Antibacterial potency, cell viability and morphological implications of copper oxide nanoparticles encapsulated into cellulose acetate nanofibrous scaffolds.

It is generally believed that the most challenging impediment for the utilization of cellulose acetate (CA) in the medical field is its hydrophobicity and disability to poison the harmful microbes. Therefore, in this contribution, we aimed to prepare an environmentally scaffold-based CA loaded with copper nanoparticles (CuONPs), which are expected to not only improve the hydrophilicity of the prepared nanofibers, but also have an effective ability to kill such harmful and infectious microbes that are abundant in wounds. The obtained results attested that the generated nanofibers became thicker with increasing the content of CuONPs in CA nanofibers. The roughness average increased from 143.2 to 157.1 nm, whereas the maximum height of the roughness (Rt) increased from 400.8 to 479.9 nm as going from the lowest to the highest content of CuONPs. Additionally, the contact angle of the prepared nanofibers decreased from 105.3° (CA alone) to 85.4° for CuONPs@CA. Significantly, biological studies revealed that cell viability and anti-bacterial potency were improved upon incorporating CuONPs into CA solution. Correspondingly, their inhibition zones reached 18 ± 3 mm, and 16 ± 2 mm for nanofibrous scaffolds having 12.0CuO@CA, besides raising the cell viability from 91.3 ± 4% to 96.4 ± 4% for 0.0CuO@CA, and 12.0CuO@CA, respectively, thereby implying that the fabricated CuONPs@CA nanocomposite has biocompatibility towards fibroblast cells. Thus, introducing biological activity into CA nanofibers via loading with CuONPs makes it suitable for numerous biomedical applications, particularly as an environmentally benign wound dressing fibers.

Behaviour of Vascular Smooth Muscle Cells on Amine Plasma-Coated Materials with Various Chemical Structures and Morphologies.

Amine-coated biodegradable materials based on synthetic polymers have a great potential for tissue remodeling and regeneration because of their excellent processability and bioactivity. In the present study, we have investigated the influence of various chemical compositions of amine plasma polymer (PP) coatings and the influence of the substrate morphology, represented by polystyrene culture dishes and polycaprolactone nanofibers (PCL NFs), on the behavior of vascular smooth muscle cells (VSMCs). Although all amine-PP coatings improved the initial adhesion of VSMCs, 7-day long cultivation revealed a clear preference for the coating containing about 15 at.% of nitrogen (CPA-33). The CPA-33 coating demonstrated the ideal combination of good water stability, a sufficient amine group content, and favorable surface wettability and morphology. The nanostructured morphology of amine-PP-coated PCL NFs successfully slowed the proliferation rate of VSMCs, which is essential in preventing restenosis of vascular replacements in vivo. At the same time, CPA-33-coated PCL NFs supported the continuous proliferation of VSMCs during 7-day long cultivation, with no significant increase in cytokine secretion by RAW 264.7 macrophages. The CPA-33 coating deposited on biodegradable PCL NFs therefore seems to be a promising material for manufacturing small-diameter vascular grafts, which are still lacking on the current market.

Superior Synaptogenic Effect of Electrospun PLGA-PEG Nanofibers Versus PLGA Nanofibers on Human Neural SH-SY5Y Cells in a Three-Dimensional Culture System.

