A new methodology for optical biosensing with drop-casting fabrication of sensor chips and irradiation/detection of a single laser beam†
We propose a new methodology for optical biosensing with drop-casting fabrication of sensor chips and irradiation/detection of a single laser beam. Glucose sensor chips were fabricated by simply depositing a solution, including o-phenylenediamine (oPD), glucose oxidase (GOD), and horseradish peroxidase (HRP), on a glass substrate. A sample solution was dropped on the sensor chip and the concentration was detected by measuring the reflection intensity of the laser beam focused on the chip. A surface deformation induced by the laser irradiation on the chip was observed by electron microscopy, demonstrating that this sensor chip converts the enzyme reactions into morphological changes using the assistance of the laser beam. The mechanism of the laser-induced surface deformation was investigated by testing the effect of sodium azide and fluorescence spectroscopy.