$\pi$-A Characteristics and Deposition Status of Biological Lipid Layers

생체 지질막의 $\pi$-A 특성 및 누적 상태

In this paper, we investigate $\pi$-A isotherms of biological lipid layer such as cholesterol and phosphatidyl choline to study a gas sensor characteristics which response only to specific materials. And, we also deposit it on the surface of quartz crystal by vertical dipping method and horizontal lifting method. Then, we evaluate the deposition status of cholesterol and phosphatidyl choline LB film using AT-cut quartz crystal. We obtain the following results: (1) Cholesterol's solid surface pressure is about 20$\sim$40(dyne/cm) and limiting area is about 50${\AA}^2$/molecule. And, phosphatidyl choline's surface pressure is about 25$\sim$40(dyne/cm) and limiting area is about 20 ${\AA}^2$/molecule. (2) When LB films are deposited, the deposition ratio is coincident with the frequency shift. Therefore, we can evaluate the deposition status of LB film. (3) For cholesterol, Y type LB films are deposited up to 15 layers by vertical dipping method. (4) For phosphatidyl choline, X typo LB films are deposited to 15 layers by horizontal lifting method. But, in case of vertical dipping method, the deposition status is not good.