Synapses are touted as the main structural and functional components of neural cells within in the nervous system, providing tissue connectivity and integration via the formation of perineuronal nets. In the present study, we evaluated the synaptogenic activity of electrospun PLGA and PLGA-PEG nanofibers on human SH-SY5Y cells after 14 days in vitro. Electrospun PLGA and PLGA-PEG nanofibers were fabricated and physicochemical properties were examined using the HNMR technique. The cells were classified into three random groups, i.e., control (laminin-coated surface), PLGA, and PLGA-PEG. Scaffolds' features, cell morphology, attachment, and alignment were monitored by SEM imaging. We performed MTT assay to measure cell survival rate. To evaluate neurite formation and axonal outgrowth, cells were stained with an antibody against ß-tubulin III using immunofluorescence imaging. Antibodies against synapsin-1 and synaptophysin were used to explore the impact of PLGA and PLGA-PEG scaffolds on synaptogenesis and functional activity of synapses. According to SEM analysis, the PLGA-PEG scaffold had less thick nanofibers compared with the PLGA scaffold. Cell attachment, expansion, neurite outgrowth, and orientation were promoted in the PLGA-PEG group in comparison with the PLGA substrate (p < 0.05). MTT assay revealed that both scaffolds did not exert any neurotoxic effects on cell viability. Notably, PLGA-PEG surface increased cell viability compared to PLGA by time (p < 0.05). Immunofluorescence staining indicated an increased ß-tubulin III level in the PLGA-PEG group days coincided with axonal outgrowth and immature neuron marker after seven compared with the PLGA and control groups (p < 0.05). Based on our data, both synaptogenesis and functional connectivity were induced in cells plated on the PLGA-PEG surface that coincide with the increase of synapsin-1 and synaptophysin in comparsion with the PLGA and control groups (p < 0.05). Taken together, our results imply that the PLGA-PEG nanofibers could provide the desirable microenvironment to develop perineuronal net formation, contributing to efficient synaptogenesis and neuron-to-neuron crosstalk.

Hidrogel de quitosana com nanofibras de Policaprolactona (PCL) associado a extratos fitoterápicos no metabolismo celular e ação antimicrobiana: estudo in vitro / Evaluation of the chitosan hydrogel with PCL nanofibers associated with phytotherapeutic extracts in cellular and microbiological activity: in vitro study

O objetivo neste estudo foi produzir hidrogel de quitosana (CH) com PCL e fitoterápicos para uso preventivo de úlcera de pressão. Os hidrogéis de CH foram produzidos com glicerofosfato (GP) e com xantana (X), associados ao PCL e foram caracterizados por estereomicroscopio, intumescimento, molhabilidade e MEV. Posteriormente foram submetidos ao teste de viabilidade (MTT) com fibroblastos HFF-1 e queratinócitos HaCat. O hidrogel que apresentou melhor resultado foi escolhido para continuar na pesquisa. Posteriormente, extratos de Pfaffia panculata K, Juglans regia L, Rosmarinus officinalis L, Zingiber officinale, Própolis e Hamamelis foram colocados em contato com cepas de Staphylococcus aureus (S.a) (ATCC 6538), Streptococcus pyogenes (S.p) (ATCC 19615), Staphylococcus epidermidis (S.e) (ATCC 12228), Pseudomonas aeruginosa (P.a) (ATCC 15442), Escherichia coli (E.c) (ATCC 25922) e Klebsiella Pneumoniae (K.p) (ATCC 4352) na forma planctônica nos testes de CIM e CMM. Os dois melhores extratos fitoterápicos foram avaliados quanto ao sinergismo no teste checkerboard e posteriormente associados ao hidrogel anteriormente eleito. A seguir, o comportamento da HaCat e HFF-1 com os hidrogéis foi analisado por MTT, proteína total, ELISA, genotoxicidade e formação de biofilme monotípico com suspensões padronizadas (107 cel/mL) de S.a, S.e, S.p, P.a, E.c e K.p. Na caracterização e viabilidade o hidrogel CHX PCL apresentou os melhores resultados. Os extratos selecionados após CIM, CMM e checkerboard foram gengibre (G) e própolis (P). O extrato G se destacou na CIM com inibição de K. p e P. a. Os extratos de G e P demonstraram ação microbicida para K. p e P. a e somente o extrato P obteve ação microbicida para S. a na CMM. Houve ação aditiva dos extratos associados no checkerboard para S.p e ação aditiva e sinérgica para S. e. Os grupos de hidrogéis foram compostos por: quitosana xantana (CHX), CHX própolis (CHXP), CHX gengibre (CHXG) e CHX própolis e gengibre associados (CHXPG), todos associados ao PCL. Todos os hidrogéis demonstraram viabilidade celular acima de 70% do grupo controle, permitindo metabolismo celular observado na proteína total. Houve quantificação de IL-6 maior no grupo CHX nas duas linhagens de células enquanto a quantificação de IL-10 não exibiu diferença estatística entre os grupos. Todos os hidrogéis promoveram redução acentuada de biofilme de K.p e E.c. Os grupos CHX, CHXP e CHXG reduziram biofilme de S.e. O grupo CHXG reduziu biofilme de S.p. Para S.a e P.a o grupo CHXPG foi mais eficaz reduzindo biofilme. Concluímos que os hidrogéis apresentaram resultados satisfatórios e promissores, trazendo inovação por associação de biopolímeros e associação de extratos fitoterápicos pouco estudados. Os resultados positivos justificam a continuidade dos estudos com esse biomaterial(AU)

