Nanosensors for Detection of Biological Threat Contaminants in Critical Buildings

A nanoscale sensing modality for detection of bacterial contaminants was developed. The modality uses fluorescent nanoparticles, also known as “Quantum dots” (QDs) conjugated to fragmented antibodies of targeted contaminants, and a quenching dye that labels an antigen surrogate. Coupling of the QD-labeled fragmented antibody and the quencher-labeled antigen allows sufficient fluorescent resonance energy transfer (FRET) to quench QD emissions. The subsequent addition of the targeted antigen displaces the dye-labeled bacteria, eliminating FRET and resulting in a concentrationdependent increase in QD photoluminescence. The novelty of this procedure lies in the applications for detection of a broad range of biological contaminants including viral and bacterial contaminants with a high degree of specificity and sensitivity. Furthermore, through the use of QDs of varying emission wavelengths the system can easily be adapted into a multiplexing immuno-assay