An injectable and biodegradable hydrogel incorporated with photoregulated NO generators to heal MRSA-infected wounds

Sunlight-triggered prebiotic nanomotors for inhibition and elimination of pathogen and biofilm in aquatic environment

Pathogen contamination in drinking water sources causes waterborne infectious diseases, seriously threatening human health. Nowadays, stimuli-responsive self-propelled nanomotors are appealing therapeutic agents for antibacterial therapy in vivo. However, achieving water disinfection using these nanobots is still a great challenge. Herein, we report on prebiotic galactooligosaccharide-based nanomotors for sunlight-regulated water disinfection. The nanomotors can utilize galactooligosaccharide-based N-nitrosamines as sunlight-responsive fuels for the spontaneous production of antibacterial nitric oxide. Such a solar-to-chemical energy conversion would power the nanomotors for self-diffusiophoresis, which could promote the diffusion of the nanomotors in water and their penetration in the biofilm, significantly enhancing the inhibition and elimination of the pathogens and their biofilms in aquatic environments. After water treatments, the prebiotic-based residual disinfectants can be selectively utilized by beneficial bacteria to effectively relieve safety risks to the environment and human health. The low-energy-cost, green and potent antibacterial nanobots show promising potential in water disinfection.

Flexible nanoplatform facilitates antibacterial phototherapy by simultaneously enhancing photosensitizer permeation and relieving hypoxia in bacterial biofilms

Antimicrobial phototherapy has gained recognition as a promising approach for addressing bacterial biofilms, however, its effectiveness is often impeded by the robust physical and chemical defenses of the biofilms. Traditional antibacterial nanoplatforms face challenges in breaching the extracellular polymeric substances barrier to efficiently deliver photosensitizers deep into biofilms. Moreover, the prevalent hypoxia within biofilms restricts the success of oxygen-reliant phototherapy. In this study, we engineered a soft mesoporous organosilica nanoplatform (SMONs) by incorporating polyethylene glycol (PEG), catalase (CAT), and indocyanine green (ICG), forming SMONs-PEG-CAT-ICG (SPCI). We compared the antimicrobial efficacy of SPCI with more rigid nanoplatforms. Our results demonstrated that unique flexible mechanical properties of SPCI enable it to navigate through biofilm barriers, markedly enhancing ICG penetration in methicillin-resistant Staphylococcus aureus (MRSA) biofilms. Notably, in a murine subcutaneous MRSA biofilm infection model, SPCI showed superior biofilm penetration and pharmacokinetic benefits over its rigid counterparts. The embedded catalase in SPCI effectively converts excess H2O2 present in infected tissues into O2, alleviating hypoxia and significantly boosting the antibacterial performance of phototherapy. Both in vitro and in vivo experiments confirmed that SPCI surpasses traditional rigid nanoplatforms in overcoming biofilm barriers, offering improved treatment outcomes for infections associated with bacterial biofilms. This study presents a viable strategy for managing bacterial biofilm-induced diseases by leveraging the unique attributes of a soft mesoporous organosilica-based nanoplatform. STATEMENT OF SIGNIFICANCE: This research introduces an innovative antimicrobial phototherapy soft nanoplatform that overcomes the inherent limitations posed by the protective barriers of bacterial biofilms. By soft nanoplatform with flexible mechanical properties, we enhance the penetration and delivery of photosensitizers into biofilms. The inclusion of catalase within this soft nanoplatform addresses the hypoxia in biofilms by converting hydrogen peroxide into oxygen in infected tissues, thereby amplifying the antibacterial effectiveness of phototherapy. Compared to traditional rigid nanoplatforms, this flexible nanoplatform not only promotes the delivery of therapeutic agents but also sets a new direction for treating bacterial biofilm infections, offering significant implications for future antimicrobial therapies.

