Abstract
The sol-gel-derived materials have recently become more attractive to immobilize biomolecules on the matrixes for biosensing application. In addition, array-based biosensor is a cutting-edge technology for the development for multi-analyte determination. However, titanium sol-gel material receives less attention on the immobilization as well as the biosensing application due to the high reactivity of the precursor. In this study, a simple vapor deposition method was developed to simultaneously immobilize urease, glucose dehydrogenase, and glutamate dehydrogenase on the glass matrix for the determination of urea, glucose and glutamate. Deposition time and temperature were optimized to control the transparency of TiO2 matrix which is suitable for optical detection. Results of SEM and AFM images showed that the doped enzymes into titania sol-gel film significantly changed the surface morphology. Urea, glucose, and glutamate could be efficiently detected by using urease-, GDH-, and GTDH-encapsulated array biosensors, and the detection limit was 20 □M for urea (RSD=2.8%), 50 □M for glucose (RSD=1.6%) and 78 □M for glutamate (RSD=4.3%). The array-based biosensors showed good analytical performance with dynamic range of 2-3 orders of magnitude. In addition, the responses of urea, glucose and glutamate to the array biosensors in real sample also showed well performances; the dynamic ranges were 1-100 □M, 40-10000 □M, and 80-10000 □M for urea, glucose, and glutamate, respectively. Also, the array biosensor showed a high relative enzyme activity and precise detection after 1-month storage. Furthermore, the shrinkage and crack of the TiO2 sol-gel matrix using vapor deposition method can be neglected. Results obtained in this study clearly demonstrate that this simple vapor deposition method can be successfully to form transparent titania sol-gel film for the fabrication of array-based biosensors that is suitable for optical detection of urea, glucose and glutamate for biomedical applications.