The aim of this study was to produce chitosan hydrogel (CH) with PCL and herbal medicines for preventive use of pressure ulcers. The CH hydrogels were produced with glycerophosphate (GP) and xanthan (X), associated with PCL and were characterized by stereomicroscope, swelling, wettability and SEM. Subsequently, they were submitted to a viability test (MTT) with HFF-1 fibroblasts and HaCat keratinocytes. The hydrogel that presented the best result was chosen to continue the research. Subsequently, extracts of Pfaffia panculata K, Juglans regia L, Rosmarinus officinalis L, Zingiber officinale, Propolis and Hamamelis were placed in contact with strains of Staphylococcus aureus (Sa) (ATCC 6538), Streptococcus pyogenes (Sp) (ATCC 19615), epidermidis (Se) (ATCC 12228), Pseudomonas aeruginosa (Pa) (ATCC 15442), Escherichia coli (Ec) (ATCC 25922) and Klebsiella Pneumoniae (Kp) (ATCC 4352) in planktonic form in CIM and CMM tests. The two best herbal extracts were evaluated for synergism in the checkerboard test and subsequently associated with the previously elected hydrogel. Next, the behavior of HaCat and HFF-1 with hydrogels was analyzed by MTT, total protein, ELISA, genotoxicity and monotypic biofilm formation with standardized suspensions (107 cel / mL) of Sa, Se, Sp, Pa, Ec and Kp In the characterization and viability the CHX PCL hydrogel presented the best results. The extracts selected after MIC, CMM and checkerboard were ginger (G) and propolis (P). The G extract stood out in the MIC with inhibition of K. p and P. a. The extracts of G and P showed microbicidal action for K. p and P. a and only the extract P obtained microbicidal action for S. a in CMM. There was an additive action of the associated extracts on the checkerboard for S.p and an additive and synergistic action for S. e. The hydrogel groups were composed of: xanthan chitosan (CHX), CHX propolis (CHXP), CHX ginger (CHXG) and CHX propolis and ginger associated (CHXPG), all associated with PCL. All hydrogels demonstrated cell viability above 70% of the control group, allowing cellular metabolism observed in the total protein. There was a greater quantification of IL-6 in the CHX group in the two cell lines while the quantification of IL-10 did not show statistical difference between the groups. All hydrogels promoted a marked reduction in the biofilm of K.p and E.c. The CHX, CHXP and CHXG groups reduced S.e biofilm. The CHXG group reduced S.p. For S.a and P.a, the CHXPG group was more effective in reducing biofilm. We conclude that the hydrogels presented satisfactory and promising results, bringing innovation through association of biopolymers and association of phytotherapic extracts little studied. The positive results justify the continuity of studies with this biomaterial(AU)

Titania Nanofiber Scaffolds with Enhanced Biointegration Activity-Preliminary In Vitro Studies.

The increasing need for novel bone replacement materials has been driving numerous studies on modifying their surface to stimulate osteogenic cells expansion and to accelerate bone tissue regeneration. The goal of the presented study was to optimize the production of titania-based bioactive materials with high porosity and defined nanostructure, which supports the cell viability and growth. We have chosen to our experiments TiO2 nanofibers, produced by chemical oxidation of Ti6Al4V alloy. Fibrous nanocoatings were characterized structurally (X-ray diffraction (XRD)) and morphologically (scanning electron microscopy (SEM)). The wettability of the coatings and their mechanical properties were also evaluated. We have investigated the direct influence of the modified titanium alloy surfaces on the survival and proliferation of mesenchymal stem cells derived from adipose tissue (ADSCs). In parallel, proliferation of bone tissue cells-human osteoblasts MG-63 and connective tissue cells - mouse fibroblasts L929, as well as cell viability in co-cultures (osteoblasts/ADSCs and fibroblasts/ADSCs has been studied. The results of our experiments proved that among all tested nanofibrous coatings, the amorphous titania-based ones were the most optimal scaffolds for the integration and proliferation of ADSCs, fibroblasts, and osteoblasts. Thus, we postulated these scaffolds to have the osteopromotional potential. However, from the co-culture experiments it can be concluded that ADSCs have the ability to functionalize the initially unfavorable surface, and make it suitable for more specialized and demanding cells.

