Bone-implant-associated infections are common after orthopedic surgery due to impaired host immune response around the implants. In particular, when a biofilm develops, the immune system and antibiotic treatment find it difficult to eradicate, which sometimes requires a second operation to replace the infected implants. Most strategies have been designed to prevent biofilms from forming on the surface of bone implants, but these strategies cannot eliminate the biofilm when it has been established in vivo. To address this issue, a nonsurgical, noninvasive treatment for biofilm infection must be developed. Herein, a red-phosphorus-IR780-arginine-glycine-aspartic-acid-cysteine coating on titanium bone implants is prepared. The red phosphorus has great biocompatibility and exhibits efficient photothermal ability. The temperature sensitivity of Staphylococcus aureus biofilm is enhanced in the presence of singlet oxygen ( O ) produced by IR780. Without damaging the normal tissue, the biofilm can be eradicated through a safe near-infrared (808 nm) photothermal therapy at 50 °C in vitro and in vivo. This approach reaches an antibacterial efficiency of 96.2% in vivo with 10 min of irradiation at 50 °C. Meanwhile, arginine-glycine-aspartic-acid-cysteine decorated on the surface of the implant can improve the cell adhesion, proliferation, and osteogenic differentiation.

The intrinsic catalytic activity at 10 mA cm for oxygen evolution reaction (OER) is currently working out at overpotentials higher than 320 mV. A highly efficient electrocatalyst should possess both active sites and high conductivity; however, the loading of powder catalysts on electrodes may often suffer from the large resistance between catalysts and current collectors. This work reports a class of bulk amorphous NiFeP materials with metallic bonds from the viewpoint of electrode design. The materials reported here perfectly combine high macroscopic conductivity with surface active sites, and can be directly used as the electrodes with active sites toward high OER activity in both alkaline and acidic electrolytes. Specifically, a low overpotential of 219 mV is achieved at the geometric current density 10 mA cm in an alkaline electrolyte, with the Tafel slope of 32 mV dec and intrinsic overpotential of 280 mV. Meanwhile, an overpotential of 540 mV at 10 mA cm is attained in an acidic electrolyte and stable for over 30 h, which is the best OER performance in both alkaline and acidic media. This work provides a different angle for the design of high-performance OER electrocatalysts and facilitates the device applications of electrocatalysts.

Despite the development of advanced antibacterial materials, bacterial infection is still a serious problem for wound healing because it usually induces severe complications and cannot be eradicated completely. Most current materials cannot simultaneously provide antibacterial activity, reusability, and biocompatibility as well as participate in stimulating cell behaviors to promote bacteria-accompanied wound healing. This work fabricated a hybrid hydrogel embedded with two-dimensional (2D) few-layer black phosphorus nanosheets (BPs) via simple electrostatic interaction. Within 10 min, 98.90% Escherichia coli and 99.51% Staphylococcus aureus can be killed rapidly by this hybrid, due to its powerful ability to produce singlet oxygen (O) under simulated visible light. In addition, this hydrogel also shows a high repeatability; that is, the antibacterial efficacy can still reach up to 95.6 and 94.58% against E. coli and S. aureus, respectively, even after challenging bacteria up to four times repeatedly. In vitro and in vivo results reveal that BPs in this hybrid hydrogel can promote the formation of the fibrinogen at the early stages during the tissue reconstruction process for accelerated incrustation. In addition, BPs can also trigger phosphoinositide 3-kinase (PI3K), phosphorylation of protein kinase B (Akt), and extracellular signal-regulated kinase (ERK1/2) signaling pathways for enhanced cellular proliferation and differentiation. Moreover, the hydrogel causes no appreciable abnormalities or damage to major organs (heart, liver, spleen, lung, and kidney) in rats during the wound healing process. Therefore, this BP-based hydrogel will have great potential as a safe multimodal therapeutic system for active wound healing and sterilization.

