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Surface Functionalization Construction and Protein Resistance on the Biomedical Polymer Materials

Author: ZhengZhiZuo
Tutor: WangYingJun
School: South China University of Technology
Course: Materials Science
Keywords: acrylate polyethylene terephthalate functionalization construction hydrophily protein resistance
CLC: R318.08
Type: PhD thesis
Year: 2013
Downloads: 65
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Abstract

The biomedical polymer has been widely used for body fluids and blood materials as itsgood mechanical activity and chemical stability. However, it is still limited by thenon-specific protein absorption on its surface. Therefore, in order to improve the proteinresistance of the polymer surface, we use several methods to activate the polymer surface toprostheses with excellent performance. This research should provide the basis for constructionof tissue-engineering application.Protein adsorption on the material surface is mainly due to hydrophobic effect.Hydrophobic and hydrophilic performance is the primary factor affecting the proteinadsorption for biomedical polymer materials. Foreign body reaction can be caused bynon-specific protein adsorption on surfaces. In this paper, ammonia plasma surfacemodification and active biological molecular grafting techniques have been applied to theacrylate and polyester material to introduce hydrophilic groups. The mechanism of proteinresistantance have also been researched for its widely application in clinical implant field.In this study, we first use ammonia low-temperature plasma technology to introducehydrophilic groups onto the surface of the hydrophobic acrylic and PMMA surfaces. Theresults showed that the hydrophilicity of the surface was improved most. Surface elementalcomposition analysis showed that the polar groups of-NH2or-NH3+were introduced to thesurfaces, and amination surfaces were constructed. After amination, no obvious surfacescratches and damage were found. The transmittance was not significantly reduced,essentially excellent optical properties were retained. Timeliness results showed that if thehydrophobic recovery would occure. Protein adsorption experiments showed that the proteinadsorption reduced on hydrophobic acrylic surface after amination, but increased on theaminiated PMMA surface. Grafting was further needed on PMMA materials to improveability to resist protein adsorption.Recombinant Hirudin (rH) peptide was first applied to modify the aminated PMMAsurfaces. After the integration, the contact angle of the surface increased slightly while thesurface had regular morphology. The-NH3+on the surface decreased with the increase of theN-C=O. The PMMA integrated with the hirudin had negative electricity, and the QCM resultsshowed that compared to the original surface and the plasma-treated surface, the surface withhirudin has better protein-resistant activity.After that, in order to test if the technology had widely used area, we use this plasma technology to treat the PET film, which was widely used for blood vessel prostheses. Theresults showed that the treatment could improve the hydrophilicity of the surface with nochange of the morphology. There were-NH2and-COOH on the surface after treatment. Theprotein-resistant activity of the materials could also be improved. Then, we integrate the MPConto the treated surface. The integration of the MPC could improve the hydrophilicity of thesurface by introducing the-COO-,-N-C=O and-P-OH groups. The FITC results also showedthat the MPC was constructed onto the PET surface. The MPC-graft PET surface was coveredwith molecular layer, and it had the lowest protein adsorption with the MPC concentration of10mg/ml.According to the relation of nonspecific protein resistantance of biomedical polymermaterials and cell adhesion, the functionalized surface generation model is constructed. Thebiological test results showed that the amino plasma treatment could decrease the adhesion ofthe cells, and the integration of hirudin or MPC could decrease this activity furthermore. Afterimplant into the animal eye, the plasma-treated IOL had fibrosis turbid immediately, while theoriginal IOL and the IOL with hirudin had excellent transparency after1month. Althoughthere was the cell migration to the center on the original IOL, it would not affect thetransparency. The cell experiments results showed that the long chain and the highhydrophilicity or hydrophobic were not benefit for the adhesion of cells.Finally, the surfacefunctionalization mechanism for protein resistance of biomedical polyester materialsconstruction was carried out in-depth analysis. It suggests that hydrophilic surface fornon-specific protein resistance is due to the presence of amphiphilic ion and hydration layer,which rejected the proteins also with zwitterionic electric charges. Thus the reduction ofnon-specific protein absorption caused by adverse reactions.It provides the theoretical basisfor more extensive application of biomedical materials for clinical implantation in the future.

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