindrical, hollow tubes consisting entirely of carbon element. Now a days, CNTs are playing an important role in drug delivery as a carrier system owing to several unique physical and chemical properties. Literature shows that CNTs are toxic in nature, which depends upon properties of CNTs material, such as their structure (SWCNTs or MWCNTs), length and aspects ratio, surface area, degree of aggregation, extent of oxidation, bound functional group(s), method of manufacturing and on their concentration as well as dose. People could get exposed to CNTs through accidental exposure by coming in contact with the aerosol form of CNTs during production, or exposure as a result of biomedical use. Numerous in vitro and in vivo studies have shown that carbon nanotubes and/or associated contaminants or catalytic materials that arise during the production process may induce oxidative stress, prominent pulmonary inflammation, apoptosis in different cell types and able to induce cytotoxic effects on lungs. Studies on the toxicity of CNTs have mainly focused on the pulmonary effects of intra-tracheal or pharyngeal administered CNTs. This review examines the potential pulmonary toxicity of CNTs.

C60 fullerene-pentoxifylline dyad nanoparticles enhance autophagy to avoid cytotoxic effects caused by the β-amyloid peptide - Uncorrected Proof

2010-07-09

Abstract: Many studies have focused on the neuroprotective effects of C60 fullerene-derived nanomaterials. The peculiar structure of C60 fullerene, which is capable of “adding” multiple radicals per molecule, serves as a “radical sponge,” and it can be an effective antioxidant by reducing cytotoxic effects caused by intracellular oxidative stress. In this study, PEG-C60-3, a C60 fullerene derivative incorporating poly(ethylene glycol), and its pentoxifylline-bearing hybrid (PTX-C60-2) were investigated against β-amyloid (Aβ)25-35-induced toxicity toward Neuro-2A cells. PEG-C60-3 and PTX-C60-2 significantly reduced Aβ25-35-induced cytotoxicity, with comparable activities in decreasing reactive oxygen species and maintaining the mitochondrial membrane potential. Aβ25-35 treatment elicited adenosine monophosphate-activated protein kinase–associated autophagy. Cytoprotection by PEG-C60-3 and PTX-C60-2 was partially diminished by an autophagy inhibitor, indicating that the elicited autophagy and antioxidative activities protect cells from Aβ damage. PTX-C60-2 was more effective than PEG-C60-3 at enduring the induced autophagy. Our results offer new insights into therapeutic drug design using C60 fullerene–PTX dyad nanoparticles against Aβ-associated diseases.Graphical Abstract: The structure of the C60 fulleropyrrolidine-xanthine hybrid particle (Figure 1)

Photothermolysis of glioblastoma stemlike cells targeted by carbon nanotubes conjugated with CD133 monoclonal antibody - Uncorrected Proof

2010-07-09

Abstract: CD133+ cells in glioblastoma (GBM) display cancer stem cell-like properties and have been considered as the culprit of tumor recurrence, justifying exploration of potential therapeutic modalities targeting CD133+ cancer stem-like cells (CSCs). For photothermolysis studies, GBM-CD133+ and GBM-CD133– cells mixed with various ratios were challenged with single-walled carbon nanotubes (SWNTs) conjugated with CD133 monoclonal antibody (anti-CD133) and then irradiated with near-infrared laser light. Results show that GBM-CD133+ cells were selectively targeted and eradicated, whereas GBM-CD133– cells remained viable. In addition, in vitro tumorigenic and self-renewal capability of GBM-CD133+ treated with localized hyperthermia was significantly blocked. Furthermore, GBM-CD133+ cells pretreated with anti-CD133-SWNTs and irradiated by near-infrared laser 2 days after xenotransplantation in nude mice did not exhibit sustainability of CSC features for tumor growth. Taken altogether, our studies demonstrated that anti-CD133-SWNTs have the potential to be utilized as a thermal-coupling agent to effectively target and destroy GBM CSCs in vitro and in vivo.Graphical Abstract: After (a) GBM-CD133– and (b) GBM-CD133+ cells incubated separately with single-walled carbon nanotubes (SWNTs) tagged with CD133 monoclonal antibody (anti-CD133-SWNTs) for 6 h, 808-nm near-infrared (NIR) laser light was harnessed to irradiate both cell types. After washed with phosphate buffered saline (PBS) and stained with calcein-AM dye, fluorescent images of cells were taken. The GBM-CD133– cells located in the laser-shining zone remained viable with green fluorescence. However, the GBM-CD133+ cells located in the laser-shining region did not reveal green fluorescence (i.e., cell necrosis). To clarify the feasibility of selectively eradicating GBM-CD133+ cells by anti-CD133-SWNTs, a mixture of GBM-CD133+ and GBM-CD133– cells (1:1 ratio) was treated with anti-CD133-SWNTs for 6 h, washed with PBS, and then exposed to NIR laser. The image of (c) was no longer dark like (b), instead sparkling green fluorescence was visualized. This indicated that there were viable GBM-CD133– cells emitting green fluorescence in the NIR laser-shining zone; however, the equally mixed GBM-CD133+ cells were specially targeted by anti-CD133-SWNTs and thermally ablated by NIR laser.

