SBIR Phase I: Development of Cadmium-Free, Water-Soluble and Multicolor Quantum Dots by Chemical Doping

This Small Business Innovation Research Phase I project will synthesize cadmium-free, water-soluble, and multicolor quantum dots (QDs) by chemical doping, which can be used as fluorophores in the fields of biology and biomedicine. As the popularity of QD labeling soars, concerns are raised on the inherent toxicity of current widely used cadmium-based QDs. The easiness in tuning different emission colors has been a big advantage of cadmium-based QDs. However, for biomedical applications, the different particle sizes of QDs could influence their mobility in cells and tissues, and thus may reduce the diagnostic accuracy and sensitivity in multianalyte studies. This NSF SBIR Phase I program will synthesize cadmium free, water-soluble, and multicolor quantum dots (QDs) by chemical doping. The doped core/shell QDs will be synthesized first and then converted to water-soluble and biocompatible through proprietary methods for biomedical applications. In Phase I, this project will develop the techniques for the synthesis of proposed QDs and Phase II will scale up the synthesis for massive production. Commercially, QDs are considered as a new class of fluorescent probes with a broad range of applications including single molecule biophysics, biomolecular profiling, optical barcoding, and in vivo imaging. In comparison with organic dyes and fluorescent proteins, QDs have unique optical and electronic properties including size-tunable light emission, improved signal brightness, resistance against photobleaching, and simultaneous excitation of multiple fluorescence colors. Despite the fast growing need for biocompatible nanocrystals by biotech as well as academia, to date, only two other companies have launched commercial products in the markets. However, all their products are cadmium based and extremely expensive. Successful development of proposed techniques will result in a new generation of biolabels and make significant advances in the biomedical applications of QDs.