Cotton cellulose nanofiber/chitosan nanocomposite: characterization and evaluation of cytocompatibility.

Cellulose is a renewable polymer quite abundant on the Earth and very attractive for applications in the construction of eco-friendly biomedical products. The aim of this study was to investigate the chemical-physical characteristics of cotton cellulose nanofiber (CCN)/chitosan nanocomposite and its cytocompatibility with human embryonic kidney cells. First, the chemical composition, swelling ratio and surface topography of the nanocomposite were evaluated. Cytocompatibility was then assessed through spreading, proliferation and viability of cells. The experimental results showed that the CCN was an effective nanomaterial agent for increasing the roughness surface of chitosan film. Cell proliferation and changes in cell morphology indicated that the nanocomposite led to improved cell spreading and growth. Cell viability did not decrease after 24 h. However, the cell survival on the nanocomposite was affected at 72 h. The results indicate that CCN/chitosan nanocomposite could be a promising biocompatible biomaterial for biomedical applications.

Evaluation of biocompatibility and immunogenicity of micro/nanofiber materials based on tilapia skin collagen.

Type I collagen, used as a raw material, plays a pivotal role in the development of medical devices and tissue engineering. Due to the risk of zoonotic transmission and religious constraints for mammalian collagen, fish collagen gains increased attention and is widely seen as an alternative. In this study, two collagen micro/nanofiber materials, self-assembled collagen nanofiber and electrospun collagen nanofiber, were prepared by tilapia skin collagen and their biocompatibility and immunogenicity was thoroughly investigated. The result revealed that the state of tilapia skin collagen in self-assembled collagen nanofiber and electrospun collagen nanofiber was different. The circular dichroism spectrum indicated that collagen in self-assembled collagen nanofiber retained the triple helical structure of the native collagen, while collagen in electrospun collagen nanofiber was denatured into gelatin. Nevertheless, the evaluation according to ISO10993, including tests of cytotoxicity, hemolysis, skin sensitization, acute systemic toxicity, mouse immunization and lymphocyte proliferation, demonstrated good biocompatibility and low immunogenicity for both self-assembled and electrospun collagen nanofiber materials. Overall, the present study highlighted that type I collagen from tilapia skin would be a promising biomaterial for the development of regenerate medical products.

Short-Term Effects of Titanium Dioxide Nanofiber on the Renal Function of Male Sprague Dawley Rats.

Titanium dioxide nanofiber (TDNF) is widely used in the manufacture of various household products, including cosmetics. As a result, the possibility exists for TDNFs to affect human health. Because the kidneys are responsible for filtering out waste from the blood, the goal of the present study was to investigate the short-term effects of TDNF on kidney function of male Sprague Dawley rats. To achieve study objectives, 6- to 7-wk-old male rats were exposed via oral gavage to a total of 0, 40, and 60 parts per million of TDNF for 2 wk. The TDNF was fabricated by electrospinning and then dissolved in water. We measured serum concentration of lactate dehydrogenase, renal histopathology, identification of TDNF in kidney tissue via scanning electron microscopy, and quantitative amounts of titanium-47 in kidney tissue. We also measured specific gene-expression analysis of transcripts involved in apoptosis, inflammation, cell-division regulation, cell structure, and motility. Results showed a slight dose-dependent reduction in renal weight. In contrast, a concentration-dependent elevation in titanium-47 amounts was noted in kidney tissue. We found no significant differences in histopathological patterns. Gnat3 and Hepacam3 were up-regulated in TDNF-treated groups. Up-regulation of NF-κB likely indicated the involvement of renal-tissue inflammation via an independent mechanism. Similarly, Gadd45-α was significantly overexpressed in kidney tissues. This transcript was previously increased following stressful growth-arrest conditions and treatment with DNA-damaging agents. Our overall results suggest marginal renal toxicity in Sprague Dawley rats after ingesting TDNF.

