Manganese Silicate with Proximity Effect and Enhanced Polarity toward Substrates for Efficient Enzymatic Biosensing

Functional nanoparticle-mediated enzymatic sensors have been extensively utilized in the colorimetric detection of biomolecules. However, low affinity toward substrates and unstable color development of oxidized substrates severely influence the detection period and reliability of results. Herein, a rapid and reliable method has been proposed by employing manganese silicate NPs (MSs) as the paradigm for enzymatic colorimetric detection of uric acid (UA). MSs demonstrate favorable catalytic kinetics (K_m = 0.046 mM). Compared with reported methods, the shortened detection period and ultralong enzymatic curve platform (∼8 min) ensure higher rapidity and reliability. Theoretical calculations based on density functional theory were further utilized to reveal the catalytic mechanism of the MSs oxidase mimic. The inherent ability to spontaneously generate ROS along with its proximity effect resulting from substrate adsorption provides robust theoretical support for ultrafast catalytic kinetics. Moreover, silicate ions reduced the degree of electron delocalization in oxidized TMB with increasing molecular polarity and decreased the solvation free energy to further improve the dissolution stability. As expected, the MSs-based method exhibits excellent accuracy and higher stability in monitoring UA change of human urine specimens, which is superior to the commercial kit. Furthermore, the integration of colorimetric methodologies with portable smart detection systems bridges fundamental scientific exploration and practical implementation, enabling both a reduced detection cost and expanded applicability of nanozyme-based sensors.