Nanofiber-acellular dermal matrix as a bilayer scaffold containing mesenchymal stem cell for healing of full-thickness skin wounds.

Full-thickness skin defect is one of the main clinical problems, which cannot be repaired spontaneously. The aim of this study was to evaluate the feasibility of combining nanofibers with ADM as a bilayer scaffold for treatment of full-thickness skin wounds in a single-step procedure. The nanofibrous polycaprolactone/fibrinogen scaffolds were fabricated by electrospinning. Subsequently, mesenchymal stem cells were isolated from rat adipose tissues and characterized by flow cytometry. Cell adhesion, proliferation, and the epidermal differentiation potential of adipose-derived stem cells (ADSCs) on nanofibrous scaffolds were investigated by scanning electron microscopy (SEM), alamarBlue, and real-time PCR, respectively. In animal studies, full-thickness excisional wounds were created on the back of rats and treated with following groups: ADM, ADM-ADSCs, nanofiber, nanofiber-ADSCs, bilayer, and bilayer-ADSCs. In all groups, wounds were harvested on days 14 and 21 after treatment to evaluate re-epithelialization, blood vessel density, and collagen content. The results indicated that ADSCs seeded on ADM, nanofiber, and bilayer scaffolds can promote re-epithelialization, angiogenesis, and collagen remodeling in comparison with cell-free scaffolds. In conclusion, nanofiber-ADSCs showed the best results for re-epithelialization (according to histological scoring), average blood vessel density (92.7 ± 6.8), and collagen density (87.4 ± 4.9%) when compared to the control and other experimental groups.

Monitoring, mapping and health risk assessment of fluoride in drinking water supplies in rural areas of Maku and Poldasht, Iran.

The aim of this study was to investigate and determine fluoride concentrations in drinking water supplies in rural areas of Maku and Poldasht in West Azerbaijan Province, the northwest of Iran. Fluorosis risk assessment and characterization was also investigated. Fluoride concentrations mapping was accomplished by using the GIS system. Totally, 356 water samples, including one sample in each season, were collected from 89 water supplies providing water for 95 and 61 rural areas of Maku and Poldasht, respectively. According to the results, in Maku and Poldasht, 25 and 30 rural areas had contaminated water sources, respectively. Average annual fluoride concentrations ranged from 3.04 to 7.31 mg/l in the contaminated villages of Maku, which is about 2-4.8 times higher than the maximum standard level of the Iranian drinking water standard, and 4.52-8.21 mg/l in the contaminated areas of Poldasht, which is about 3-5.47 times higher than the maximum standard level. The maximum fluoride level was determined 11.12 mg/l and 10.98 mg/l in one of villages of Maku and Poldasht Counties in summer, respectively. Neither in Maku nor in Poldasht, water resources showed dental cavity risk, while dental fluorosis risk and skeletal fluorosis risk were very significant in some villages of both cities. Children were at most risk of fluorosis. New alternative water supplies for the contaminated villages if possible, consumption of bottled water and application of reverse osmosis are recommended as remedial actions in the contaminated areas.

Novel electro-conductive nanocomposites based on electrospun PLGA/CNT for biomedical applications.

Electro-conductive nanocomposites have several applications in biomedical field. Development of a biocompatible electro-conductive polymeric materials is therefore of prime importance. In this study, electro-conductive nanofibrous mats of PLGA/CNT were fabricated through different methods including blend electrospinning, simultaneous PLGA electrospinning and CNT electrospraying and ultrasound-induced adsorption of CNTs on the electrospun PLGA nanofibers. The morphology and diameter of fibers were characterized by SEM and TEM, showing the lowest average diameters of 477 ± 136 nm for PLGA/MWCNT blend nanocomposites. MWCNT-sprayed PLGA specimens showed significant lower water contact angle (83°), electrical resistance (3.0 × 104 Ω) and higher mechanical properties (UTS: 5.50 ± 0.46 MPa) compared to the untreated PLGA scaffolds. Also, results of PC12 cell study demonstrated highest viability percentage on the MWCNT-sprayed PLGA nanofibers. We propose that the conductive nanocomposites have capability to use as tool for the neural regeneration and biosensors.

Fluorescent multi-responsive cross-linked P(N-isopropylacrylamide)-based nanocomposites for cisplatin delivery.

