Potential use of a bone tissue engineering scaffold based on electrospun poly (ɛ-caprolactone) - Poly (vinyl alcohol) hybrid nanofibers containing modified cockle shell nanopowder.

Today, the construction of scaffolds promoting the differentiation of stem cells is an intelligent innovation that accelerates the differentiation toward the target tissue. The use of calcium and phosphate compounds is capable of elevating the precision and efficiency of the osteogenic differentiation of stem cells. In this research, osteoconductive electrospun poly (ɛ-caprolactone) (PCL) - poly (vinyl alcohol) (PVA) hybrid nanofibrous scaffolds containing modified cockle shell (CS) nanopowder were prepared and investigated. In this regard, the modified CS nanopowder was prepared by grinding and modifying with phosphoric acid, and it was then added to PVA nanofibers at different weight percentages. Based on the SEM images, the optimum content of the modified CS nanopowder was set at 7 wt %, since reaching the threshold of agglomeration restricted this incorporation. In the second step, the PVA-CS7 nanofibrous sample was hybridized with different PCL ratios. Concerning the hydrophilicity and mechanical strength, the sample named PCL50-PVA50-CS7 was ultimately selected as the optimized and suitable candidate scaffold for bone tissue application. The accelerated hydrolytic degradation of the sample was also studied by FTIR and SEM analyses, and the results confirmed that the mineral deposits of CS are available approximately 7 days for mesenchymal stem cells. Moreover, Alizarin red staining illustrated that the presence of CS in the PCL50-PVA50-CS7 hybrid nanofibrous scaffold may potentially lead to an increase in calcium deposits with high precipitates, authenticating the differentiation of stem cells towards osteogenic cells.

Polyacrylic acid/ polyvinylpyrrolidone hydrogel wound dressing containing zinc oxide nanoparticles promote wound healing in a rat model of excision injury.

Developing and designing efficient wound dressings have gained increasing attention and shown beneficial results in improved wound healing effects. This study was conducted to improve wound healing properties and introduce a novel potential wound dressing. A novel hydrogel based on polyvinylpyrrolidone/poly acrylic acid containing Zinc oxide nanoparticles was prepared as an antibacterial wound dressing and examined in a rat excisional wound model. This hydrogel prepared by free radical polymerization using potassium persulfate (KPS) as an initiator, N, N-methylene bisacrylamide (MBA) as a cross-linker, poly acrylic acid (PAA) as a monomer in the presence of polyvinylpyrrolidone (PVP) and Zinc oxide nanoparticles (ZnO NPs). Analyses such as Scanning Electron Microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), and Thermal gravimetric analysis (TGA) were used to study morphology structure. After choosing the optimal sample, in vivo characterization of excisional wound injury on a rat model was done. The healing rate and histological analysis were calculated and compared among the groups. The therapeutic potential of the PAA-PVP-ZnO-%2 was investigated in a rat model of excisional injury compared to the control group. Results showed that the polyacrylic acid/polyvinylpyrrolidone hydrogel wound dressing containing zinc oxide nanoparticles accelerated wound contraction, had antibacterial effects, and promoted wound healing compared to other groups.

Preparation of colloidal nanoparticles PVA-PHEMA from hydrolysis of copolymers of PVAc-PHEMA as anticancer drug carriers.

The novel pH-responsive polymer nanoparticles have been widely used for drug delivery and cancer therapy. The pH-sensitive nanoparticles include chemical structures that can accept or donate protons in response to an environmental pH change. Polybases which mostly contain alkaline groups such as amines and hydroxy, accept protons at low pH and are neutral at higher pH values. This study aimed to prepare pH-sensitive colloidal amphiphilic poly(vinyl alcohol-2-hydroxyethyl methacrylate) (PVA-PHEMA) copolymers in cancer therapy applications. For this purpose, poly(vinyl acetate-2-hydroxyethyl methacrylate) (PVAc-PHEMA) copolymer nanoparticles were synthesized in different polymerization medium fractions from water and methanol and different monomer feed concentration. Then acetate groups were hydrolyzed, and the PHEMA-PVA nanoparticles were synthesized. The nanoparticles were further characterized using dynamic light scattering, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis to identify the structural and morphological changes. The Methotrexate (MTX) was loaded into the nanoparticles, and drug release kinetics were evaluated. The results confirmed that PHEMA-PVA copolymeric nanoparticles could be favorably used in cancer therapy.