Nanoscale phase dynamics of the normal tear film - Accepted Manuscript

Santosh Khanal, Thomas J. Millar — 2010-07-05

Abstract: The tear film is a dynamic multilayered structure. The interactions and the interfacial dynamics between the layers that occur during a blink cycle must be such that they allow for maintenance of a stable tear film. Attempts to understand these dynamics have been limited by the techniques and biomarkers used. Quantum dots (qdots) offer a new potential to monitor the dynamics of the tear film layers in real without the drawbacks of previously used methodologies. Indium galium posphide (InGaP) qdots were used to differentially assess the dynamics of the lipid and aqueous layers of the tear film in real time. In the aqueous, qdots dispersed to form a stable local region which was swept away into the upper and lower menisci during a blink. They did not redisperse onto the ocular surface, but were progressively removed from the menisci through the puncta. Some of these qdots adhered to the mucin layer on the ocular surface in a mesh-like pattern and remained there for 5 – 6 blinks before they were removed. The organic qdots dispersed quickly but patchily over the whole outer surface of the tear film. They also strongly marked both eyelid margins and slowly dispersed onto the skin and eyelashes and not through the puncta. Some were trapped in the menisci as blobs that rolled along the meniscus. These data support the view of a distinct three layered tear film: an inner mucin layer attached to the epithelial cells; a fluid aqueous layer; and an outer viscoelastic lipid layer.

Preparation and characterization of ketoprofen loaded solid lipid nanoparticles made from beeswax and carnauba wax - Accepted Manuscript

2010-07-05

Abstract: Solid lipid nanaoparticles (SLNs) have been proposed as suitable colloidal carriers for delivery of drugs with limited solubility. Ketoprofen as model drug was incorporated into SLNs prepared from a mixture of beeswax and carnauba wax using tween 80 and egg lecithin as emulsifiers. The characteristics of the SLNs with various lipid and surfactant composition were investigated. The mean particle size of drug loaded SLNs decreased by mixing tween 80 and egg lecithin as well as by increasing total surfactant concentration. SLNs of 75±4 nm with a polydispersity index of 0.2±0.02 were obtained using 1% (v/v) mixed surfactant at a ratio of 60:40 tween80 to egg lecithin. The zeta potential of these SLNs varied at the range of-15 to-17 (mV) suggesting the presence of similar interface properties. High drug entrapment efficiency of 97% revealed the ability of SLNs to incorporate low water soluble drug such as ketoprofen. DSC thermograms and HPLC analysis indicated the stability of nanoparticles with negligible drug leakage after 45 days of storage. It was also found that nanoparticles with more beeswax content in their core, exhibited faster drug release compared to those containing more carnauba wax in their structure.

