Development of ion sensitive field effect transistor for urinary microalbumin detection by silanization

For the first time, ISFET surface is modified using silanization on layer for Anti-HSA immobilization using 3-aminopropyltriethoxysilane (APTES) to obtain an amino layer on each surface. And incorporation with glutaraldehyde(GA) to obtain aldehyde layer of APTES-GA modified surfaces. The wetting properties, chemical bonding composition, are determined by contact angle(CA) measurement, the CA values decreased from non-functionalization, to silanization and cross link GA of 65.26 ± 0.11° to 85.54 ± 0.32 and 95.26 ± 0.67°. The binding ability to albumin shows the response range between 0-500 μg/ml and gave the gate potential change of 1 ± 0, 4 ± 0.58, 6 ± 0, 7 ± 1.12 and 10.33 ± 0.58 mV, respectively. This study provides an advantages of ion sensitive field effect transistor(ISFET) based biosensor for detect albumin in microgram range.