Adsorption, and controlled release of doxorubicin from cellulose acetate/polyurethane/multi-walled carbon nanotubes composite nanofibers.

The cellulose acetate (CA)/poly (ε-caprolactone diol)/poly (tetramethylene ether) glycol-polyurethane (PCL-Diol/PTMG-PU)/multi-walled carbon nanotubes (MWCNTs) composite nanofibers were prepared via two-nozzle electrospinning on both counter sides of the collector. The performance of synthesized composite nanofibers was investigated as an environmental application and anticancer delivery system for the adsorption/release of doxorubicin (DOX). The synergic effect of MWCNTs and DOX incorporated into the nanofibers was investigated against LNCaP prostate cancer cells. The status of MWCNTs and DOX in composite nanofibers was demonstrated by SEM, FTIR and UV-vis determinations. The adsorption tests using nanofibrous adsorbent toward DOX sorption was evaluated under various DOX initial concentrations (100-2000 mg l-1), adsorption times (5-120 min), and pH values (pH:2-9). Due to the fitting of isotherm and kinetic data with Redlich-Peterson and pseudo-second order models, both chemisorption and surface adsorption of DOX molecules mechanisms have been predicted. The drug release from both nanofibers and MWCNTs-loaded nanofibers was compared. The better drug sustained release profiles verified in the presence of composite nanofibers. LNCaP prostate cancer and L929 normal cells were treated to investigate the cytotoxicity and compatibility of synthesized composite nanofibers. The apoptosis/necrosis of hybrid nanofibers and MWCNTs loaded-nanofibers was investigated. The obtained results demonstrated the synergic effects of MWCNTs and DOX loaded-nanofibers on the LNCaP prostate cancer cells death.

Polycaprolactone/Polyethylene Glycol Blended with Dipsacus asper Wall Extract Nanofibers Promote Osteogenic Differentiation of Periodontal Ligament Stem Cells.

Dipsacus asper wall (DA) is an ancient Chinese medicinal material that has long been used to maintain the health of human bones. The present study aimed to evaluate the osteogenic differentiation of periodontal ligament stem cells (PDLSCs) of Dipsacus asper wall extracts (DAE). Microwave-assisted alcohol extraction of 100 mesh DA powder under optimal conditions can obtain 58.66% (w/w) yield of the crude extract. PDLSCs have excellent differentiation potential. PDLSCs treated with DA extract (DAE) underwent osteogenesis, exhibiting a higher expression of the Col-1, ALP, Runx2, and OCN genes, and had a 1.4-fold increase in mineralization, demonstrating the potential of DAE to promote osteogenic differentiation. After the addition of PI3K inhibitor LY294002, the expression of osteogenic genes was significantly inhibited, confirming that PI3K is an important pathway for DAE to induce osteogenesis. Mix DAE with polycaprolactone/polyethylene glycol (PCL/PEO) to obtain nanofibers with a diameter of 488 nm under optimal electrospinning conditions. The physical property analysis of nanofibers with and without DAE includes FTIR, mechanical strength, biodegradability, swelling ratio and porosity, and cell compatibility. When cells induced by nanofibers with or without DAE, the mineralization of PDLSCs cultured on PCL/PEO/DAE was 2.6-fold higher than that of PCL/PEO. The results of the study confirm that both DAE and PCL/PEO nanofibers have the effect of promoting osteogenic differentiation. In order to obtain the best induction effect, the optimal amount of DAE can be discussed in future research.

Step-by-step design of poly (ε-caprolactone) /chitosan/Melilotus officinalis extract electrospun nanofibers for wound dressing applications.

