Accounts of materials research最新文献

Single-atom nanozymes (SANs)represent a transformative frontierin artificial enzymes, addressing limitations of natural enzymes andconventional nanomaterial-based catalysts. Natural enzymes are fragileand costly, and traditional nanozymes often lack well-defined activesites. Our research leverages single-atom catalysis to engineer highlyefficient and stable enzyme mimics for biosensing and environmentalremediation.

SANs exhibit a diverse range of enzyme-like activities,includingperoxidase, catalase, oxidase (OXD), and superoxide dismutase (SOD)mimetic functions. By focusing on atomically dispersed metal centers,SANs maximize atomic utilization and provide well-defined active sites,enabling unprecedented control over catalytic performance, e.g., copper-basedsystems that exhibit remarkable OXD-like activity mimicking galactoseoxidase.

To decode the active site and clarify the underlyingcatalyticmechanism, we combined experimental techniques and theoretical modeling.Kinetic assays revealed ultrahigh substrate affinity and catalyticefficiency, and advanced characterization provided direct evidencefor high-valent metal-oxo intermediate formation, mirroring naturalheme-containing enzymes. However, this pathway is not universal; SANmechanisms are highly coordination-dependent, with alternative routesincluding surface-confined redox cycling, radical-mediated processes,and metal–ligand cooperative pathways. Density functional theorycalculations confirmed that the precise electronic structure and coordinationenvironment endowed the SANs with biomimetic catalytic mechanisms.

These mechanistic insights formed the bedrock for rational designprinciples: judicious choice of metal, strategic selection of supportmaterials, and precise control of the coordination environment. UsingMOF-derived and wet-chemistry approaches, we developed a zinc-centeredSAN (Zn-SAN) that mimics the CO₂ hydration activity ofcarbonic anhydrase and bimetallic Cu/Zn-SANs mimicking SOD, with enhancedstability and recyclability.

SANs offer robust, cost-effectiveplatforms for sensitive biosensing,controlled ROS generation for antibacterial treatments, and CO₂ capture and conversion, with applications in point-of-carediagnostics, food safety monitoring, and therapeutics. Challengesin long-term stability, scalable synthesis, and ultrahigh selectivityremain, but integrating AI and advanced computational design promisesto accelerate discovery toward multifunctional SANs with cascade catalyticcapabilities.

Rather than a discrete subclass of nanozymes,SANs should be viewedas atomically engineered catalytic materials bridging heterogeneouscatalysis and biological redox chemistry. Continued integration ofoperando characterization, theoretical modeling, and rational coordinationdesign will be essential for establishing structure–mechanism–functionrelationships that guide translational applications.

Electrochemical biosensors holdpromise for autonomous molecularmonitoring owing to their sensitivity, electronic compatibility, andsuitability for wearable, implantable, and point-of-care platforms.However, conventional operation relies on external calibration thaterodes with batch-to-batch variability and environmental fluctuations,ultimately compromising long-term accuracy in complex biofluids andin vivo environments. Calibration-free electrochemical sensing addressesthis challenge through three complementary strategies. First, intrinsicdual-signal encoding strategy embeds two distinct redox-reportersto generate ratiometric outputs that convert absolute faradaic currentsinto self-normalized readouts, thereby eliminating the need for externalcalibration. Second, operationally programmed self-referencing strategyextracts drift-differentiated kinetics from a single reporter by varyingmeasurement parameters or environmental conditions. Third, interfacialengineering slows signal decay and drift at its molecular origin throughcoordinated optimization of redox reporters, self-assembled monolayers,protective layers and nuclease-resistant nucleic-acid scaffolds. ThisAccount summarizes recent advances, outlines these signal- and interface-leveldesigns and their principles, and discusses opportunities toward long-lastingautonomous biosensing in clinical settings.

Iron oxide (nano)minerals are abundant and reactivecomponentsof natural systems, exerting a profound influence on the environmentalfate of contaminants. Among these, pharmaceutical pollutants havegained increasing attention due to their ubiquitous presence in aquaticand terrestrial environments, their persistence, and their potentialto harm ecosystems and human health, particularly through contributionsto antimicrobial resistance.

Iron oxides play a dual role inmitigating pharmaceutical pollution:they serve as adsorptive surfaces and as redox-active materials capableof transforming pharmaceutical compounds. Adsorption is governed bythe affinity between pharmaceutical functional groups and specificiron oxide surface sites, while redox-active pharmaceuticals may undergoabiotic transformations upon electron transfer with Fe(III) or mixed-valent(Fe(II)–Fe(III)) minerals. These interactions can yield breakdownproducts with altered bioactivity and toxicity, adding complexityto environmental risk assessments. However, these processes remainpoorly understood due to experimental limitations and the absenceof reliable predictive models. Predicting pharmaceutical behaviorunder environmentally relevant conditions requires bridging multiplespatial and temporal scales.