Magnetic, pH and temperature-sensitive, poly(N-isopropylacrylamide) (PNIPAM)-based nanocomposites with fluorescent properties were synthesized by free radical copolymerization-cross linking of NIPAM, N,N-dimethylaminoethyl methacrylate (DMAEMA) and 4-acrylamidofluorescein (AFA). The model anti-cancer drug, cisplatin (CDDP), was loaded into the resulted nanogel. For the production of CDDP-loaded nanocomposite, Fe3O4 magnetic nanoparticles (MNPs) and CDDP were loaded into the nanogel. Field-emission scanning electron microscopy (FE-SEM) indicated that the size of nanogel and CDDP-loaded nanocomposite were about 90 and 160 nm, respectively. The encapsulation efficiency of CCDP was found up to 65%. The loaded CCDP showed sustained thermal and pH-responsive drug release. A high level of drug release was observed under the conditions of low pH and high temperature. The lower critical solution temperature (LCST) of synthesized nanogel was about 40 °C. CDDP-loaded nanocomposite showed a volume phase transition from 282 to 128 nm at its LCST. Accordingly, in this study, the synthesized nanocomposite can be employed as a stimuli-responsive anti-cancer drug delivery system and the pH and temperature of solution have the potential to monitor the drug release.

Evaluation of drug-eluting nanoparticle coating on magnesium alloy for development of next generation bioabsorbable cardiovascular stents.

Since the introduction of bioabsorbable magnesium alloys into cardiovascular stent technology, many researches have been conducted to improve these metallic scaffolds. Various coatings and different coating techniques, super plastic deformation techniques and synthesizing different Mg-based alloy are examples of such efforts. In this study, a magnesium based alloy (WE43) was coated with dexamethasone loaded polymeric nanoparticles via electrospraying method. Drug release behavior, drug inhibitory effects, surface properties and cell responses to the surface were evaluated. Drug release profile was investigated and compared to drug-loaded nanoparticle on stainless steel as a control. The inhibitory effects of the drug-loaded nanoparticle coatings on smooth muscle cells was evaluated via MTT assay. Endothelial cells response to the surface was investigated by SEM. The results showed that contact angle and roughness of the surface were 131° and 600-800 nm, respectively. Drug release studies showed a burst release less than 30% after 24 h which followed by nearly zero order release kinetic. MTT assay showed that SMCs viability decreased to 60% and 25% after 24 and 72 h, respectively. SEM images indicated proper adhesion and proliferation of endothelial cells on the surface. The findings suggest that nanoparticle-coated surfaces could effectively inhibit SMC proliferation meanwhile provide desirable surface features for adhesion and proliferation of endothelial cell on magnesium alloy based stents.

Hybrid PCL/chitosan-PEO nanofibrous scaffolds incorporated with A. euchroma extract for skin tissue engineering application.

Skin tissue engineering is an advanced method to repair and regenerate skin injuries. Recent research is focused on the development of scaffolds that are safe, bioactive, and cytocompatible. In this work, a new hybrid nanofibrous scaffold composed of polycaprolactone/chitosan-polyethylene oxide (PCL/Cs-PEO) incorporated with Arnebia euchroma (A. euchroma) extract were synthesized by the two-nozzle electrospinning method. Then the synthesized scaffold was characterized for morphology, sustainability, chemical structure and properties. Moreover, to verify their potential in the burn wound healing process, biodegradation rate, contact angle, swelling properties, water vapor permeability, mechanical properties, antibacterial activity and drug release profile were measured. Furthermore, cytotoxicity and biocompatibility tests were performed on human dermal fibroblasts cell line via XTT and LDH assay. It is shown that the scaffold improved and increased proliferation during in-vitro studies. Thus, results confirm the efficacy and potential of the hybrid nanofibrous scaffold for skin tissue engineering.

A nanocage for nanomedicine: polyhedral oligomeric silsesquioxane (POSS).