Composition of polymers and choosing the type of solvents in electrospinning systems is of great importance to achieve a mat with optimal properties. In this work, with emphasizing the influence of a novel solvent system, an electrospun wound dressing was designed in four steps. Firstly, to study the effect of polymer-solvent interactions and electrospinning distance, a constant amount of polycaprolactone (PCL) was dissolved at different compositions of formic acid (FA)/dichloromethane (DCM) and was electrospun at different distances. The composition of 80FA/20DCM and distance of 15 cm were selected as optimal conditions by lowest average diameter of fibers and simultaneously good surface uniformity. In the second step, the concentration of PCL was considered variable to achieve the lowest diameter of fibers. Finally, in the third and fourth steps, different concentrations of chitosan (CN) and constant dosage of Melilotus officinalis (MO) extract were added to the solution. The extract contained fibers had a mean diameter of 275 ± 41 nm which is in the required condition for wound caring. Eventually, the optimized PCL/CN and PCL/CN/MO specimens were evaluated by FTIR, DSC, Tensile, water contact angle, antibacterial assays, cell viability, and drug release analysis for determining their function and properties.

Osteogenic differentiation of mesenchymal stem cells on the bimodal polymer polyurethane/polyacrylonitrile containing cellulose phosphate nanowhisker.

Polycaprolactone diol is the cornerstone, equipped with polyacrylonitrile and cellulose nanowhiskers (CNWs), of biocompatible and biodegradable polyurethanes (PUs). The solvent casting/particulate leaching technique was employed to contracting foam scaffolds with bimodal sizes from the combination of polyurethane/polyacrylonitrile/cellulose nanowhisker nanocomposites. Sugar and sodium chloride are components used as porogens to develop the leaching method and fabricate the 3D scaffolds. Incorporation of different percentages of cellulose nanowhisker leads to the various efficient structures with biodegradability and biocompatibility properties. All nanocomposites scaffolds, as revealed by MTT assay using mesenchymal stem cell (MSC) lines, were non-cytotoxic. PU/PAN/CNW foam scaffolds were used for osteogenic differentiation of human mesenchymal stem cells (hMSCs). Based on the results, PU/PAN/CNW nanocomposites could not only support osteogenic differentiation but can also enhance the proliferation of hMSCs in three-dimensional synthetic extracellular matrix.

Biological and structural properties of graphene oxide/curcumin nanocomposite incorporated chitosan as a scaffold for wound healing application.

AIMS: The purpose of this research is to fabricate chitosan (CS)/graphene oxide (GO)/curcumin (Cur) 3D scaffolds through the freeze-drying method for wound dressing applications. MAIN METHODS: GO is produced by Hammer's method; then, it is characterized by X-ray diffraction and TEM analysis. Fabricated scaffolds are characterized by FTIR, FESEM, AFM, water vapor transmission rate, PBS absorption, contact angle, tensile strength, porosity measurement, biodegradability, and drug release methods. The cell viability and morphology of NIH/3 T3 cells are investigated by WST assay kit and FESEM analysis, and the antibacterial activity of scaffolds is determined by the optical density (OD) method. The photothermal antibacterial activity is characterized by NIR irradiation, too. KEY FINDINGS: The mean pore diameter of scaffolds adjusted by the incorporation of about 0-1.5%wt. of GO/Cur nanocomposite into CS matrix, decreasing from 87 to 40 µm that can be attributed to the intermolecular bonds between CS and GO/Cur nanocomposite. Besides, the PBS absorption of scaffolds enhances by the addition of GO/Cur, especially 1% of it. Furthermore, the overall average of cell viability of nanocomposite scaffolds is about 95%, and the FESEM images show that NIH/3T3 fibroblasts well spread on the nanocomposite scaffolds. GO/Cur has a significant influence on the antibacterial activity of CS scaffolds as CS/GO/Cur 0.5 scaffold diminishes the bacterial growth to about 52% of the control sample's growth. SIGNIFICANCE: The results evidence the antibacterial CS/GO/Cur scaffolds are excellent supports for cell growth and proliferation, and they could be promising candidates for wound dressing applications.

Enhanced osteogenesis using poly (l-lactide-co-d, l-lactide)/poly (acrylic acid) nanofibrous scaffolds in presence of dexamethasone-loaded molecularly imprinted polymer nanoparticles.

