Amorphous hollow manganese silicate nanosphere oxidase mimic for ultrasensitive and high-reliable colorimetric detection of biothiols

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 (Km = 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.

Advances in the application of logic gates in nanozymes

Nanozymes are a class of nanomaterials with biocatalytic function and enzyme-like activity, whose advantages include high stability, low cost, and mass production. They can catalyze the substrates of natural enzymes based on specific nanostructures and serve as substitutes for natural enzymes. Their applied research involves a wide range of fields such as biomedicine, environmental governance, agriculture, and food. Molecular logic gates are a new cross-disciplinary discipline, which can simulate the function of silicon circuits on a molecular scale, perform single or multiple input logic operations, and generate logic outputs. A molecular logic gate is a binary operation that converts an input signal into an output signal according to the rules of Boolean logic, generating two signals, a high level, and a low level. The high and low levels represent the "true" and "false" values of the logic gates, and their outputs correspond to "l" and "0" of the molecular logic gates, respectively. The combination of nanozymes and logic gates is a novel and attractive research direction, and the cross-application of the two brings new opportunities and ideas for various fields, such as the construction of efficient biocomputers, intelligent drug delivery systems, and the precise diagnosis of diseases. This review describes the application of logic gates based on nanozymes, which is expected to provide a certain theoretical foundation for researchers' subsequent studies.

Recent Advances in Hollow Nanostructures: Synthesis Methods, Structural Characteristics, and Applications in Food and Biomedicine

The development and investigation of innovative nanomaterials stand poised to advance technological progress and meet the contemporary demand for efficient, environmentally friendly, and intelligent products. Hollow nanostructures (HNS), characterized by their hollow architecture, exhibit diverse properties such as expansive specific surface area, low density, high drug-carrying capacity, and customizable structures. These elaborated structures, encompass nanospheres, nanoboxes, rings, cubes, and nanowires, have wide-ranging applications in biomedicine, materials chemistry, food industry, and environmental science. Herein, HNS and their cutting-edge synthesis methods, including solvothermal methods, liquid-interface assembly methods, and the self-templating methods are discussed in-depth. Meanwhile, the potential applications of HNS in food and biomedicine such as food packing, biosensor, and drug delivery over the past three years are summarized, together with a prospective view of future research directions and challenges. This review will offer new insights into designing next generation of hollow nanomaterials for food and biomedicine applications.