Doped Sol-Gel Silica for Optical Sensing

• Main Authors: Chia-I Li, 李佳怡
• Other Authors: Lai-Kwan Chau
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/96691633163355943918

碩士 === 國立中正大學 === 化學研究所 === 88 === Sol-gel technique has been used for the immobilization of β-cyclodextrin and L-lactate dehydrogenase for optical sensing. A sol-gel-derived film doped withβ-cyclodextrin was used to construct a fiber-optic evanescent-wave fluorosensor. For the detection of riboflavin, the fluorescence enhancement by the film coated at the distal end of an optical fiber is 10.6 times than that of an unmodified optical fiber. To investigate the factors responsible for the fluorescence enhancement of the system, a series of sorption experiments were conducted. The results indicate that the enhancement is due to the accumulation of riboflavin in the sol-gel cladding and the more constrained microenvironment for riboflavin. Leaching has been found to be a problem when L-lactate dehydrogenase (L-LDH) was trapped in a sol-gel matrix. The effect of different processing parameters on the effectiveness of entrapment of L-LDH in sol-gel is reported. These factors include the aging time of sol-gel, and the concentration of buffer, NAD+ and L-LDH. According to the study, we got four better entrapment conditions. The activity of L-LDH in the four sol-gel matrixes were also estimated. By assuming a sufficiently large concentration in cofactor, the apparent Vmax was determined via Lineweaver-Burk transformation. By keeping the solution NAD+ concentration at 100 mM, Vmax values at those entrapment conditions were 2.23×10-7 ~ 3.07×10-7 M/min. The Vmax of L-LDH in solution was 4.05×10-4 M/min. The results indicate that the activity of L-LDH after entrapment is much less than that in solution. Hence sol-gel is not a suitable entrapment method for the development of reusable L-lactate optical sensor.