The aim of this work is to prepare nanofibrous scaffolds based on poly (l-lactide-d, l-lactide)/poly (acrylic acid) [PLDLLA/PAAc] blends in the presence of Dexamethasone [Dexa]-loaded poly (2-hydroxyethyl methacrylate) [HEMA] as molecular imprinted polymer [MIP] nanoparticles [NPs] for enhancing osteogenesis. By adding 10 wt% of PAAc to the PLDLLA and employing response surface methodology, the average diameter of the electrospun nanofibers is approximately 237 nm. To increase the osteogenesis performance of the optimized nanofibrous scaffolds, the MIP nanoparticles are synthesized using HEMA monomer and Dexa template with a molar ratio of 10 to 1. Accordingly, these crosslinked drug nanocarriers exhibit an average diameter of around 122 nm and imprinting factor of approximately 1.8, enabling to adsorb Dexa molecules around 57%. Afterward, the Dexa-loaded MIP NPs have capability of a controlled drug release with ultimate value of 60% during 72 h. The simultaneous use of PLDLLA/PAAc-10 nanofibrous scaffold and Dexa-loaded MIP NPs within the cultivation media of fibroblast and mesenchymal stem cells is carried out by thiazolyl blue assay and acridine/ethidium bromide staining as well as alkaline phosphate/calcium content test, and alizarin red staining. The results reveal the remarkable efficiency of the blend nanofibers besides the MIP containing Dexa, thereby using for bone tissue engineering applications, potentially.

Amphipathic Substrates Based on Crosslinker-Free Poly(ε-Caprolactone):Poly(2-Hydroxyethyl Methacrylate) Semi-Interpenetrated Networks Promote Serum Protein Adsorption.

A simple procedure has been developed to synthesize uncrosslinked soluble poly(hydroxyethyl methacrylate) (PHEMA) gels, ready for use in a subsequent fabrication stage. The presence of 75 wt % methanol (MetOH) or dimethylformamide (DMF) impedes lateral hydroxyl-hydroxyl hydrogen bonds between PHEMA macromers to form during their solution polymerization at 60 °C, up to 24 h. These gels remain soluble when properly stored in closed containers under cold conditions and, when needed, yield by solvent evaporation spontaneous physically-crosslinked PHEMA adapted to the mould used. Moreover, this two-step procedure allows obtaining multicomponent systems where a stable and water-affine PHEMA network would be of interest. In particular, amphiphilic polycaprolactone (PCL):PHEMA semi-interpenetrated (sIPN) substrates have been developed, from quaternary metastable solutions in chloroform (CHCl3):MetOH 3:1 wt. and PCL ranging from 50 to 90 wt % in the polymer fraction (thus determining the composition of the solution). The coexistence of these countered molecules, uniformly distributed at the nanoscale, has proven to enhance the number and interactions of serum protein adsorbed from the acellular medium as compared to the homopolymers, the sIPN containing 80 wt % PCL showing an outstanding development. In accordance to the quaternary diagram presented, this protocol can be adapted for the development of polymer substrates, coatings or scaffolds for biomedical applications, not relying upon phase separation, such as the electrospun mats here proposed herein (12 wt % polymer solutions were used for this purpose, with PCL ranging from 50% to 100% in the polymer fraction).

Preparation of superabsorbent eco-friendly semi-interpenetrating network based on cross-linked poly acrylic acid/xanthan gum/graphene oxide (PAA/XG/GO): Characterization and dye removal ability.

In this work, a novel environmentally friendly semi-interpenetrating anionic hydrogel based on Xanthan gum/cross-linked polyacrylic acid/graphene oxide was prepared as superabsorbent for removing methylene blue as cationic dye from the water. Acrylic acid (AA) was crosslinked in xanthan (XG)/graphene oxide (GO) solution by a novel synthetic acrylic-urethane crosslinker (MS). Various analyses such as SEM, FT-IR, 1H NMR, XRD, and TGA were used to study morphology, structure, and thermal stability of MS and semi-IPNs. The synthesized hydrogels showed pH-sensitive behavior in water uptake, with the highest and lowest swelling in alkaline and acidic media, respectively. The nanocomposites had better dimension stability and dye adsorption with increasing GO from 0 to 1%. Hydrogel containing 1% GO showed 485% and 88.5% swelling and dye adsorption efficiency, respectively. Different kinetic models including 1st order, 2nd order, intra-particle diffusion, and Elovich kinetics were studied. All models except 2nd order model are in good agreement with the experimental data. GO-containing hydrogels had a significant effect on methylene blue adsorption and this effect increased with an increase in the amount of GO. PAA/XG/GO hydrogels can be introduced as an eco-friendly adsorbent with high efficiency for the removal of cationic dye pollutions.

