Biomedical subjects

Yabin Zhu

Publications and source records attributed to Yabin Zhu.

6 recordsLinked to original sources

PubMed2004

Endothelium regeneration on luminal surface of polyurethane vascular scaffold modified with diamine and covalently grafted with gelatin.

Using the recently developed surface modification technique, free amino groups have been introduced onto polyester-type polyurethane (PU) scaffolds. The introduction of these free amino groups increases the surface energy and provides a convenient way to further immobilize bioactive species such as gelatin, collagen or chitosan, etc. on the scaffold surface by employing glutaraldehyde as a coupling agent. These modifications are advantageous to enhance cell-material interaction. The culture of human umbilical vein endothelial cells (HUVECs) in vitro proved that the cell proliferation ratio of both the aminolyzed and the biomacromolecules-immobilized PU membranes was improved greatly comparing with the control PU. Scanning electron microscopy and confocal laser scanning microscopy observations displayed that the gelatin-immobilized PU vascular scaffold had formed a monolayer of endothelial intima on its luminal surface after HUVECs were cultured for 6 d. Therefore, the aminolysis and the following biomacromolecule immobilization is a promising way to enhance the cell-PU interaction that can accelerate the endothelium regeneration, which is crucial for blood vessel tissue engineering.

Biocompatible Materials↗

PubMed2003

Engineering porous polyurethane scaffolds by photografting polymerization of methacrylic acid for improved endothelial cell compatibility.

Using a preadsorbing-monomer method, polyurethane (PU) porous scaffolds were modified by grafting polymerization of methacrylic acid (MAA) initiated under UV light. Fourier transform infrared-attenuated total reflection spectroscopy and X-ray photoelectron spectroscopy characterizations confirmed the occurrence of the grafting polymerization of poly(methacrylic acid) (PMAA) on PU scaffolds and the measurement of water adsorption also demonstrated enhanced hydrophilicity. The PMAA grafting degree correlated to the amount of MAA adsorbed, the pore average diameter, and the porosity. It was verified that the higher porosity the scaffold has, the larger porous area (or the larger contact area with MAA) it has, and therefore the higher amount of MAA adsorbed and higher grafting degree obtained. The results of human endothelial cells cultured in vitro showed that the PU scaffolds modified with the hydrophilic PMAA had more improved cell compatibility than the control matrix.

Cell Adhesion↗

PubMed2003

[Polymeric materials for tissue engineering].

As regeneration scaffolds or templates in tissue engineering, polymeric materials play key roles in inducing tissue regeneration, and mediating cell growth and differentiation, i.e. functioning as artificial extracellular matrix. The polymeric materials including biological derived biopolymers and synthetic polymers, which are usually employed in tissue engineering, are reviewed in this paper.

Biocompatible Materials↗

PubMed2002

Surface modification of polycaprolactone with poly(methacrylic acid) and gelatin covalent immobilization for promoting its cytocompatibility.

Polycaprolactone (PCL) membrane was modified by grafting copolymerization of methacrylic acid (MAA) initiated under UV light. The covalent immobilization of gelatin on PCL-g-PMAA surface was consequently performed by using condensing agent, 1-ethyl-3-(3-dimethylamino propyl) carbodiimide hydrochloride. The occurrence of grafting copolymerization of PMAA and further immobilization of gelatin was confirmed by ATR-FTIR and X-ray photoelectron spectroscopy characterizations. The existence of carboxyl groups grafted on PCL surface was verified quantitatively by absorbance spectroscopy where rhodamine 6G was employed to react with carboxyl groups to generate an absorbance at 512 nm. The endothelial cell culture proved that the PCL membrane slightly modified with suitable amount of PMAA or gelatin had better cytocompatibility than control PCL or PCL membrane heavily modified with PMAA or gelatin.

Biocompatible Materials↗

PubMedDate not supplied

Surface modification of polycaprolactone membrane via aminolysis and biomacromolecule immobilization for promoting cytocompatibility of human endothelial cells.

Amino groups were covalently introduced onto a polycaprolactone (PCL) surface by the reaction between 1,6-hexanediamine and the ester groups of PCL. The occurrence of the aminolysis and the introduction of free NH(2) groups were verified qualitatively by fluorescence spectroscopy, where rhodamine B isothiocyanate was employed to label NH(2) groups, and quantitatively by absorbance spectroscopy, where ninhydrin was used to react with NH(2) to generate a blue product. Due to the presence of deep pores on the PCL membrane, the aminolysis reaction could penetrate as deep as 50 microm to yield NH(2) density as high as 2 x 10(-7) mol/cm(2). By use of the NH(2) groups as active sites, biocompatible macromolecules such as gelatin, chitosan, or collagen were further immobilized on the aminolyzed PCL membrane via a cross-linking agent, glutaraldehyde. X-ray photoelectron spectroscopy (XPS) and surface wettability measurements confirmed the coupling of the biomacromolecules. The endothelial cell culture proved that the cytocompatibility of the aminolyzed PCL was improved slightly regardless of the NH(2) amount on the surface. After immobilization of the biomacromolecules, however, the cell attachment and proliferation ratios were obviously improved and the cells showed a similar morphology to those on tissue culture polystyrene. Measurement of the von Willebrand factor (vWF) secreted by these endothelial cells (ECs) verified the endothelial function. Hence, a better EC-compatible PCL was produced.

Amination↗

PubMedDate not supplied

Layer-by-layer assembly to modify poly(l-lactic acid) surface toward improving its cytocompatibility to human endothelial cells.

A novel technique to introduce free amino groups onto polyester scaffolds via aminolyzing the ester groups with diamine has been developed recently. Positively charged chitosan was then deposited onto the aminolyzed poly(l-lactic acid) (PLLA) membrane surface in a layer-by-layer assembly manner using poly(styrene sulfonate, sodium salt) (PSS) as a negatively charged polyelectrolyte. The layer-by-layer deposition process of PSS and chitosan was monitored by UV-vis absorbance spectroscopy, energy transfer by fluorescence spectroscopy, and advancing contact angle measurements. The existed chitosan obviously improved the cytocompatibility of PLLA to human endothelial cells. The cell attachment, activity, and proliferation on the PLLA membranes assembled with three or five bilayers of PSS/chitosan with chitosan as the outermost layer were better than those with one bilayer of PSS/chitosan or the control PLLA. The cells also showed morphology of an elongated shape with abundant cytoplasm, and a confluent cell layer was reached after being cultured for 4 days. Measurement of von Willebrand factor secreted by these endothelial cells (ECs) verified the endothelial function. Hence, better ECs compatible PLLA were produced.

Cells, Cultured↗