Bacterial lipase-responsive polydopamine nanoparticles for detection and synergistic therapy of wound biofilms infection

Wound biofilms represent an elusive conundrum in contemporary treatment and diagnostic options, accredited to their escalating antibiotic resistance and interference in chronic wound healing processes. Here, we developed mesoporous polydopamine (mPDA) nanoparticles, and grafted with rhodamine B (Rb) as biofilm lipase responsive detection probe, followed by π - π stacking mediated ciprofloxacin (CIP) loading to create mP-Rb@CIP nanoparticles. mPDA NPs with a melanin structure could quench fluorescence emissions of Rb. Once encountering biofilm in vivo, the ester bond in Rb and mPDA is hydrolyzed by elevated lipase concentrations, triggering the liberation of Rb and restore fluorescence emissions to achieve real-time imaging of biofilm-infected wounds. Afterwards, the 808 nm near-infrared (NIR) illumination initiates a spatiotemporal controlled antibacterial photothermal therapy (PTT), boosting its effectiveness through photothermal-triggered CIP release for synergistic biofilm eradication. The mP-Rb@CIP platform exhibits dual diagnostic and therapeutic functions, efficaciously treating biofilm-infected wounds in vivo and in vitro. Particularly, the mP-Rb@CIP/NIR procedure expedites wound-healing by alleviating oxidative stress, modulating inflammatory mediators, boosting collagen synthesis, and promoting angiogenesis. Taken together, the theranostic nanosystem strategy holds significant potential for addressing wound biofilm-associated infections.

Nanotechnology-driven strategies to enhance the treatment of drug-resistant bacterial infections

The misuse of antibiotics has led to increased bacterial resistance, posing a global public health crisis and seriously endangering lives. Currently, antibiotic therapy remains the most common approach for treating bacterial infections, but its effectiveness against multidrug-resistant bacteria is diminishing due to the slow development of new antibiotics and the increase of bacterial drug resistance. Consequently, developing new a\ntimicrobial strategies and improving antibiotic efficacy to combat bacterial infection has become an urgent priority. The emergence of nanotechnology has revolutionized the traditional antibiotic treatment, presenting new opportunities for refractory bacterial infection. Here we comprehensively review the research progress in nanotechnology-based antimicrobial drug delivery and highlight diverse platforms designed to target different bacterial resistance mechanisms. We also outline the use of nanotechnology in combining antibiotic therapy with other therapeutic modalities to enhance the therapeutic effectiveness of drug-resistant bacterial infections. These innovative therapeutic strategies have the potential to enhance bacterial susceptibility and overcome bacterial resistance. Finally, the challenges and prospects for the application of nanomaterial-based antimicrobial strategies in combating bacterial resistance are discussed. This article is categorized under: Biology-Inspired Nanomaterials > Nucleic Acid-Based Structures Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.

Mitochondrial Targeted Thermosensitive Nanocarrier for Near-Infrared-Triggered Precise Synergetic Photothermal Nitric Oxide Chemotherapy

Nitric oxide (NO) intervenes, that is, a potential treatment strategy, and has attracted wide attention in the field of tumor therapy. However, the therapeutic effect of NO is still poor, due to its short half-life and instability. Therapeutic concentration ranges of NO should be delivered to the target tissue sites, cell, and even subcellular organelles and to control NO generation. Mitochondria have been considered a major target in cancer therapy for their essential roles in cancer cell metabolism and apoptosis. In this study, mesoporous silicon-coated gold nanorods encapsulated with a mitochondria targeted and the thermosensitive lipid layer (AuNR@MSN-lipid-DOX) served as the carrier to load NO prodrug (BNN6) to build the near-infrared-triggered synergetic photothermal NO-chemotherapy platform (AuNR@MSN(BNN6)-lipid-DOX). The core of AuNR@MSN exhibited excellent photothermal conversion capability and high loading efficiency in terms of BNN6, reaching a high value of 220 mg/g (w/w), which achieved near-infrared-triggered precise release of NO. The outer biocompatible lipid layer, comprising thermosensitive phospholipid DPPC and mitochondrial-targeted DSPE-PEG2000-DOX, guided the whole nanoparticle to the mitochondria of 4T1 cells observed through confocal microscopy. In the mitochondria, the nanoparticles increased the local temperature over 42 °C under NIR irradiation, and a high NO concentration from BNN6 detected by the NO probe and DSPE-PEG2000-DOX significantly inhibited 4T1 cancer cells in vitro and in vivo under the synergetic photothermal therapy (PTT)-NO therapy-chemotherapy modes. The built NIR-triggered combination therapy nanoplatform can serve as a strategy for multimodal collaboration.