Antibacterial nanofibers based on poly(l-lactide-co-d, l-lactide) and poly(vinyl alcohol) used in wound dressings potentially: a comparison between hybrid and blend properties.

Morphology, hydrophilicity, degradation, mechanical properties, drug release, bacterial resistance, and cell viability are indispensable parameters for a bioactive wound dressing. In this work, the aforementioned terms between hybrid and blend nanofibrous samples based on poly (L-lactide-co-D, L-lactide) (PLDLLA) and poly (vinyl alcohol) (PVA) containing triclosan (Tri) as an antibacterial drug were investigated. The FE-SEM images showed that the presence of Tri in the hybrid and blend samples led to bimodal, and unimodal diameter size distributions. The FTIR spectra revealed that the addition of PVA caused to shift the carbonyl bond of PLDLLA in the blend sample, and DSC thermograms exhibited the immiscibility of PVA and PLDLLA polymers in the blend. Moreover, the hybrid sample showed higher hydrophilicity with water contact angle (WCA) of 53[Formula: see text] than the blend ones with WCA of 73[Formula: see text] which proved by water up-take test. In the following, the antibacterial evaluation showed better results for hybrid-Tri with the maximum growth inhibitory zones of 35 mm and 48 mm for E. coli and S. aureus, respectively. On the other hand, the hybrid nanofibrous sample showed remarkable mechanical properties (tensile stress ∼19 MPa, and Young's modulus ∼532 MPa). Finally, the SNL 76/7 fibroblast cell line culture confirmed that the hybrid-Tri nanofibrous sample had better proliferation performance than the blend-Tri sample because of the minimal cytotoxicity and maximal cell viability by MTT and acridine orange/ethidium bromide staining.

Preparation and characterization of semi-IPNs of polycaprolactone/poly (acrylic acid)/cellulosic nanowhisker as artificial articular cartilage.

Cartilage is a semi-solid resilient and smooth elastic connective tissue and upon damage, its repair is almost impossible or occurs with a very slow recovery process. Polycaprolactone (PCL), used as a biocompatible polymer, withholds all required mechanical properties, except suitable cell adhesion due to its hydrophobicity. In order to resolve this issue, we sought to introduce appropriate semi-IPNs into the system to regain its hydrophilicity base on increasing of the hydrophilic polymer. PCL and Cellulose nanowhiskers (CNWs) were entrapped in a network of poly (acrylic acid) that had been crosslinked via a novel acrylic-urethane crosslinker. The influential synthetic parameters on the preparation of artificial articular cartilages were investigated based on the Taguchi test design. The prepared CNW, acrylic-urethane crosslinker and semi-IPNs were studied via 1H NMR, FTIR, SEM, TEM, TGA, water swelling, water contact angle, tensile, and MTT analyses. According to the results, the optimal amount of monomer was about 46%. Incorporation of an optimized amount of CNW, which was 0.5%, improved the mechanical properties of artificial cartilage. After a 30 h time period, semi-IPNs showed the water absorption of about 30%. MTT on days 1, 3 and 5, as well as cell attachment, confirmed the biocompatibility of the semi-IPNs.

Fabrication and characterization of graphene oxide-chitosan-zinc oxide ternary nano-hybrids for the corrosion inhibition of mild steel.

In this study, graphene oxide-chitosan (GO-CS) and graphene oxide-chitosan-ZnO (GO-CS-ZnO) hybrids were synthesized in order to examine the effectiveness of hybridization in enhancing the corrosion inhibition activity of graphene oxide (GO). In this way, the synthesized GO and nano-hybrids were firstly characterized by using FTIR, UV-Vis, FE-SEM, AFM, TEM and subsequently were studied in term of corrosion inhibition. Our primary results indicated that, single-layer GO, GO-CS hybrids and also GO-CS-ZnO ternary nano-hybrids were appropriately synthesized. The corrosion inhibition results demonstrated superior performance of GO-CS hybrids than pure GO. In addition, GO-CS-ZnO ternary nano-hybrids revealed the highest corrosion inhibition activity compared with all nano-materials studied here. The corrosion inhibition efficiency of GO (η = 42.35%) was enhanced to 83.81% and 85.61% for GO-CS and GO-CS-ZnO nanocomposites in 500 ppm conc., respectively. Generally, our results demonstrated that hybridization strategy successfully promoted the corrosion inhibition efficiency of GO. Furthermore, Langmuir isotherm was used in three methods (PDP, EIS and LPR) to study the adsorption of synthesized nano-materials on mild steel.

