The main aim of this study is to develop a new method to prepare porous microbeads. Silver nanoparticles (AgNPs) were synthesized in an alginate colloidal solution, and then the porous microbeads containing AgNPs were prepared. The prepared alginate/AgNPs microbeads were ∼300 μm in diameter. The resulting alginate/AgNPs microbeads were placed in a solvent of N,N-dimethylformamide with AgNPs, which resulted in the formation of pores in the block microbeads composite. The formation of AgNPs was confirmed by UV–vis spectroscopy and TEM; the results showed that the AgNPs have a diameter range of 6–21 nm. The microbeads are characterized by using SEM, EDX, as well as FTIR. The porous alginate/AgNPs microbeads were examined against different pathogenic bacterial strains, and the result was compared with another alginate/AgNPs microbeads. The porous alginate/AgNPs microbeads exhibit a strong antimicrobial activity compared to the alginate/AgNPs microbeads.

Osteochondral defects affect both the articular cartilage and the underlying subchondral bone, but poor osteochondral regeneration is still a daunting challenge. Although the tissue engineering technology provides a promising approach for osteochondral repair, an ideal biphasic scaffold is in high demand with regards to proper biomechanical strength. In this study, an oriented poly(l-lacticacid)-co-poly(ε-caprolactone) P(LLA-CL)/collagen type I(Col-I) nanofiber yarn mesh, fabricated by dynamic liquid electrospinning served as a skeleton for a freeze-dried Col-I/Hhyaluronate (HA) chondral phase (SPONGE) to enhance the mechanical strength of the scaffold. In vitro results show that the Yarn Col-I/HA hybrid scaffold (Yarn-CH) can allow the cell infiltration like sponge scaffolds. Using porous beta-tricalcium phosphate (TCP) as the osseous phase, the Yarn-CH/TCP biphasic scaffold was then assembled by freeze drying. After combination of bone marrow mesenchymal stem cells, the biphasic complex was successfully used to repair the osteochondral defects in a rabbit model with greatly improved repairing scores and compressive modulus. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 581–592, 2015.

Cellulose acetate butyrate nanofibers were prepared separately by two electrospinning techniques; a needleless electrospinning using a disc as spinneret and a rotary drum as collector and a conventional needle electrospinning using a rotary drum as collector. Compared to the needle-electrospun nanofibers, the disc-electrospun nanofibers were coarser with a wider diameter distribution. Both fibers had a similar surface morphology and they showed no difference in chemical components, but the disc-electrospun nanofibers were slightly higher in crystallinity. The productivity of disc electrospinning was 150 times larger than that of needle electrospinning. The disc-electrospun nanofiber mats were found to have a three dimensional fibrous structure with an average pore size of 9.1 μm, while the needle-electrospun nanofibers looked more like a two-dimensional sheet with a much smaller average pore size (3.2 μm). Fibroblasts and Schwann cells were cultured on the fibrous matrices to assess the biocompatibility. The disc-electrospun nanofiber webs showed enhanced cellular growth for both fibroblasts and Schwann cells, especially in a long culture period. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:115–122, 2013.

For blood vessel tissue engineering, an ideal vascular graft should possess excellent biocompatibility and mechanical properties. For this study, a elastic material of poly (L-lactic acid-co-ϵ-caprolactone) (P(LLA-CL)), collagen and chitosan blended scaffold at different ratios were fabricated by electrospinning. Upon fabrication, the scaffolds were evaluated to determine the tensile strength, burst pressure, and dynamic compliance. In addition, the contact angle and endothelial cell proliferation on the scaffolds were evaluated to demonstrate the structures potential to serve as a vascular prosthetic capable of in situ regeneration. The collagen/chitosan/P(LLA-CL) scaffold with the ratio of 20:5:75 reached the highest tensile strength with the value of 16.9 MPa, and it was elastic with strain at break values of ∼112%, elastic modulus of 10.3 MPa. The burst pressure strength of the scaffold was greater than 3365 mmHg and compliance value was 0.7%/100 mmHg. Endothelial cells proliferation was significantly increased on the blended scaffolds versus the P(LLA-CL). Meanwhile, the endothelial cells were more adherent based on the increase in the degree of cell spreading on the surface of collagen/chitosan/P(LLA-CL) scaffolds. Such blended scaffold especially with the ratio of 20:5:75 thus has the potential for vascular graft applications. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.