Ground-breaking advances in nanomedicine (defined as the application of nanotechnology in medicine) have proposed novel therapeutics and diagnostics, which can potentially revolutionize current medical practice. Polyhedral oligomeric silsesquioxane (POSS) with a distinctive nanocage structure consisting of an inner inorganic framework of silicon and oxygen atoms, and an outer shell of organic functional groups is one of the most promising nanomaterials for medical applications. Enhanced biocompatibility and physicochemical (material bulk and surface) properties have resulted in the development of a wide range of nanocomposite POSS copolymers for biomedical applications, such as the development of biomedical devices, tissue engineering scaffolds, drug delivery systems, dental applications, and biological sensors. The application of POSS nanocomposites in combination with other nanostructures has also been investigated including silver nanoparticles and quantum dot nanocrystals. Chemical functionalization confers antimicrobial efficacy to POSS, and the use of polymer nanocomposites provides a biocompatible surface coating for quantum dot nanocrystals to enhance the efficacy of the materials for different biomedical and biotechnological applications. Interestingly, a family of POSS-containing nanocomposite materials can be engineered either as completely non-biodegradable materials or as biodegradable materials with tuneable degradation rates required for tissue engineering applications. These highly versatile POSS derivatives have created new horizons for the field of biomaterials research and beyond. Currently, the application of POSS-containing polymers in various fields of nanomedicine is under intensive investigation with expectedly encouraging outcomes.

The effect of surface modification of poly-lactide-co-glycolide/carbon nanotube nanofibrous scaffolds by laminin protein on nerve tissue engineering.

The presence of biological cues to promote the attachment, proliferation, and differentiation of neuronal cells is important in the process of nerve regeneration. In this study, laminin as a neurite promoting protein, has been used to modify poly-lactide-co-glycolide/carbon nanotube (PLGA/CNT) electrospun nanofibrous scaffolds by means of either mussel-inspired poly(dopamine) (PD) coating or via direct physical adsorption as a simple route for the functionalization of biomaterials. The laminin-modified scaffolds were characterized by a combination of field emission scanning electron microscopy (SEM), X-ray photoelectron spectroscopy, and contact angle measurements. Subsequently, various properties of scaffolds such as degradation time, amount of attached laminin and the rate of CNT release were investigated. The synergistic effect of topographical and biological cues for PC12 cell attachment, proliferation, and differentiation were then studied by SEM and confocal microscopy. The results of degradation study showed that laminin-modified scaffolds were biodegradable with good structural integrity that persisted about 4 weeks. The amount of laminin attached to the PLGA/CNT and PLGA/CNT-PD scaffolds was 3.12 ± 0.6 and 3.04 ± 071 µg per mg of the scaffold, respectively. Although laminin-modified scaffolds could improve cell proliferation identically, neurite extensions on the PLGA/CNT scaffold modified via PD coating (PLGA/CNT-PD-lam scaffold) were significantly longer than those observed on PLGA/CNT scaffold modified via physical adsorption (PLGA/CNT-lam scaffold) and unmodified scaffolds. Together, these results indicated that surface modification via PD coating could be a promising strategy to fabricate biomimetic scaffolds capable of sustaining longer neuronal growth for nerve tissue engineering.

Preparation and characterization of polyurethane/chitosan/CNT nanofibrous scaffold for cardiac tissue engineering.

Myocardial infarction of cardiomyocytes is a leading cause of heart failure (HF) worldwide. Since heart has very limited regeneration capacity, cardiac tissue engineering (TE) to produce a bioactive scaffold is considered. In this study, a series of polyurethane solutions (5-7%wt) in aqueous acetic acid were prepared using electrospinning. A variety of Polyurethane (PU)/Chitosan (Cs)/carbon nanotubes (CNT) composite nanofibrous scaffolds with random and aligned orientation were fabricated to structurally mimic the extracellular matrix (ECM). Electrospun nanofibers were then characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), water contact angle, degradation studies, tensile tests, electrical resistance measurement and cell viability assay. The biocompatibility of electrospun random and aligned nanofibrous scaffolds with H9C2 Cells was confirmed. The results revealed that fabricated PU/Cs/CNT composite nanofibrous scaffolds were electro-conductive and aligned nanofibers could be considered as promising scaffolds with nano-scale features for regeneration of infarcted myocardium.

Effect of Paclitaxel/etoposide co-loaded polymeric nanoparticles on tumor size and survival rate in a rat model of glioblastoma.

The aim of this work is to co-load paclitaxel (PTX) and etoposide (ETP) in methoxy poly(ethylene glycol)-poly(lactic-co-glycolic acid) nanoparticles (mPEG-PLGA NPs) to overcome pharmacokinetics and physiological limitations and enhance therapeutic efficacy for treating intracranial glioblastoma. Both drugs were loaded into mPEG-PLGA NPs by a nano-precipitation method. The resultant NPs demonstrated an enhanced cytotoxic effect indicated by lower IC50 values and augmented cell apoptosis to U87 and C6 glioma cell lines compared to both free drugs. Additionally, blood compatibility assays showed that the PTX/ETP co-loaded mPEG-PLGA NPs did not induce blood hemolysis, blood clotting, or platelet aggregation. In vivo anti-glioma efficacy evaluation in rats bearingintracranialC6glioma revealed a superior anti-glioma activity for the treatment with PTX/ETP co-loaded mPEG-PLGA NPs compared to other formulations, particularly a significantly longer median survival, 76 days compared to 36 days for free PTX and 37 days for free ETP treatment, respectively, and higher tumor regression, proved by magnetic resonance imaging (MRI).

