Specific Detection of Antibiotics by Silicon-on-Chip Photonic Crystal Biosensor Arrays

Photonic crystal (PC) microcavities formed by 2-D air holes on silicon-on-insulator substrates were utilized as biosensors to detect antibiotics with high specificity. The antibiotic, gentamicin, with molecular weight of only 478 g/mol, was successfully detected via its binding to corresponding antibody pre-immobilized on the sensor surface. Detection range (in concentration) was extended by combining different types of PC biosensors on a single silicon chip, covering from 0.1 nM to 1 mu M. Specificity of detection was also verified on the studied antibiotic.