Multisize CdSe nanocrystal/polymer nanocomposites for selective vapor detection identified from high-throughput screening experimentation.

We have implemented high-throughput spectroscopic screening tools for the investigation of vapor-selectivity of CdSe semiconductor nanocrystals of different size (2.8- and 5.6-nm diameter) upon their incorporation in a library of rationally selected polymeric matrices. This library of resulting sensing materials was exposed to polar and nonpolar vapors in air. Each of the sensing materials demonstrated its own photoluminescence vapor-response patterns. Two criteria for the evaluation of vapor responses of the library of sensing materials included the diversity and the magnitude of sensing responses. We have found several polymer matrices that simultaneously meet these criteria. Our new sensing materials based on polymer-embedded semiconductor nanocrystal reagents of different size promise to overcome photobleaching and short shelf life limitations of traditional fluorescent organic reagent-based sensing materials.

Improved specific biodetection with ion trap mobility spectrometry (ITMS): a 10-min, multiplexed, immunomagnetic ELISA.

Enabling trace chemical detection equipment utilized in the field to transduce a biodetection assay would be advantageous from a logistics, training, and maintenance standpoint. Described herein is an assay design that uses an unmodified, commercial off-the-shelf (COTS) ion trap mobility spectrometer to analyze an immunomagnetic enzyme-linked immunosorbant assay (ELISA). The assay, which uses undetectable enzymatic substrates and ELISA-generated detectable products, was optimized to quantitatively report the amount of target in the sample. Optimization of this ELISA design retained the assay specificity and detection limit (approximately 10(3) E. coli per assay) while decreasing the number of user steps and reducing the assay time to 10 min (>9-fold decrease as compared to past studies). Also discussed are previously undescribed, independent substrate/enzyme/product combinations used in the immunomagnetic ELISA. These discoveries allow for the possibility of a quantitative, multiplexed, 10-min assay that is analyzed by the ion trap mobility spectrometer trace chemical detector.