Effective Schwann cells (SCs) attachment is a prerequisite for the successful construction of tissue-engineered nerve. The present study aimed to investigate the role of an avidin-biotin binding system (ABBS) for neural tissue engineering. The attachment, proliferation, and morphology of biotinylated SCs on avidin-treated scaffolds were examined, and the effects of avidin, biotin, and the avidin-biotin binding system on SCs gene expressions were also studied. The results indicated that the attachment of biotinylated SCs onto avidin-treated scaffolds was promoted obviously within a short time (10 min). Meanwhile, there were no great differences in terms of proliferation and morphology of SCs between the two groups after cultivation for 14 days. The gene expressions of S100, GDNF, BDNF, NGF, CNTF, and PMP22 were up-regulated significantly by biotin rather than aligned scaffolds or avidin. The present study demonstrated that ABBS enhanced the attachment and maturation of SCs onto the electrospun scaffolds without adverse effects on the proliferation of SCs in the long term, suggesting the potential application of ABBS in the neural tissue engineering. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011.

Electrospinning using natural proteins and synthetic polymers offers an attractive technique for producing fibrous scaffolds with potential for tissue regeneration and repair. Nanofibrous scaffolds of silk fibroin (SF) and poly(L-lactic acid-co-ϵ-caprolactone) (P(LLA-CL)) blends were fabricated using 1,1,1,3,3,3-hexafluoro-2-propanol as a solvent via electrospinning. The average nanofibrous diameter increased with increasing polymer concentration and decreasing the blend ratio of SF to P(LLA-CL). Characterizations of XPS and ¹³C NMR clarified the presence of SF on their surfaces and no obvious chemical bond reaction between SF with P(LLA-CL) and SF in SF/P(LLA-CL) nanofibers was present in a random coil conformation, SF conformation transformed from random coil to β-sheet when treated with water vapor. Whereas water contact angle measurements conformed greater hydrophilicity than P(LLA-CL). Both the tensile strength and elongation at break increased with the content increasing of P(LLA-CL). Cell viability studies with pig iliac endothelial cells demonstrated that SF/P(LLA-CL) blended nanofibrous scaffolds significantly promoted cell growth in comparison with P(LLA-CL), especially when the weight ratio of SF to P(LLA-CL) was 25:75. These results suggested that SF/P(LLA-CL) blended nanofibrous scaffolds might be potential candidates for vascular tissue engineering. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010

Electrospinning offers an attractive opportunity for producing silk fibroin (SF) nano/micro fibrous scaffolds with potential for tissue regeneration and repair. Electrospun scaffolds of silk fibroin were fabricated as a biomimetic scaffold for tissue engineering. The morphology of the electrospun scaffolds was investigated with SEM and AFM. The SEM images indicated that electrospun SF fibers were ribbon-shaped and the average width increased with increasing SF concentrations. The AFM images revealed that, after treated with methanol, there was a groove on the surface of fiber, which is conducive to cell attachment. The structure of electrospun SF fibers was characterized by NMR, WAXD, and DSC. The results displayed that SF in electrospun fibers was present in a random coil conformation, SF conformation transformed from random coil to β-sheet when treated with methanol. Cell attachment and proliferation studies with pig iliac endothelial cells (PIECs) demonstrated that electrospun SF scaffolds significantly promoted cell attachment and proliferation in comparison with cast SF films. These results suggest electrospun SF scaffolds may be potential candidates for cardiovascular tissue engineering. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010

