PNA IMMOBILIZED ON PAPER FOR DNA DETECTION

Abstract

In the past few years, DNA sensors based on immobilized DNA oligonucleotides have become an essential tool in DNA analysis. However, sensitivity and selectivity were still problematic in many applications. One efficient way to improve the performance of DNA sensors was a replacement of traditional DNA probe by other DNA mimics which possessed superior properties. AcpcPNA is an attractive candidate DNA replacement because of its excellent stability and specificity of the acpcPNA-DNA hybrid. In this work, the acpcPNA was immobilized on cellulose paper by employing divinyl sulfone as a crosslinker. AcpcPNA acting as a capture probe rapidly hybridized with DNA target which was delivered through capillary transport. After that, DNA detection was carried out by simple staining with azure A. The results showed high specificity which can clearly discriminate single-base mismatch although the sensitivity was somewhat low (detection limit was 3.3 pmol). The signal intensity could have been theoretically enhanced by increasing the length of hanging sequence; nevertheless, preliminary experiments suggest that longer sequence led to more steric effect and therefore the detection of very long DNA sequences still requires further development. In conclusion, a prototype of paper-based macroarray with immobilized acpcPNA probes for DNA detection was developed for a simple and rapid label-free DNA detection with high specificity.