AgBiS2@CQDs/Ti nanocomposite coatings for combating implant-associated infections by photodynamic /photothermal therapy

Biofilm-mediated implant-associated infections are one of the most serious complications of implantation surgery, posing a grave threat to patient well-being. Effectively addressing bacterial infections is crucial for the success of implantation procedures. In this study, we prepared a bismuth sulfide silver@carbon quantum dot composite coating (AgBiS2@CQDs/Ti) on a medical titanium surface by surface engineering design to treat implant-associated infections. The photocatalytic/photothermal activity test results confirmed the excellent photogenerated ROS and photothermal properties of AgBiS2@CQDs/Ti under near-infrared laser irradiation. In vitro antibacterial and in vivo anti-infection experiments showed that the coating combined with photodynamic and photothermal therapies to eradicate bacteria and disrupt mature biofilms under 1064 nm laser irradiation. Consequently, AgBiS2@CQDs/Ti shows promise as an implant coating for treating implant-associated infections post-surgery, thereby enhancing the success rate of implantation procedures. This study also provides a new idea for combating implant-associated infections.

Biodegradable hollow mesoporous bimetallic nanoreactors to boost chemodynamic therapy

As an endogenous catalytic treatment, chemodynamic therapy (CDT) was attracting considerable attention, but the weak catalytic efficiency of Fenton agents and the non-degradation of nanocarriers severely limited its development. In this work, a biodegradable bimetallic nanoreactor was developed for boosting CDT, in which Fe-doped hollow mesoporous manganese dioxide (HMnO2) was selected as nanocarrier, and the Fe/HMnO2@DOX-GOD@HA nanoprobe was constructed by loading doxorubicin (DOX) and modifying glucose oxidase (GOD) and hyaluronic acid (HA). The glutathione (GSH) responsive degradation of HMnO2 promoted the release of DOX, by which the release rate significantly increased to 96.6%. Moreover, by the GSH depletion, the reduction of Mn2+/Fe2+ achieved strong bimetallic Fenton efficiency, and the hydroxyl radicals (·OH) generation was further enhanced using the self-supplying H2O2 of GOD. Through the active targeting recognition of HA, the bimetallic nanoreactor significantly enriched the tumor accumulation, by which the enhanced antitumor efficacy was realized. Thus, this work developed biodegradable bimetallic nanoreactor by consuming GSH and self-supplying H2O2, and provided a new paradigm for enhancing CDT.

Injectable Microparticle-containing hydrogel with controlled release of bioactive molecules for facial rejuvenation

The skin is the largest organ and a crucial barrier for protection against various intrinsic and extrinsic factors. As we age, the skin's components become more vulnerable to damage, forming wrinkles. Among different procedures, hyaluronic acid-based hydrogel has been extensively utilized for skin regeneration and reducing wrinkles. However, it has limitations like low retention and weak mechanical properties. In this study, we suggested the poly(l-lactic acid) (PLLA) microparticles containing alkaline magnesium hydroxide and nitric oxide-generating zinc oxide and rejuvenative hyaluronic acid (HA) hydrogels including these functional microparticles and asiaticoside, creating a novel delivery system for skin rejuvenation and regeneration. The fabricated rejuvenative hydrogels have exhibited enhanced biocompatibility, pH neutralization, reactive oxygen species scavenging, collagen biosynthesis, and angiogenesis capabilities in vitro and in vivo. Additionally, an excellent volume retention ability was demonstrated due to the numerous hydrogen bonds that formed between hyaluronic acid and asiaticoside. Overall, our advanced injectable hydrogel containing functional microparticles, with controlled release of bioactive molecules, has a significant potential for enhancing the regeneration and rejuvenation of the skin.

Photo-Controllable Smart Hydrogels for Biomedical Application: A Review

Nowadays, smart hydrogels are being widely studied by researchers because of their advantages such as simple preparation, stable performance, response to external stimuli, and easy control of response behavior. Photo-controllable smart hydrogels (PCHs) are a class of responsive hydrogels whose physical and chemical properties can be changed when stimulated by light at specific wavelengths. Since the light source is safe, clean, simple to operate, and easy to control, PCHs have broad application prospects in the biomedical field. Therefore, this review timely summarizes the latest progress in the PCHs field, with an emphasis on the design principles of typical PCHs and their multiple biomedical applications in tissue regeneration, tumor therapy, antibacterial therapy, diseases diagnosis and monitoring, etc. Meanwhile, the challenges and perspectives of widespread practical implementation of PCHs are presented in biomedical applications. This study hopes that PCHs will flourish in the biomedical field and this review will provide useful information for interested researchers.

