Ferrocene-functionalized hybrid hydrogel dressing with high-adhesion for combating biofilm

Current strategies for monitoring and controlling bacterial biofilm formation on medical surfaces

Biofilms, intricate microbial communities that attach to surfaces, especially medical devices, form an exopolysaccharide matrix, which enables bacteria to resist environmental pressures and conventional antimicrobial agents, leading to the emergence of multi-drug resistance. Biofilm-related infections associated with medical devices are a significant public health threat, compromising device performance. Therefore, developing effective methods for supervising and managing biofilm growth is imperative. This in-depth review presents a systematic overview of strategies for monitoring and controlling bacterial biofilms. We first outline the biofilm creation process and its regulatory mechanisms. The discussion then progresses to advancements in biosensors for biofilm detection and diverse treatment strategies. Lastly, this review examines the obstacles and new perspectives associated with this domain to facilitate the advancement of innovative monitoring and control solutions. These advancements are vital in combating the spread of multi drug-resistant bacteria and mitigating public health risks associated with infections from biofilm formation on medical instruments.

Nanozybiotics: Advancing Antimicrobial Strategies Through Biomimetic Mechanisms

Infectious diseases caused by bacterial, viral, and fungal pathogens present significant global health challenges. The rapid emergence of antimicrobial resistance exacerbates this issue, leading to a scenario where effective antibiotics are increasingly scarce. Traditional antibiotic development strategies are proving inadequate against the swift evolution of microbial resistance. Therefore, there is an urgent need to develop novel antimicrobial strategies with mechanisms distinct from those of existing antibiotics. Nanozybiotics, which are nanozyme-based antimicrobials, mimic the catalytic action of lysosomal enzymes in innate immune cells to kill infectious pathogens. This review reinforces the concept of nanozymes and provides a comprehensive summary of recent research advancements on potential antimicrobial candidates. Initially, nanozybiotics are categorized based on their activities, mimicking either oxidoreductase-like or hydrolase-like functions, thereby highlighting their superior mechanisms in combating antimicrobial resistance. The review then discusses the progress of nanozybiotics in treating bacterial, viral, and fungal infections, confirming their potential as novel antimicrobial candidates. The translational potential of nanozybiotic-based products, including hydrogels, nanorobots, sprays, bandages, masks, and protective clothing, is also considered. Finally, the current challenges and future prospects of nanozybiotic-related products are explored, emphasizing the design and antimicrobial capabilities of nanozybiotics for future applications.

Antibacterial Chemodynamic Therapy: Materials and Strategies

The wide and frequent use of antibiotics in the treatment of bacterial infection can cause the occurrence of multidrug-resistant bacteria, which becomes a serious health threat. Therefore, it is necessary to develop antibiotic-independent treatment modalities. Chemodynamic therapy (CDT) is defined as the approach employing Fenton and/or Fenton-like reactions for generating hydroxyl radical (•OH) that can kill target cells. Recently, CDT has been successfully employed for antibacterial applications. Apart from the common Fe-mediated CDT strategy, antibacterial CDT strategies mediated by other metal elements such as copper, manganese, cobalt, molybdenum, platinum, tungsten, nickel, silver, ruthenium, and zinc have also been proposed. Furthermore, different types of materials like nanomaterials and hydrogels can be adopted for constructing CDT-involved antibacterial platforms. Besides, CDT can introduce some toxic metal elements and then achieve synergistic antibacterial effects together with reactive oxygen species. Finally, CDT can be combined with other therapies such as starvation therapy, phototherapy, and sonodynamic therapy for achieving improved antibacterial performance. This review first summarizes the advancements in antibacterial CDT and then discusses the present limitations and future research directions in this field, hoping to promote the development of more effective materials and strategies for achieving potentiated CDT.

In situ gelation strategy based on ferrocene-hyaluronic acid organic copolymer biomaterial for exudate management and multi-modal wound healing

Exudate management remains a major concern in slow or non-healing wound management. Therefore, there is a need to devise a massive exudate-absorbing, exudate-locking, and stable extracellular matrix structure-maintaining functional wound dressing. Inspired by metal-organic frameworks, we chemically introduced sandwich ferrocene (Fc) into hyaluronic acid (HA) to fabricate an innovative metal Fc-HA organic copolymer (FHoC) as the skeleton material for in situ gelation, which was then gently compressed into a pre-hydrogel patch (FHoCP). Fc promoted the rearrangement of polymer chains to form additional microcrystalline and hydrophobic regions, which improved hydrogel transition and the exudate-locking ability. Thus, the simple composition FHoCP(5) absorbed 150 times its weight of water and maintained a firm three-dimensional network, which contributed to reducing inflammation and acted as a physical barrier against hemostasis and anti-bacterial invasion. Meanwhile, multi-modal processes, including fibroblast migration, angiogenesis, and antibacterial effects, were integrated into the gelled FHoCP(5) guided by Fe to promote wound healing. This study suggested that FHoC biomaterial could accelerate the closure of chronic wounds. We believe that this unique FHoCP(5)-based in situ gelation strategy could provide a solid drug-loaded scaffold for cell or adjunctive drug therapies, which holds great potential for the development of multifunctional biomaterials. STATEMENT OF SIGNIFICANCE: Hydrogels that absorb excessive exudates while maintaining stable ECM-like network as well as exert multimodal wound healing activities are ideal dressings for accelerating chronic wound contraction. Herein, we reported an innovative metal ferrocene-hyaluronic acid organic copolymer patch (FHoCP) and FHoCP-mediated in situ gelation strategy. Ferrocene (Fc) induced in situ gelation by promoting polymer chain rearrangement, acting as a physical barrier for hemostasis and anti-bacterial invasion, and absorbing massive exudates, resulting in reducing delayed inflammation. As the structural core, rigid Fc enhanced the stability of the hydrogel backbone, and hydrophobic Fc improved fibroblast migration. In addition, Fe²⁺ chemically inhibited bacteria and increased angiogenesis. These results indicated the potential of FHoCP-based hydrogel for application in clinical skin reconstruction.