The application of photothermal therapy to treat bacterial infections remains a challenge, as the high temperatures required for bacterial elimination can damage healthy tissues. Here, we develop an exogenous antibacterial agent consisting of zinc-doped Prussian blue (ZnPB) that kills methicillin-resistant Staphylococcus aureus in vitro and in a rat model of cutaneous wound infection. Local heat triggered by the photothermal effect accelerates the release and penetration of ions into the bacteria, resulting in alteration of intracellular metabolic pathways and bacterial killing without systemic toxicity. ZnPB treatment leads to the upregulation of genes involved in tissue remodeling, promotes collagen deposition and enhances wound repair. The efficient photothermal conversion of ZnPB allows the use of relatively few doses and low laser flux, making the platform a potential alternative to current antibiotic therapies against bacterial wound infections.

Bacterial infection and associated complications are threats to human health especially when biofilms form on biomedical devices and artificial implants. Herein, a hybrid polydopamine (PDA)/Ag3PO4/graphene oxide (GO) coating is designed and constructed to achieve rapid bacteria killing and eliminate biofilms in situ. By varying the amount of GO in the hybrid coating, the bandgap can be tuned from 2.52 to 2.0 eV so that irradiation with 660 nm visible light produces bacteria-killing effects synergistically in concert with reactive oxygen species (ROS). GO regulates the release rate of Ag+ to minimize the cytotoxicity while maintaining high antimicrobial activity, and a smaller particle size enhances the yield of ROS. After irradiation with 660 nm visible light for 15 min, the antimicrobial rates of the PDA/Ag3PO4/GO hybrid coating against Escherichia coli and Staphylococcus aureus are 99.53% and 99.66%, respectively. In addition, this hybrid coating can maintain a repeatable and sustained antibacterial efficacy. The released Ag+ and photocatalytic Ag3PO4 produce synergistic antimicrobial effects in which the ROS increases the permeability of the bacterial membranes to increase the probability of Ag+ to enter the cells to kill them together with ROS synergistically.

Biofilms have been related to the persistence of infections on medical implants, and these cannot be eradicated because of the resistance of biofilm structures. Therefore, a biocompatible phototherapeutic system is developed composed of MoS 2 , IR780 photosensitizer, and arginine–glycine–aspartic acid–cysteine (RGDC) to safely eradicate biofilms on titanium implants within 20 min. The magnetron‐sputtered MoS 2 film possesses excellent photothermal properties, and IR780 can produce reactive oxygen species (ROS) with the irradiation of near‐infrared (NIR, λ = 700–1100 nm) light. Consequently, the combination of photothermal therapy (PTT) and photodynamic therapy (PDT), assisted by glutathione oxidation accelerated by NIR light, can provide synergistic and rapid killing of bacteria, i.e., 98.99 ± 0.42% eradication ratio against a Staphylococcus aureus biofilm in vivo within 20 min, which is much greater than that of PTT or PDT alone. With the assistance of ROS, the permeability of damaged bacterial membranes increases, and the damaged bacterial membranes become more sensitive to heat, thus accelerating the leakage of proteins from the bacteria. In addition, RGDC can provide excellent biosafety and osteoconductivity, which is confirmed by in vivo animal experiments.

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.

The electrocatalytic nitrogen reduction reaction (NRR) is an alternative eco‐friendly strategy for sustainable N2 fixation with renewable energy. However, NRR suffers from sluggish kinetics owing to difficult N2 adsorption and N≡N cleavage. Now, nanoporous palladium hydride is reported as electrocatalyst for electrochemical N2 reduction under ambient conditions, achieving a high ammonia yield rate of 20.4 μg h−1 mg−1 with a Faradaic efficiency of 43.6 % at low overpotential of 150 mV. Isotopic hydrogen labeling studies suggest the involvement of lattice hydrogen atoms in the hydride as active hydrogen source. In situ Raman analysis and density functional theory (DFT) calculations further reveal the reduction of energy barrier for the rate‐limiting *N2H formation step. The unique protonation mode of palladium hydride would provide a new insight on designing efficient and robust electrocatalysts for nitrogen fixation.