Gold nanoparticle-loaded hollow Prussian Blue nanoparticles with peroxidase-like activity for colorimetric determination of L-lactic acid.

The intrinsic peroxidase-like activity of hollow Prussian Blue nanoparticle-loaded with gold nanoparticles (Au@HMPB NPs) were applied to oxidize the substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to give a blue-green coloration. The morphology of the Au@HMPB NPs and its peroxidase-mimicking activity was characterized in detail. The catalytic activity follows Michaelis-Menten kinetics and is higher than that of HMPB NPs not loaded with gold nanoparticles. The NPs were employed to detect L-lactic acid colorimetrically (at 450 nm) via detection of H2O2 that is generated during enzymatic oxidation by L-lactate oxidase (LOx). The limit of detection is 4.2 μM. The assay was successfully applied to the quantitation of L-lactic acid in spiker human serum samples. Graphical abstract Gold nanoparticle-loaded hollow Prussian Blue nanoparticles (Au@HMPB NPs) with peroxidase-like catalytic activity can oxidize the substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2. The nanoparticles were applied for the detection of L-lactic acid through detection of H2O2 that is generated by L-lactate oxidase (LOx) catalyzed oxidation of L-lactic acid.