Vacancy-tailored NiFe PBA nanocages supported Au NPs with enhanced catalytic activity for fingertip sweat electrochemical sensing of glucose

Abstract

Sweat glucose (Glu) monitored by a non-enzymatic electrochemical sensing platform can function as a promising alternative for diabetes management, due to its non-invasive nature and great efficiency. Nevertheless, the low level of Glu in sweat has hindered the advancement of present sensors. Herein, we engineered a cyanide (CN) vacancy-defected hollow NiFe Prussian blue analogue (H-NiFe PBA) nanocage anchored with Au nanoparticles (NPs) through an acid etching and electrodeposition process. Integrated with a flexible laser-induced graphene (LIG) electrode array, a novel Au@H-NiFe PBA/LIG sensor was constructed for touch-based electrochemical sensing of Glu in fingertip sweat. The vacancy-defect and hollow structure of H-NiFe PBA endows it with abundant active sites and charge transport channels, while highly dispersed Au NPs and LIG substrate with 3D porous structure ensure rapid electron transfer. Based on this, the Au@H-NiFe PBA/LIG sensor displays outstanding electrocatalytic activity toward Glu oxidation, achieving a wide linear range (1-2332 & micro;M), a satisfactory detection limit (0.67 & micro;M) and sensitivity (3.484 & micro;A & micro;M-1 cm(-2)), along with good anti-interference capability, response speed, flexibility, stability and repeatability. Moreover, calcium alginate (CA) gels with favorable biocompatibility and swelling properties were utilized for modification, achieving fast touch analysis of Glu in fingertip sweat. This study offers a CN-vacancy engineering strategy for constructing highly efficient electrocatalysts, evolving the advancement of high-performance sensors for noninvasive analysis of Glu in sweat.