Photonic crystals are fabricated on plastic surfaces, producing narrow bandwidth resonances at any desired wavelength. While shifts in the resonant wavelength quantify the density of adsorbed biomaterial, the resonances also enhance the output of adsorbed fluorophores. The combined attributes of photonic crystals enable highly sensitive label-free detection and greatly amplified sensitivity of any fluorescence-based assay for applications in life science research, drug discovery, and environmental pathogen detection. Applications for label-free selective detection of viral pathogens with sensitivity of ∼30 focal forming units, and detection of spore pathogens with single-unit resolution are highlighted. Amplified fluorescence, meanwhile, enables gene expression detection of DNA at concentrations ∼2 orders of magnitude lower than detection on optically passive surfaces.