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Proceedings Paper

CdTe quantum dots: aqueous phase synthesis, stability studies and protein conjugation for development of biosensors
Author(s): Vivek Borse; Mayur Sadawana; Rohit Srivastava
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Paper Abstract

Synthesis of quantum dots (QDs) in aqueous medium is advantageous as compared to the organic solvent mediated synthesis, as the aqueous synthesis is less toxic, reagent effective, easily reproducible and importantly, synthesized QDs have biological compatibility. The QDs should be aqueous in nature for use in cell imaging, drug labeling, tracking and delivery. Structural modifications are necessary to enable their use in biosensing application. In this work, mercaptopropionic acid capped cadmium telluride QDs (MPA-CdTe QDs) were synthesized by hydrothermal method and characterized by various techniques. Water and various biochemical buffers were used to study the fluorescence intensity stability of the QDs at different physicochemical conditions. QDs stored in 4° C showed excellent stability of fluorescence intensity values as compared to the samples stored at room temperature. Staphylococcal protein A (SPA) was conjugated with the QDs (SPA-QDs) and characterized using UV and fluorescence spectroscopy, zeta potential, HRTEM, FTIR, and AFM. Blue shift was observed in the fluorescence emission spectra that may be due to reduction in the surface charge as carboxyl groups on QDs were replaced by amino groups of SPA. This SPA conjugated to QDs enables binding of the C-terminal of antibodies on its surface allowing N-terminal binding site remain free to bind with antigenic biomarkers. Thus, the biosensor i.e. antibody bound on SPA-QDs would bind to the antigenic biomarkers in sample and the detection system could be developed. As QDs have better fluorescence properties than organic dyes, this biosensor will provide high sensitivity and quantitative capability in diagnostics.

Paper Details

Date Published: 19 April 2016
PDF: 12 pages
Proc. SPIE 9884, Nanophotonics VI, 988423 (19 April 2016); doi: 10.1117/12.2225262
Show Author Affiliations
Vivek Borse, Indian Institute of Technology Bombay (India)
Mayur Sadawana, Indian Institute of Technology Bombay (India)
Rohit Srivastava, Indian Institute of Technology Bombay (India)

Published in SPIE Proceedings Vol. 9884:
Nanophotonics VI
David L. Andrews; Jean-Michel Nunzi; Andreas Ostendorf, Editor(s)

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