Quantum dots sniff out bug
doi:10.1038/nindia.2011.20 Published online 10 February 2011
Researchers have designed a new biosensor that uses fluorescent quantum dots to detect the presence of bacteria in biological samples, providing an inexpensive way of screening for multiple diseases.
Conventional methods of bacterial detection and identification require high cell densities and are usually time-consuming and laborious. There is a need for sensitive and low-cost sensors that can rapidly detect bacteria in a wide variety of samples.
To devise a cost-effective and simple sensor, the researchers developed a chip comprising microfluidic channels made from copper wires and poly(dimethyl siloxane) (PDMS). They placed anti-E. coli antibodies tagged with fluorescent cadmium telluride quantum dots into the microchannels, and then allowed E. coli to flow through the channels.
Microchannels having captured E. coli exhibited strong fluorescence due to the quantum-dot-tagged antibodies.
This technique is a flexible and simple procedure for fabricating a range of multistack, three-dimensional circular microchannels of various dimensions and geometries. A circular geometry avoids problems associated with trapped bubbles, which can affect flows.
"The study opens up many possibilities for using microchannels in pathogen detection and bioimaging, leading to useful lab-on-a-chip diagnostics suitable for use in developing countries," says lead researcher Dhananjay Bodas.
The authors of this work are from: Center for Nanobioscience, Agharkar Research Institute, Center for Sensor Studies, University of Pune, and Physical and Materials Chemistry Division, National Chemical Laboratory, Pune, India and Center for Materials for Information Technology, University of Alabama, Tuscaloosa, USA.