FeMn layered double hydroxides: an efficient bifunctional electrocatalyst for real-time tracking of cysteine in whole blood and dopamine in biological samples

摘要

A peculiar clock-regulated design of FeMn-LDHs (FMH) with specific physiochemical attributes has been developed and used for highly sensitive detection of cysteine (CySH) and dopamine (DA). The FMH nanoparticles were synthesizedviaa facile hydrothermal approach clocked at various (6 h, 12 h and 18 h) operating periods. Under optimal conditions, FMH were obtained in three unique morphologies such as hexagonal plate like, cubic, and spherical structures corresponding to the clocked periods of 6 h, 12 h, and 18 h, respectively. Among these, FMH-12 h possess the minimal particle size (54.45 nm), a large surface area (7.60 m(2)g(-1)) and the highest pore diameter (d= 4.614 nm). In addition to these superior physiochemical attributes, the FMH nanocubes exhibit excellent electrochemical behaviors with the lowest charge transfer resistance (R-ct; 96 omega), a high heterogeneous rate constant (7.81 x 10(-6)cm s(-1)) and a good electroactive surface area (0.3613 cm(2)), among the three. The electrochemical biosensor based on the FMH nanocubes exhibits a remarkable catalytic activity toward CySH and DA with a low detection limit (9.6 nM and 5.3 nM) and a broad linear range (30 nM-6.67 mM and 20 nM-700 mu M). The FMH based biosensor is also feasible for the real-world detection of CySH in whole blood and DA in biological fluids with satisfactory results. The proposed sensor possessed high selectivity, good repeatability, and reproducibility toward CySH and DA sensing.