| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 87 === A stable connection between the biomaterial surface and the surrounding tissue is an important factor determining the biocompatibility of biomaterials. Besides, serum is an essential ingredient of cell culture medium. The surface properties of materials influence the adsorption of serum components, and thus affect the cell adhesion and proliferation on these surfaces. In this study, the surface roughness and wettability of materials were varied by chemical treatment or coating with substances. The amounts of serum proteins adsorbed onto these surfaces were measured by FITC-labeled biomolecules. Additionally, Chinese hamster ovary (CHO) cells and bovine aortic endothelial cells (BAEC) were cultured on these surfaces to investigate how surface properties influence serum protein adsorption and cell proliferation.
As results indicated, the adsorption of albumin in the serum increased as the material surface roughness increased. The amounts of albumin adsorbed were about 300 ng/cm2 on rough surfaces, and about 100 ng/cm2 on smooth ones. On the surfaces with different wettabilities, it was found that decreasing wettability resulted in elevated adsorption of albumin. The amounts of albumin adsorbed were up to 650 ng/cm2 on more hydrophobic surface (SI). Besides, the adsorption of albumin on collagen surfaces sterilized by UV or ethanol treatment was significant, and the adsorption density was about 500 ng/cm2. On the surfaces of PGA and PLA, the albumin adsorbed were both about 200 ng/cm2. The experiment of protein adsorption indicated that the presence of albumin reduced the amounts of adsorbed fibronectin.
The cell culture studies revealed that the proliferation of both CHO cells and BAEC was decreased as the surface roughness increased. As aforementioned, rough surfaces would enhance the adsorption of albumin. The existence of albumin on the surfaces would impede cell adhesion, and thus inhibit cell proliferation. The surface wettability, however, had different effects on CHO cells and BAEC. The proliferation of CHO cells was enhanced by increasing the surface wettability (decreasing contact angle), but an optimal wettability (contact angle: 55-60°) was found in BAEC culture. In general, cell proliferation on hydrophilic surfaces was better than hydrophobic ones, possibly due to less adsorption of albumin on hydrophilic surfaces. Comparing several biomaterials, collagen sterilized by UV was more suitable for cell proliferation than that sterilized by ethanol. In addition, cell proliferation on PLA was better than that on PGA, since PLA had a less rough surface with lower adsorption of albumin. In summary, this study demonstrated that surface roughness and wettability influenced the adsorption of serum proteins, and thus modulated cell proliferation.
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