A chemically-defined plastic scaffold for the xeno-free production of human pluripotent stem cells.

Clinical use of human pluripotent stem cells (hPSCs) is hampered by the technical limitations of their expansion. Here, we developed a chemically synthetic culture substrate for human pluripotent stem cell attachment and maintenance. The substrate comprises a hydrophobic polyvinyl butyral-based polymer (PVB) and a short peptide that enables easy and uniform coating of various types of cell culture ware. The coated ware exhibited thermotolerance, underwater stability and could be stored at room temperature. The substrate supported hPSC expansion in combination with most commercial culture media with an efficiency similar to that of commercial substrates. It supported not only the long-term expansion of examined iPS and ES cell lines with normal karyotypes during their undifferentiated state but also directed differentiation of three germ layers. This substrate resolves major concerns associated with currently used recombinant protein substrates and could be applied in large-scale automated manufacturing; it is suitable for affordable and stable production of clinical-grade hPSCs and hPSC-derived products.

Polymer nanoparticles regulate macrophage repolarization for antitumor treatment.

We demonstrate an intrinsic antitumor effect of polymer nanoparticles (P-NPs), which could re-program tumor-associated macrophages to pro-inflammatory phenotype. The intrinsic effect of P-NPs on macrophage repolarization and its combination with other therapies provide new ideas for drug delivery, macrophage regulation and immunotherapy in cancer treatment.

Characterization of the roles of activated charcoal and Chelex in the induction of PrfA regulon expression in complex medium.

The foodborne pathogen Listeria monocytogenes is able to survive across a wide range of intra- and extra-host environments by appropriately modulating gene expression patterns in response to different stimuli. Positive Regulatory Factor A (PrfA) is the major transcriptional regulator of virulence gene expression in L. monocytogenes. It has long been known that activated charcoal is required to induce the expression of PrfA-regulated genes in complex media, such as Brain Heart Infusion (BHI), but not in chemically defined media. In this study, we show that the expression of the PrfA-regulated hly, which encodes listeriolysin O, is induced 5- and 8-fold in L. monocytogenes cells grown in Chelex-treated BHI (Ch-BHI) and in the presence of activated charcoal (AC-BHI), respectively, relative to cells grown in BHI medium. Specifically, we show that metal ions present in BHI broth plays a role in the reduced expression of the PrfA regulon. In addition, we show that expression of hly is induced when the levels of bioavailable extra- or intercellular iron are reduced. L. monocytogenes cells grown Ch-BHI and AC-BHI media showed similar levels of resistance to the iron-activated antibiotic, streptonigrin, indicating that activated charcoal reduces the intracellular labile iron pool. Metal depletion and exogenously added glutathione contributed synergistically to PrfA-regulated gene expression since glutathione further increased hly expression in metal-depleted BHI but not in BHI medium. Analyses of transcriptional reporter fusion expression patterns revealed that genes in the PrfA regulon are differentially expressed in response to metal depletion, metal excess and exogenous glutathione. Our results suggest that metal ion abundance plays a role in modulating expression of PrfA-regulated virulence genes in L. monocytogenes.

Cell Adhesion-Mediated Piezoelectric Self-Stimulation on Polydopamine-Modified Poly(vinylidene fluoride) Membranes.

Cell adhesion-mediated piezoelectric stimulation provides a noninvasive method for in situ electrical regulation of cell behavior, offering new opportunities for the design of smart materials for tissue engineering and bioelectronic medicines. In particular, the surface potential is mainly dominated by the inherent piezoelectricity of the biomaterial and the dynamic adhesion state of cells. The development of an efficient and optimized material interface would have important implications in cell regulation. Herein, we modified the surface of poled poly(vinylidene fluoride) (PVDF) membranes through polymerization of dopamine and investigated their influence on cell adhesion and electromechanical self-stimulation. Our results demonstrated that mesenchymal stem cells seeded on the poled PVDF membrane exhibited stronger cell spreading and adhesion. Meanwhile, the surface modification through polydopamine significantly improved the hydrophilicity of the samples and contributed to the formation of cell actin bundles and maturation of focal adhesions, which further positively modulated cell piezoelectric self-stimulation and induced intracellular calcium transients. Combining with theoretical simulations, we found that the self-stimulation was enhanced mainly due to the increase of the adhesion site and adhesion force magnitude. These findings provide new insights for probing the cell regulation mechanism on piezoelectric substrates, offering more opportunities for the rational design of piezoelectric biomaterial interfaces for biomedical engineering.