Progress in hydrogels for skin wound repair

As the first defensive line between the human body and the outside world, the skin is vulnerable to damage from the external environment. Skin wounds can be divided into acute wounds (mechanical injuries, chemical injuries and surgical wounds, etc.) and chronic wounds (burns, infections, diabetes, etc.). In order to manage skin wound, a variety of wound dressings have been developed, including gauze, films, foams, nanofibers, hydrocolloids and hydrogels. Recently, hydrogels have received much attention because of their natural extracellular matrix (ECM)-mimik structure, tunable mechanical properties, and facile bioactive substance delivery capability. They show great potential application in skin wound repair. This paper first introduces the anatomy and function of the skin, the process of wound healing and conventional wound dressings, and then introduces the composition and construction methods of hydrogels. Next, this paper introduces the necessary properties of hydrogels in skin wound repair and the latest research progress of hydrogel dressings for skin wound repair. Finally, the future development goals of hydrogel materials in the field of wound healing are proposed. This article is protected by copyright. All rights reserved.

Chemodynamic Therapy via Fenton and Fenton-Like Nanomaterials: Strategies and Recent Advances

Chemodynamic therapy (CDT), a novel cancer therapeutic strategy defined as the treatment using Fenton or Fenton-like reaction to produce •OH in the tumor region, was first proposed by Bu, Shi, and co-workers in 2016. Recently, with the rapid development of Fenton and Fenton-like nanomaterials, CDT has attracted tremendous attention because of its unique advantages: 1) It is tumor-selective with low side effects; 2) the CDT process does not depend on external field stimulation; 3) it can modulate the hypoxic and immunosuppressive tumor microenvironment; 4) the treatment cost of CDT is low. In addition to the Fe-involved CDT strategies, the Fenton-like reaction-mediated CDT strategies have also been proposed, which are based on many other metal elements including copper, manganese, cobalt, titanium, vanadium, palladium, silver, molybdenum, ruthenium, tungsten, cerium, and zinc. Moreover, CDT has been combined with other therapies like chemotherapy, radiotherapy, phototherapy, sonodynamic therapy, and immunotherapy for achieving enhanced anticancer effects. Besides, there have also been studies that extend the application of CDT to the antibacterial field. This review introduces the latest advancements in the nanomaterials-involved CDT from 2018 to the present and proposes the current limitations as well as future research directions in the related field.

Highly Flexible Hydrogel Dressing with Efficient Antibacterial, Antioxidative, and Wound Healing Performances

Bacterial induced wound infection is very common in real life, but the abuse of antibiotics brings a potential threat to human health. The development of non-antibiotic type antibacterial materials appears...

Pd-Cu nanoalloy for dual stimuli-responsive chemo-photothermal therapy against pathogenic biofilm bacteria

Photothermal therapy (PTT) is a promising strategy for antimicrobial therapy. However, the application of PTT to treat bacterial infections remains a challenge as the high temperature required for bacterial elimination can partly damage healthy tissues. Selecting the appropriate treatment temperature is therefore a key factor for PTT. In this work, we designed a near-infrared/pH dual stimuli-responsive activated procedural antibacterial system based on zeolitic imidazolate framework-8 (ZIF-8), which was bottom-up synthesized and utilized to encapsulate both Pd-Cu nanoalloy (PC) and the antibiotic amoxicillin (AMO). This procedural antibacterial therapy comprises chemotherapy (CT) and PTT. The former disrupts the bacterial cell wall by releasing AMO in an acidic environment, which depends on the sensitive response of ZIF-8 to pH value change. With the progression in time, the AMO release rate decreased gradually. The latter can then significantly stimulate drug release and further complete the antibacterial effect. This impactful attack consisted of two waves that constitute the procedural therapy for bacterial infection. Accordingly, the treatment temperature required for antibacterial therapy can be significantly lowered under this mode of treatment. This antibacterial system has a significant therapeutic effect on planktonic bacteria (G⁺/G^-) and their biofilms and also has good biocompatibility; thus, it provides a promising strategy to develop an effective and safe treatment against bacterial infections. STATEMENT OF SIGNIFICANCE: We have developed a near infrared/pH dual stimuli-responsive activated procedural antibacterial system that combines enhanced antibiotic delivery with photothermal therapy and has highly efficient antimicrobial activity. The antibacterial effect of this therapy was based on two mechanisms of action: chemotherapy, in which the bacterial cell wall was first destroyed, followed by photothermal therapy. After exposure to irradiation with an 808 nm laser, the inhibition rates were 99.8% and 99.1% for Staphylococcus aureus and Pseudomonas aeruginosa, respectively, and the clearance rates for their established biofilms were 75.3% and 74.8%, respectively. Thus, this procedural antibacterial therapy has shown great potentiality for use in the photothermal therapy of bacterial infectious diseases, including biofilm elimination.

Synthesis and characterization of photothermal antibacterial hydrogel with enhanced mechanical properties

Based on Fe3O4 nanoparticles, a hydrogel with controllable crosslinking density, good mechanical properties, photothermal and antibacterial abilities was constructed.