The how, when and why of the aging signals appearing on the human erythrocyte membrane: An atomic force microscopy study of surface roughness - Accepted Manuscript

2010-07-05

Abstract: We recently developed an Atomic Force Microscopy-based protocol to use the roughness of the plasma membrane of erythrocytes as a morphological parameter, independently from the cell shape, to investigate the membrane-skeleton integrity in healthy and pathological cells.Here, we apply the method to investigate a complex physiological phenomenon, such as the RBCs aging, that plays a major role in the regulation of the erythrocytes’ turnover. The aging, monitored morphologically and biochemically, has been accelerated and modulated by preventing oxidative stresses, effects of proteases and divalent cations, and by artificially consuming the intracellular ATP. The collected data evidence that the progression of aging causes a drastic decrease of the measured roughness, that is diagnostic of a progressive, ATP-dependent, alteration of the membrane-skeleton properties. Lastly, the degree of reversibility of such effects have been investigated as function of aging time, enabling the detection of irreversible transformation in the erythrocytes’ structure and metabolism.

MR and fluorescence imaging of doxorubicin loaded nanoparticles using a novel in vivo model - Accepted Manuscript

2010-07-05

Abstract: We report here the in vivo combined-modality imaging of multifunctional drug delivery nanoparticles. These dextran core-based stealth liposomal nanoparticles (nanosomes) contained doxorubicin, iron oxide for MRI contrast, and Bodipy for fluorescence. The particles were long-lived in vivo due to surface decoration with polyethylene glycol (PEG) and the incorporation of acetylated lipids which were UV cross-linked for physical stability. We developed a rodent dorsal skinfold window chamber which facilitated both MRI and non-destructive optical imaging of nanoparticle accumulation in the same tumors. Chamber tumors were genetically labeled with DsRed-2 that enabled the MR images, the red fluorescence of the tumor, and the blue fluorescence of the nanoparticles to be co-localized. The nanoparticle design and MR imaging developed with the window chamber were then extended to orthotopic pancreatic tumors expressing DsRed-2. The tumors were MR imaged using iron oxide-dextran liposomes and by fluorescence to demonstrate the deep imaging capability of these nanoparticles.

Aidebenone-loaded nanoparticles based on chitosan and N-carboxymethylchitosan - Uncorrected Proof

2010-07-05

Abstract: Nanoparticles based on chitosan (Ch) and N-carboxymethylchitosan (N-CMCh) cross-linked with tripolyphosphate (TPP) were developed by co-drying with idebenone in different polymer-to-drug ratios (1.3:1 to 16:1) with 20% (wt/wt) colloidal silicon dioxide and tripolyphosphate (0.2 mg/mL). At high ratios (8:1 and 16:1) the spray-dried powder showed spherical and dense particles with a size close to 1 μm, allowing almost complete drug coating by the polymeric system and a high efficiency of drug incorporation (>90% and >80%, for Ch and N-CMCh, respectively). The nanoparticles showed a 10-fold increase of drug stability in comparison with free drug and preserved antioxidant activity in vitro. Compared with the severely irritative free form of idebenone, the nanoparticle formulation showed decreased mucous membrane irritation. These results revealed the potential of Ch and N-CMCh nanoparticles as carriers for a hydrophobic and irritative drug such as idebenone for topical or nasal use.Graphical Abstract: The nanoparticles of Chitosan (Ch) or N-carboxymethylchitosan (N-CMCh) (< 1 μm) showed a high increase of antioxidant Idebenone (IDB) stability in comparison with the free drug and preserved its antioxidant activity in vitro. Compared to the severely irritative free form of IDB, the nanoparticles showed decreased mucous-membrane irritation. These results revealed the potential of Ch and N-CMCh nanoparticles as carrier for a hydrophobic and irritative drug such as idebenone for topical or nasal use.

