Layer-by-layer assembly of chitosan and platelet monoclonal antibody to improve biocompatibility and release character of PLLA coated stent.

The aim of this study is to construct a biocompatible coating of a drug-eluting stent through the incorporation of chitosan with monoclonal antibody (mAb) to a platelet glycoprotein (GP) IIIa receptor, by electrostatic layer-by-layer (LBL) adsorption of oppositely charged polyelectrolytes and proteins. The platelet maximum aggregation rate and aggregation inhibition rate tests confirm the bioactivity of mAb in different pH assembly environments. The fluorescence spectra test and confocal laser scanning microscopy observation were used to monitor the LBL assembly process of the mAb/chitosan multilayer on the surface of the aminolyzed Poly-L-lactic acid (PLLA) membrane, when using Rhodamine B isothiocyanate-labeled mAb and Fluorescein isothiocyanate-labeled chitosan. The in vitro platelet adhesion experiment demonstrated the amicable blood compatibility of the mAb/chitosan multilayer. The endothelial cell adhesion and migration test revealed that the multilayer could improve the cytocompatibility of the PLLA matrix in terms of cell attachment, proliferation, and migration. An in vitro perfusion circuit was designed to evaluate the release rates measured by a radioisotope technique with ¹²⁵I-labeled GP IIIa mAb. The different eluting curves of the mAb/chitosan-assembled stent and mAb physically absorbed stent showed the improvement of mAb's release character when using LBL self-assembly technology. Our method to prepare a biocompatible stent surface with mAb/chitosan multilayers has proved to be favorable and effective in vitro, thus justifying further evaluation to improve the biocompatibility in an animal model test.