The role of pores in structure of polyethylenglycol diacrylate based‐inverse opal photonic crystal in binding protein applicable to optical biosensor

Here, the role of pores in the structure of inverse opal photonic crystals (IOPC) in binding proteins in comparison with their parent photonic crystal (PC) templates has been investigated. For this purpose, polyethyleneglycol diacrylate (PEGDA) coated with SiO2‐based PC (PEGDA/SiO2‐based PC) and PEGDA‐based IOPC were attached with fluorophore Alexa 488, which is a polyclonal secondary antibody, to investigate their fluorescence emission. Scanning electron microscopy (SEM) images showed face centered cubic (fcc) packing of the PEGDA/SiO2‐based PC. And it remained after the formation of PEGDA‐based IOPC. The presence of 3‐aminopropyl triethoxysilane (APTES) and Alexa 488 that immobilized the PEGDA‐based PC and PEGDA‐based IOPC was recognized by the appearance of bands at 850, 1175, and a dominant increase in the band at 1750 cm−1. Those were attributed to (N─H) wagging, (C─N) stretching, and (C═O) stretching vibrations, respectively. Reflectance spectra showed a blue shift of the Bragg photonic band gap of the PEGDA‐based IOPC in comparison with that of the PEGDA/SiO2‐based PC. The fluorescence images showed a significant increase in the fluorescence intensity of PEGDA‐based IOPC owing to the resonance effect. These obtained results indicated the role of pores in structure of PEGDA‐based IOPC in improvement of the attachment of Alexa 488 protein.