Detection of clinically relevant point mutations by a novel piezoelectric biosensor.

Piezoelectric sensing is here applied to point mutation detection in human DNA. The mutation investigated is in the TP53 gene, which results inactivated in most cancer types. TP53 gene maps on chromosome 17 (17p13.1). It contains 11 exons and codifies for the relative protein, involved in cell proliferation. The TP53 gene has a wide mutation spectrum that is related to different tumours. In particular, those occurring in the structurally important L2 and L3 zinc-binding domains, have been linked to patient prognosis and more strongly to radiotherapy and chemotherapy resistance in several major cancers. For this reason, the identification of these mutations represents an important clinical target and biosensors could represent good candidate for fast mutation screening. In this paper, a DNA-based piezoelectric biosensor for the detection of the TP53 gene mutation at codon 248 is reported. A biotinylated probe was immobilised on the sensor surface via dextran-streptavidin modified surfaces. The sensor was optimised using synthetic oligonucleotides. Finally, the sensor system was successfully applied to polymerase chain reaction (PCR)-amplified real samples of DNA extracted from two cell lines, one normal (wild-type) and one mutated, carrying the mutation at codon 248 of the TP53 gene. The results obtained demonstrate that the DNA-based piezoelectric biosensor is able to detect the point mutations in PCR-amplified samples showing the potentialities of this approach for routine analysis.