Intelligent superabsorbents based on a xanthan gum/poly (acrylic acid) semi-interpenetrating polymer network for application in drug delivery systems.

In the present study, semi-interpenetrating polymer networks (semi-IPNs) were synthesized based on crosslinked acrylic acid (AA)/xanthan gum (XG) biopolymer in the presence of N, N'-hexane-1, 6-dilbisprop-2-enamide (MS) or 1,4-butandioldimethacrylate (BDOD) as the cross-linking agent. MS is a novel acrylic-urethane diene monomer prepared through the condensation reaction between AA and hexamethylene diisocyanate (HDI). Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR), X-ray diffraction (XRD) and thermogravimetric (TGA) analyses were used to study the morphology, structure and thermal stability of MS and semi-IPNs. The effect of crosslinking agent type on different behaviors such as morphology, stability, swelling, and water-retention capabilities of the synthesized hydrogels were investigated. XG-PAA semi-IPNs exhibited a very high adsorption potential and stability. Hydrogel biocompatibility was confirmed by the outcomes of MTT assay and cell staining. We recommend XG-PAA semi-IPNs as an environmentally benign and readily non-toxic material with an excellent adsorption capacity for application in drug delivery systems, wound healing and dye removal.

Osteogenic differentiation of hMSCs on semi-interpenetrating polymer networks of polyurethane/poly(2­hydroxyethyl methacrylate)/cellulose nanowhisker scaffolds.

Poly (2­hydroxyethyl methacrylate) (PHEMA) was crosslinked in the presence of biocompatible and biodegradable poly(caprolactone) (PCL) based polyurethanes (PUs) and cellulose nanowhiskers (CNWs). The CNWs were obtained from wastepaper. In order to crosslink PHEMA (10 wt%), a novel acrylic-urethane cross-linker was produced by a condensation reaction of PHEMA and hexamethylene diisocyanate (HDI). The PU-PHEMA-CNWs scaffolds were prepared by solvent casting/particulate leaching method in different weight percentages of CNWs (i.e., 0, 0.1, 0.5, and 1 wt%). The structural, mechanical, and in vitro biological properties of bio-nanocomposites were evaluated via FTIR, SEM, tensile, and MTT assay. The tensile strength of PU-PHEMA-0, PU-PHEMA-0.1, PU-PHEMA-0.5, and PU-PHEMA-1 were 76.2, 95.8, 98.1, and 89.8 kPa, respectively. Incorporation of CNWs also resulted in improved cell proliferation on PU-PHEMA-CNWs scaffolds. The bone marrow derived human mesenchymal stem cells (hMSCs) were seeded on the prepared porous scaffolds and incubated in osteogenic medium. Based on the results including calcium content assay, alkaline phosphatase assay, and mineralization staining, PU-PHEMA-CNW scaffolds were introduced as a suitable election for imitating the behavior of cellular niche. Bone mineralization and osteogenesis differentiation of hMSCs on PU-PHEMA-CNW scaffolds were significantly more than control after 14 days.

Performance evaluation of poly (l-lactide-co-D, l-lactide)/poly (acrylic acid) blends and their nanofibers for tissue engineering applications.

Poly (l-lactide-co-D, l-lactide) (PLDLLA) is a biodegradable polymer predominantly used in biomedical applications. Despite unprecedented characteristics of PLDLLA, its wettability, mechanical properties, degradation, and cell attachment are main issues to improve. In this work, different blend films based on PLDLLA/poly (acrylic acid) (PAAc) are prepared to evaluate their miscibility, hydrophilicity, hydrolytic degradation and mechanical properties. For this purpose, a series of experiments such as DSC alongside SEM, water contact angle (WCA)/water up-take, weight measurements in phosphate buffer saline (PBS) and NaOH as well as tensile test are carried out. The DSC and SEM results show a miscibility for the blends, and hence by increasing PAAc, the WCA values and degradation rates are decreased and increased, respectively. Moreover, the degradation mechanisms of the blend samples follow surface/bulk erosion and bulk process in the alkaline and PBS environments, respectively. Subsequently, PLDLLA and its blends are electrospun to prepare nanofibrous samples, thereby assessing their cytotoxicity and cell viability by the use of thiazolyl blue assay and acridine orange/ethidium bromide staining, respectively. The in vitro SNL 76/7 fibroblast cells cultivation onto the surface of the blend with 10% wt. of PAAc revealed that this sample is a promising candidate for tissue engineering applications.

