Sep 15, 2011
Green routes deliver bright nanocrystals for bio-applications
Researchers in China have established several green routes to synthesize various high-quality II-VI semiconductor nanocrystals and their core/shell counterparts. The nanocrystals produced by the team were very stable following an overcoat of multishells and photoluminescence quantum yields (QYs) could reach as high as 80%. Emissions from the core/multi-shell nanocrystals were not susceptible to ligand loss and were stable in various physiological conditions. The further application of the as-prepared nanocrystals to detect human hepatitis B surface antigens showed the particles to be well-suited to such an immunological assay system.
As shown in the study, after the overgrowth of multi-shells on the core nanocrystals, the QYs were improved to 75–85%, and the stability was significantly enhanced. Even after the phase-transfer experiment, the QYs were still kept above 70%. Using this low-cost, "green" synthesis route, more than 10 g of high-quality core/shell nanocrystals were synthesized successfully in a large-scale reaction. The total cost savings could be as high as 50% compared with synthesis via a selenium phosphine precursor.
There is no doubt that such high-quality core/shell nanocrystals could have potential applications across a wide range of areas including bioimaging, biolabeling, LEDs, solid-state lighting and solar cells.
The team published its work in the journal Nanotechnology.
About the author
The study was conducted by researchers from the Key Laboratory for Special Functional Materials at Henan University and the Life Science Division of the Graduate School at Tsinghua University (Shenzhen). Dr Huaibin Shen and Prof. Lin Song Li at Henan University performed green routes to synthesize various high-quality II-VI semiconductor nanocrystals. Dr Hang Yuan and Prof. Lan Ma at Tsinghua University developed a biosensor system for the detection of human hepatitis B surface antigen (HBsAg) using the water-soluble core/multishell nanocrystals as a fluorescent label. Currently, the team is working to manufacture high-quality monodisperse metal chalcogenidesnanocrystals without using air-sensitive alkylphosphine and to prepare water-soluble nanocrystals from organic solvent-soluble nanocrystals, which are adapted for large-scale production of biological labeling materials, imaging reagents and biological assay kits, etc.