A study o the Adsorption Mechanism of Some Globular Proteins at the Air/Liquid Interface

• Main Authors: Ping-chieh Wu, 吳秉杰
• Other Authors: Ruey-Yug Tsay
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/38060487919254900499

碩士 === 國立陽明大學 === 醫學工程研究所 === 87 === Abstract The bio/hemocompatibility of a biomaterial is the most important thing to be considered in developing biomaterials. After implanted or be contacted with blood, The adsorption behavior of proteins is a crucial factor in determining the bio/hemocompatibility of a biomaterial. It is believed that the bio/hemocompatibility of a material will be affected by the amount of the protein adsorbed, kinds of the protein adsorbed and the conformational change of the protein at the interface. The conformational change of protein at interface often accompanies the loss of protein activity therefore it is important not only to know the amount but also the state of the protein adsorbed. Previous studies indicated that protein adsorption at air-liquid interface can be well described by a two-step model, i.e. first adsorbed quickly and reversibly onto the interface and then go through a conformational change slowly. According to this adsorption model, it suggests that although judging from the amount of protein adsorbed, it seems that l the process has reached its equilibrium state, however, a slow change in the states of its interfacial will still lead to a continuous increase in surface pressure. In this research, the adsorption behavior of lysozyme and human serum albumin has been studied. In order to delineate the dynamic adsorption behavior and the state of protein adsorbed at interface, long term dynamic surface pressure of protein adsorptions and short term compression isotherm were monitored. The results show that the adsorption behaviors of these two proteins are very similar; i.e., at constant bulk concentration, their dynamic adsorption curves both showed a two-step increase pattern. Also, the adsorption isotherm based on the pseudo steady state surface pressure both showed phase transition behavior. Using fluorescence microscopy to directly visualize the microdomain appeared in the adsorption process in-situ for different bulk concentrations and together with our dynamic surface pressure measurement, it is believed that those transition regions appeared in the adsorption isotherm curve corresponds to a surface molecule rearrangement and while the second—stage increasing on surface pressure appeared in a dynamic adsorption curve should be due to the conformational change of protein molecule at the air-water interface.