| Assays using fluorescent molecules have become popular tools across various life sciences disciplines because of their ability to localize and quantify relevant biomolecules such as DNA and proteins. Microarrays in particular have enabled researchers and clinicians to monitor gene expression and protein concentrations in a high-throughput fashion, providing valuable information about cellular and systemic function. Despite the proliferation of research on modifying fluorescence with optical resonances, there have been few evaluations of the practical impact of enhanced fluorescence on high-throughput biological assays such as microrarrays. This work details the application of photonic crystal (PC) surfaces as a platform for fluorescence enhancement. The enhancement properties of PCs are explored as a function of resonant wavelength, and these properties are applied to design a PC optimized to enhance fluorescence in a commercial microarray scanner. The impact of PC enhanced fluorescence on the sensitivity of a protein microarray is evaluated, demonstrating the assay detection limit is reduced by an order of magnitude for a cytokine biomarker. Finally, PCs are applied as substrates in a DNA microarray, increasing the signal-to-noise ratio by one order of magnitude and increasing the number of genes identified as differentially expressed by a factor of >2x relative to glass slides. |
