Hydrogel Coatings of Implants for Pathological Bone Repair.

Hydrogels are well-suited for biomedical applications due to their numerous advantages, such as excellent bioactivity, versatile physical and chemical properties, and effective drug delivery capabilities. Recently, hydrogel coatings have developed to functionalize bone implants which are biologically inert and cannot withstand the complex bone tissue repair microenvironment. These coatings have shown promise in addressing unique and pressing medical needs. This review begins with the major functionalized performance and interfacial bonding strategy of hydrogel coatings, with a focus on the novel external field response properties of the hydrogel. Recent advances in the fabrication strategies of hydrogel coatings and their use in the treatment of pathologic bone regeneration are highlighted. Finally, challenges and emerging trends in the evolution and application of physiological environment-responsive and external electric field-responsive hydrogel coatings for bone implants are discussed.

Localized Surface Plasmon Resonance-Enhanced Photocatalytic Antibacterial of In-situ Sprayed 0D/2D Heterojunction Composite Hydrogel for Treating Diabetic Wound.

Chronic diabetic wounds pose significant challenges due to uncontrolled bacterial infections, prolonged inflammation, and impaired angiogenesis. The rapid advancement of photo-responsive antibacterial therapy showed promise in addressing these complex issues, particularly utilizing 2D heterojunction materials, which offer unique properties. Herein, we designed an in situ sprayed Bi/BiOCl 0D/2D heterojunction composite fibrin gel with the characteristics of rapid formation and effective near-infrared activation for the treatment of non-healing diabetes-infected wounds. The sprayed composite gel can provide protective shielding for skin tissues and promote endothelial cell proliferation, vascularization, and angiogenesis. The Bi/BiOCl 0D/2D heterojunction, with its localized surface plasmon resonance (LSPR), can overcome the wide bandgap limitation of BiOCl, enhancing the generation of local heat and reactive oxygen species under near-infrared irradiation. This facilitated bacterial elimination and reduced inflammation, supporting the accelerated healing of diabetes-infected wounds. Our study underscores the potential of LSPR-enhanced heterojunctions as advanced wound therapies for chronic diabetic wounds. This article is protected by copyright. All rights reserved.

NIR-responsive micropatterned nanocomposite functionalized implant for sequential antibacterial and osteogenesis.

The long-term durability of the implant is influenced by two significant clinical challenges, namely bacterial infection and fixation loosening. Conventional implant materials have failed to meet the demands of the dynamic process of infectious bone repair, which necessitates early-stage bacterial sterilization and a conducive environment for late-stage osteogenesis. Consequently, there is an urgent requirement for an implant material that can sequentially regulate antibacterial properties and promote osteogenesis. The study aimed to develop a micropatterned graphene oxide nanocomposite on titanium implant (M-NTO/GO) for the sequential management of bacterial infection and osteogenic promotion. M-NTO/GO exhibited a micropattern nanostructure surface and demonstrated responsiveness to near-infrared (NIR) light. Upon NIR light irradiation, M-NTO/GO exhibited effective antibacterial properties, achieving antibacterial rates of 96.9% and 98.6% against E. coli and S. aureus, respectively. Under no-light condition, the micropatterned topography of M-NTO/GO exhibited the ability to induce directed cell growth, enhance cell adhesion and spreading, and facilitate osteogenic differentiation. These findings suggest the successful development of a functionalized micropatterned nanocomposite implant capable of sequentially regulating antibacterial and osteogenesis activity. Consequently, this highly effective strategy holds promise for expanding the potential applications of orthopedic implants.

Space-Confined Synthesis of Thin Polypyrrole Nanosheets in Layered Bismuth Oxychloride for a Photoresponse Antibacterial within the Near-Infrared Window and Accelerated Wound Healing.