Exposure assessments for a cross-sectional epidemiologic study of US carbon nanotube and nanofiber workers.

BACKGROUND: Recent animal studies have suggested the potential for wide-ranging health effects resulting from exposure to carbon nanotubes and nanofibers (CNT/F). To date, no studies in the US have directly examined the relationship between occupational exposure and potential human health effects. OBJECTIVES: Our goal was to measure CNT/F exposures among US workers with representative job types, from non-exposed to highly exposed, for an epidemiologic study relating exposure to early biologic effects. METHODS: 108 participants were enrolled from 12 facilities across the US. Personal, full-shift exposures were assessed based on the mass of elemental carbon (EC) at the respirable and inhalable aerosol particle size fractions, along with quantitatively characterizing CNT/F and estimating particle size via transmission electron microscopy (TEM). Additionally, sputum and dermal samples were collected and analyzed to determine internal exposures and exposures to the hands/wrists. RESULTS: The mean exposure to EC was 1.00 µg/m3 at the respirable size fraction and 6.22 µg/m3 at the inhalable fraction. Analysis by TEM found a mean exposure of 0.1275 CNT/F structures/cm3, generally to agglomerated materials between 2 and 10 µm. Internal exposures to CNT/F via sputum analysis were confirmed in 18% of participants while ∼70% had positive dermal exposures. CONCLUSIONS: We demonstrated the occurrence of a broad range of exposures to CNT/F within 12 facilities across the US. Analysis of collected sputum indicated internal exposures are currently occurring within the workplace. This is an important first step in determining if exposures in the workforce have any acute or lasting health effects.

Three-dimensional multiscale fiber matrices: development and characterization for increased HepG2 functional maintenance for bio-artificial liver application.

The development of a cell-growth substrate that provides a nature-like microenvironment, promotes cell adhesion, and maintains the cells' functional activities is a research focus in the field of tissue engineering. In the present study, three-dimensional micro-nano multiscale fiber-based substrates were developed by depositing biocompatible polycaprolactone (PCL)/PCL-Chitosan (C)/PCL-C-Gelatin (G) electrospun nanofibers (NFs) on the outer surface of hollow fiber membranes (HFMs) in one step. A comparison study with regard to physico-chemical characterization, hemocompatibility, cytotoxicity, and cellular functionality was performed with the developed matrices. The PCL-C-G NFs-deposited HFMs-based matrix showed superior hemocompatibility for blood-contact applications. The cytotoxicity of these matrices was found to be minimal. HepG2 cells exhibited an exceptionally robust adherence and proliferated growth on the matrix with the formation of characteristic multi-cellular spheroids. Furthermore, cell functional activities such as albumin secretion, urea synthesis, and cytochrome P450 specific activity were measured for the developed matrices. The developed three-dimensional multiscale fibers-based matrix can be a potential membrane for bioreactor and bio-artificial liver applications.

Biphasic drug release from electrospun polyblend nanofibers for optimized local cancer treatment.

The application of the biphasic release profile furnished by electrospun polyblend nanofibers for local cancer treatment was investigated. By adjusting the weight ratio of the hydrophilic polymer (poly(ethylene oxide), PEO) and hydrophobic polymer (poly(l-lactide), PLA), PEO10-PLA90 fibers with typical biphasic release kinetics were successfully prepared. Due to their unique release profile, PEO10-PLA90 fibers can quickly access the tumor site in vivo at a high drug content within 1 h and keep at a high level for longer than two weeks. In vivo antitumor and safety studies demonstrated that PEO10-PLA90 fibers can achieve optimized local cancer treatment efficacy and avoid undesired adverse reactions. The biphasic drug release profile provided by the polyblend electrospun technology was proven to be a new conception for local chemotherapy.

Medium Chain-Length Polyhydroxyalkanoate Copolymer Modified by Bacterial Cellulose for Medical Devices.