Polypropylene and polyvinylidene fluoride transobturator slings for the treatment of female stress urinary incontinence: 1-Year outcomes from a multicentre randomized trial.

AIMS: To compare the effectiveness and safety of polypropylene (PP) and polyvinylidene fluoride (PVDF) transobturator tapes (TOT) for the treatment of female stress urinary incontinence (SUI). METHODS: This is a multicentre randomized trial. Women with SUI or stress-predominant mixed urinary incontinence and scheduled for a TOT procedure were randomized to PP or PVDF slings. The primary outcome was 1-year cure or improvement rate using composite criteria. Complications were also compared. Relationships with outcomes were analyzed using multivariable logistic regressions models. RESULTS: From April 2016 to January 2018 285 participants were randomized. PP and PVDF slings showed similar high cure or improvement rate (91.0% vs. 95.6%, p = .138). Improvement in validated questionnaires was also similar. PVDF slings were associated with a lower rate of de novo urgency incontinence (adjusted odds ratio = 0.35; 95% confidence interval = 0.15-0.80). We found no statistical differences in complications rates, although a higher incidence of long-term pain events were observed in the PP group. The study is underpowered to find differences in specific complications owing to the low number of events. CONCLUSION: PP and PVDF TOTs are equally effective, although PVDF is associated with fewer cases of de novo urgency incontinence. Further studies are needed to give robust conclusions on safety profiles.

Transvenous Embolization of Carotid Cavernous Fistula through Inferior Petrosal Sinus with Detachable Coils and Ethylene Vinyl Alcohol Copolymer.

Carotid cavernous fistula (CCF) is a rare disease caused by abnormal communications between the internal carotid artery (direct fistula) or meningeal branches of the external carotid artery (indirect fistula) and the cavernous sinus (CS). Trauma is the most common cause of CCF. The clinical presentation of CCF is closely related to the venous drainage pattern. Orbital and neuro-ophthalmological symptoms are the most common clinical presentation of CCF with drainage through the superior ophthalmic vein (SOV). Endovascular embolization by arterial or venous approaches is the most common management of CCF. Transvenous embolization using detachable coils and ethylene-vinyl alcohol copolymer (EVOH) is an alternative method for the treatment of CCF. Endovascular embolization offers different options to treat CCF by minimally invasive approach decreasing morbidity and residual fistulas. The purpose of this article is to report our treatment experiences via the inferior petrosal sinus (IPS), and immediate-term outcomes of endovascular embolization of CCF by using detachable coils and EVOH.

Assessing the viability of Soluplus® self-assembled nanocolloids for sustained delivery of highly hydrophobic lapatinib (anticancer agent): Optimisation and in-vitro characterisation.

Nanocolloids are considered ideal carriers for hydrophobic drugs owing to their core-shell structure. Lapatinib is a potential anti-cancer agent, but its clinical use is limited because of its poor aqueous solubility, thus requiring larger oral doses with the associated toxicity. Thus, in the present study, we fabricated self-assembled nanocolloidal polymeric micelles (LP-PMs) of Soluplus® and Pluronic® F127 by the thin-film hydration method and assessed their delivery potential of the hydrophobic anti-cancer drug lapatinib (LP) and optimised these nanocolloidal polymeric micelles using Quality-by-Design approach. Amorphisation of the drug and no typical incompatibility other than hydrogen bonding in the LP-PMs was confirmed by solid-state characterisation. The LP-PMs exhibited a uniform size of 92.9 ± 4.07 nm, with a 5.06 mV zeta potential and approximately 87% drug encapsulation. The critical micellar concentration (CMC) of Soluplus® decreased from 6.63 × 10-3 to 4.4 × 10-3 mg/mL by incorporating Pluronic® F127. Further, the sustained release of LP from the LP-PMs was confirmed by in-vitro release studies showing 36% and 60% of LP released from the LP-PMs within 48 h in release media of pH 7.4 and pH 5.0, respectively. These results support their capability of preferential release at acidic tumor environment. Their hemocompatibility evidenced by hemolysis below accepted limits and no platelet aggregation with resistance to instant dilution illustrated their admirable blood compatibility and suitability for intravenous administration. The encapsulation of LP inside micelles enhanced the cytotoxicity of LP against SKBr3 breast cancer cells. Further, the LP-PMs were found to be stable over six months when stored at 2-8 °C. These findings indicate the improved potential of nanocolloidal polymeric micelles as promising carriers for the preferential and sustained delivery of hydrophobic anticancer drugs such as lapatinib to tumours.

