Hydrogel-Involved Colorimetric Platforms Based on Layered Double Oxide Nanozymes for Point-of-Care Detection of Liver-Related Biomarkers

Abstract

Monitoring the liver status in a convenient and low-cost way is significant for obtaining a warning about drug-indued liver diseases promptly. Herein, we designed a novel colorimetric point-ofcare (POC) platform for the determination of three liver-related biomarkersaspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP). This platform integrated agarose hydrogels into a portable device, where hydrogels were loaded with nanozymes and different reaction substances for triggering specific reactions and generating colorimetric signals. Typically, Au-decorated CoAl-layered double oxide (Au/LDO) was for the first time developed as the nanozyme with peroxidase (POD) mimic activity, which can accelerate the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxTMB with the coexistence of hydrogen peroxide (H 2 O 2 ). The detection mechanism of AST and ALT is based on the fact that they can cause individual cascade reactions to generate H 2 O 2 , and H 2 O 2 further activates the Au/LDO nanozyme to catalyze the chromogenic reaction of TMB. As for ALP, it can catalytically hydrolyze L-ascorbic acid-2-phosphate to ascorbic acid. The latter then discolored the oxTMB that was produced with the assistance of Au/LDO. Teaming up with a smartphone, the color information of hydrogels can be converted to hue values, which allow quantitative analysis of ALT, AST, and ALP with detection limits of 15, 10, and 5 U/L, respectively. Moreover, the simple and cost-effective platform was successfully applied for the simultaneous determination of the three analytes in human plasma. Additionally, since the hydrogel is disposable and can be replaced by new ones loaded with different reaction regents, the platform is expected to serve the POC testing of various chem/bio targets.

Nanozymes from Cu(II) Metal–Organic Gel and Melamine for Highly Active Peroxidase-Like Activity to Detect Alkaline Phosphatase

“…49 Hence, it is necessary to establish an efficient and accurate colorimetric method for elevating the ALP level in the human serum. Inspired by the fact that ALP can efficiently the catalyze substrate AAP into AA, 50 which can inhibit the oxidation process of TMB as • OH reacts with AA instantly (Scheme 1B). Finally, the absorbance values at 652 nm of Cu-C 3 N 4 -550/TMB/H 2 O 2 system were different when various concentrations of ALP were added.…”

A Copper-Based Biosensor for Dual-Mode Glucose Detection

“…In the comparison with some other nanomaterial sensors for glucose detection ( Han et al, 2017 ; Guo et al, 2019 ; Ren et al, 2019 ; Ren et al, 2020 ; Li et al, 2021 ; Liu et al, 2022 ), our proposed sensor shows a broad linear response in the range of 0.28–2.8 mM, which has wide prospects and great application values in the direct detection of glucose from human serum or other biological samples ( Gluchowska et al, 2021 ). Currently, most glucose detection methods with low LOD can only realize standard samples analysis, while our work greatly achieved glucose detection from 31 serum samples.…”

Spherical Hydrogel Sensor Based on PB@Fe-COF@Au Nanoparticles with Triplet Peroxidase-like Activity and Multiple Capture Sites for Effective Detection of Organophosphorus Pesticides

“…Hydrogels with porous polymeric networks feature optical transparent property, outstanding mechanical stability, high loading capacity, and flexibility, which are quite promising in colorimetric sensing as appropriate carriers. − After being embedded into hydrogel systems, the stability of nanomaterials could be enhanced along with suppression of nanomaterials aggregating, further increasing the catalytic activity of nanozymes. Besides, the nanometer-scale porous structure of hydrogels not only allowed the diffusion of substrates and intermediates but also blocked the interference of the large molecules in real samples at the same time. − These advantages provide the possibility to design a nanozyme-based colorimetric hydrogel system for the in-field detection of OPs.…”