Screening for mutations in BRCA1 and BRCA2 genes by measuring the acoustic ratio with QCM

Abstract

Screening for mutations in the tumor-suppressor genes BRCA1 and BRCA2 is of great importance for breast and ovarian cancer prevention. We describe a methodology for mutation screening and detection based on acoustic wave devices. In particular, we detect four mutations located in BRCA1 and BRCA2 genes using the quartz crystal microbalance technique. The detection is based on measurements of the acoustic ratio of dissipation versus frequency change (ΔD/ΔF) of double-stranded DNA molecules bound to the device surface that are produced after PCR amplification and restriction digestion; the acoustic ratio has been shown to be a measure of the intrinsic viscosity of the attached molecules, which, in turn, depends on the size of the dsDNAs. Novel features of this approach are the lack of a hybridization step, the label free sensing of the length, rather than mass, of the DNA molecules and the direct detection of the digested DNA products without prior purification. The method is generic, simple and capable of detecting single base mutations to long genomic rearrangements; it is also suitable and applicable to a Lab-on-a-chip concept.