Development of a porphyrin based optoelectrical platform for DNA sensing

Optical methods offer exceptional sensitivity for probing intricate biological interactions. Here, we employ a photoactive porphyrin molecule as a sensing probe to monitor DNA hybridisation. We achieved real-time absorption spectral analysis of the DNA binding process by immobilising porphyrin on a U-bent fiber probe. Spectral shifts and intensity changes correlated with DNA binding and hybridization, respectively. Leveraging these spectral signatures, we developed a novel optoelectrical platform for DNA sensing. A porphyrin-based photodiode architecture demonstrated enhanced sensitivity, with a ~1V negative shift in threshold voltage and a threefold increase in photocurrent upon complete DNA hybridization. This platform effectively distinguishes between single-stranded and hybridized DNA, minimising false positives. The proposed optoelectrical approach holds promise for the development of cost-effective, portable DNA sensing devices.