Study Of Protein Adsorption Behavior On Materals Surfaces Based On Quartz Crystal Microbalance Technology

As known,the biocompatibility of materials plays an important role in biomaterial and tissue engineering.It is generally accepted that biomaterials immediately and spontaneously acquire a layer of host proteins in the very early process of implantation,prior to interacting with host cells.Consequently,the types, levels,conformations,and orientations of the adsorbed proteins,which depend on the chemical,physical,and morphological characteristics of the biomaterial surface,may modulate the host cells reactions.In a word,the biocompatibility of biomaterials is direct influenced by the protein adsorption behavior on its surface,however,the mechanism of interaction between proteins and materials is not clear now.In the cross sectional studies,the surface topography,hydrophobicity,hydrated process and protein adsorption behavior of poly(lactic acid)(PLA),polycarbonate (PCL),polymethylmethacrylate,chitosan and alginate were investigated with the QCM-D(quartz crystal microbalance) and AFM(atomic force microscopy) techniques.In the longitudinal research,the protein adsorption behaviors on PLA, influenced by factors such as concentrations,types and velocity of flow of protein, were also studied.In addition,a quantitative way has been introduced to study the binary competitive protein adorption system between BSA and fibrinogen.Finally,we investigated the protein adsorption of BSA on chitosan/PCL blend films with microphase separation structure.The cross sectional study reveals:for the natural polysaccharides,the hydration process of calcium alginate was faster to reach higher hydrature than that of chitosan,which could effect the protein adsorption behavior on their sufaces.The protein adsorption mass on calcium alginate was less than that on chitosan.The result, however,was opposite to the desorption.Besides,the viscoelastic properties decreased after desorption,and the adsorption curve indicated that the adsorption rate constant of calcium alginate was bigger than that of chitosan;For the synthetic macromolecules,with the increasinghydrophobicity of films,the adsorbed protein amount increased while the viscoelastic property of adsorbed protein layer decreased, and adsorption rate constant increased with the increasing hydrophobicity of films. We also found that protein molecules spread with the adsorbing time on different surfaces.The change rate of viscoelastic properties of the film was also investigated by a quantitative way.The longitudinal study reveals:the isothermal adsorption curve fitted for the Langmuir model in a low concentration but deviated in a high concentration,owing to the change of arrangement mode of BSA.The adsorption of three different proteins (bovine serum albumin(BSA),fibrinogen and collagen-â… ) showed that protein characteristics could greatly affect the adsorption kinetics,structure and viscoelastic properties of adsorbed protein layers.Compared with BSA,collagen-â… trended to form a loose,dissipative layer and had a slower adsorption rate and larger adsorption reversibility,which was consistent with the AFM observation.Fibrinogen trended to form a dense,rigid layer and had a fastest adsorption rate and smallest adsorption reversibility because of its complete denaturation observed by AFM;the amino groups on the surface of aminolyzed PLA improved its hydrophilicity.It was found that larger adsorbed amount,lower protein denaturation,lower adsorption rate and smaller reversibility on the surface of aminolyzed PLA compared with the surface of pure PLA.The binary competitive protein adorption system study reveals:fibrinogen made up 78.8%in the adsorbed protein layer after adding a mixture solusion of fibrinogen and BSA(mass ratio=1:1).The data showed that protein competition adsorption existed between fibrinogen and BSA.The study of the micromorphology of chitosan/PCL blend films reveals:The results suggested that compared with other chitosan/PCL blend films,BSA absorbed on the 25 wt%chitosan/PCL blend film(with microphase separation structure) showed larger adsorption reversibility,and preferred to form a loose,dissipative layer.