Photothermal synergistic nitric oxide controlled release injectable self-healing adhesive hydrogel for biofilm eradication and wound healing

The development of injectable self-healing adhesive hydrogel dressings with excellent bactericidal activity and wound healing ability is urgently in demand for combating biofilm infections. Herein, a multifunctional hydrogel (QP/QT-MB) with near-infrared (NIR) light-activated mild photothermal/gaseous antimicrobial activity was developed based on the dynamic reversible borate bonds and hydrogen bonds crosslinking between quaternization chitosan (QCS) derivatives alternatively containing phenylboronic acid and catechol-like moieties in conjunction with the in situ encapsulation of BNN6-loaded mesoporous polydopamine (MPDA@BNN6 NPs). Given the dynamic reversible cross-linking feature, the versatile hybrid hydrogel exhibited injectability, flexibility, and rapid self-healing ability. The numerous phenylboronic acid and catechol-like moieties on the QCS backbone confer the hydrogel with specific bacterial affinity, desirable tissue adhesion, and antioxidant stress ability that enhance bactericidal activity and facilitate the regeneration of infection wounds. Under NIR irradiation, the QP/QT-MB hydrogels exhibited a desirable mild photothermal effect and NIR-activity controllable NO delivery, combined with the endogenous contact antimicrobial activity of hydrogel, contributing jointly to induce dispersal of biofilms and disruption of the bacterial plasma membranes, ultimately leading to bacteria inactivation and biofilm elimination. In vivo experiments demonstrated that the fabricated QP/QT-MB hydrogel platform was capable of inducing efficient eradication of the S. aureus biofilm in a severely infected wound model and accelerating infected wound repair by promoting collagen deposition, angiogenesis, and suppressing inflammatory responses. Additionally, the QP/QT-MB hydrogel demonstrated excellent biocompatibility in vitro and in vivo. Collectively, the hydrogel (QP/QT-MB) reveals great potential application prospects as a promising alternative in the field of biofilm-associated infection treatment.

Biofilm formation: mechanistic insights and therapeutic targets

Biofilms are complex multicellular communities formed by bacteria, and their extracellular polymeric substances are observed as surface-attached or non-surface-attached aggregates. Many types of bacterial species found in living hosts or environments can form biofilms. These include pathogenic bacteria such as Pseudomonas, which can act as persistent infectious hosts and are responsible for a wide range of chronic diseases as well as the emergence of antibiotic resistance, thereby making them difficult to eliminate. Pseudomonas aeruginosa has emerged as a model organism for studying biofilm formation. In addition, other Pseudomonas utilize biofilm formation in plant colonization and environmental persistence. Biofilms are effective in aiding bacterial colonization, enhancing bacterial resistance to antimicrobial substances and host immune responses, and facilitating cell‒cell signalling exchanges between community bacteria. The lack of antibiotics targeting biofilms in the drug discovery process indicates the need to design new biofilm inhibitors as antimicrobial drugs using various strategies and targeting different stages of biofilm formation. Growing strategies that have been developed to combat biofilm formation include targeting bacterial enzymes, as well as those involved in the quorum sensing and adhesion pathways. In this review, with Pseudomonas as the primary subject of study, we review and discuss the mechanisms of bacterial biofilm formation and current therapeutic approaches, emphasizing the clinical issues associated with biofilm infections and focusing on current and emerging antibiotic biofilm strategies.

Stimuli-Actuated Turn-On Theranostic Nanoplatforms for Imaging-Guided Antibacterial Treatment

Antibacterial theranostic nanoplatforms, which integrate diagnostic and therapeutic properties, exhibit gigantic application prospects in precision medicine. However, traditional theranostic nanoplatforms usually present an always-on signal output, which leads to poor specificity or selectivity in the treatment of bacterial infections. To address this challenge, stimuli-actuated turn-on nanoplatforms are developed for simultaneous activation of diagnostic signals (e.g., fluorescent, photoacoustic, magnetic signals) and initiation of antibacterial treatment. Specifically, by combining the infection microenvironment-responsive activation of visual signals and antibacterial activity, these theranostic nanoplatforms exert both higher accurate diagnosis rates and more effective treatment effects. In this review, the imaging and treatment strategies that are commonly used in the clinic are first briefly introduced. Next, the recent progress of stimuli-actuated turn-on theranostic nanoplatforms for treating bacterial infectious diseases is summarized in detail. Finally, current bottlenecks and future opportunities of antibacterial theranostic nanoplatforms are also outlined and discussed.