Effect of stem cells combined with a polymer/ceramic membrane on osteoporotic bone repair.

Cell therapy associated with guided bone regeneration (GBR) can be used to treat bone defects under challenging conditions such as osteoporosis. This study aimed to evaluate the effect of mesenchymal stem cells (MSCs) in combination with a poly(vinylidene-trifluoroethylene)/barium titanate (PVDF-TrFE/BT) membrane on bone repair in osteoporotic rats. Osteoporosis was induced in female rats by bilateral removal of the ovaries (OVX) or sham surgery (SHAM), and the osteoporotic condition was characterized after 5 months by microtomographic and morphometric analyses. Calvarial defects were created in osteoporotic rats that immediately received the PVDF-TrFE/BT membrane. After 2 weeks, bone marrow-derived MSCs from healthy rats, characterized by the expression of surface markers using flow cytometry, or phosphate-buffered saline (PBS) (Control) were injected into the defects and bone formation was evaluated 4 weeks post-injection by microtomographic, morphometric, and histological analyses. A reduction in the amount of bone tissue in the femurs of OVX compared with SHAM rats confirmed the osteoporotic condition of the experimental model. More bone formation was observed when the defects were injected with MSCs compared to that with PBS. The modification that we are proposing in this study for the classical GBR approach where cells are locally injected after a membrane implantation may be a promising therapeutic strategy to increase bone formation under osteoporotic condition.

Tissue reaction after subcutaneous implants of a new material composed of ethylene-vinyl acetate and starch for future use as a biomaterial.

This study aimed to evaluate the tissue reaction of ethylene-vinyl acetate (EVA) in 4 different compositions and processing: EVA foamed at high pressure with ultrasound (EVACU); EVA with 15% starch foamed at high pressure with ultrasound (EVAMCU); EVA with 15% starch foamed at high pressure without ultrasound and EVA foamed at high pressure without ultrasound as future use as a porous scaffold. Scanning electron microscopy images showed the influence of starch, reducing the diameter of pores. The number of open pores was also reduced with the addition of starch. The ultrasound applied during the manufacturing of composites does not affect these characteristics. Eighteen rats were used to test the tissue reaction of materials and PTFE (polytetrafluoroethylene), proven biocompatible material. After 7, 15, and 60 days of surgery, the materials were removed and processed for microscopic evaluation and counting of the inflammatory infiltrate. The data shows inflammatory reaction similar to PTFE. However, in the quantitative analysis at 60 days, the EVACU and EVAMCU showed less quantity of mononuclear cells (p < 0.05). Thus, the results suggest that the use of ultrasound in the production method (EVA) seems to have improved cell behavior regarding the reduction of infiltration over the period, with tissue response equivalent to the PTFE. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 400-407, 2019.

Hair-Follicle-Associated Pluripotent (HAP) Stem Cells Encapsulated on Polyvinylidene Fluoride Membranes (PFM) Promote Functional Recovery from Spinal Cord Injury.