In situ synthesized TiO2-polyurethane nanocomposite for bypass graft application: In vitro endothelialization and degradation.

The in vitro endothelial response of human umbilical vein endothelial cells was investigated on a poly (caprolactone)-based polyurethane surface vs an in situ TiO2-polyurethane nanocomposite surface, which has been produced as scaffolds for artificial vascular graft. The in situ synthesis of TiO2 nanoparticles in polyurethane provided surface properties that facilitated cellular adhesion, cell sensing, cell probing and especially cell migration. Cells on the nanocomposite surface have elongated morphology and were able to produce more extracellular matrix. All of these advantages led to an increase in the rate of endothelialization of the nanocomposite scaffold surface vs pure polyurethane. The presence of TiO2 nanoparticles with very good distribution in polyurethane increased the degradability of the scaffolds by increasing the phase separation and hydrophilicity in the nanocomposite film. The results showed that the degradation mechanism of nanocomposite films prompted the interconnectivity of spaces inside structures that probably could give extra chances to improve migration and proliferation of cells, as well as, the delivery of nutrients and metabolites inside the pores of the scaffold. The outcomes revealed that the rate of endothelialization of the nanocomposite scaffold after 7 days of in vitro cell culture was 1.5 times and the rate of degradation of the nanocomposite film was 2 times after 8 weeks of immersion scaffolds in PBS compared to the polyurethane scaffolds. In addition, the nanocomposite scaffold possessed good mechanical properties. Despite its high modulus, it was flexible with a 500% elongation at break.

Development of poly (mannitol sebacate)/poly (lactic acid) nanofibrous scaffolds with potential applications in tissue engineering.

Developing a biomimetic substrate with intrinsic potential for cell attachment and growth has always been a tissue engineering challenge. In the present research, we successfully fabricated PMS:PLA nanofibrous scaffolds for the first time using electrospinning process by adjusting blending ratios, feed rates and polymer concentrations. A desirable composition was found when homogenous nanofibers with an average fiber diameter of 235 ±â€¯38 nm were achieved at 10% w/v for PMS:PLA 60:40. The scaffolds were then characterized for their microstructure, mechanical strength and elasticity, degradation rate, porosity, wettability and cell/tissue compatibility. Mechanical analysis and degradation behavior of PMS:PLA nanofibrous scaffolds revealed appropriate elasticity, stiffness and strength, as well as degradation rate appropriate for soft tissues. Nitrogen adsorption-desorption analysis discovered that mesoporous nanofibers with enhanced specific surface area were fabricated. Further in vitro and in vivo biocompatibility evaluations revealed enhanced cytocompatibility, proliferation and tissue responses of PMS:PLA nanofibrous scaffolds with desirable cell-scaffold interactions. Moreover, PMS:PLA nanofibrous scaffolds exhibited negligible inflammatory responses with significantly thinner fibrotic capsule formation and minor infiltration of inflammatory cells compared to PLA nanofibers. These findings suggest that PMS/PLA nanofibrous scaffolds could be introduced as potential candidates with improved properties for soft tissue engineering applications.

Exosome loaded alginate hydrogel promotes tissue regeneration in full-thickness skin wounds: An in vivo study.

Wound healing is known as one of the most complicated biological processes for injured skin caused by surgical, trauma, burns, or diabetic diseases, which causes a nonfunctioning mass of fibrotic tissue. Recent reports have suggested that exosomes (EXOs) secreted by this type of stem cells may contribute to their paracrine effect. In this study, the EXOs were isolated from the supernatant of cultured adipose-derived stem cells (ADSCs) via ultracentrifugation and filtration. The EXO loaded in the alginate-based hydrogel was used as a bioactive scaffold to preserve the EXO in the wound site in the animal model. The physical and biochemical properties of EXO loaded Alg hydrogel were characterized and results proved that fabricated structure was biodegradable and biocompatible. This bioactive wound dressing technique has significantly improved wound closure, collagen synthesis, and vessel formation in the wound area. Results offer a new viewpoint and a cell-free therapeutic strategy, for wound healing through the application of the composite structure of EXO encapsulated in alginate hydrogel.

