Ultrasensitive Label- and PCR-Free Genome Detection Based on Cooperative Hybridization of Silicon Nanowires Optical Biosensors.

The realization of an innovative label- and PCR-free silicon nanowires (NWs) optical biosensor for direct genome detection is demonstrated. The system is based on the cooperative hybridization to selectively capture DNA and on the optical emission of quantum confined carriers in Si NWs whose quenching is used as detection mechanism. The Si NWs platform was tested with Hepatitis B virus (HBV) complete genome and it was able to reach a Limit of Detection (LoD) of 2 copies/reaction for the synthetic genome and 20 copies/reaction for the genome extracted from human blood. These results are even better than those obtained with the gold standard real-time PCR method in the genome analysis. The Si NWs sensor showed high sensitivity and specificity, easy detection method, and low manufacturing cost fully compatible with standard silicon process technology. All these points are key factors for the future development of a new class of genetic point-of-care devices that are reliable, fast, low cost, and easy to use for self-testing including in the developing countries.