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.

Detection platform

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.