| Summary: | 博士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 99 === Biomedical materials with proper surface properties could provide physical support to guide cell growth. When cells attach to a biomaterial surface, they respond to three main physicochemical factors, namely topographical, chemical, and mechanical properties. In this study, three biomaterials that are generally used in biomedical applications are investigated. Surface properties associated with cell-surface interactions were assessed by creating distinct surface conditions.
In the study of biomaterial substrate, a dense poly L-lactic acid (PLLA) film fabricated using a solvent casting procedure exhibited a relatively smooth surface. A porous PLLA film fabricated using a gas forming procedure contained a variety of connected pores. For the latter, the connected wall among pores provided flat surfaces, enabling cell adhesion and the chemical structures of the porous PLLA film to remain unchanged. Nevertheless, the mechanical properties of the porous PLLA film were significantly lowered due to the porous structure. 3T3 fibroblast cells spread well and formed fibrous structures on the dense PLLA surface, which indicates that cell-surface interaction was influenced by the mechanical properties of the biomaterial substrate. Porous structures provided more pathways for cell growth.
In the study of modified surface, various self-assembled monolayers (SAMs) adsorbed on Au were prepared. The relatively ordered octadecanethiol (ODT) and dodecanethiol (DDT) molecules had an unfavorable effect on cell adhesion due to their hydrophobic characteristic. 11-mercaptoundecanoic acid (MUA) molecules provided a hydrophilic surface which significantly promoted cell adhesion. ODT/Au and DDT/Au had the same tail groups and their nano-mechanical properties were similar, both being stiffer than MUA/Au; however, the differences were too small to be a major factor in cell adhesion. The chemical properties were the main factor in cell adhesion for the modified surface.
In the study of two distinct surfaces, micro-scale Au clusters, ≒150 μm in diameter and ≒20 nm in thickness, were evaporated onto a chitosan substrate. Experimental results demonstrate that the Au clusters and their boundary area promoted cell adhesion, spreading, and growth. The nano-hardness on Au clusters and the boundary area significantly increased. Cultured fibroblast cells aggregated on the Au clusters and the boundary area, indicating that cell-surface interaction was influenced by both chemical and mechanical properties.
The results show that biomaterials with different surface characteristics have different physiochemical and mechanical properties (i.e., topographical, chemical, and mechanical properties) associated with cell-surface interaction and exactly have the efficiency and the development to influence cell adhesion and proliferation upon the specific region via proper surface property control.
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