Jan 12, 2009
QDs make DNA detection faster and simpler
The Nanobioelectronics and Biosensors Group at the Catalan Institute of Nanotechnology (CIN2, ICN-CSIC) in Bellaterra (Barcelona), Spain, is working on the design of low-cost, user-friendly and efficient nanomaterial-based electrochemical sensors and biosensors. Easy to operate, these devices can be used by non-specialists to perform fast diagnostic functions at home or in the doctor's office. Other uses include the control of food quality and security applications.
Arben Merkoçi and his team have developed a novel quantum dot-based genomagnetic sensor for fast and low-cost detection of DNA strands. The system employs the advantage of an efficient magnetic separation/mixing process and the use of cadmium sulphide (CdS) quantum-dot tracers for DNA detection. It combines the magnetic isolation of a DNA hybridization sandwich with the efficient, direct and sensitive electrochemical detection of electroactive quantum dots.
The assay employs paramagnetic microparticles modified with streptavidin and linked through a sandwich hybridized DNA target and probes, and features the use of CdS quantum dots as electrochemical tags. The detection method is simple. It is based on the use of screen-printed electrodes as a detection platform and a hand-held potentiostatic device as a measuring system. Detection is based on the stripping of electrochemical reduced cadmium at hybridization solution using square wave voltammetry.
The proposed method allows for the simultaneous detection of several DNA strands modified with various quantum dots. Moreover, it permits the direct detection of DNA strands onto the surface of the electrode rather than the previous method based on dissolving quantum dots. In addition, there is a possibility of applying the same detection methodology to an array composed of several electrodes and using the same quantum dot, but allowing for the simultaneous and independent detection of each tag connected with the corresponding DNA target.
The team hopes that its nanoparticle biosensing system will open the way for the clinical analysis of genetic-related illnesses in addition to several other applications.
About the author
Prof. Arben Merkoçi, is director of the Nanobioelectronics and Biosensors Group at CIN2(ICN-CSIC), in Bellaterra, Spain. He did his PhD at Tirana University and afterwards several postdoctoral researches at labs in the EU and US. This work is done by his team composed of several postdoctoral fellows, PhD students and a technician. Most of the work in the published article is part of Marin's PhD thesis, which is to be presented soon. For more information on the group visit their website.