Abstract
Owing to the poor penetration depth of light, phototherapy, including photothermal and photodynamic therapies, remains severely ineffective in treating deep tissue infections such as ...methicillin-resistant
Staphylococcus aureus
(MRSA)-infected osteomyelitis. Here, we report a microwave-excited antibacterial nanocapturer system for treating deep tissue infections that consists of microwave-responsive Fe
3
O
4
/CNT and the chemotherapy agent gentamicin (Gent). This system, Fe
3
O
4
/CNT/Gent, is proven to efficiently target and eradicate MRSA-infected rabbit tibia osteomyelitis. Its robust antibacterial effectiveness is attributed to the precise bacteria-capturing ability and magnetic targeting of the nanocapturer, as well as the subsequent synergistic effects of precise microwaveocaloric therapy from Fe
3
O
4
/CNT and chemotherapy from the effective release of antibiotics in infection sites. The advanced target-nanocapturer of microwave-excited microwaveocaloric-chemotherapy with effective targeting developed in this study makes a major step forward in microwave therapy for deep tissue infections.
Clinically, it is difficult to endow implants with excellent osteogenic ability and antibacterial activity simultaneously. Herein, the self-activating implants modified with hydroxyapatite (HA)/MoS
...coating are designed to prevent Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) infections and accelerate bone regeneration simultaneously. The electron transfer between bacteria and HA/MoS
is triggered when bacteria contacted with the material. RNA sequencing data reveals that the expression level of anaerobic respiration-related genes is up-regulated and the expression level of aerobic respiration-related genes is down-regulated when bacteria adhere to the implants. HA/MoS
presents a highly effective antibacterial efficacy against both S. aureus and E. coli because of bacterial respiration-activated metabolic pathway changes. Meanwhile, this coating promotes the osteoblastic differentiation of mesenchymal stem cells by altering the potentials of cell membrane and mitochondrial membrane. The proposed strategy exhibits great potential to endow implants with self-activating anti-infection performance and osteogenic ability simultaneously.
Despite the widespread observations on the osteogenic effects of magnesium ion (Mg
), the diverse roles of Mg
during bone healing have not been systematically dissected. Here, we reveal a previously ...unknown, biphasic mode of action of Mg
in bone repair. During the early inflammation phase, Mg
contributes to an upregulated expression of transient receptor potential cation channel member 7 (TRPM7), and a TRPM7-dependent influx of Mg
in the monocyte-macrophage lineage, resulting in the cleavage and nuclear accumulation of TRPM7-cleaved kinase fragments (M7CKs). This then triggers the phosphorylation of Histone H3 at serine 10, in a TRPM7-dependent manner at the promoters of inflammatory cytokines, leading to the formation of a pro-osteogenic immune microenvironment. In the later remodeling phase, however, the continued exposure of Mg
not only lead to the over-activation of NF-κB signaling in macrophages and increased number of osteoclastic-like cells but also decelerates bone maturation through the suppression of hydroxyapatite precipitation. Thus, the negative effects of Mg
on osteogenesis can override the initial pro-osteogenic benefits of Mg
. Taken together, this study establishes a paradigm shift in the understanding of the diverse and multifaceted roles of Mg
in bone healing.
MXenes have emerged as potential antimicrobial materials. Here, the authors report on the creation of a Schottky junction to increase the charge separation between MXenes and semiconductor to ...increase photodynamic creation of reactive oxygen species under near infrared irradiation for antibacterial purposes.
Metallic lithium (Li) is a promising anode material for next‐generation rechargeable batteries. However, the dendrite growth of Li and repeated formation of solid electrolyte interface during Li ...plating and stripping result in low Coulombic efficiency, internal short circuits, and capacity decay, hampering its practical application. In the development of stable Li metal anode, the current collector is recognized as a critical component to regulate Li plating. In this work, a lithiophilic Cu‐CuO‐Ni hybrid structure is synthesized as a current collector for Li metal anodes. The low overpotential of CuO for Li nucleation and the uniform Li+ ion flux induced by the formation of Cu nanowire arrays enable effective suppression of the growth of Li dendrites. Moreover, the surface Cu layer can act as a protective layer to enhance structural durability of the hybrid structure in long‐term running. As a result, the Cu‐CuO‐Ni hybrid structure achieves a Coulombic efficiency above 95% for more than 250 cycles at a current density of 1 mA cm−2 and 580 h (290 cycles) stable repeated Li plating and stripping in a symmetric cell.
A lithiophilic Cu‐CuO‐Ni hybrid structure is synthesized on a Ni foam substrate as a current collector for lithium (Li) metal anodes. The collective effects of low overpotential of the Cu‐CuO‐Ni hybrid structure for Li nucleation, nanowire array configuration, and the Cu buffer layer are demonstrated to be keys for achieving an outstanding overall performance of the current collector.