In this Account, we provide a multiscaleevaluation of how ironoxides influence the fate and remediation potential of pharmaceuticalpollutants, integrating findings from experimental and modeling studiesat molecular, interface, pore, column, and field levels. We also explorehow Machine Learning can link across scales and uncover emergent patternsin complex data sets. Environmental factors, including solution chemistry,mineral properties, and co-occurring components, significantly influencethese interactions.

This approach allows us to identify keyknowledge gaps, draw connectionsbetween molecular-scale reactivity and macroscale environmental processes,and highlight opportunities for developing predictive tools for environmentalrisk assessment. The insights gained extend beyond pharmaceuticalsto a wide range of emerging organic contaminants. Advancing this fieldrequires interdisciplinary collaboration at the intersection of moleculargeochemistry, environmental materials science, mineralogy, hydrology,and microbiology.

Two-dimensional(2D) transition-metal carbides and nitrides, collectivelyknown as MXenes, have emerged as a highly promising class of layeredmaterials owing to their tunable physicochemical properties and broadapplicability in electrochemical energy storage. However, their practicaldeployment is still limited by structural instability and the difficultyof achieving precise structural control, both of which stem from complexand insufficiently understood phase-evolution pathways during synthesisand operation. In this Account, we present a review on recent progressin MXenes structural engineering and synthesis regulation, emphasizingthe important role of synchrotron X-ray techniques in revealing structure–propertyrelationships and phase-evolution mechanisms. We first summarize keypostetching structural regulation strategies, including intercalation,surface termination engineering, and atomic-scale configuration control.Synchrotron-based X-ray characterization enables quantitative identificationof structural features that are difficult to probe by conventionalmethods, including the local coordination environments of intercalantsand the spatial distributions of surface terminations and defects.Meanwhile, advances in in situ and operando synchrotron techniquesallow direct observation of microstructural evolution under realisticoperating conditions. These studies demonstrate that structural regulationstrongly influences ion transport, redox behavior, and mechanicalstability, thereby governing MXenes performance in diverse electrochemicalenergy-storage systems. We further discuss an emerging paradigm shiftin the field: from postsynthetic structural tuning to active controlof structural evolution during synthesis. This shift offers a moredeterministic pathway toward MXenes with controlled microstructuresand improved quality. In particular, synchrotron-based operando studiesenable real-time monitoring of the top-down etching of MAX phases,making it possible to capture the formation of MXenes frameworks,identify transient intermediates, and elucidate the evolution of surfaceterminations and defects─information that is difficult to obtainusing conventional ex situ methods. Finally, we highlight future opportunitiesin MXenes research. A deeper understanding of MXenes microstructures,their dynamic evolution, and the associated synthesis mechanisms willprovide the foundation for controllable synthesis, precise structuralregulation, and the scalable production of high-performance MXenes.

Achieving strong and durableadhesion in aquatic,dynamic environmentsis a significant challenge. Marine mussels address this through byssalthreads secured by Mussel Foot Proteins (Mfps). Comprising severalmain variants (Mfp-1 to Mfp-6) with distinct structures, Mfps serveas an important model in bioadhesion, providing key insights for syntheticmaterial design. Their functionality is due to 3,4-dihydroxyphenylalanine(DOPA), which is “A significant yet not the sole chemical factor”and “one of the key sources of inspiration” within complexadhesion systems. These catechol groups of DOPA mediate a two-stageadhesion process. Initially, they facilitate rapid surface wettingand attachment through noncovalent interactions such as hydrogen bonding,cation-π interactions, and hydrophobic effects. Subsequently,oxidation can convert catechols to quinones, which enable covalentcross-linking for cohesion and stable substrate anchoring via reactionswith nucleophiles or metal ion coordination. This combination of reversibleand irreversible interactions underpins the robust adhesion of Mfpsin marine settings.

Understanding these natural mechanisms hassignificantly advancedadhesive technology, leading to diverse Mfp materials. Beyond mimickingnatural proteins, synthetic biology and polymer chemistry have beenemployed to replicate and extend these principles. Recombinant expressionallows the production of tailored proteins, while synthetic peptidescapture core functional motifs. This approach has led to a range offunctional biomaterials with applications extending beyond adhesion,including tissue adhesives, antifouling coatings, drug delivery systems,self-healing hydrogels, and biosensors.

Current research isexploring more dynamic and multifunctionalsystems based on the Mfps principles. Future efforts may focus onenvironmentally responsive materials that offer spatiotemporal controlover the adhesion. Integrating Mfp designs with synthetic biologycould also contribute to developing engineered living materials. Keyresearch directions include the computational design of adhesive peptides,protein engineering for stability, optimization of microbial expressionsystems for production, and improved purification strategies. Realizingthe practical potential of Mfp-based technologies will require addressingpersistent challenges in scalable production and controlling catecholoxidation through interdisciplinary efforts in molecular design, materialsscience, and engineering.