Medium chain-length polyhydroxyalkanoates (mPHAs) are flexible elastomeric biopolymers with valuable properties for biomedical applications like artificial arteries and other medical implants. However, an environmentally friendly and high productivity process together with the tuning of the mechanical and biological properties of mPHAs are mandatory for this purpose. Here, for the first time, a melt processing technique was applied for the preparation of bionanocomposites starting from poly(3-hydroxyoctanoate) (PHO) and bacterial cellulose nanofibers (BC). The incorporation of only 3 wt % BC in PHO improved its thermal stability with 25 °C and reinforced it, increasing the Young's modulus with 76% and the tensile strength with 44%. The percolation threshold calculated with the aspect ratio of the fibers after melt processing was very low and close to 3 wt %. We showed that this bionanocomposite is able to preserve the ductile behavior during storage, no important aging being noted between 3 h and one month after compression-molding. Moreover, this study is the first to investigate the melt processability of PHO nanocomposite for tube extrusion. In addition, biocompatibility study showed no proinflammatory immune response and better cell adhesion for PHO/BC nanocomposite with 3 wt % BC and demonstrated the high feasibility of this bionanocomposite for in vivo application of tissue-engineered blood vessels.

Supramolecular Peptide Nanofiber Morphology Affects Mechanotransduction of Stem Cells.

Chirality and morphology are essential factors for protein function and interactions with other biomacromolecules. Extracellular matrix (ECM) proteins are also similar to other proteins in this sense; however, the complexity of the natural ECM makes it difficult to study these factors at the cellular level. The synthetic peptide nanomaterials harbor great promise in mimicking specific ECM molecules as model systems. In this work, we demonstrate that mechanosensory responses of stem cells are directly regulated by the chirality and morphology of ECM-mimetic peptide nanofibers with strictly controlled characteristics. Structural signals presented on l-amino acid containing cylindrical nanofibers (l-VV) favored the formation of integrin ß1-based focal adhesion complexes, which increased the osteogenic potential of stem cells through the activation of nuclear YAP. On the other hand, twisted ribbon-like nanofibers (l-FF and d-FF) guided the cells into round shapes and decreased the formation of focal adhesion complexes, which resulted in the confinement of YAP proteins in the cytosol and a corresponding decrease in osteogenic potential. Interestingly, the d-form of twisted-ribbon like nanofibers (d-FF) increased the chondrogenic potential of stem cells more than their l-form (l-FF). Our results provide new insights into the importance and relevance of morphology and chirality of nanomaterials in their interactions with cells and reveal that precise control over the chemical and physical properties of nanostructures can affect stem cell fate even without the incorporation of specific epitopes.

Self-assembled nanofiber coatings for controlling cell responses.

Nanofibers are thought to enhance cell adhesion, growth, and function. We demonstrate that the choice of building blocks in self-assembling nanofiber systems can be used to control cell behavior. The use of 2 D-coated, self-assembled nanofibers in controlling lens epithelial cells, fibroblasts, and mesenchymal stem cells was investigated, focusing on gene and protein expression related to the fibrotic response. To this end, three nanofibers with different characteristics (morphology, topography, and wettability) were compared with two standard materials frequently used in culturing cells, TCPS, and a collagen type I coating. Cell metabolic activity, cell morphology, and gene and protein expression were analyzed. The most hydrophilic nanofiber with more compact network consisting of small fibers proved to provide a beneficial 2 D environment for cell proliferation and matrix formation while decreasing the fibrotic/stress behavior in all cell lines when compared with TCPS and the collagen type I coating. This nanofiber demonstrates the potential to be used as a biomimetic coating to study the development of fibrosis through epithelial-to-mesenchymal transition. This study also shows that nanofiber structures do not enhance cell function by definition, because the physico-chemical characteristics of the nanofibers influence cell behavior as well and actually can be used to regulate cell behavior toward suboptimal performance. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2252-2265, 2017.

Stimuli-sensitive thiolated hyaluronic acid based nanofibers: synthesis, preclinical safety and in vitro anti-HIV activity.