Seawater electrolysis under alkaline conditions presents an attractive alternative to traditional freshwater electrolysis for mass sustainable high‐purity hydrogen production. However, the lack of ...active and robust electrocatalysts severely impedes the industrial application of this technology. Herein, carbon‐doped nanoporous cobalt phosphide (C‐Co2P) prepared by electrochemical dealloying is reported as an electrocatalyst for hydrogen evolution reaction (HER). The C‐Co2P achieves an overpotential of 30 mV at a current density of 10 mA cm−2 in 1 m KOH, along with impressive catalytic activity and stability at large current densities in artificial alkaline seawater electrolyte containing mixed chlorides of NaCl, MgCl2, and CaCl2. Experimental analysis and density functional theory calculations reveal that the C atom with strong electronegativity and small atomic radius can tailor the electronic structure of Co2P, leading to weakened Co–H bonding toward promoted HER kinetics. Moreover, the C doping introduces a two‐stepped H delivery pathway by forming C–Had intermediate, thus reducing the energy barrier of water dissociation. This study offers a new vision toward the development of seawater electrolysis for large‐scale hydrogen production.
Seawater electrolysis under alkaline conditions presents an attractive alternative to traditional freshwater electrolysis for mass sustainable high‐purity hydrogen production. Nanoporous carbon‐doped cobalt phosphide provides a hydrogen delivery pathway for water dissociation and optimizes desorption of hydrogen due to the electrons modulation by carbon doping, resulting in efficient catalytic activity and durability toward alkaline hydrogen evolution.
Owing to the existence of the outer membrane barrier, most antibacterial agents cannot penetrate Gram-negative bacteria and are ineffective. Here, we report a general method for narrow-spectrum ...antibacterial Garcinia nanoparticles that can only be effective to kill Gram-positive bacteria, to effectively eliminate Gram-negative bacteria by creating transient nanopores in bacterial outer membrane to induce drug entry under microwaves assistance. In vitro, under 15 min of microwaves irradiation, the antibacterial efficiency of Garcinia nanoparticles against Escherichia coli can be enhanced from 6.73% to 99.48%. In vivo, MV-assisted GNs can effectively cure mice with bacterial pneumonia. The combination of molecular dynamics simulation and experimental results reveal that the robust anti-E. coli effectiveness of Garcinia nanoparticles is attributed to the synergy of Garcinia nanoparticles and microwaves. This work presents a strategy for effectively treating both Gram-negative and Gram-positive bacteria co-infected pneumonia using herbal medicine nanoparticles with MV assistance as an exogenous antibacterial auxiliary.
Bacterial infection and lack of bone tissue integration are two major concerns of orthopedic implants. In addition, osteoinductivity often decreases and toxicity may arise when antibacterial agents ...are introduced to increase the antibacterial ability. Here hybrid ZnO/polydopamine (PDA)/arginine-glycine-aspartic acid-cysteine (RGDC) nanorod (NR) arrays are designed and prepared on titanium (Ti) implants to not only enhance the osteoinductivity but also effectively kill bacteria simultaneously, which are ascribed to the selective physical puncture and the biofunctionalization of ZnO/PDA/RGDC nanorods during the competition between bacteria and osteoblasts. That is, owing to the much larger size of osteoblasts than bacteria, the hybrid NRs can puncture bacteria but not damage osteoblasts. Meanwhile, the cytocompatibility can be enhanced through the suppression of both reactive oxygen species and higher Zn2+ concentration by the covering of PDA and RGDC. The in vitro results confirm the selective puncture of the bacterial membrane and the better osteoinductivity. In vivo tests also show much higher antibacterial efficacy of the hybrid NRs with far less amounts of lobulated neutrophils and adherent bacteria in the surrounding tissues. In addition, the hybrid NRs also accelerate formation of new bone tissues (20.1% higher than pure Ti) and osteointegration between implants and newly formed tissues (32.0% higher than pure Ti) even in the presence of injected bacteria. This work provides a surface strategy for designing implants with desirable ability of osseointegration and infection prevention simultaneously, which will exhibit tremendous clinical potential in orthopedic and dental applications.
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.
Abstract
In view of increasing drug resistance, ecofriendly photoelectrical materials are promising alternatives to antibiotics. Here we design an interfacial Schottky junction of Bi
2
S
3
/Ti
3
C
2
...T
x
resulting from the contact potential difference between Ti
3
C
2
T
x
and Bi
2
S
3
. The different work functions induce the formation of a local electrophilic/nucleophilic region. The self-driven charge transfer across the interface increases the local electron density on Ti
3
C
2
T
x
. The formed Schottky barrier inhibits the backflow of electrons and boosts the charge transfer and separation. The photocatalytic activity of Bi
2
S
3
/Ti
3
C
2
T
x
intensively improved the amount of reactive oxygen species under 808 nm near-infrared radiation. They kill 99.86% of
Staphylococcus aureus
and 99.92% of
Escherichia coli
with the assistance of hyperthermia within 10 min. We propose the theory of interfacial engineering based on work function and accordingly design the ecofriendly photoresponsive Schottky junction using two kinds of components with different work functions to effectively eradicate bacterial infection.
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