Bacterial infection greatly affects the rate of wound healing. Both photothermal and photodynamic antibacterial therapies activated by near-infrared (NIR) light with semiconductor nanomedicine are two effective approaches to address bacterial infections, but they cannot coexist synergistically to kill bacteria more efficiently because of the limitation of the band structure. Here, inspired by the natural core-shell structure and photosynthesis simultaneously, polypyrrole (PPy) is synthesized in the two-dimensional restricted area of the layered bismuth oxychloride (BiOCl) nanosheets through the in situ ultrasonic recombination method. The atomic-level interface contact and bonding formed in the PPy-BiOCl intercalated nanosheets not only improve the light-to-heat conversion capabilities of PPy but also promote the transmission of PPy photogenerated charge carriers to the BiOCl semiconductor. The nanocomposites take advantage of the deeper tissue penetration under NIR light irradiation and exhibit excellent photothermal and photodynamic synergistic antibacterial activity. In addition, PPy-BiOCl intercalated nanosheets have good biocompatibility and accelerate wound healing through their antimicrobial activity and skin repair function. The space-confined synthesis of thin PPy nanosheets in layered structures offers an efficient NIR photoresponsive nanomedicine for the treatment of pathogen infection, with promising applications in infected wound healing.

Programmable biological state-switching photoelectric nanosheets for the treatment of infected wounds.

Recurrent bacterial infection is a major problem that threatens the tissue repair process. However, most current therapeutic strategies fail to deal with management of the overlap dynamics of bacterial killing and tissue repair. Here, in accord with the different responses of eukaryotic and prokaryotic cells to electric potential, we developed high performance photoelectric BiOCl nanosheets that dynamically switch between conditions that favor either tissue regrowth or antibacterial microenvironments due to light stimulated and bi-modal switching of their surface electrical polarization. In vitro assays demonstrate that, under light illumination, the mannitol modified BiOCl nanosheets show high relative surface potential and achieve robust antibacterial performance. Conversely, under dark conditions, the nanosheets exhibit relatively low surface potential and promote Bone Marrow Stem Cell (BMSCs) proliferation. In vivo studies indicate that BiOCl nanosheets with light switch capabilities promote the significant regeneration of infected skin wounds. This work offers a new insight into treating recurrent bacterial infections with photoelectric biomaterials for light controlled selection of alternative electrical microenvironments, thereby benefiting the capability for either antisepsis or repair of damaged tissues.

Enhancement of solar-driven photocatalytic activity of oxygen vacancy-rich Bi/BiOBr/Sr2LaF7:Yb3+,Er3+ composites through synergetic strategy of upconversion function and plasmonic effect.

For better use of solar energy, the development of efficient broadband photocatalyst has attracted extraordinary attention. In this study, a ternary composite consisting of Sr2LaF7:Yb3+,Er3+ upconversion (UC) nanocrystals and Bi nanoparticles loaded BiOBr nanosheets with oxygen vacancies (OVs, SLFBB) was designed and synthesized by multistep solvent-thermal method. Mechanisms of in-situ formation of Bi nanoparticles and OVs in BiOBr/Sr2LaF7:Yb3+,Er3+ composites (SFLB) are clarified. The Bi metal and OVs enhanced the light-harvesting capacity in the region of visible-near-infrared (Vis-NIR), and promoted the separation of electron-hole (e-/h+) pairs. Furthermore, the surface plasmon resonance (SPR) effect of Bi metal can improve the energy transfer from Sr2LaF7:Yb3+,Er3+ to BiOBr via nonradiative energy transfer process, resulting in enhancing the light utilization from upconverting NIR into Vis light. Due to the synergistic effects of UC function, SPR and OVs, the SFLBB exhibited obviously enhanced photocatalytic ability for the degradation of BPA with a rate of 8.9 × 10-3 min-1, which is about 2.78 times higher than 3.2 × 10-3 min-1 of BiOBr (BOB) under UV-Vis-NIR light irradiation. This work provides a novel strategy for the project of high-efficiency Bismuth-based broadband photocatalysts, which is helpful to further understand the mechanism of enhanced photocatalysis by UC function and plasmonic effect.