Photodynamic therapy (PDT) is an important technique to deal with drug-resistant bacterial infections in the post-antibiotic era. However, the hypoxic environment in intractable infections such as refractory keratitis and periodontitis, makes PDT more difficult. In this work, spontaneous oxygen-producing cyanobacteria were used as the carrier of photosensitizer (Ce6), and ultrasmall Cu
5.4
O nanoparticles (Cu
5.4
O USNPs) with catalase activity for infection and inflammation elimination and rapid tissue repair (CeCycn-Cu
5.4
O). The loading of Ce6 and Cu
5.4
O USNPs onto cyanobacteria surface were confirmed by transmission electron microscopy, nano particle size analyzer, scanning electron microscopy.
In vitro
sterilization and biofilm removal experiments demonstrated that the restriction of hypoxic environment to PDT was significantly alleviated due to the oxygen production of cyanobacteria. Under laser irradiation, the close transfer of energy photons to oxygen produced by cyanobacteria reduced more than 90% of Ce6 dosages (660 nm, 200 mW/cm
2
, 2 min). It is worth mentioning that both rapid sterilization through PDT and long-term oxidized free radicals elimination were achieved by adjusting the ratio of Ce6 and Cu
5.4
O USNPs. Both periodontitis and refractory keratitis animal models proved the excellent self-oxygenation enhanced antibacterial property and promotion of tissue repair.
According to International Diabetes Federation Diabetes Atlas statistics, diabetic retinopathy (DR) is the leading cause of vision loss in blinding diseases. The underlying cause of retinal vasculopathy progression in diabetic patients is hyperglycemia and hypoxia features in microvascular region. Hence, cyanobacteria are used as carriers to load both gold nanoparticles (Au NPs) with glucose oxidase‐like activity and iridium nanoparticles (Ir NPs) with catalase‐like activity, respectively (Cyano@Au@Ir). The Au NPs nanozyme first degrades glucose into hydrogen peroxide, which is further decomposed into H2O and O2 by the Ir NPs to complete the cascade hypoglycemic reaction. Based on the unique light transmittance of eyeball and the accumulation of light in the retinal area, the sustainable O2 production by Cyano greatly alleviates the hypoxia of microenvironment, leading to the decrease of angiogenic growth factor and hypoxia‐inducible factor expressions. Simultaneously, the highly expressed peroxide in the DR microenvironment can also be eliminated by Ir NPs for anti‐inflammatory property. Furthermore, it is demonstrated in DR animal model that Cyano@Au@Ir significantly reduces neovascular progression and vascular leakage. This novel treatment mode fundamentally degrades blood glucose, continuously supplies O2, and scavenges free radicals for comprehensive microenvironment regulation, providing inspirations for solving fundus complications of DR.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.