Xianglin Zhang

Novel fabrication of hierarchically porous hydroxyapatite scaffolds with refined porosity and suitable strength

Abstract Based on extrusion deposition and foaming technique, a novel method for biological hydroxyapatite (HA) scaffolds was introduced in this paper. The scaffolds were primarily characterised by interconnected and hierarchically porous structures with high porosity, adjustable distribution of pore sizes, as well as considerable mechanical strength. In order to confirm that fine control of bulk porosity and mechanical strength was possible and feasible, further analysis of obtained scaffolds was carried out by field emission scanning electron microscope (FESEM), compressive test and calculation of volumetric shrinkage; in particular, the additional porosity resulting from the introduction of pore former was evaluated. The results indicated that this method can have a great potential to construct HA scaffolds of suitable quality for spongy bone in bone tissue engineering.

Bioprinting and its Applications in Tissue Engineering and Regenerative Medicine

Bioprinting of three-dimensional constructs mimicking natural-like extracellular matrix has revolutionized biomedical technology. Bioprinting technology circumvents various discrepancies associated with current tissue engineering strategies by providing an automated and advanced platform to fabricate various biomaterials through precise deposition of cells and polymers in a premeditated fashion. However, few obstacles associated with development of 3D scaffolds including varied properties of polymers used and viability, controlled distribution, and vascularization, etc. of cells hinder bioprinting of complex structures. Therefore, extensive efforts have been made to explore the potential of various natural polymers (e.g. cellulose, gelatin, alginate, and chitosan, etc.) and synthetic polymers in bioprinting by tuning their printability and cross-linking features, mechanical and thermal properties, biocompatibility, and biodegradability, etc. This review describes the potential of these polymers to support adhesion and proliferation of viable cells to bioprint cell laden constructs, bone, cartilage, skin, and neural tissues, and blood vessels, etc. for various applications in tissue engineering and regenerative medicines. Further, it describes various challenges associated with current bioprinting technology and suggests possible solutions. Although at early stage of development, the potential benefits of bioprinting technology are quite clear and expected to open new gateways in biomedical, pharmaceutics and several other fields in near future.

Electrospinning of Polycaprolactone/Pluronic F127 dissolved in glacial acetic acid: fibrous scaffolds fabrication, characterization and in vitro evaluation

Abstracts The Polycaprolactone (PCL) fibrous scaffolds in nano to micro scale have been considered as excellent templates for cell culture and tissue growth. The hydrophobic nature of the PCL, however, yields low initial cell seeding density, heterogeneous cell spreading and slow cell growth rate. Therefore, in this study the surface hydrophilic fibrous scaffolds were directly fabricated by the electrospinning of PCL solutions with small quantities (0.5–5%) of Pluronic F127 (PEO100-PPO65-PEO100) dissolved in benign solvent of glacial acetic acid. The clear and miscible solutions were achieved by controlling the proper F127 content in the blend solutions. The continuous and smooth fibers with average diameters from 0.71 to 1.43 μm made up the fibrous scaffolds in non-woven mode. Then the water wetting angle of the scaffolds could be adjusted from 126° to 0° by varying F127 content owing to its hydrophilic PEO chains presented on surface the blended fibers. Finally, it was demonstrated that the blended fibrous scaffolds with the F127 content less than 1% exhibited better cell attachment, proliferation and spreading performance than those of pure PCL scaffolds.

Application of Sodium Alginate Hydrogel

Tissue engineering and 3D cell cutler involving the use of three-dimensional scahffold for cell and tissue cultural ,is a promising technique for establishing in vitro culture models that mimc in vivo environment . In vitro models present ethical and cost advantages over in vivo models, and allow for tissue devolpmint.alginate , aliner polysaccharide derived from brown algae .has properties that make it a favorable materials as a 3D extracellular matrix for in vitro cell and tissue models and some of sodium Hydrogyl materials are higly appealing as 3D scaffold for in vitro 3D cell cutlre and tissue culture due their ability to mimic the physical properties native tissue as well as their high porosity for effcient diffusion of proteins and nutrients Alginate hydrogel is widely ysed in tissue engineering application due to its desirable propertis as

Inkjet printing of silver nano particles doped PEDOT:PSS thin film

Inkjet technology is utilized to deposit Ag-PEDOT:PSS thin films in this study. The obtained experimental results indicate that the addition of silver nanoparticles has improved the conductivity of PEDOT:PSS thin film up to two orders of magnitude, but as expected, a decrease in transparency simultaneously has occurred. The morphology of oxide on the surface of deposited PEDOT:PSS thin film has also been affected due to the introduction of the silver nanoparticles. However, application of preheating on the substrate has led to an anisotropic conductivity in the thin film possibly being observed as the coffee stain effect resulted from the uneven dispersion of the silver nano particles. It has been found that post baking process is not beneficial in terms of enhancement of the conductivity of such composite thin films.