Rapid discrimination of DNA strands using an opto-calorimetric microcantilever sensor

A rapid technique for quantitative detection and discrimination of DNA strands without using immobilized probe molecules is demonstrated using an opto-calorimetric, self-powered sensor based on a Pb(Zr_0.52Ti_0.48)O₃ (PZT) microcantilever. Microcalorimetric infrared (IR) spectroscopy provides excellent chemical selectivity based on the unique molecular vibrational characteristics of each nucleotide in the mid IR region. The piezoelectric and pyroelectric properties of the PZT microcantilever were exploited in the quantitative detection and discrimination of adsorbed DNA strands with their spectral characteristics. We report the unique spectral characteristics of different DNA nucleotides that are monitored by wavelength-dependent temperature variations for different relative molar ratio of each nucleotide. This approach offers a fast, label-free technique which is highly sensitive and selective for the detection of single nucleotide differences in DNA strands and has the potential to be used as a rapid prescreening biosensor for various biomolecules.