Sol-Gel Derived Silica Structures for Enhanced Fluorescence Sensing

Lin, Sophia ;   Khine, Michelle

Efforts to improve the detection sensitivity and signal-to-noise ratios (SNRs) of low-abundance target molecules have resulted in engineered surface structures for fluorescent signal enhancement. Surfaces include metal nanostructures and nanoparticles that couple excitation and surface plasmons and photonic crystals that act as optical resonators. While these methods yield large fluorescence enhancements, such plasmon-coupled effects suffer from practical limitations including: localized near-field, heterogeneous enhancements with small areas of ?hot spots?, and enhancements which are wavelength dependent. Such practical drawbacks impede progress in translating these large enhancements into solutions for deployable robust detection needed for POC diagnostics. We overcome these problems and show the ability to use sol-gel processing to selectively pattern silica structures for enhanced fluorescence detection of biomolecules. Sol-gel-derived materials represent robust and tunable substrates suitable for biosensor applications. Integration of this low-cost method for SiO2 micro- and nanostructure fabrication has applications in point-of-care (POC) detection of infectious diseases.