Photonic Crystal Surfaces as a General Purpose Platform for Label-Free and Fluorescent Assays

Photonic crystal (PC) surfaces can be designed to provide a wide range of functions that are used to perform biochemical and cell-based assays. Detection of the optical resonant reflections from PC surfaces enables high sensitivity label-free biosensing, whereas the enhanced electromagnetic (EM) fields that occur at resonant wavelengths can be used to enhance the detection sensitivity of any surface-based fluorescence assay. Fabrication of PCs from inexpensive plastic materials over large surface areas enables them to be incorporated into standard formats that include microplates, microarrays, and microfluidic channels. This report reviews the design of PC biosensors, their associated detection instrumentation, and biological applications. Applications including high-throughput screening of small molecules, cell membrane integrin activation, gene expression analysis, and protein biomarker detection are highlighted. Recent results in which PC surfaces are used for enhancing the detection of surface-enhanced Raman spectroscopy, and the development of high-resolution PC-based laser biosensors are also described.