Nitric Oxide-Assisted Photodynamic Therapy for Enhanced Penetration and Hypoxic Bacterial Biofilm Elimination

The presence of a biofilm matrix barrier and hypoxic microenvironment within the biofilm significantly impedes the efficacy of photodynamic therapy for bacterial biofilm infections. Herein, a phototherapeutic nanoagent with type-I photodynamic behavior and nitric oxide (NO) release performance is reported for overcoming biofilm-associated infectious diseases. Sodium nitroprusside (SNP), a NO donor, is loaded onto amino-modified mesoporous silica nanoparticles (MSN) to form MSN@SNP NPs. The resulting nanoparticles are further modified with a porphyrin-based metal-organic framework (Ti-TCPP MOF) to obtain MSN@MOF/SNP NPs (MMS NPs) for phototherapeutic applications. In the hypoxia biofilm microenvironment, the MMS NPs release NO to enhance the biofilm permeability and induce the generation of hydroxyl radical (•OH) and superoxide anion radical (O2 •- ) via Type-I photodynamic pathway under laser irradiation. Subsequently, the biofilm-associated infections are effectively eliminated through reactive oxygen species (ROS) and NO gas synergistic therapy. In addition, NO also stimulates collagen deposition and promotes angiogenesis in vivo. Therefore, the MMS NPs efficiently treat biofilm-related infections, providing an alternative approach to combat biofilm-associated infectious diseases.

Dye-sensitized rare-earth-doped nanoprobe for simultaneously enhanced NIR-II imaging and precise treatment of bacterial infection

Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for causing life-threatening infections that result in high morbidity and mortality rates. The development of advanced imaging and therapeutic methods for in vivo diagnosis and treatment of MRSA infections remains challenging. Here, we develop a hybrid nanoplatform based on rare-earth-doped nanoparticles (RENPs) sensitized by a moiety-engineered near-infrared (NIR) TPEO-820 dye and with a ZIF-8 layer that incorporates CysNO, a photochemically triggered nitric oxide donor. We then use the hybrid for both NIR-II bioimaging and photoactivatable treatment of MRSA-infected wounds. We show that the NIR dye sensitization leads to an 8.5-fold enhancement of the downshifting emission and facilitates deep-tissue NIR-II imaging of bacterial infections. Moreover, the sensitization strategy enhances the UV emission of RENPs by two orders of magnitude, leading to the efficiently controllable release of nitric oxide for effective disinfection of MRSA in vitro and in vivo. The hybrid nanoplatform thus offers promising opportunities for simultaneous localization and controllable treatment of MRSA. STATEMENT OF SIGNIFICANCE: Early detection and treatment of MRSA infections are crucial for reducing public health risks. It is a significant challenge that develops sensitive in vivo diagnosis and complete elimination of drug-resistant bacterial infections. Herein, a nanoplatform has been developed for photoactivatable therapy of MRSA infections and deep tissue NIR-II imaging. This platform utilizes lanthanide-doped rare earth nanoparticles (RENPs) that are sensitized by a moiety-engineered near-infrared (NIR) dye TPEO-820. The TPEO-820 sensitized RENPs exhibit 5 times increase in the release of NO concentration for MRSA treatment compared to unsensitized RENPs, enabling precise therapy of MRSA infection both in vitro and in vivo. Moreover, the platform demonstrates NIR-II luminescence in vivo, allowing for sensitive imaging in deep tissue for MRSA infection.

First-Aid Hydrogel Wound Dressing with Reliable Hemostatic and Antibacterial Capability for Traumatic Injuries

First-aid for severe traumatic injuries in the battlefield or pre-hospital environment, especially for skin defects or visceral rupture, remains a substantial medical challenge even in the context of the rapidly evolving modern medical technology. Hydrogel-based biomaterials are highly anticipated for excellent biocompatibility and bio-functional designability. Yet, inadequate mechanical and bio-adhesion properties limit their clinical application. To address these challenges, a kind of multifunctional hydrogel wound dressing is developed with the collective multi-crosslinking advantages of dynamic covalent bonds, metal-catechol chelation, and hydrogen bonds. The mussel-inspired design and zinc oxide-enhanced cohesion strategy collaboratively reinforce the hydrogel's bio-adhesion in bloody or humoral environments. The pH-sensitive coordinate Zn2+ -catechol bond and dynamic Schiff base with reversible breakage and reformation equip the hydrogel dressing with excellent self-healing and on-demand removal properties. In vivo evaluation in a rat ventricular perforation model and Methicillin-resistant Staphylococcus aureus (MRSA)-infected full-thickness skin defect model reveal excellent hemostatic, antibacterial and pro-healing effectiveness of the hydrogel dressing, demonstrating its great potential in dealing with severe bleeding and infected full-thickness skin wounds.