Our previous studies showed that nestin-expressing hair follicle-associated-pluripotent (HAP) stem cells, which reside in the bulge area of the hair follicle, could restore injured nerve and spinal cord and differentiate into cardiac muscle cells. Here we transplanted mouse green fluorescent protein (GFP)-expressing HAP stem-cell colonies enclosed on polyvinylidene fluoride membranes (PFM) into the severed thoracic spinal cord of nude mice. After seven weeks of implantation, we found the differentiation of HAP stem cells into neurons and glial cells. Our results also showed that PFM-captured GFP-expressing HAP stem-cell colonies assisted complete reattachment of the thoracic spinal cord. Furthermore, our quantitative motor function analysis with the Basso Mouse Scale for Locomotion (BMS) score demonstrated a significant improvement in the implanted mice compared to non-implanted mice with a severed spinal cord. Our study also showed that it is easy to obtain HAP stem cells, they do not develop teratomas, and do not loose differentiation ability when cryopreserved. Collectively our results suggest that HAP stem cells could be a better source compared to induced pluripotent stem cells (iPS) or embryonic stem (ES) cells for regenerative medicine, specifically for spinal cord repair.

Effect of stem cells combined with a polymer/ceramic membrane on osteoporotic bone repair

Abstract Cell therapy associated with guided bone regeneration (GBR) can be used to treat bone defects under challenging conditions such as osteoporosis. This study aimed to evaluate the effect of mesenchymal stem cells (MSCs) in combination with a poly(vinylidene-trifluoroethylene)/barium titanate (PVDF-TrFE/BT) membrane on bone repair in osteoporotic rats. Osteoporosis was induced in female rats by bilateral removal of the ovaries (OVX) or sham surgery (SHAM), and the osteoporotic condition was characterized after 5 months by microtomographic and morphometric analyses. Calvarial defects were created in osteoporotic rats that immediately received the PVDF-TrFE/BT membrane. After 2 weeks, bone marrow-derived MSCs from healthy rats, characterized by the expression of surface markers using flow cytometry, or phosphate-buffered saline (PBS) (Control) were injected into the defects and bone formation was evaluated 4 weeks post-injection by microtomographic, morphometric, and histological analyses. A reduction in the amount of bone tissue in the femurs of OVX compared with SHAM rats confirmed the osteoporotic condition of the experimental model. More bone formation was observed when the defects were injected with MSCs compared to that with PBS. The modification that we are proposing in this study for the classical GBR approach where cells are locally injected after a membrane implantation may be a promising therapeutic strategy to increase bone formation under osteoporotic condition.

Immunotoxicity assessment of ordered mesoporous carbon nanoparticles modified with PVP/PEG.

With large surface area and three-dimensional pore structure, mesoporous carbon nanoparticles (MCN) have attracted enormous interests as potential drug carriers. However, MCN immunotoxicity has not been clarified clearly up to now. Herein we reported the effect of MCN with and without PVP or DSPE mPEG2000 (PEG) modification on immune cells including dendritic cells (DCs), T lymphocytes and RAW264.7 macrophages in vitro. Furthermore, blood biochemical tests, alexin C3 assay and histological analysis were used to investigate the toxicity of MCN in vivo. The synthesized MCN with average particle size about 90 nm was naturally insoluble in water. Surface modification with PVP (MCN-PVP) or PEG (MCN-PEG) slightly increased the particle size and Zeta potential, and effectively improved the dispersion of mesoporous carbon. MCN, MCN-PVP and MCN-PEG promoted the differentiation and maturation of the DCs, while the levels of secreted TNF-α and IL-6 were significantly suppressed by MCN-PVP and MCN-PEG. These materials significantly induced apoptosis of T lymphocytes. The histopathologic results showed that there was no significant difference between nanoparticles with or without modification. Importantly, the materials deposition was observed in the lung, which could potentially inhibit lung metastasis. In conclusion, the ordered mesoporous carbon nanoparticles superficially modified by PVP or PEG perform well in immunological biocompatibility, and are likely to be a promising candidate as medicine carrier in pharmaceutics and clinic.

Modulating Surface Potential by Controlling the ß Phase Content in Poly(vinylidene fluoridetrifluoroethylene) Membranes Enhances Bone Regeneration.

