Sea urchin-like Bi2S3/curcumin heterojunction rapidly kills bacteria and promotes wound healing under near-infrared light.

Bacterial infection is an urgent public health problem. We design a novel photo-responsive hybrid material by growing small molecules of curcumin (Cur) in situ on a sea urchin-like Bi2S3 surface by a one-step hydrothermal reaction method, thus forming an organic-inorganic hybrid material with interfacial contact. The Bi2S3/Cur hybrid material has good antibacterial effect under 808 nm near-infrared (NIR) light irradiation. The antibacterial mechanism is that the electron redistribution at the interface of Bi2S3/Cur excited by 808 nm NIR light will cause a large number of electrons to gather on the side of Bi2S3, forming an internal electric field to drive the excited electrons from Bi2S3 to Cur, which accelerates the separation of photoexcited electron-hole pairs and enhances the production of reactive oxygen species (ROS). In conclusion, due to these synergistic effects of the photothermal properties of Bi2S3, the production of more ROS and the release of small molecules of Cur from traditional Chinese medicine in Bi2S3/Cur, the antibacterial efficacy against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) is 99.96% and 99.03%, respectively. In vivo experiments in animals show that Bi2S3/Cur can reduce the inflammatory response and promote wound healing. This paper presents a simple, rapid and safe strategy for the treatment of wound infections with near-infrared light.

Photoelectrons Mediating Angiogenesis and Immunotherapy through Heterojunction Film for Noninvasive Disinfection.

A light-inspired hydroxyapatite (Hap)/nitrogen-doped carbon dots (NCDs) modified graphene oxide (GO) heterojunction film is developed, which shows a promoted separation of interfacial electrons and holes and an inhibited recombination efficiency via hole depletion. The metabolism of bacteria on this film is significantly inhibited under light irradiation, due to the enhanced photocatalytic and photothermal effects. In addition, the electron transfer from the plasmonic membrane to the GO/NCD/Hap film further inhibits the adenosine triphosphate process of bacteria, thus leading to the synergetic antibacterial efficacy. Meanwhile, the electron transfer between film and cell membrane induces the Ca2+ flow after irradiation, which can promote the migration and proliferation of cells and alkaline phosphatase enhancement, thus favoring the tissue reconstruction. An in vivo test discloses that the vascular injury repair is achieved through the Ca2+-activated PLCγ1/ERK pathway, identified by the enhanced CD31 expression. Moreover, the increased CD4+/CD8+ lymphocytes are ameliorative by activating the PI3K/P-AKT pathway. Consequently, the electron transfer boosts the synergic photodynamic and photothermal therapeutic effects for bacterial infection by Ca2+ flow for immunotherapy. This mild phototherapy approach with GO/NCDs/Hap, which can simultaneously repair injured vessels and relieve inflammation reactions, will increase the clinical application of noninvasive phototherapy in the near future.

Near-Infrared Light Triggered Phototherapy and Immunotherapy for Elimination of Methicillin-Resistant Staphylococcus aureus Biofilm Infection on Bone Implant.

Clinically, methicillin-resistant Staphylococcus aureus (MRSA) biofilm infection inevitably induces the failure of bone implants. Herein, a hydrophilic and viscous hydrogel of poly(vinyl alcohol) modified with chitosan, polydopamine, and NO release donor was formed on a red phosphorus nanofilm deposited on a titanium implant (Ti-RP/PCP/RSNO). Under the irradiation of near-infrared light (NIR), peroxynitrite (•ONOO-) was formed by the reaction between the released NO and superoxide (•O2-) produced by the RP nanofilm. Specifically, we revealed the antibacterial mechanism of the ONOO- against the MRSA biofilm. In addition, osteogenic differentiation was promoted and inflammatory polarization was regulated by the released NO without NIR irradiation through upregulating the expression of Opn and Ocn genes and TNF-α. The MRSA biofilm was synergistically eradicated by •ONOO-, hyperthermia, and •O2- under NIR irradiation as well as the immunoreaction of the M1 polarization. The in vivo results also confirmed the excellent osteogenesis and biofilm eradication by released NO from the RP/PCP/RSNO system under NIR irradiation, indicating the noninvasive tissue reconstruction of MRSA-infected tissues through phototherapy and immunotherapy.

Lysozyme-Assisted Photothermal Eradication of Methicillin-Resistant Staphylococcus aureus Infection and Accelerated Tissue Repair with Natural Melanosome Nanostructures.

Patients often face the challenge of antibiotic-resistant bacterial infections and lengthy tissue reconstruction after surgery. Herein, human hair-melanosome derivatives (HHMs), comprising keratins and melanins, are developed using a simple "low-temperature alkali heat" method for potentially personalized therapy. The mulberry-shaped HHMs have an average width of ∼270 nm and an average length of ∼700 nm, and the negatively charged HHMs can absorb positively charged Lysozyme (Lyso) to form the HHMs-Lyso composites through electrostatic interaction. These naturally derived biodegradable nanostructures act as exogenous killers to eliminate methicillin-resistant Staphylococcus aureus (MRSA) infection with a high antibacterial efficacy (97.19 ± 2.39%) by synergistic action of photothermy and "Lyso-assisted anti-infection" in vivo. Additionally, HHMs also serve as endogenous regulators of collagen alpha chain proteins through the "protein digestion and absorption" signaling pathway to promote tissue reconstruction, which was confirmed by quantitative proteomic analysis in vivo. Notably, the 13 upregulated collagen alpha chain proteins in the extracellular matrix (ECM) after HHMs treatment demonstrated that keratin from HHMs in collagen-dependent regulatory processes serves as a notable contributor to augmented wound closure. The current paradigm of natural material-tissue interaction regulates the cell-ECM interaction by targeting cell signaling pathways to accelerate tissue repair. This work may provide insight into the protein-level pathways and the potential mechanisms involved in tissue repair.