Environment-Responsive Therapeutic Platforms for the Treatment of Implant Infection

The application of medical implants has greatly improved the survival rate and life quality of patients. Nevertheless, in recent years, there are increasing cases of implant dysfunction or failure because of bacterial infections. Despite significant improvements in biomedicine, there are still serious challenges in the treatment of implant-related infections. With the formation of bacterial biofilms and the development of bacterial resistance, these limitations lead to a low efficacy of conventional antibiotics. To address these challenges, it is urgent to exploit innovative treatment strategies for implant-related infections. Based on these ideas, environment-responsive therapeutic platforms with high selectivity, low drug resistance, and minor dose-limiting toxicity have attracted widespread attention. By using exogenous/endogenous stimuli, the antibacterial activity of therapeutics can be activated on demand and exhibit remarkable therapeutic effects. Exogenous stimuli include photo, magnetism, microwave, and ultrasound. Endogenous stimuli mainly include the pathological characteristics of bacterial infections such as acidic pH, anomalous temperature, and abnormal enzymatic activities. In this review, the recent progress of environment-responsive therapeutic platforms with spatiotemporally controlled drug release/activation is systematically summarized. Afterward, the limitations and opportunities of these emerging platforms are highlighted. Finally, it is hoped that this review will offer novel ideas and techniques to combat implant-related infections.

Multifunctional PDO Thread Coated with Mg(OH)2/ZnO Nanoparticles and Asiaticoside for Improved Facial Lifting

As interest in skin aesthetics increases, treatments to suppress aging are increasing. Among them, a facelift is the most effective procedure for improving wrinkles. However, side effects including inflammatory reactions occur due to the limitations of the PDO thread itself used during the procedure. In this paper, to improve the function of PDO thread, inorganic particles such as magnesium hydroxide (MH) and zinc oxide (ZO) and a biologically active agent, asiaticoside, were coated on the surface of PDO thread using ultrasonic coating technology. The coated thread exhibited excellent biocompatibility, promoted collagen synthesis, reduced inflammation, and stimulated angiogenesis in vitro and in vivo. The multifunctional PDO thread has shown promising potential for skin regeneration without inducing fibrosis. Such a practical coating system and the developed multifunctional PDO thread suggest new possibilities for developing safer and more effective materials in cosmetic and regenerative medicine to prevent aging and improve skin aesthetics.

Bacteria-Targeted Combined with Photothermal/NO Nanoparticles for the Treatment and Diagnosis of MRSA Infection In Vivo

Currently, undeveloped diagnosis and delayed treatment of bacteria-infected sites in vivo not only expand the risk of tissue infection but are also a major clinical cause of multiple drug-resistant bacterial infections. Herein, an efficient nanoplatform for near-infrared (NIR)-light-controlled release and bacteria-targeted delivery of nitric oxide (NO) combined with photothermal therapy (PTT) is presented. Using maltotriose-decorated mesoporous polydopamine (MPDA-Mal) and BNN6, a smart antibacterial (B@MPDA-Mal) is developed to combine bacterial targeting, gas-controlled release, and PTT. Utilizing bacteria's unique maltodextrin transport system, B@MPDA-Mal can accurately distinguish bacterial infection from sterile inflammation and target the bacteria-infected sites for efficient drug enrichment. Moreover, NIR-light causes MPDA to generate heat, which not only effectively induces BNN6 to produce NO, but also raises the temperature to harm the bacteria further. NO/photothermal combination therapy effectively eliminates biofilm and drug-resistant bacteria. The myositis model of methicillin-resistant Staphylococcus aureus infection is established and indicates that B@MPDA-Mal can successfully eradicate inflammation and abscesses in mice. Meanwhile, magnetic resonance imaging technology is used to monitor the treatment procedure and healing outcomes. Given the aforementioned advantages, the smart antibacterial nanoplatform B@MPDA-Mal can be used as a potential therapeutic tool in the biomedical field against drug-resistant bacterial infections.