Polymeric heart valves: new materials, emerging hopes.

Heart valve (HV) replacements are among the most widely used cardiovascular devices and are in rising demand. Currently, clinically available devices are restricted to slightly modified mechanical and bioprosthetic valves. Polymeric HVs could represent an attractive alternative to the existing prostheses, merging the superior durability of mechanical valves and the enhanced haemodynamic function of bioprosthetic valves. After early unsatisfactory clinical results, polymeric HVs did not reach commercialization, mainly owing to their limited durability. Recent advances in polymers, nanomaterials and surface modification techniques together with the emergence of novel biomaterials have resulted in improved biocompatibility and biostability. Advances in HV design and fabrication methods could also lead to polymeric HVs that are suitable for long-lasting implantation. Considering all these progresses, it is likely that the new generation of polymeric HVs will find successful long-term clinical applications in future.

Resveratrol-loaded polyurethane nanofibrous scaffold: viability of endothelial and smooth muscle cells.

Acellular small-caliber tissue-engineered vascular grafts (SCTEVGs) have low patency rate due to complications including thrombosis and intimal hyperplasia. Rapid endothelialization, antithrombosis and antiproliferation approaches are suitable for dispelling these complications. Nevertheless, common antithrombosis and antiproliferation techniques are usually incompatible with rapid endothelialization on vascular grafts. To overcome these obstacles, we developed nanofibrous polyurethane scaffolds loaded with resveratrol drug, which is a natural compound extracted from plants and shows multifaceted effects in cardiovascular protection. It was found that the tensile strength and Young's modulus in modified scaffolds were significantly increased by resveratrol loading into membranes. The tensile strengths and breaking strains of resveratrol-loaded scaffolds were close to that of native vessels. The resveratrol release profile from the nanofibrous scaffolds occurred in a sustained manner. The anti-thrombogenicity of resveratrol-loaded nanofibers increased compared to polyurethane alone, with the result that prolonged human blood clotting time and lower hemolysis were detected on these scaffolds. The viability of human umbilical vein endothelial cells and smooth muscle cells on resveratrol-loaded scaffolds was evaluated. Our findings demonstrated that resveratrol-loaded nanofibers resulted in not only appropriate antithrombotic properties, but the formation of a monolayer of endothelial cells on the scaffold surface and lower smooth muscle cell growth. These resveratrol-loaded nanofibers are suggested as potential scaffolds for SCTEVGs.

Development of electrically conductive hybrid nanofibers based on CNT-polyurethane nanocomposite for cardiac tissue engineering.

Conductive nanofibers have been considered as one of the most interesting and promising candidate scaffolds for cardiac patch applications with capability to improve cell-cell communication. Here, we successfully fabricated electroconductive nanofibrous patches by simultaneous electrospray of multiwalled carbon nanotubes (MWCNTs) on polyurethane nanofibers. A series of CNT/PU nanocomposites with different weight ratios (2:10, 3:10, and 6:10wt%) were obtained. Scanning electron microscopy, conductivity analysis, water contact angle measurements, and tensile tests were used to characterize the scaffolds. FESEM showed that CNTs were adhered on PU nanofibers and created an interconnected web-like structures. The SEM images also revealed that the diameters of nanofibers were decreased by increasing CNTs. The electrical conductivity, tensile strength, Young's modulus, and hydrophilicity of CNT/PU nanocomposites also enhanced after adding CNTs. The scaffolds revealed suitable cytocompatibility for H9c2 cells and human umbilical vein endothelial cells (HUVECs). This study indicated that simultaneous electrospinning and electrospray can be used to fabricate conductive CNT/PUnanofibers, resulting in better cytocompatibility and improved interactions between the scaffold and cardiomyoblasts.

Comparative study of different polymeric coatings for the next-generation magnesium-based biodegradable stents.