AIM: To develop a seminal enzyme bioresponsive, mucoadhesive nanofibers (NFs) as safe and effective nanocarriers for the prevention of HIV vaginal transmission. METHODS: A novel thiolated hyaluronic acid (HA-SH) polymer was synthesized to fabricate tenofovir (TFV)-loaded electrospun NFs (HA-SH-NFs) and characterized in vitro/in vivo. RESULTS: A triggered drug release (87% w/w) from the engineered HA-SH-NFs (mean diameter ∼75 nm) occured within 1 h under the influence of seminal hyaluronidase enzyme. HA-SH-NFs were noncytotoxic, induced no damage on the C57BL/6 mice genital-tract and other organs. No significant CD45 cell-infiltration and changes in cytokines level in cervicovaginal tissues were observed. HA-SH-NFs significantly enhanced both TFV retention and bioavailability in vaginal tissue compared with the 1% TFV-gel. The anti-HIV activity of TFV (on pseudotyped virus followed by luciferase assay) was not adversely affected by the electrospinning process. CONCLUSION: HA-SH-NFs developed in this study could potentially serve as a safe nanotemplate for topical intravaginal delivery of HIV/AIDS microbicides.

Novel nanostructured supramolecular hydrogels for the topical delivery of anionic drugs.

A bis-imidazolium-based amphiphilic molecule was used to form novel supramolecular gels in ethanol-water mixtures. The proportion of solvents, the concentration of gellant and the temperature are factors that strongly influence the gelling process. The physical gels that are formed comprise entangled fibers of around 100nm in diameter, able to incorporate anionic drugs, whose morphology varies depending on the drug they incorporate. These hydrogels are soft and therefore optimum for skin application. They show good stability when compared to previously reported gels. Suitable drug release and skin permeation profiles were obtained, and, moreover, they seem to promote the retention of the drug inside the skin. Finally, effective in vivo anti-inflammatory activity was observed, especially with the indomethacin-incorporated gel, which indicates that these supramolecular hydrogels are a good option for the delivery of poor water soluble drugs for the treatment of acute inflammation or other skin diseases.

Fabrication of electrospun poly(D,L lactide-co-glycolide)80/20 scaffolds loaded with diclofenac sodium for tissue engineering.

BACKGROUND: Adaptation of nanotechnology into materials science has also advanced tissue engineering research. Tissues are basically composed of nanoscale structures hence making nanofibrous materials closely resemble natural fibers. Adding a drug release function to such material may further advance their use in tissue repair. METHODS: In the current study, bioabsorbable poly(D,L lactide-co-glycolide)80/20 (PDLGA80/20) was dissolved in a mixture of acetone/dimethylformamide. Twenty percent of diclofenac sodium was added to the solution. Nanofibers were manufactured using electrospinning. The morphology of the obtained scaffolds was analyzed by scanning electron microscopy (SEM). The release of the diclofenac sodium was assessed by UV/Vis spectroscopy. Mouse fibroblasts (MC3T3) were seeded on the scaffolds, and the cell attachment was evaluated with fluorescent microscopy. RESULTS: The thickness of electrospun nanomats was about 1 mm. SEM analysis showed that polymeric nanofibers containing drug particles formed very interconnected porous nanostructures. The average diameter of the nanofibers was 500 nm. Drug release was measured by means of UV/Vis spectroscopy. After a high start peak, the release rate decreased considerably during 11 days and lasted about 60 days. During the evaluation of the release kinetics, a material degradation process was observed. MC3T3 cells attached to the diclofenac sodium-loaded scaffold. CONCLUSIONS: The nanofibrous porous structure made of PDLGA polymer loaded with diclofenac sodium is feasible to develop, and it may help to improve biomaterial properties for controlled tissue repair and regeneration.

Development of small diameter nanofiber tissue engineered arterial grafts.

