In Situ Derivation of Lamellar NiCo-LDH Nanoflowers from Co-ZIF Formed on Carbon Nanotubes for Biomimetic Glucose Sensor

In this study, a template-assisted method was successfully employed to derive NiCo layered double hydroxide nanoflowers (NiCo-LDH NFs) with a size of 400–600 nm from cobalt-zeolitic imidazolate framework (Co-ZIF) grown on carbon nanotubes (CNTs). These nanoflowers self-assembled on the CNTs into a distinctive three-dimensional (3D) lamellar architecture, resulting in the NiCo-LDH NFs/CNTs nanocomposite material, which was further leveraged to develop a novel nanozyme-based electrochemical glucose biosensor. The precise regulation of Ni2+ concentration facilitated the directional formation of NiCo-LDH into a 3D lamellar nanoflowers structure, effectively precluding the formation of disordered stacking configurations and thereby endowing it with a high specific surface area and abundant electrochemical active sites. In addition, the synergy between NiCo-LDH NFs and CNTs promoted efficient electron transfer during electrocatalysis, leading to excellent catalytic oxidation ability for glucose. With these merits, the NiCo-LDH NFs/CNTs showed a significant current response to various concentrations of glucose within the detection ranges of 0.5–1000 and 1000–5000 μM, having sensitivities of 1151 and 928.8 μA·mM–1·cm–2, respectively, with a limit of detection of 0.092 μM (S/N = 3). Moreover, the NiCo-LDH NFs/CNTs biosensor was successfully applied to the glucose detection of actual human serum samples, demonstrating the applicability of the biosensor and showing broad application prospects.