Abstract
Optical techniques have received significant attention for label-free biosensing. Technologies including surface plasmon resonance (SPR) and interference spectroscopy have been employed in label-free biosensors. SPR have advanced label-free biosensing significantly; however, its instrumental setup is expensive and complicated. In order to overcome the problems associated with the SPR systems, interference biosensors based on optically flat porous silicon thin films were developed. The advantages of using porous silicon include its easy fabrication and compatibility with conventional silicon microfabrication. However, porous silicon absorbs visible light strongly, and the strong optical absorption limits the sensitivity of the porous silicon interference biosensors. A photonic band-gap nanosensor based on porous silica is proposed in the study. The photonic band-gap silica nanosensor is easy to fabricate and simple to use. Its optical characteristics can be easily modulated by electrochemical etching and its large internal surface area can be easily modified by different types of biomolecules. The photonic band-gap silica nanosensor can provide inexpensive, real time, simple to use and high-throughput assays for biomolecular reactions. The advantages of low cost, high sensitivity and versatile use in the photonic band-gap silica nanosensor make it surpass SPR and porous silicon interference biosensors.