A RFID Tag Based Remote DNA sensing System

Different from traditional detection methods including polymerase chain reaction (PCR) based assays and enzyme-linked immunosorbent assays (ELISA) which are expensive and time consuming for biochemical analysis, in our study, a DNA chip assay using gold nanoparticle (AuNP) immunological amplification method and RFID communication platform were applied to detect DNA sequences rapidly and conveniently. First the capture DNA (cDNA) was immobilized to the substrate on which the capacitor locates. Then the target DNA (tDNA) and probe DNA (pDNA) with a AuNP at the 3´ end were added to form several layers of AuNP linked structures. Since the permittivity of the medium in which the capacitor is located changed due to the AuNP-linking structures between the gaps of the microcapacitor, the resonant frequency of series LC circuit shifted immediately. The lab-on-a-chip proposed in this study was power supplied by the radiofrequency identification (RFID) system. The shift of the LC resonant frequency determined whether the tDNA existed. Thus the detection chip needed no any other internal power supply or expensive instruments for electrical signal measurement. The study provides a simple, fast and convenient platform for biochemical detection