Advances in Polymeric Micelles for Drug Delivery and Tumor Targeting - Accepted Manuscript

Uttam Kedar, Prasanna Phutane, Supriya Shidhaye, Vilasrao Kadam — 2010-06-14

Abstract: Plethora of the formulation techniques were reported in literature for targeting the drug to specific site. Polymeric micelle can be targeted to tumor site by passive as well as active mechanism. Some inherent properties of polymeric micelle such as size in nanorange, stability in plasma, longevity in vivo and pathological characteristics of tumor make polymeric micelles to be targeted at the tumor site by passive mechanism called enhanced permeability and retention (EPR) effect. Polymeric micelle formed from the amphiphilic block copolymer is suitable for encapsulation of poorly water soluble, hydrophobic anticancer drugs. Other characteristics of polymeric micelles like separated functionality at the outer shell are useful for targeting the anticancer drug to tumor by active mechanisms. Polymeric micelles can be conjugated with many ligands such as antibodies fragments, epidermal growth factors, α2-glycoprotein, transferrin, folate to target micelles to cancer cells. Application of heat, ultrasound are the alternative method to enhance drug accumulation in tumoral cells. Targeting using micelles can also be done to tumor angiogenesis which is the potentially promising target for anticancer drugs. Polymeric micelles have been used for the delivery of many anticancer agents in the pre-clinical and clinical studies. This review summarizes about recently available information regarding targeting the anticancer drug to the tumor site using polymeric micelles.

New metal-based nanoparticles for intravenous use: requirements for clinical success with focus on medical imaging - Corrected Proof

Tore Skotland, Tore-Geir Iversen, Kirsten Sandvig — 2010-05-31

Abstract: Animal studies have during the last years revealed a large potential for in vivo imaging with new metal-based nanoparticles and will certainly during the next years also continue to improve our understanding of basic biological processes. In the present article we discuss what is needed to bring such non–iron oxide particles into clinical imaging. For imaging agents it is essential to have a rapid clearance from blood so as to obtain low background signals and good images. The surface charge and hydrodynamic diameter of the nanoparticles in the presence of plasma proteins are important for their biodistribution, excretion. and a rapid clearance from blood. As discussed, some major challenges remain to be met regarding safety and metabolism issues. Measurements and optimization of the critical parameters will shorten the time needed for such particles to be accepted for widespread medical use.

Reduced dose-limiting toxicity of intraperitoneal mitoxantrone chemotherapy using cardiolipin-based anionic liposomes - Corrected Proof

2010-05-31

Abstract: Intraperitoneal chemotherapy confers limited clinical benefit as a result of the dose-limiting toxicity of anticancer drugs. We aimed to develop optimized liposomes for mitoxantrone (MTO) administration that provide high encapsulation efficiency and increase the therapeutic index. Cationic MTO was loaded onto anionic liposomes by electrostatic surface complexation. The anticancer activity was evaluated in a peritoneal carcinomatosis model. The retention of MTO at the tumor site was monitored by molecular imaging. MTO loading efficiencies by electrostatic complexation were >95% for all anionic liposomes but <5% for neutral liposomes. Among anionic liposomes, cardiolipin liposomes (CLs) exhibited the strongest binding affinity for MTO, the highest anticancer activity, and the lowest toxicity. MTO delivered by CLs showed prolonged retention at tumor sites. Unlike free MTO showing significant cardiotoxicity, MTO administered in CLs provided negligible cardiotoxicity. CL-mediated delivery may increase the therapeutic index of MTO chemotherapy by prolonged retention and reduced cardiotoxicity.

Phosphate ester hydrolysis of biologically relevant molecules by cerium oxide nanoparticles - Corrected Proof

2010-05-31

Abstract: In an effort to characterize the interaction of cerium oxide nanoparticles (CNPs) in biological systems, we explored the reactivity of CNPs with the phosphate ester bonds of p-nitrophenylphosphate (pNPP), ATP, o-phospho-l-tyrosine, and DNA. The activity of the bond cleavage for pNPP at pH 7 is calculated to be 0.860 ± 0.010 nmol p-nitrophenol/min/μg CNPs. Interestingly, when CNPs bind to plasmid DNA, no cleavage products are detected. While cerium(IV) complexes generally exhibit the ability to break phosphorus-oxygen bonds, the reactions we report appear to be dependent on the availability of cerium(III) sites, not cerium(IV) sites. We investigated the dephosphorylation mechanism from the first principles and find the reaction proceeds through inversion of the phosphate group similar to an SN2 mechanism. The ability of CNPs to interact with phosphate ester bonds of biologically relevant molecules has important implications for their use as potential therapeutics.Graphical Abstract: Graphical Abstract Figure