Recent progress in nanozymes for the treatment of diabetic wounds

The slow healing of diabetic wounds has seriously affected human health. Meanwhile, the open wounds are susceptible to bacterial infection. Clinical therapeutic methods such as antibiotic therapy, insulin treatment, and surgical debridement have made great achievements in the treatment of diabetic wounds. However, drug-resistant bacteria will develop after long-term use of antibiotics, resulting in decreased efficacy. To improve the therapeutic effect, increasing drug concentration is a common strategy in clinical practice, but it also brings serious side effects. In addition, hyperglycemia control or surgical debridement can easily bring negative effects to patients, such as hypoglycemia or damage of normal tissue. Therefore, it is essential to develop novel therapeutic strategies to effectively promote diabetic wound healing. In recent years, nanozyme-based diabetic wound therapeutic systems have received extensive attention because they possess the advantages of nanomaterials and natural enzymes. For example, nanozymes have the advantages of a small size and a high surface area to volume ratio, which can enhance the tissue penetration of nanozymes and increase the reactive active sites. Moreover, compared with natural enzymes, nanozymes have more stable catalytic activity, lower production cost, and stronger operability. In this review, we first reviewed the basic characteristics of diabetic wounds and then elaborated on the catalytic mechanism and action principle of different types of nanozymes in diabetic wounds from three aspects: controlling bacterial infection, controlling hyperglycemia, and relieving inflammation. Finally, the challenges, prospects and future implementation of nanozymes for diabetic wound healing are outlined.

Nanotherapeutics with immunoregulatory functions for the treatment of bacterial infection

The advent of drug-resistant pathogens results in the occurrence of stubborn bacterial infections that cannot be treated with traditional antibiotics. Antibacterial immunotherapy by reviving or activating the body's immune system to eliminate pathogenic bacteria has confirmed promising therapeutic strategies in controlling bacterial infections. Subsequent studies found that antimicrobial immunotherapy has its own benefits and limitations, such as avoiding recurrence of infection and autoimmunity-induced side effects. Current studies indicate that the various antibacterial therapeutic strategies inducing immune regulation can achieve superior therapeutic efficacy compared with monotherapy alone. Therefore, summarizing the recent advances in nanomedicine with immunomodulatory functions for combating bacterial infections is necessary. Herein, we briefly introduce the crisis caused by drug-resistant bacteria and the opportunity for antibacterial immunotherapy. Then, immune-involved multimodal antibacterial therapy for the treatment of infectious diseases was systematically summarized. Finally, the prospects and challenges of immune-involved combinational therapy are discussed.

Physical dual-network photothermal antibacterial multifunctional hydrogel adhesive for wound healing of drug-resistant bacterial infections synthesized from natural polysaccharides

Wound-healing of drug-resistant bacterial infections has always been a clinical challenge. The design and development of effective and economically safe wound dressings with antimicrobial activity and healing-promoting properties is highly desirable, especially in the context of wound-infections. Herein, we designed a physical dual-network multifunctional hydrogel adhesive based on polysaccharide material for the treatment of full-thickness skin defects infected with multidrug-resistant bacteria. The hydrogel utilized ureido-pyrimidinone (UPy)-modified Bletilla striata polysaccharide (BSP) as the first physical interpenetrating network for providing some brittleness and rigidity; and then branched macromolecules formed after cross-linking Fe³⁺ with dopamine-conjugated di-aldehyde-hyaluronic acid as the second physical interpenetrating network for providing some flexibility and elasticity. In this system, BSP and hyaluronic acid (HA) are used as synthetic matrix materials to provide strong biocompatibility and wound-healing ability. In addition, ligand cross-linking of catechol-Fe³⁺ and quadrupole hydrogen-bonding cross-linking of UPy-dimer can form a highly dynamic physical dual-network structure, which imparts good rapid self-healing, injectability, shape-adaptation, NIR/pH responsiveness, high tissue-adhesion and mechanical properties of this hydrogel. Meanwhile, bioactivity experiments demonstrated that the hydrogel also possesses powerful antioxidant, hemostatic, photothermal-antibacterial and wound-healing effects. In conclusion, this functionalized hydrogel is a promising candidate for clinical treatment of full-thickness bacteria-stained wound dressing materials.

