Surface Enhanced Raman Spectroscopy Assisted With Photonic Crystal

Raman-scattered photons from a molecule can directly reveal the signature of vibrational energy states of the molecule and their intensities can be greatly enhanced by plasmon of metal nanostructures or surfaces, which leads... [ view full abstract ]

Raman-scattered photons from a molecule can directly reveal the signature of vibrational energy states of the molecule and their intensities can be greatly enhanced by plasmon of metal nanostructures or surfaces, which leads to high sensitivity. Therefore, surface enhanced Raman spectroscopy (SERS) attracts more and more attentions in bioanalysis recently. The probability of spontaneous Raman scattering is directly proportionally to the photon density of state (DOS) at related frequency. Therefore, structures that can increase DOS are desired in SERS applications. Photonic crystal (PC), which has periodic nanostructures relevant to the length of light, has photonic band gaps that forbidden the propagation of light in some frequency range. Therefore, PC has increased DOS at the band edge with respect to homogenous medium and provides a good candidate medium for the boost of light and plasmonic materials interactions. In this paper, I would like to discuss factors that affect SERS signals in the transducing process of biosensors and introduce our methods to boost SERS signals by combining self-assembled colloidal photonic crystal and plasmonic materials with respect to high sensitivity, multiplicity and simplicity. Our results showed that the micro/nano structure of photonic crystal could be used as a good platform for SERS sensors in biomedical applications like point of care testing (POCT), bacteria detection, cell analysis or multiplex bioassays.