基于金纳米颗粒生长的液晶生物传感器检测酪氨酸

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

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AuCl-4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6×10-7mol/L.

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 method,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 appearances 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- 7mol / L. Furthermore,this study offers a simple,high-specific and label-free method with naked eye for Tyr.