Recently, the performance of aptasensors has been significantly improved when combined with new nanomaterials. Herein, the amorphous Ni(OH)2 nano-boxes with intact shell structure were synthesized and, then, were used as an efficient substrate for covalent immobilization of the NH2-functionalized aptamer to develop label-free electrochemical aptasensor for ultrasensitive analysis of trypsin. This multidimensional hollow structure places a large amount of surface area in a small space of electrode surface and, thus, increasing the loading of the aptamer strings which significantly increases the sensitivity of measurement. A good linear relationship was found between logarithmic value of trypsin and Rct from 1 fg mL−1 to 500 ng mL−1 with a low detection limit of 0.3 fg mL−1. Furthermore, the proposed aptasensor showed good reproducibility, high stability and excellent feasibility in biological samples. This study showed that the Ni(OH)2 nano-boxes nanocomposite have various advanced electrochemical properties making them suitable electrode materials for aptasensor application.
