Development of optical biosensor based on the surface-enhanced raman scattering (SERS) for DNA analysis

DNA analysis is extremely crucial in biomedical research. The DNA sequence of the gene affects the structure of the synthesized protein and thus if it is abnormal many diseases and genetic problems could be caused. Rapid, accurate and precise DNA analysis in the diagnosis of genetic diseases is highly imperative. The most commonly used method for DNA analysis is the fluorescence-based microarray technique. However, this method has some disadvantages. The most important of them is the overlapping of the obtained fluorescence spectrum depending on the band sizes. There are also disadvantages such as photo-fragmentation and fluorescence quenching in fluorescence-based techniques. Raman spectroscopy has many advantages compared to fluorescence techniques. Raman spectra of different molecules can be easily obtained with a single wavelength of light source. There is no need to have the fluorescence property of the molecule to be used in order to obtain the Raman spectrum from the molecules, and even with the slightest chemical modification, a different Raman spectrum can be obtained. Due to these advantages, DNA analysis studies based on Surface-Enhanced Raman Scattering (SERS) are quite extensive in recent years. In this study, for the first time in the literature without using any Raman active dye and independent of the SERS substrate feature, a SERS- based method was developed for DNA analysis. In this method, instead of obtaining the Raman active molecule spectrum in the presence of the target DNA, the presence of the target DNA molecule was shown by the peak shift of the small molecule bound to the SERS substrate surface. Keywords: SERS, DNA analysis, Biosensor, Peak shift.