Effect of cholesterol and amyloid-β peptide on structure and function of mixed-lipid films and pulmonary surfactant BLES. An atomic force microscopy study - Corrected Proof

Francis Hane, Elizabeth Drolle, Zoya Leonenko — 2010-05-21

Abstract: Pulmonary surfactant forms a thin molecular film inside mammalian lung alveoli and lowers the surface tension of the air/fluid interface to reduce the work of breathing. Upon compression functional surfactant forms characteristic multilayer structures, which indicate surfactant surface activity. We showed that cholesterol adversely affects both structural and surface-active properties of BLES surfactant and DPPC/DOPG lipid films. Incorporation of small concentrations of fibril-forming peptide amyloid-β 1-40 helps to counteract the distractive effect of cholesterol by improving characteristic multilayer formation that occurs upon compression. In contrast to many negative effects of amyloid-forming peptides reported earlier, we report a positive effect of amyloid-β peptide on surfactant function, which may aid in the designing of novel surfactant formulations.

Study of the stabilization of zinc phthalocyanine in sol-gel TiO2 for photodynamic therapy applications - Corrected Proof

2010-05-21

Abstract: Photodynamic therapy (PDT) has emerged as an alternative and promising noninvasive treatment for cancer. It is a two-step procedure that uses a combination of molecular oxygen, visible light, and photosensitizer (PS) agents; phthalocyanine (Pc) was supported over titanium oxide but has not yet been used for cell inactivation. Zinc phthalocyanine (ZnPc) molecules were incorporated into the porous network of titanium dioxide (TiO2) using the sol-gel method. It was prepared from stock solutions of ZnPc and TiO2. ZnPc-TiO2 was tested with four cancer cell lines. The characterization of supported ZnPc showed that phthalocyanine is linked by the N-pyrrole to the support and is stable up to 250 °C, leading to testing for PDT. The preferential localization in target organelles such as mitochondria or lysosomes could determine the cell death mechanism after PDT. The results suggest that nanoparticulated TiO2 sensitized with ZnPc is an excellent candidate as sensitizer in PDT against cancer and infectious diseases.

Caspase-9-dependent decrease of nuclear pore channel hydrophobicity is accompanied by nuclear envelope leakiness - Corrected Proof

Armin Kramer, Ivan Liashkovich, Hans Oberleithner, Victor Shahin — 2010-05-13

Abstract: Advances in nanomedicine require conceptual understanding of physiological processes. Apoptosis is a fundamental physiological process that is characterized, among other things, by an increased permeability of the nuclear envelope (NE). The latter is a tight transport barrier, known to restrict nuclear delivery rate of therapeutic nanoparticles. Therefore, an understanding of the underlying mechanism that leads to the breakdown of the barrier during apoptosis could stimulate the development of new approaches in gene therapy. We set out to elucidate this mechanism following induction of apoptosis on isolated cell nuclei. We tested the hypothesis whether caspases, mediators of apoptosis, trigger the NE leakiness at the level of the nuclear pore complexes (NPCs) using fluorescence techniques. As the permeability barrier inside the NPC channel is thought to be based on hydrophobic–hydrophobic protein interactions we further investigated the NPC channel hydrophobicity using atomic force microscopy. Caspase-9 was found to induce NE leakiness to large macromolecules. Leakiness was prevented by pretreatment of NPCs with an importin-β mutant, which irreversibly binds and thereby obstructs the NPC channel. Utilizing an ultra-sharp, hydrophobic atomic force microscope tip as a chemical nanosensor that reaches deep into the apoptotic NPC channel, a remarkable decrease of hydrophobic binding sites was detected therein. We conclude that caspase 9 gives rise to NE leakiness by perturbing the hydrophobicity-based barrier inside the NPC channel. This explains the high passive NE permeability in early apoptosis.

