Theory-guided design of S-doped Fe/Co dual-atom nanozymes for highly efficient oxidase mimics.

The advent of dual-atom nanozymes (DAzymes) featuring distinctive bimetallic active sites garnered significant attention, representing enhanced iterations of conventional single-atom nanozymes. The quest for an effective and universal strategy to modulate the catalytic activity of DAzymes posed a formidable challenge, yet few published reports addressed this. Herein, we designed and synthesized S-doped Fe/Co DAzymes (S-FeCo-NC) under theoretical guidance and revealed their excellent oxidase-like activity. Experimental and theoretical calculations indicated that the superior oxidase-like activity exhibited by S-FeCo-NC was attributed to the S-doping, which modulated the local electronic structure of the dual-atom active site. This modulation of the local electronic structure significantly optimizes oxygen adsorption energy, thereby accelerating the rate of enzyme-catalyzed reactions. As a proof-of-concept, this study integrated S-FeCo-NC with the cascade inhibition reaction of acetylcholinesterase (AChE) to devise a sensitive analytical platform for detecting organophosphorus pesticides. This study paved the way for elucidating the correlation between the local electronic structure of the active site and enzyme activity, offering novel methodologies and insights for the rational design of DAzymes.

Three-dimensional DNA biomimetic networks (B-3D Net)-based ratiometric fluorescence platform for cancer-related gene biosensing.

Efficient detection of cancer-related nucleic acids is pivotal for early cancer diagnosis. This study introduces a target induced three-dimensional DNA biomimetic networks (B-3D Net)-based ratiometric fluorescence platform using manganese dioxide nanosheets (MnO2 NS)/o-phenylenediamine in combination with hybridization chain reaction to detect cancer-related genes (p53 gene). The incorporation of multiple signals within the B-3D networks can significantly enhance catalytic activity and amplify the output signals, enabling a high sensitivity. Compared with traditional ratio fluorescence platforms, there is no demand to synthesize fluorescent nanoprobes due to the in-situ formation of fluorescence species, which is simple and cost-effective. The corresponding assay demonstrated exceptional sensitivity (with a detection limit as low as 2 fM), selectivity, reproducibility, and accuracy, which mitigates disturbances caused by instrument errors, an inaccurate probe count, and the microenvironment. Furthermore, the ease and straightforwardness of discerning changes in fluorescent brightness and colour by the naked eye are evident. Using the relevant software, a linear relationship between fluorescent images using a smartphone and target concentration was obtained. Hence, the novel ratiometric sensing system will demonstrate new opportunities on determination of target DNA samples in complex biological environments.

Antifatigue effect of functional cookies fortified with mushroom powder (Tricholoma Matsutake) in mice.

Bakery products made by cereal and edible fungi powder have a unique flavor and health benefits, dramatically enhancing the nutritional value of the products. In this study, we investigated the antifatigue effect of a novel Tricholoma matsutake cookie (TMC) by the exhaustive swimming test. Male Kunming ICR mice were randomly divided into seven groups (each group, n = 10), fed with saline, ordinary cookies (4, 8, 16 g/kg B.W./day), and TMC (4, 8, 16 g/kg B.W./day) by gavage. After 30-day administration, the weight-loaded swimming test was carried out on the mice to evaluate the antifatigue effect of TMC. In comparison with the effect of ordinary cookies, the intake of TMC significantly prolonged the exhaustive swimming time of mice and increased the level of muscle glycogen and liver glycogen, accompanied by the reduction of lactic acid and urea nitrogen level in serum. Additionally, TMC dramatically improved the activity of superoxide dismutase and glutathione peroxidase in serum and largely decreased the level of malondialdehyde. All in all, TMC could enforce exhaustive swimming tolerance, accelerate the decomposition of sports-related metabolites such as lactic acid and urea nitrogen, and increase the activity of the antioxidant enzyme, thereby improving sports-related energy storage and relieving fatigue. Our findings broadened the application of T. matsutake in the processing of bakery products and provided the theoretical basis and technical support for the development of antifatigue products. PRACTICAL APPLICATION: In this study, we investigated the antifatigue effect of a novel Tricholoma matsutake cookie by the exhaustive swimming test. Collectively, the results of the present study suggested that the cookies fortified with T. matsutake could be considered as an antifatigue bakery product. Furthermore, our findings broadened the application of T. matsutake in the processing of bakery products and provided the theoretical basis and technical support for the development of antifatigue products.