A research team led by Profs. CHEN Chunying and LIU Jing from the National Center for Nanoscience and Technology (NCNST) of the Chinese Academy of Sciences (CAS) developed liposome encapsulated N-doping titanium-based nanozyme enhanced catalytic tumor therapy. This work was published in Angewandte Chemie International Edition.
Nanozyme is an important kind of nanomaterials with enzyme-like activity. Nanozyme-based tumor microenvironment responsive tumor therapy has attracted much attention these years. However, insufficient enzymatic activity and lack of catalytic substrate, such as hydrogen peroxide, limit their antitumoral efficiency. The enzymatic activity of metal-based nanozymes was mostly considered due to the Fenton-like reaction of metal ions, while the effect of non-metallic atoms towards enzymatic activity is still unknown.
In recent years, Prof. CHEN and Prof. LIU focus on the prevention and treatment of cancer and bacterial infection using bioactive nanomaterials. They developed two-dimensional palladium-based graphdiyne nanocomposite with catalase activity for tumor hypoxia attenuation and treatment (Nano Today 2020, 34, 100907), defect-rich adhesive molybdenum disulfide/rGO vertical heterostructures with enhanced nanozyme activity for antibacterial application (Adv. Mater. 2020, 32, 2005423), microRNA-loaded graphdiyne-cerium oxide nanozymes for tumor hypoxia attenuation and radiotherapy of esophageal cancer (Adv. Mater. 2021, 2100556), a nanovaccine with durable and robust anti-virus capacity using MnARK nanoadjuvant to deliver recombinant SARS-CoV-2 spike protein RBD subunit for efficient immune response (Nano Today 2021, 38, 101139), and enzymatic colorimetric method for accurate biomacromolecule detection in physiological environment (Anal. Chem. 2021, 93, 11123).
Inspired by the active center of natural enzymes that mostly comes from coordination between metal atoms and nitrogen atoms, researchers focus the improvement of nanozyme activity on nitrogen-doping. Authors demonstrated that N-doping greatly enhanced the peroxidase-like activity of TiO2 nanoparticles. DFT calculations indicated that lower electronegativity of N than O provided favorable environment for peroxidase reaction. Besides, TiN NPs had strong absorption covering the both NIR-I and NIR-II regions. Due to the temperature effect and surface plasmon resonance effect, TiN NPs exhibited enhanced enzymatic activity under NIR irradiation. On this basis, the researchers developed a novel nanocomposite with cascade enzymatic activity by using TiN NPs encapsulated liposomes linked with pH-responsive PEG-modified glucose oxidase for effective tumor therapy.