Reinforced Poly(ε-caprolactone) Bimodal Foams via Phospho-Calcified Cellulose Nanowhisker for Osteogenic Differentiation of Human Mesenchymal Stem Cells.

In this work, phospho-calcified cellulose nanowhiskers (PCCNWs) were prepared from wastepaper powder (WPP) and were dispersed in poly(ε-caprolactone) (PCL). The biocompatible and biodegradable (PCL)/PCCNW bimodal foam nanocomposites with two species cell sizes were prepared by the solvent casting/particulate leaching method in different weight percentage of PCCNWs. The mechanical, thermal, and in vitro biological properties of PCL/PCCNW nanocomposites were investigated. All PCL/PCCNW scaffolds were hydrophilic, biodegradable, and also noncytotoxic. The human mesenchymal stem cells were cultured on the prepared PCL/PCCNW bimodal foam nanocomposites and differentiated to osteoblasts. On the basis of evaluating tests such as MTT assay, acridine orange/ethidium bromide staining, alkaline phosphatase assay, calcium content assay, and alizarin red staining, PCL/PCCNW scaffolds were introduced as an appropriate option for emulating the behavior of extracellular matrix. Increasing PCCNWs improves the mechanical, hydrophilic, and biodegradability properties of the nanocomposites as well as their osteoconductivity.

High aspect ratio phospho-calcified rock candy-like cellulose nanowhiskers of wastepaper applicable in osteogenic differentiation of hMSCs.

The aim of this study was to prepare cellulose nanowhiskers (CNWs) from wastepaper powder (WPP), as an environmentally friendly approach for obtaining the source material, which is a highly available and low-cost precursor for cellulose nanomaterial processing. Acid hydrolysis and calcification treatments were employed for extraction of CNWs and preparation of novel phospho-calcified cellulose nanowhiskers (PCCNWs). CNWs and PCCNWs were analyzed through optical microscopy (OM), scanning electron microscopy (SEM), Fourier-transformed infrared spectra (FTIR) and X-ray diffraction analysis (XRD). Cell behaviors in the presence of CNWs and PCCNWs were studied by MTT assay and live-dead staining. Finally, the effect of these particles on osteogenic differentiation of stem cells was evaluated based on alkaline phosphatase activity (ALP), calcium mineralization as well as von Kossa and alizarin red staining. Based on the results, PCCNWs had a positive effect on osteogenic differentiation of human mesenchymal stem cells (hMSCs) and can be used for developing new approaches for bone tissue engineering.

Neural differentiation of human induced pluripotent stem cells on polycaprolactone/gelatin bi-electrospun nanofibers.

In the present study, for the first time, polycaprolactone (PCL) and gelatin (GEL) were used for neural differentiation of human induced pluripotent stem cells (hiPSCs) in the form of bi-electrospun nanofibers. The electrospun fibers were evaluated by FTIR and tensile analysis. MTT assay was used to evaluate the toxicity on the scaffolds. The hiPSCs were seeded on the fibers and after 14days in neural differentiation medium. To confirm the differentiation, real-time PCR and immunocytochemistry (ICC) analyses were performed. For morphological studies of fibers and cultured cells on them, scanning electron microscopy (SEM) and optical microscopy (OM) were used. Our results indicated that hiPSCs had differentiated to neural cells completely after incubation time. Our study demonstrates that PCL/GEL bi-electrospun nanofibers not only have the capability to support hiPSCs differentiation to neural cells, but they also are able to enhance and improve such process. Overall, PCL/GEL scaffolds seem to be a feasible, reliable and easily accessed composite for further tissue engineering experiments.