Research progress on the application of molecularly imprinted nanozymes in the field of biosensing

Enzymes， as biological catalysts， have garnered significant interest due to their exceptional efficiency and specificity. However， the fragility of natural enzymes under varying temperature and pH conditions significantly restricts their broader utilization. In the past few years， noteworthy advancements have been achieved in creating biomimetic enzyme systems. Scientists have effectively designed artificial enzyme-mimicking systems that exhibit outstanding performance through the integration of various components， including small molecule compounds， deoxyribonucleic acid， and nanomaterials. These systems not only exhibit remarkable catalytic efficiency but also offer considerable benefits， such as adjustable activity， simplicity in modification， and enhanced stability and reusability. Nanomachines， as a new type of enzyme analogues， specifically refer to nanomaterials with enzyme-like catalytic functions. They have played a significant role in the development of biomimetic enzyme systems. Since the first report in 2007 that iron oxide nanoparticles have peroxidase （POD） mimicking activity， hundreds of nanomaterials have been confirmed to have catalytic activities similar to those of natural enzymes such as POD and oxidase （OXD）. These novel enzyme analogues not only exhibit a wide range of enzyme-like activities and structural similarity to natural enzymes， but also possess unique nanomaterial characteristics， making their catalytic activities controllable and stable. As effective substitutes for natural enzymes， nanomachines have been widely applied in fields such as biosensing， medical treatment， and environmental remediation. While every cutting-edge technology presents certain limitations， nanozymes are not an exception. They encounter notable challenges， especially concerning substrate selectivity， which is essential for effective targeted catalysis and widespread applicability. To address the aforementioned imitation， researchers have been investigating effective approaches to improve the catalytic selectivity of nanozymes. Primarily， two methods are utilized to achieve selective bioanalysis based on nanozyme catalysis： the first method involves merging nanozymes with biological recognition factors （such as natural enzymes， antibodies， DNA strands， and aptamers）， while the second focuses on developing nanozymes that possess intrinsic catalytic specificity through techniques like structure-mimetic design， surface modifications， or molecular imprinting. Incorporating external biological recognition elements can undermine both the stability and cost-effectiveness of nanozymes. Additionally， the methods available for the effective conjugation of nanozymes with biological components are still in their infancy. The creation of structure-mimetic nanozymes tends to be intricate and requires meticulous regulation. In contrast， a straightforward and accessible method for generating substrate recognition sites on nanozymes is the application of molecular imprinting technology （MIT）. MIT replicates interactions between enzyme substrates or antibody-antigen pairs to fabricate a cavity that is precisely shaped and sized for a particular template molecule， thus facilitating accurate molecular recognition. Due to its exceptional specificity， stability， and reproducibility， MIT is widely utilized in various fields such as biosensing， medical diagnostics， pharmaceutical assessment， sample preparation， and fluorescent detection. Moreover， the inherent advantages of molecularly imprinted polymers （MIPs）， such as their economical nature， exceptional selectivity， remarkable thermochemical resilience， and the removal of the need for biologically derived techniques， have rendered molecular imprinting a feasible strategy for mimicking the roles of natural enzymes. Natural enzymes exhibit substrate specificity primarily due to the three-dimensional structure of their active sites. These active sites are meticulously shaped to ensure a perfect match with the spatial configuration of the intended substrate. Following this concept， molecular imprinting nanoenzymes cleverly integrate molecular imprinting techniques with the properties of nanoenzymes， allowing biomimetic catalysts to retain catalytic selectivity while also demonstrating remarkable substrate specificity. This paper first summarizes the fundamental characteristics of nanozymes， then elaborates on the conventional preparation processes for molecularly imprinted nanozymes， and thoroughly explores the impact of molecular imprinting on the catalytic performance of nanozymes. Through an analysis of typical cases， the latest research advancements in molecularly imprinted nanozymes biosensing field are introduced. Finally， this paper discusses the challenges encountered and future development directions in this area， aiming to provide theoretical references and practical guidance for the application of molecular imprinting and nanozymes in biosensing.