Bioelectricity plays a vital role in living organisms. Although electrical stimulation is introduced in the field of bone regeneration, the concept of a dose-response relationship between surface potential and osteogenesis is not thoroughly studied. To optimize the osteogenic properties of different surface potentials, a flexible piezoelectric membrane, poly(vinylidene fluoridetrifluoroethylene) [P(VDF-TrFE)], is fabricated by annealing treatment to control its ß phases. The surface potential and piezoelectric coefficients (d33 ) of the membranes can be regulated by increasing ß phase contents. Compared with d33  = 20 pC N-1 (surface potential = -78 mV) and unpolarized membranes, bone marrow mesenchymal stem cells (BM-MSCs) cultured on the d33  = 10 pC N-1 (surface potential = -53 mV) membranes have better osteogenic properties. In vivo, d33  = 10 pC N-1 membranes result in rapid bone regeneration and complete mature bone-structure formation. BM-MSCs on d33  = 10 pC N-1 membranes have the lowest reactive oxygen species level and the highest mitochondrial membrane electric potential, implying that these membranes provide the best electrical qunantity for BM-MSCs' proliferation and energy metabolism. This study establishes an effective method to control the surface potential of P(VDF-Trfe) membranes and highlights the importance of optimized electrical stimulation in bone regeneration.

Risk management of ochratoxigenic fungi and ochratoxin A in maize grains by bioactive EVOH films containing individual components of some essential oils.

Aspergillus steynii and Aspergillus tubingensis are possibly the main ochratoxin A (OTA) producing species in Aspergillus section Circumdati and section Nigri, respectively. OTA is a potent nephrotoxic, teratogenic, embryotoxic, genotoxic, neurotoxic, carcinogenic and immunosuppressive compound being cereals the first source of OTA in the diet. In this study bioactive ethylene-vinyl alcohol copolymer (EVOH) films containing cinnamaldehyde (CINHO), linalool (LIN), isoeugenol (IEG) or citral (CIT) which are major components of some plant essential oils (EOs) were produced and tested against A. steynii and A. tubingensis growth and OTA production in partly milled maize grains. Due to the favourable safety profile, these bioactive compounds are considered in the category "GRAS". The study was carried out under different water activity (0.96 and 0.99 aw), and temperature (24 and 32 °C) conditions. ANOVA showed that class of film, fungal species, aw and temperature and their interactions significantly affected growth rates (GR), ED50 and ED90 and the doses for total fungal growth inhibition and OTA production. The most effective EVOH films against both species were those containing CINHO. ED50, ED90 and doses for total growth and OTA inhibition were 165-405, 297-614, 333-666 µg of EVOH-CINHO/plate (25 g of maize grains), respectively, depending on environmental conditions. The least efficient were EVOH-LIN films. ED50, ED90 and doses for total growth and OTA inhibition were 2800->3330, >3330 and >3330 µg of EVOH-LIN/plate (25 g of maize grains), respectively. The effectiveness of the bioactive films increased with increasing doses. Overall, A. tubingensis was less sensitive to treatments than A. steynii. Depending on the species, aw and temperature affected GR and OTA production in a different way. In A. steynii cultures, optimal growth occurred at 0.96 aw and 32 °C while optimal OTA production happened at 0.99 aw and 32 °C. In A. tubingensis cultures optimal growth happened at 0.99 aw and 32 °C, although the best conditions for OTA production were 0.99 aw and 24 °C. Thus, these species can be very competitive in warm climates and storage conditions. The EVOH-CINHO films followed by EVOH-IEG and EVOH-CIT films, designed in this study and applied in vapour phase, can be potent antifungal agents against A. steynii and A. tubingensis and strong inhibitors of OTA biosynthesis in maize grains at very low doses. This is the first study on the impact that interacting environmental conditions and bioactive films containing individual components of EOs have on the growth of these ochratoxigenic fungi and on OTA production in maize grains.

Novel antibacterial mouthguard material manufactured using silver-nanoparticle-embedded ethylene-vinyl acetate copolymer masterbatch.

