A fingerprint-like supramolecular-assembled Ag3PO4/polydopamine/g-C3N4 heterojunction nanocomposite for enhanced solar-driven oxygen evolution in vivo

Biocompatible photocatalytic water-splitting systems are promising for tissue self-oxygenation. Herein, a structure-function dual biomimetic fingerprint-like silver phosphate/polydopamine/graphitic carbon nitride (Ag3PO4/PDA/g-C3N4) heterojunction nanocomposite is proposed for enhanced solar-driven oxygen (O2) evolution in vivo in situ. Briefly, a porous nitrogen-defected g-C3N4 nanovoile (CN) is synthesized as the base. Dopamine molecules are controllably inserted into the CN interlayer, forming PDA spacers (4.28 nm) through self-polymerization-induced supramolecular-assembly. Ag3PO4 nanoparticles are then in situ deposited to create Ag3PO4/PDA/CN. The fingerprint-like structure of PDA/CN enlarges the layer spacing, thereby accelerating mass transfer and increasing reaction sites. The PDA spacer roles as excellent light harvester, electronic-ionic conductor, and redox pair through conformational changes, resulting in tailored electronic band structure, optimized carrier behavior, and reduced electrochemical impedance. In physiological conditions, Ag3PO4/PDA/CN exhibits O2 evolution rate of 45.35 μmol⋅g-1⋅h-1, 9-fold of bulk g-C3N4. The biocompatibility and in vivo oxygen supply effectiveness for biomedical applications have been verified in animal models.

A Poloxamer 407/chitosan-based thermosensitive hydrogel dressing for diabetic wound healing via oxygen production and dihydromyricetin release

The current clinical treatment of diabetic wounds is still based on oxygen therapy, and the slow healing of skin wounds due to hypoxia has always been a key problem in the repair of chronic skin injuries. To overcome this problem, the oxygen-producing matrix CaO2NPS based on the temperature-sensitive dihydromyricetin-loaded hydrogel was prepared. In vitro activity showed that the dihydromyricetin (DHM) oxygen-releasing temperature-sensitive hydrogel composite (DHM-OTH) not only provided a suitable oxygen environment for cells around the wound to survive but also had good biocompatibility and various biological activities. By constructing a T2D wound model, we further investigated the repairing effect of DHM-OTH on chronic diabetic skin wounds and the mechanisms involved. DHM-OTH was able to reduce inflammatory cells and collagen deposition and promote angiogenesis and cell proliferation for diabetic wound healing. These in vitro and in vivo data suggest that DHM-OTH accelerates diabetic wound repair as a novel method to efficiently deliver oxygen to wound tissue, providing a promising strategy to improve diabetic wound healing.

Antibacterial microneedle patch releases oxygen to enhance diabetic wound healing

Cell growth and metabolism require an adequate supply of oxygen. However, obtaining sufficient oxygen from the blood circulating around diabetic wounds is challenging. Nevertheless, achieving a continuous and stable oxygen supply is required for these wounds to heal. Hence, in this study, we report a novel antibacterial oxygen-producing silk fibroin methacryloyl hydrogel microneedle (MN) patch comprising tips encapsulated with calcium peroxide and catalase and a base coated with antibacterial Ag nanoparticles (AgNPs). The tip of the MN patch continuously releases oxygen and inhibits the production of reactive oxygen species. This accelerates diabetic wound healing by promoting cellular accretion and migration, macrophage M2 polarization, and angiogenesis. The AgNPs at the base of the MN patch effectively combat microbial infection, further facilitating wound repair. These findings suggest that using this multifunctional oxygen-producing MN patch may be a promising strategy for diabetic wound healing in clinical settings.

Synergistic chemotherapy/PTT/oxygen enrichment by multifunctional liposomal polydopamine nanoparticles for rheumatoid arthritis treatment

Amultifunctional liposomal polydopamine nanoparticle (MPM@Lipo) was designed in this study, to combine chemotherapy, photothermal therapy (PTT) and oxygen enrichment to clear hyperproliferating inflammatory cells and improve the hypoxic microenvironment for rheumatoid arthritis (RA) treatment. MPM@Lipo significantly scavenged intracellular reactive oxygen species and relieved joint hypoxia, thus contributing to the repolarization of M1 macrophages into M2 phenotype. Furthermore, MPM@Lipo could accumulate at inflammatory joints, inhibit the production of inflammatory factors, and protect cartilage in vivo, effectively alleviating RA progression in a rat adjuvant-induced arthritis model. Moreover, upon laser irradiation, MPM@Lipo can elevate the temperature to not only significantly obliterate excessively proliferating inflammatory cells but also accelerate the production of methotrexate and oxygen, resulting in excellent RA treatment effects. Overall, the use of synergistic chemotherapy/PTT/oxygen enrichment therapy to treat RA is a powerful potential strategy.