Adaptive Coatings with Anticorrosion and Antibiofouling Properties

Biofouling on surfaces immersed in aquatic environment induces catastrophic corrosion of metallic materials in petrochemical infrastructures, maritime facilities, and power plants. To combat the synergistic effect of biofouling and corrosion on the deterioration of metallic materials, smart coatings possessing a dual function of antibiofouling and anticorrosion properties are needed. Herein, redox-responsive copolymer conjugates are synthesized and employed as coatings with the dual function of biofouling and corrosion mitigation. The dual function of copolymers is attributed to fluorinated units and the corrosion inhibitor 2-mercaptobenzothiazole (MBT) conjugated via disulfide linkages. Indeed, the disulfide linkages can be cleaved in a reducing environment, yielding controlled release of the corrosion inhibitor MBT during corrosion process. The antibiofouling action against protein adsorption and algal attachment is enabled by cooperation of the repellent characteristic of fluorinated moieties and the biocidal effect of conjugated MBT.     

Red‐Light‐Controlled Release of Drug–Ru Complex Conjugates from Metallopolymer Micelles for Phototherapy in Hypoxic Tumor Environments

Traditional photodynamic phototherapy is not efficient for anticancer treatment because solid tumors have a hypoxic microenvironment. The development of photoactivated chemotherapy based on photoresponsive polymers that can be activated by light in the “therapeutic window” would enable new approaches for basic research and allow for anticancer phototherapy in hypoxic conditions. This work synthesizes a novel Ru‐containing block copolymer for photoactivated chemotherapy in hypoxic tumor environment. The polymer has a hydrophilic poly(ethylene glycol) block and a hydrophobic Ru‐containing block, which contains red‐light‐cleavable (650–680 nm) drug–Ru complex conjugates. The block copolymer self‐assembles into micelles, which can be efficiently taken up by cancer cells. Red light induces release of the drug–Ru complex conjugates from the micelles and this process is oxygen independent. The released conjugates inhibit tumor cell growth even in hypoxic tumor environment. Furthermore, the Ru‐containing polymer for photoactivated chemotherapy in a tumor‐bearing mouse model is applied. Photoactivated chemotherapy of the polymer micelles demonstrates efficient tumor growth inhibition. In addition, the polymer micelles do not cause any toxic side effects to mice during the treatment, demonstrating good biocompatibility of the system to the blood and healthy tissues. The novel red‐light‐responsive Ru‐containing polymer provides a new platform for phototherapy against hypoxic tumors.     

Upconversion Nanocarriers Encapsulated with Photoactivatable Ru Complexes for Near‐Infrared Light‐Regulated Enzyme Activity

Enzyme activity is important for metabolism, cell functions, and treating diseases. However, remote control of enzyme activity in deep tissue remains a challenge. This study demonstrates near‐infrared (NIR) light‐regulated enzyme activity in living cells based on upconverting nanoparticles (UCNPs) and a photoactivatable Ru complex. The Ru complex is a caged enzyme inhibitor that can be activated by blue light. To prepare a nanocarrier for NIR photoinhibition of enzyme activity, a UCNP and the caged enzyme inhibitors are encapsulated in a hollow mesoporous silica nanoparticle. In such a nanocarrier, the UCNP can harvest NIR light and convert it into blue light, which can activate the caged enzyme inhibitors. This photoactivation process is feasible in deep tissue because of the tissue penetration ability of NIR light. The nanocarrier is compatible to LNCaP, PC3, and SAOS‐2 cells, which show high enzyme expression. NIR irradiation induces release of the inhibitors and inhibition of enzyme activity in living cells. NIR light provides high spatiotemporal resolution to regulate enzyme activity in deep tissue.