Single Step Synthesis of 2-D Marcasite FeS2 Micro-Flowers Based Electrochemical Sensor for Simultaneous Detection of Four DNA Bases

Abstract

This work demonstrates the single-step solvothermal synthesis of marcasite FeS₂ as a low-cost electrochemical platform for the separation-less sensing of four nucleobases of DNA. FESEM micrographs reveal high surface area micro-flowers like morphology of the marcasite FeS₂ wherein each micro-flower comprises vertically grown interwoven 2D nanosheets. XRD and Raman spectra further confirm the successful synthesis of the marcasite FeS₂. A detailed optimization study on the impact of electrolytic pH values on the simultaneous determination of four DNA bases (adenine (A), thymine (T), guanine (G) and cytosine (C)) is performed. Under optimal pH conditions, the marcasite FeS₂ based electrode is capable of identifying DNA bases altogether over the linear range of 500-2000 &#x00B5;M with excellent reproducibility and stability. The superior electrochemical sensing properties of the marcasite FeS₂ towards simultaneous detection of four bases can be ascribed to high electro-active surface area and conductivity from the active sites of this unique 2D nanosheets-like structure. Besides, to establish its efficacy in real-time applications, the sensor is successfully utilized for the detection of nucleobases of denatured DNA of calf-thymus, and the obtained value of <inline-formula><tex-math notation="LaTeX">$\frac{{( {G + C} )}}{{( {A + T} )}}$</tex-math></inline-formula> is found to be 0.77. These results establish that the marcasite FeS₂ has enormous potential to be used as a promising low-cost, functional transition metal di-chalcogenide (TMD) nanomaterial for bio-analytical and sensing applications.