Catalytic Biomaterials

ConspectusCatalytic biomaterials, an emerging frontier in biomaterials research, offer tremendous potential to circumvent the limitations of traditional treatment approaches, such as low specificity and adverse effects. By harnessing the intrinsic physicochemical properties of materials, catalytic biomaterials, especially nanoscale catalytic biomaterials (termed catalytic nanomedicine), can directly engage with a range of biogenic substrates to initiate various chemical or biochemical reactions in vivo. Chemically designed nanozymes can emulate endogenous enzymes in regulating intracellular redox homeostasis, offering distinct advantages over their natural counterparts, such as design flexibility, adjustable functionalities, robust stability in harsh conditions, and cost-effective production. The extensively investigated natural enzymes mimicked by catalytic biomaterials include peroxidases, oxidases, superoxide dismutases, catalase, and glutathione peroxidase. To improve the enzyme-mimicking activities of catalytic biomaterials, their physicochemical properties, such as their composition, size, morphology, exposed crystal facets, and surface chemistry, are finely tuned for reactive oxygen species (ROS)-producing pro-oxidative or ROS-eliminating antioxidative applications. As the interdisciplinary research of catalysis and biomedicine deepens, cutting-edge concepts of catalysis, including single-atom catalysis, photocatalysis, electrocatalysis, and piezoelectric and thermoelectric catalysis, have gradually merged with biomaterials. The resultant catalytic biomaterials can be activated spatiotemporally by light, ultrasound, magnetic fields, heat, etc., beyond the scope of the aforementioned endogenously responsive nanozymes. Given the semiconductor nature of these externally activated catalytic biomaterials, defect engineering and heterojunction strategies are utilized to enhance the separation and suppress the recombination of electron–hole pairs by modulating the bandgap structures. Consequently, the efficacy of rationally engineered catalytic biomaterials in generating and scavenging ROS can be profoundly improved. Apart from ROS-centered catalytic applications, the content of catalytic biomaterials has also been extended to the catalytic transformation of biochemical substrates, such as glutathione depletion, glucose/lactate consumption, and gas production by inorganic nanocatalysts. Collectively, catalytic biomaterials, which are purposefully designed to influence cellular redox homeostasis and regulate cell signaling pathways, are assumed to play a pivotal role in addressing a spectrum of pathophysiological disorders associated with oxidative stress or dysfunctions, such as cancer, inflammation, immunomodulation, neurodegeneration, and cardiovascular diseases. Given the connections among the concepts of catalytic biomaterials, catalytic nanomedicine, and nanozymes, we present our insights here and clarify the potential distinctions. Catalytic biomaterials have a broader scope, including biomaterials spanning the nanoscale, microscale, and macroscale that possess specific catalytic activities. The involved catalytic activities encompass both enzyme-mimetic catalysis and chemical catalysis as well as endogenously/exogenously activated reactions initiated by biomaterials. Catalytic nanomedicine emphasizes the integration of nanoscale biomaterials with nanotechnology for therapeutic applications. Nanozymes specifically focus on the enzyme-mimicking activities of nanomaterials. Thus, we utilize the term “catalytic biomaterials” to describe this fast-evolving field and anticipate that this will motivate deeper interdisciplinary research between materials science, chemical catalysis, and medicine.In this Account, we provide a concise introduction to the fundamental understanding of catalytic biomaterials, categorizing them into three distinct groups based on their action mechanisms. Then, we highlight our group’s work in the design and fabrication of catalytic biomaterials for diverse biomedical applications, including cancer therapy, antibacterial, anti-inflammation, tissue engineering, and regenerative medicine applications. Our primary focus is on the deliberate design and tailor-made application of sophisticated catalytic biomaterials for specific biomedical scenarios. The biological effects of catalytic biomaterials arising from their intrinsic physicochemical properties are also elucidated. Furthermore, the perspectives associated with the clinical translation and application of catalytic biomaterials are discussed. We envision that the rapid development of catalytic biomaterials could spur the evolution of highly effective therapeutic/regenerative approaches with minimal toxicity for a wide range of medical conditions.