A GQD/g-C₃N₄-modified nanochip for electrochemical detection of dengue serotype 3

A graphene quantum dot/2D graphitic carbon nitride (GQD)/g-C₃N₄-based ultrasensitive DNA biosensor was constructed using 5′ aminated DNA probes immobilized onto the surface of a screen-printed paper electrode (SPPE) for detecting DENV 3 (dengue serotype 3). FTIR, UV-Vis, TEM, and particle size measurements were used to characterize the synthesized nanocomposites. These results were then used to fabricate an affordable DNA sensor based on an SPPE that detects DENV 3. Initially, bioinformatics methods were used to develop DNA probes unique to DENV 3. The findings indicated that the most effective DNA probe for identifying DENV 3 was a 20-nucleotide sequence, which was immobilized onto a GQD/g-C₃N₄-modified SPPE. The electrochemical response was studied via differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The electrode surface at each step of fabrication was characterized via FE-SEM, EIS and FTIR. The developed DNA sensor showed excellent analytical performance in terms of LOD and sensitivity. In CV, the LOD was 1 pg μl⁻¹, with a sensitivity of 7993 ng μA⁻¹ mm⁻². However, in DPV, the LOD and sensitivity were 1 pg μl⁻¹ and 11 116 ng μA⁻¹ mm⁻², respectively. This method should be preferable in the future for detecting DENV 3 in biological and clinical samples.