Viral nanoparticles as platforms for next-generation therapeutics and imaging devices - Corrected Proof

Nicole F. Steinmetz — 2010-04-30

Abstract: Nanomaterials have been developed for potential applications in biomedicine, such as tissue-specific imaging and drug delivery. There are many different platforms under development, each with advantages and disadvantages, but viral nanoparticles (VNPs) are particularly attractive because they are naturally occurring nanomaterials, and as such they are both biocompatible and biodegradable. VNPs can be designed and engineered using both genetic and chemical protocols. The use of VNPs has evolved rapidly since their introduction 20 years ago, encompassing numerous chemistries and modification strategies that allow the functionalization of VNPs with imaging reagents, targeting ligands, and therapeutic molecules. This review discusses recent advances in the design of “smart” targeted VNPs for therapeutic and imaging applications.

Inorganic nanomedicine—Part 2 - Corrected Proof

Bhupinder S. Sekhon, Seema R. Kamboj — 2010-04-23

Abstract: Inorganic nanomaterials (INMs) and nanoparticles (NPs) are important in our lives because of their use as drugs, imaging agents, and antiseptics. Among the most promising INMs being developed are metal, silica, dendrimers, organic-inorganic hybrids, and bioinorganic hybrids. Gold NPs are important in imaging, as drug carriers, and for thermotherapy of biological targets. Gold NPs, nanoshells, nanorods, and nanowires have the extensive potential to be an integral part of our imaging toolbox and useful in the fight against cancer. Metal NP contrast agents enhance magnetic resonance imaging and ultrasound results in biomedical applications of in vivo imaging. Hollow and porous INMs have been exploited for drug and gene delivery, diagnostic imaging, and photothermal therapy. Silver NPs show improved antimicrobial activity. Silica NPs have been used in drug delivery and gene therapy. Biomolecular inorganic nanohybrids and nanostructured biomaterials have been exploited for targeted imaging and therapy, drug and gene delivery, and regenerative medicine. Dendrimers find use as drug or gene carriers, contrast agents, and sensors for different metal ions.

Delivery of a peptide via poly(d,l-lactic-co-glycolic) acid nanoparticles enhances its dendritic cell–stimulatory capacity - Corrected Proof

2010-03-29

Abstract: Nanoparticles (NPs) are attractive carriers for vaccines. We have previously shown that a short peptide (Hp91) activates dendritic cells (DCs), which are critical for initiation of immune responses. In an effort to develop Hp91 as a vaccine adjuvant with NP carriers, we evaluated its activity when encapsulated in or conjugated to the surface of poly(d,l-lactic-co-glycolic) acid (PLGA) NPs. We found that Hp91, when encapsulated in or conjugated to the surface of PLGA-NPs, not only activates both human and mouse DCs, but is in fact more potent than free Hp91. Hp91 packaged within NPs was about fivefold more potent than the free peptide, and Hp91 conjugated to the surface of NPs was ∼20-fold more potent than free Hp91. Because of their capacity to activate DCs, such NP-Hp91 systems are promising as delivery vehicles for subunit vaccines against infectious disease or cancer.

Nanostructured surfaces for enhanced protein detection toward clinical diagnostics - Corrected Proof

2010-03-29

Abstract: “Label-free” biomolecule sensors for detection of inflammatory cardiovascular biomarker associated with vulnerable coronary vascular plaque rupture were designed and fabricated using micro- and nanotextured polystyrene (PS) polymer structures that functioned as sensing elements coupled with electronic measurement equipment. We demonstrated that scaling down the surface texturing from the micro- to the nanoscale enhances the amplitude of the measured detected signal strength. We believe that the nanoscale fiber morphology provides size-matched spaces for trapping and immobilizing the protein biomolecule, resulting in improved detection signal strength. We selected PS as the model system and demonstrated the detection of human serum C-reactive protein. We employed these findings in designing a platform “lab-on-a-chip” protein sensor. Comparative studies were performed on PS textured surfaces of two different surface features: a PS microsphere mat and an electrospun PS nanofiber matrix.