The purpose of the present study was to develop an antibacterial mouthguard (MG) material using a masterbatch of silvernanoparticle-embedded ethylene-vinyl acetate (EVA) copolymers. In order to verify that the testing material was clinically applicable as an antibacterial MG material, we conducted an antibacterial test, a shock absorption test, and analysis of in vitro silver release. The colony-forming activity of Streptococcus sobrinus, Porphyromonas gingivalis, and Escherichia coli were significantly inhibited on the testing materials compared with the commercial EVA sheet (p<0.05). The shock absorption capability of the testing material was not significantly different from that of the commercial EVA sheet. Cumulative silver release (in pure water) from the testing materials were infinitesimal after soaking for 20 days, which implied that there could be no harm in wearing the MG during exercise. These results showed that this testing material could be clinically applicable as an antibacterial MG material.

The unique calcium chelation property of poly(vinyl phosphonic acid-co-acrylic acid) and effects on osteogenesis in vitro.

There is a clear clinical need for a bioactive bone graft substitute. Poly(vinyl phosphonic acid-co-acrylic acid) (PVPA-co-AA) has been identified as a promising candidate for bone regeneration but there is little evidence to show its direct osteogenic effect on progenitor or mature cells. In this study mature osteoblast-like cells (SaOS-2) and human bone marrow-derived mesenchymal stem cells (hBM-MSCs) were cultured with PVPA-co-AA polymers with different VPA:AA ratio and at different concentrations in vitro. We are the first to report the direct osteogenic effect of PVPA-co-AA polymer on bone cells and, more importantly, this effect was dependent on VPA:AA ratio and concentration. Under the optimized conditions, PVPA-co-AA polymer not only has an osteoconductive effect, enhancing SaOS-2 cell mineralization, but also has an osteoinductive effect to promote hBM-MSCs' osteogenic differentiation. Notably, the same PVPA-co-AA polymer at different concentrations could lead to differential osteogenic effects on both SaOS-2 and hBM-MSCs in vitro. This study furthers knowledge of the PVPA-co-AA polymer in osteogenic studies, which is critical when utilizing the PVPA-co-AA polymer for the design of novel bioactive polymeric tissue engineering scaffolds for future clinical applications. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 168-179, 2018.

Antibacterial [2-(Methacryloyloxy) ethyl] Trimethylammonium Chloride Functionalized Reduced Graphene Oxide/Poly(ethylene-co-vinyl alcohol) Multilayer Barrier Film for Food Packaging.

The objective of present work was to construct antibacterial [2-(methacryloyloxy) ethyl] trimethylammonium chloride functionalized reduced graphene oxide/poly(ethylene-co-vinyl alcohol) (MTAC-rGO/EVOH) multilayer barrier films by using layer-by-layer assembly under a parallel electric field. Besides barrier and mechanical properties, the antibacterial activities of the film and cytotoxicity of MTAC-rGO nanosheets were extensively investigated. The functionalization of rGO was achieved by grafting MTAC onto a graphene framework through C (sp3)-C bonds. The assembly of MTAC-rGO on the EVOH matrix not only significantly improved film mechanical strength, but also endowed the targeting film with outstanding moisture barrier even under a relative humidity of 99% (e.g., 0.019 g m-2 s-1 atm-1 for (MTAC-rGO/EVOH)20) besides good oxygen barrier (e.g., 0.07 cm3 m-2 d-1 atm-1 for (MTAC-rGO/EVOH)20). Among the testing films, MTAC-rGO/EVOH film had the best antibacterial activity, and the activity against S. aureus was better than E. coli. Meanwhile, the cytotoxicity of MTAC-rGO nanosheets was very low. Results suggest that MTAC-rGO/EVOH film may have great potential in food active packaging.

Poly (ethylene-co-vinyl alcohol) is a suitable substrate for human olfactory neuroepithelial cell differentiation in vitro through a defined regulatory pathway.