Development of next-generation bioabsorbable stents based on magnesium alloys is gaining lots of attention. However, finding an appropriate coating in order to enhance its corrosion resistance along with preserving other requirements is still a challenge. In this study, three FDA-approved polymers, namely poly(lactic acid), polycaprolactone and poly(lactic-co-glycolic acid), have been investigated as potential coatings for magnesium-based stents to enhance their corrosion resistance, biocompatibility and haemocompatibility. Potentiodynamic and electrochemical impedance spectroscopy results demonstrated that PLA and PLGA coating performed better in improving corrosion resistance in comparison with uncoated and other coated samples. Although all coated and bare samples displayed desirable results of haemocompatibility assays, PLA-coated samples showed better outcome in terms of biocompatibility. The results revealed that PLA can be considered as a potential coating material to enhance the main characteristics of magnesium-based bioabsorbable stents.

In vitro physical and biological characterization of biodegradable elastic polyurethane containing ferulic acid for small-caliber vascular grafts.

Demand for small diameter vascular grafts is growing. The main limitations of these grafts include induced thrombotic events, lack of in situ endothelialization, intimal hyperplasia and poor mechanical properties which impair the graft patency rate in long-term applications. Most anti-thrombotic modification methods currently in use usually conflict with the formation of an endothelial cell monolayer on the grafts. Here, we synthesized a novel biodegradable poly(ether ester urethane)urea elastomer (PEEUU) using poly(ethylene glycol) and poly(diethylene glycol adipate) as soft segments. To improve hemocompatibility, synthesized PEEUU was blended with ferulic acid (FA). Scanning electron microscopy, water contact angle measurement, and tensile testing were used to characterize the scaffolds. The PEEUU and PEEUU-FA scaffolds revealed appropriate mechanical properties, with tensile strengths and strains similar to a coronary artery. In vitro assay demonstrated that the release of FA from the scaffold is in a sustained manner. Hemocompatibility tests indicated that the PEEUU-FA sample induced lower platelet adhesion compared to the PEEUU sample. Reductions in hemolysis and fibrinogen adsorption were detected on the PEEUU-FA sample. Cell studies showed that PEEUU-FA supported the adhesion, expansion and proliferation of endothelial cells. The cells maintained an endothelial cell phenotype through the expression of the endothelial cell marker CD31. The results revealed that the new PEEUU modified with FA can be considered as a promising candidate for vascular applications with enhanced blood compatibility and vascular cell-compatibility.

Biomimetic modification of polyurethane-based nanofibrous vascular grafts: A promising approach towards stable endothelial lining.

The emerging demand for small caliber vascular grafts to replace damaged vessels has attracted research attention. However, there is no perfect replacement in clinical use yet, mainly due to low patency rate of synthetic small caliber grafts. The main pathology behind low patency rate include thrombosis and graft/vessel hemodynamic mismatch, leading to intimal hyperplasia. Rapid in-situ endothelialization of vascular grafts is considered as one of the best strategies to overcome these complications. In the present study, Heparin and VEGF were immobilized via self-polymerization and deposition of polydopamine (PDA) on polyurethane (PU) nanofibrous scaffolds to improve endothelialization. Polyurethane nanofibrous scaffold (PUNF) that mimics vascular extracellular matrix (ECM) was chosen owing to its biocompatibility, biodegradability. Scanning electron microscopy (SEM), water contact angle (CA) measurement and Raman spectroscopy were used to characterize the surface, and tensile test was used to analyze mechanical properties before and after surface modification of the scaffolds. It was found that tensile strength and young's modulus were significantly increased after PDA coating on PUNF membranes. The hemocompatibility tests revealed that surface heparinization significantly inhibited the adhesion of platelet on the scaffolds. Immobilization of VEGF on the scaffolds significantly enhanced the proliferation of human umbilical vein endothelial cells (HUVECs) through enhanced cells adhesion and improved cell-scaffold interactions. The results suggest that dual-factor immobilization resulted in not only confluent monolayer of endothelial cells but also conferred excellent antithrombotic properties to the surface. This method of surface modification (immobilization of Heparin, VEGF by PDA layer) is suggested as a promising modification technique to increase hemocompatibility of small-diameter vascular grafts.

Biocompatibility and nanostructured materials: applications in nanomedicine.

There has been huge interest in applications of nanomaterials in biomedical science, including diagnosis, drug delivery, and development of human organs. Number of these nanomaterials has been already studied in human or at pre-clinical trial. There is a growing concern on potential toxicity and adverse effects of nanomaterials on human health, including lack of standard method of assessment of toxicology of these materials. Our investigation indicated that the bare and small nanoparticle have higher toxicity than modified and bulk materials, respectively. In addition, spherical nanoparticles have less toxicity than rod nanoparticles due to immune response of body.