In vivo evaluation of the biodistribution and safety of PLGA nanoparticles as drug delivery systems - Corrected Proof

2010-03-15

Abstract: The remarkable physicochemical properties of particles in the nanometer range have been proven to address many challenges in the field of science. However, the possible toxic effects of these particles have raised some concerns. The aim of this article is to evaluate the effects of poly(lactide-co-glycolide) (PLGA) nanoparticles in vitro and in vivo compared to industrial nanoparticles of a similar size range such as zinc oxide, ferrous oxide, and fumed silica. An in vitro cytotoxicity study was conducted to assess the cell viability following exposure to PLGA nanoparticles. Viability was determined by means of a WST assay, wherein cell viability of greater than 75% was observed for both PLGA and amorphous fumed silica particles and ferrous oxide, but was significantly reduced for zinc oxide particles. In vivo toxicity assays were performed via histopathological evaluation, and no specific anatomical pathological changes or tissue damage was observed in the tissues of Balb/C mice. The extent of tissue distribution and retention following oral administration of PLGA particles was analyzed for 7 days. After 7 days, the particles remained detectable in the brain, heart, kidney, liver, lungs, and spleen. The results show that a mean percentage (40.04%) of the particles were localized in the liver, 25.97% in the kidney, and 12.86% in the brain. The lowest percentage was observed in the spleen. Thus, based on these assays, it can be concluded that the toxic effects observed with various industrial nanoparticles will not be observed with particles made of synthetic polymers such as PLGA when applied in the field of nanomedicine. Furthermore, the biodistribution of the particles warrants surface modification of the particles to avoid higher particle localization in the liver.

Synthesis, characterization, and evaluation of antimicrobial and cytotoxic effect of silver and titanium nanoparticles - Corrected Proof

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 requires that they wear medical devices for an extended period of time. In this work, an evaluation of the antimicrobial activity of both silver and titanium nanoparticles was carried out against a panel of selected pathogenic and opportunistic microorganisms, some of them commonly associated with device-associated infections. Cytotoxicity assays 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 among 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 nonambulatory medical devices.

Cerium oxide nanoparticles protect gastrointestinal epithelium from radiation-induced damage by reduction of reactive oxygen species and upregulation of superoxide dismutase 2 - Corrected Proof

2010-02-22

Abstract: The ability of rare earth cerium oxide (CeO2) nanoparticles to confer radioprotection against gastrointestinal epithelium was examined. The pretreatment of normal human colon cells (CRL 1541) with varying concentrations of CeO2 nanoparticles 24 hours before single-dose radiation exposure conferred protection from radiation-induced cell death by reducing the amount of reactive oxygen species produced and increasing the expression of superoxide dismutase 2 (SOD2), in a dose-dependent manner. In subsequent experiments athymic nude mice were pretreated with intraperitoneal injections of CeO2 nanoparticles before 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 after radiation. In sharp contrast, a significant increase in SOD2 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 SOD2 before radiation insult.

Discriminated effects of thiolated chitosan-coated pMMA paclitaxel-loaded nanoparticles on different normal and cancer cell lines - Corrected Proof

2010-02-22

Abstract: The aim of the present work was to prepare and characterize poly(methyl methacrylate) nanoparticles coated by chitosan–glutathione conjugate so as to encapsulate insoluble anticancer drugs. Nanoparticles were synthesized through radical polymerization of methyl methacrylate initiated by cerium (IV) ammonium nitrate. Paclitaxel (PTX), 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 NIH 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 - Corrected Proof

2010-02-22

Abstract: Previously uncharacterized 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 a diameter of 100 nm showed significantly lower systemic toxicity than did bare MNPs, as well as doxorubicin encapsulation efficiency of 72%, and significantly higher doxorubicin release at 41°C compared with 37°C, demonstrating their temperature sensitivity. Released drugs were also active in destroying prostate cancer cells (JHU31). Furthermore, the nanoparticle uptake by JHU31 cells was dependent on dose and incubation time, 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.

Nanotopographical modification: a regulator of cellular function through focal adhesions - Corrected Proof

Manus Jonathan Paul Biggs, R. Geoff Richards, Matthew 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 has evolved from the exquisite ability of biological systems to respond to topographical features or chemical stimuli, a process that 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 behavior through 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 medical constructs with regenerative applications.