Olfactory dysfunction significantly influences patients' life quality, but currently has no adequate treatment. Poly (ethylene-co-vinyl alcohol) (EVAL) mediates cell adhesion, growth and modulates differentiation of neural stem cells. However, whether EVAL is a suitable substrate to establish an in vitro culture system that can promote development and differentiation of human olfactory neuroepithelial cells (HONCs) remains unexplored. This study isolates and cultures HONCs on controls and EVAL films for 21 days. The effects of treatment are assessed using immunocytochemistry, microarray analysis, quantitative PCR, ELISA and western blots following culturing. Most of the cell morphology on controls is epithelial and expresses markers of sustentacular cells (SCs), cadherin-1 and cytokeratin18, whereas the main population on EVAL presents as morphology with extended thin processes and possesses markers of mature olfactory sensory neurons (OSNs), olfactory marker protein (OMP). Microarray analyses reveal neuropeptide Y (NPY) and amphiregulin (AREG) are the two important regulating factors on EVAL films. HONCs cultured on EVAL films enhance the development of mature OSNs through NPY signaling, and significantly decrease the growth of SCs by blocking epidermal growth factor receptor (EGFR) activation. EVAL is a potential biomaterial to serve as an ideal substrate for treating olfactory dysfunction in the future. STATEMENT OF SIGNIFICANCE: Olfaction not only contributes to enjoyments of food, but provides a clue to escape from dangerous environmental hazards. However, loss of smell is commonly progressive and there is no good prognostic approach for olfactory dysfunction. Here, we use poly (ethylene-co-vinyl alcohol) (EVAL) to establish an in vitro culture system that promotes development and differentiation of human olfactory neuroepithelial cells. We show that EVAL not only enhances the development of mature olfactory sensory neurons through neuronpeptide Y signaling, but significantly protects the olfactory neuroepithelium from metaplasia by inhibiting EGFR activation. Therefore, EVAL is a potential biomaterial to serve as an ideal substrate for treating olfactory dysfunction in the future.

Human Mesenchymal Stem Cells Growth and Osteogenic Differentiation on Piezoelectric Poly(vinylidene fluoride) Microsphere Substrates.

The aim of this work was to determine the influence of the biomaterial environment on human mesenchymal stem cell (hMSC) fate when cultured in supports with varying topography. Poly(vinylidene fluoride) (PVDF) culture supports were prepared with structures ranging between 2D and 3D, based on PVDF films on which PVDF microspheres were deposited with varying surface density. Maintenance of multipotentiality when cultured in expansion medium was studied by flow cytometry monitoring the expression of characteristic hMSCs markers, and revealed that cells were losing their characteristic surface markers on these supports. Cell morphology was assessed by scanning electron microscopy (SEM). Alkaline phosphatase activity was also assessed after seven days of culture on expansion medium. On the other hand, osteoblastic differentiation was monitored while culturing in osteogenic medium after cells reached confluence. Osteocalcin immunocytochemistry and alizarin red assays were performed. We show that flow cytometry is a suitable technique for the study of the differentiation of hMSC seeded onto biomaterials, giving a quantitative reliable analysis of hMSC-associated markers. We also show that electrosprayed piezoelectric poly(vinylidene fluoride) is a suitable support for tissue engineering purposes, as hMSCs can proliferate, be viable and undergo osteogenic differentiation when chemically stimulated.

Facile Preparation of Doxorubicin-Loaded and Folic Acid-Conjugated Carbon Nanotubes@Poly(N-vinyl pyrrole) for Targeted Synergistic Chemo-Photothermal Cancer Treatment.

We developed a bifunctional nanoplatform for targeted synergistic chemo-photothermal cancer treatment. The nanoplatform was constructed through a facile method in which poly(N-vinyl pyrrole) (PVPy) was coated on cut multiwalled carbon nanotubes (c-MWNTs); FA-PEG-SH was then linked by thiol-ene click reaction to improve the active targeting ability, water dispersibility, and biocompatibility and to extend the circulation time in blood. The PVPy shell not only enhanced the photothermal effect of c-MWNTs significantly but also provided a surface that could tailor targeting molecules and drugs. The resulting MWNT@PVPy-S-PEG-FA possessed high drug-loading ratio as well as pH-sensitive unloading capacity for a broad-spectrum anticancer agent, doxorubicin. Owing to its outstanding efficiency in photothermal conversion and ability in targeted drug delivery, the material could potentially be used as an efficient chemo-photothermal therapeutic nanoagent to treat cancer.