基于金纳米颗粒生长的液晶生物传感器检测酪氨酸

基于酶介导金纳米颗粒(AuNPs)生长构建了液晶生物传感器, 并用于检测酪氨酸(Tyr). 将酪氨酸酶(TR)固定于经戊二醛活化的二甲基十八烷基(3-三甲氧基硅烷] 丙基)氯化铵/3-氨丙基三乙氧基硅烷(DMOAP/APTES)混合自组装修饰的玻片表面, 当向玻片表面滴加含Tyr的生长溶液时, TR催化Tyr羟基化为左旋多巴(L-Dopa), L-Dopa还原生长溶液中的AuCl₄^-生成AuNPs并沉积于玻片表面, 导致玻片表面地貌发生变化, 这一变化能诱导液晶取向发生变化进而调控透光量, 从而实现对Tyr的检测, 且检测浓度可低至6×10^-7 mol/L.

Liquid Crystal Biosensor Based on Growth of Gold Nanoparticles for Detection of Tyrosine

A new-style liquid crystal(LC) biosensor based on enzymatic growth of gold nanoparticles(AuNPs) was developed for detection of tyrosine(Tyr). Tyrosinase(TR) was immobilized on the glass slides modified with APTES/DMOAP mixed self-assembled monolayers(SAM) and activated by glutaraldehyde, which, afterwards, were immersed in a growth solution containing different concentrations of Tyr. In this me-thod, TR stimulated the biocatalyzed hydroxylation of Tyr to L-Dopa which could reduce Au³⁺ in the growth solution into AuNPs. The formation of AuNPs could greatly change the surface topology and induce a homeotropic-to-tiled transition of the LC molecules, resulting in significant change in corresponding of optical appea-rances under the crossed polarized light. The results showed that the presented LC biosensor can highly sensitive to Tyr with a limit of detection of 6×10^-7 mol/L. Furthermore, this study offers a simple, high-specific and label-free method with naked eye for Tyr.