In this study, three kinds of two-component adhesive glues were prepared, namely, gel-dext glue made from modified gelatin and dextran, gel-HES glue made from modified gelatin and hydroxyethyl starch (HES), and chit-dext glue made from chitosan and modified dextran. Upon mixing the two-component solution together crosslinking occurred and a gel formed in several seconds, which would seal the wound tissue and stop the bleeding. The adhesive ability of those three prepared glues was evaluated in vitro and in vivo separately by measuring the bonding strength to two piece of porcine skin and the adhesive strength after sealing the skin incisions on the back of rat. Fibrin glue was used as comparing. Gel-dext glue and gel-HES glue shown higher bonding strength and adhesive strength than chit-dext glue and fibrin glue. Histology test of incision tissues given by both HE and MTC methods, the former shown that gel-dext and gel-HES glues, like fibrin glue, have only normal initial inflammation to skin tissue, which almost disappear from 9 days but chit-dext glue seams have heaver inflammation, which may last to 12 days; the later shown gel-dext and gel-HES glues similar to fibrin glue, can heal the wound fast than that of chit-dext glue. The hemostatic ability for gel-HES glue was also tested on a cut liver of rat, which depend on the gel formation speed when the two-composite solutions were mixed together. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010

A coaxial electrospun technique to fabricate core-shell microfibers (MFs) for drug delivery application is described. In one-step, Paclitaxel (PTX)-loaded poly(L-lactic acid-co-ε-caprolactone) (75:25) (P(LLA-CL)(core/shell)) was electrospun into MFs using 2,2,2-trifluoroethanol as the solvent. The physical and chemical properties of electrospun fibers were characterized by various techniques, such as scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, and Fourier-transform infrared. The fiber diameter depended on both the polymer concentration and the flow ratio of PTX to P(LLA-CL). The encapsulation efficiency and in vitro release profile were measured using high performance liquid chromatography methods. PTX released from the MFs in a short burst over 24 h followed by very slow release over the following 60 days. In addition, the cytotoxicity of PTX-loaded P(LLA-CL) MFs was evaluated using 3-[4,5-dimehyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide assay on HeLa cell lines. These results indicate that PTX could be released from P(LLA-CL) fibers in a steady manner and effectively inhibit the activity of HeLa cells. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2009.

The aim of this study was to investigate electrospinning of emulsions to prepare core-shell type of nanofibers for being an innovative type of cell-growth scaffolds with potentially controllable drug-releasing capabilities. The hypothesis was that the poly(L-lactide-co-ε-caprolactone) [P(LLA-CL), shell] nanofibrous mats containing sorbitan monooleate (Span-80, core) could be appropriate scaffolds for growing pig iliac endothelium cells (PIECs). To test the hypothesis, the electrospinning of emulsions made of P(LLA-CL), chloroform, Span-80, and distilled water to prepare P(LLA-CL)/Span-80 nanofibers was systematically investigated. The effects of water content and P(LLA-CL) concentration in the emulsions on the morphologies of the nanofibers were studied. The morphologies, mechanical properties, and surface hydrophilicity of the nanofibrous mats were examined. The performance for being scaffolds was investigated by examination of the viability (anchorage and proliferation) and morphology of PIECs on the nanofibrous mats. There were no statistically significant differences in endothelial cell growth on the core-shell nanofibrous mats compared to the polymeric nanofibrous mats, and the P(LLA-CL)/Span-80 nanofiber mats could be used as an innovative type of scaffolds with potentially controllable drug-releasing capabilities. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009

In this article, core-shell structure nanofibers were fabricated by coaxial electrospinning with biodegradable copolymer Poly(L-Lactic-ε-Caprolactone) [P(LLA-CL) 50 : 50] as shell and bovine serum albumin (BSA) as core. Morphology and microstructure of the nanofibers were characterized by scanning electron microscopy and transmission electron microscopy. The mechanical properties were investigated by stress-strain tests. In vitro degradation rates of the nanofibrous membranes were determined by measuring their weight loss when immersed in phosphate-buffered saline (pH 7.4) for a maximum of 14 days. Release behavior of BSA was measured by an ultraviolet-visible spectroscopy, and the results demonstrated that BSA could release from P(LLA-CL) nanofibers in a steady manner. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009