NH2-Ni-MOF electrocatalysts with tunable size/morphology for ultrasensitive C-reactive protein detection via an aptamer binding induced DNA walker–antibody sandwich assay

Here we report a general approach for synthesizing size/morphology-controlled NH₂-Ni-MOFs by optimizing the solvent composition in the reaction system, and their correlating catalytic performances are clearly explored for the first time. Interestingly, the electrocatalytic performance was found to increase 2.7 fold when the particle size is reduced from 1.5 μm for NH₂-Ni-MOF(a) to 300 nm for NH₂-Ni-MOF(c). Subsequently, this work exhibits an example of a high-performance NH₂-Ni-MOF(c) electrocatalyst for application in constructing an electrochemical aptasensor to achieve sensitive C-reactive protein (CRP) detection based on an aptamer binding induced DNA walker-antibody sandwich assay. The proposed aptasensor shows a wide linear range from 0.1 pg mL^-1 to 100 ng mL^-1 with a low detection limit of 0.029 pg mL^-1. The work presented here can thus offer an atypical approach to size- and morphology-controlled MOFs in electrocatalysis and biosensing.