The surgical repair of heart and vascular disease often requires implanting synthetic grafts. While synthetic grafts have been successfully used for medium-to-large sized arteries, applications for small diameter arteries (<6 mm) is limited due to high rates of occlusion by thrombosis. Our objective was to develop a tissue engineered vascular graft (TEVG) for small diameter arteries. TEVGs composed of polylactic acid nanofibers with inner luminal diameter between 0.5 and 0.6 mm were surgically implanted as infra-renal aortic interposition conduits in 25 female C17SCID/bg mice. Twelve mice were given sham operations. Survival of mice with TEVG grafts was 91.6% at 12 months post-implantation (sham group: 83.3%). No instances of graft stenosis or aneurysmal dilatation were observed over 12 months post-implantation, assessed by Doppler ultrasound and microCT. Histologic analysis of explanted TEVG grafts showed presence of CD31-positive endothelial monolayer and F4/80-positive macrophages after 4, 8, and 12 months in vivo. Cells positive for α-smooth muscle actin were observed within TEVG, demonstrating presence of smooth muscle cells (SMCs). Neo-extracellular matrix consisting mostly of collagen types I and III were observed at 12 months post-implantation. PCR analysis supports histological observations. TEVG group showed significant increases in expressions of SMC marker, collagen-I and III, matrix metalloproteinases-2 and 9, and itgam (a macrophage marker), when compared to sham group. Overall, patency rates were excellent at 12 months after implantation, as structural integrity of these TEVG. Tissue analysis also demonstrated vessel remodeling by autologous cell.

Implication of nanofibers in oral drug delivery.

Nanofibers has gained significant prominence in recent years due to its wide applications in medicinal pharmacy, textile, tissue engineering and in various drug delivery system. In oral drug delivery system (DDS), nanofibers can be delivered as Nanofiber scaffolds, electrosponge nanofibers as oral fast delivery system, multilayered nanofiber loaded mashes, surface modified cross-linked electrospun nanofibers. Nanofibers are of 50- 1000 nm size fibres having large surface area, high porosity, small pore size, low density. Various approaches for formulation of nanofibers are molecular assembly, thermally induced phase separation, electrospining. Most commonly used by using electrospining polymer nanofibres with different range can be produced collective usage of electro spinning with pharmaceutical polymers offers novel tactics for developing drug delivery system (DDS). Different polymers used in preparation of nanofibers include biodegradable hydrophilic polymers, hydrophobic polymers and amphiphilic polymers. Electrospun nanofibers are often used to load insoluble drugs for enhancing their dissolution properties due to their high surface area per unit mass. Besides the water insoluble drugs freely water soluble sodium can also spun into the fibers. The most commonly polymers used for nanofibers are gelatin, dextran, nylon, polystyrene, polyacrylonitrile, polycarbonate, polyimides, poly vinyl alchol, polybenzimidazole. Delivery systems reviewed rely on temporal control, changes in pH along the GIT, the action of local enzymes to trigger drug release, and changes in intraluminal pressure. Dissolution of enteric polymer coatings due to a change in local pH and reduction of azo-bonds to release an active agent are both used in commercially marketed products. In vitro and in vivo studies have demonstrated that the release rates of drugs from these nanofiber formulations are enhanced compared to those from original drug substance. This review is focused on the different type of polymers used, different used in the preparation of nanofibers, cytotoxicity studies and application of nanofiber by using oral drug delivery.

In vitro and in vivo ocular biocompatibility of electrospun poly(ɛ-caprolactone) nanofibers.

Biocompatibility is a requirement for the development of nanofibers for ophthalmic applications. In this study, nanofibers were elaborated using poly(ε-caprolactone) via electrospinning. The ocular biocompatibility of this material was investigated. MIO-M1 and ARPE-19 cell cultures were incubated with nanofibers and cellular responses were monitored by viability and morphology. The in vitro biocompatibility revealed that the nanofibers were not cytotoxic to the ocular cells. These cells exposed to the nanofibers proliferated and formed an organized monolayer. ARPE-19 and MIO-M1 cells were capable of expressing GFAP, respectively, demonstrating their functionality. Nanofibers were inserted into the vitreous cavity of the rat's eye for 10days and the in vivo biocompatibility was investigated using Optical Coherence Tomography (OCT), histology and measuring the expression of pro-inflammatory genes (IL-1ß, TNF-α, VEGF and iNOS) (real-time PCR). The OCT and the histological analyzes exhibited the preserved architecture of the tissues of the eye. The biomaterial did not elicit an inflammatory reaction and pro-inflammatory cytokines were not expressed by the retinal cells, and the other posterior tissues of the eye. Results from the biocompatibility studies indicated that the nanofibers exhibited a high degree of cellular biocompatibility and short-term intraocular tolerance, indicating that they might be applied as drug carrier for ophthalmic use.