Effect of nickel incorporation on the physicochemical properties and performance of HKUST-1-based MOF immunosensor for DENV-3 NS1 detection

An electrochemical immunosensor was developed using a modified metal-organic framework (MOF) for detecting dengue virus serotype 3 (DENV-3) NS1. CuNi-MOF frameworks with varying Cu:Ni molar ratios—1:0 (CuNi-1), 5:1 (CuNi-2), 3:1 (CuNi-3), and 1:1 (CuNi-4)—were synthesized, incorporating 10 wt% triethanolamine (TEOA) as a modulator to enhance performance. X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectra confirm the successful formation of CuNi-MOF. Morphological evolution was observed as the Ni content increased to 50 % (CuNi-4), resulting in a transformation from octahedral to bar-like particles. Among the synthesized materials, CuNi-4 exhibited the highest redox current, making it the optimal choice for electrochemical measurements targeting dengue virus (DENV) detection. Using DPV technique, it was found that linear range of DENV-3 antigen concentration is 0.001 ng mL⁻¹ - 5 ng mL⁻¹ with a limit of detection (LoD) of 0.1 pg mL⁻¹. In addition, the CuNi-4 exhibited remarkable selectivity for DENV-3 over the other three dengue virus serotypes. Real sample testing using DENV-3 antigen with variation concentration of 0.001; 0.01; 0.1; 1; and 10 ng mL⁻¹ in commercial human serum resulted in the recovery of 98 %, 94 %, 97 %, 95 %, and 98 %, respectively. The findings highlight the promise of the CuNi-4-based electrochemical immunosensor for detecting NS-1 antigens of DENV-3 with high specificity and sensitivity.