Plasma Protein Adsorption And Platelet And Leukocyte Adhesion On PBT Flat Membrane With Different Functional Groups

Background The study of protein-surface interaction represents one of the most important topics in the field of biomaterials, because of its correlation to biocompatibility. When the surface of the materials comes in contact with a fluid that contains soluble proteins (e.g. blood, interstitial fluid), proteins rapidly adsorb onto the surface of the materials first, and then living cells approach. Therefore, cells contact and interact with the molecular structure of protein layer rather than contact the material surface itself actually. Thus, to a certain extent, adjusting protein layer on biomaterial surface can regulate the specificity interaction between cell and protein and the rest of a series signal of transduction in cells to decide cell’s biological response. And it becomes an important research direction that controlling the mounts and the types of proteins adsorbed and their orientation, conformation, and packing arrangement on the biomaterial surface to control cell biological response.Objective Prepare PBT flat membrane with different functional groups (-CH3,-COOH,-OH, amphoteric groups), and make a preliminary study on the adsorption of plasma protein, and the adhesion of leukocytes and platelets.Methods (1) Different monomers were grafted onto the surface of PBT by UV to obtain PBT-AA(-COOH), PBT-HEMA(-OH), PBT-SMDB(amphoteric groups) and their characterization.(2) The adsorbing capacity of four kinds of materials for human serum Albumin(HSA) and fibrinogen(Fgn)was investigated by ELISA method. And it was measured whether the grafting rate has influence on protein content.(3)The adhesion of leukocyte and platelet was measured by SEM.(4) The interactions between proteins and material surfaces were characterized by atomic force microscopy (AFM).Results (1) Hydrophilic ranking for four materials:PBT-HEMA> PBT-SMDB> PBT-AA> PBT.(2) PBT-AA adsorption capacity of HSA was much higher than the other three (p<0.05); PBT and PBT-AA adsorption capacity of Fgn was higher than PBT-HEMA and PBT-SMDB (p<0.05).(3) Four kinds of materials adhesion of leukocyte and platelet changed significantly before and after protein adsorption. Two kinds of cells significantly increased after adsorption of Fgn, while leukocytes reduced after adsorption of HSA.(4) Fgn only had special adsorption for PBT; HSA had non-special adsorption for four kinds of materials.Conclusion HSA had non-special adsorption for four kinds of materials. while the Fgn adsorption may be tend to adsorbed on hydrophobic surface. Fgn promoted the adhesion of both leukocyte (WBC) and platelet (PLT); while HSA had a certain inhibiting on leukocyte adhesion. The influence of HSA on blood cells may be mainly determined by its conformation adsorbed on surface rather than the adsorption quantity.