Combating Bacterial Biofilms: Current and Emerging Antibiofilm Strategies for Treating Persistent Infections

Biofilms are intricate multicellular structures created by microorganisms on living (biotic) or nonliving (abiotic) surfaces. Medically, biofilms often lead to persistent infections, increased antibiotic resistance, and recurrence of infections. In this review, we highlighted the clinical problem associated with biofilm infections and focused on current and emerging antibiofilm strategies. These strategies are often directed at disrupting quorum sensing, which is crucial for biofilm formation, preventing bacterial adhesion to surfaces, impeding bacterial aggregation in viscous mucus layers, degrading the extracellular polymeric matrix, and developing nanoparticle-based antimicrobial drug complexes which target persistent cells within the biofilm core. It is important to acknowledge, however, that the use of antibiofilm agents faces obstacles, such as limited effectiveness in vivo, potential cytotoxicity to host cells, and propensity to elicit resistance in targeted biofilm-forming microbes. Emerging next generation antibiofilm strategies, which rely on multipronged approaches, were highlighted, and these benefit from current advances in nanotechnology, synthetic biology, and antimicrobial drug discovery. The assessment of current antibiofilm mitigation approaches, as presented here, could guide future initiatives toward innovative antibiofilm therapeutic strategies. Enhancing the efficacy and specificity of some emerging antibiofilm strategies via careful investigations, under conditions that closely mimic biofilm characteristics within the human body, could bridge the gap between laboratory research and practical application.

Nanomaterials for photothermal cancer therapy

Cancer has emerged as a pressing global public health issue, and improving the effectiveness of cancer treatment remains one of the foremost challenges of modern medicine. The primary clinical methods of treating cancer, including surgery, chemotherapy and radiotherapy, inevitably result in some adverse effects on the body. However, the advent of photothermal therapy offers an alternative route for cancer treatment. Photothermal therapy relies on photothermal agents with photothermal conversion capability to eliminate tumors at high temperatures, which offers advantages of high precision and low toxicity. As nanomaterials increasingly play a pivotal role in tumor prevention and treatment, nanomaterial-based photothermal therapy has gained significant attention owing to its superior photothermal properties and tumor-killing abilities. In this review, we briefly summarize and introduce the applications of common organic photothermal conversion materials (e.g., cyanine-based nanomaterials, porphyrin-based nanomaterials, polymer-based nanomaterials, etc.) and inorganic photothermal conversion materials (e.g., noble metal nanomaterials, carbon-based nanomaterials, etc.) in tumor photothermal therapy in recent years. Finally, the problems of photothermal nanomaterials in antitumour therapy applications are discussed. It is believed that nanomaterial-based photothermal therapy will have good application prospects in tumor treatment in the future.

Recent advances in Prussian blue-based photothermal therapy in cancer treatment

Malignant tumours are a serious threat to human health. Traditional chemotherapy has achieved breakthrough improvements but also has significant detrimental effects, such as the development of drug resistance, immunosuppression, and even systemic toxicity. Photothermal therapy (PTT) is an emerging cancer therapy. Under light irradiation, the phototherapeutic agent converts optical energy into thermal energy and induces the hyperthermic death of target cells. To date, numerous photothermal agents have been developed. Prussian blue (PB) nanoparticles are among the most promising photothermal agents due to their excellent physicochemical properties, including photoacoustic and magnetic resonance imaging properties, photothermal conversion performance, and enzyme-like activity. By the construction of suitably designed PB-based nanotherapeutics, enhanced photothermal performance, targeting ability, multimodal therapy, and imaging-guided cancer therapy can be effectively and feasibly achieved. In this review, the recent advances in PB-based photothermal combinatorial therapy and imaging-guided cancer therapy are comprehensively summarized. Finally, the potential obstacles of future research and clinical translation are discussed.

Intestine-inspired wrinkled MXene microneedle dressings for smart wound management

Composite MXene-based materials are prone to crack propagation, thus limiting their tensile properties. Numerous efforts have been devoted to removing material constraints and fabricating unitary MXene elastic films. Here, for the first time, inspired by the intestinal wrinkles and villi structure, we presented a ductile, biologically friendly, and highly conductive MXene-based microneedle (MMN) dressing composed of stacked MXene film and superfine microneedle arrays through a simple stretching and laser engraving strategy for wound healing. By utilizing photothermal responsive MXene, periodic porous structures, and a temperature-responsive polymer to construct the MMN dressing, the system can act as an effective route for facilitating controllable drug delivery controlled by near-infrared (NIR) irradiation. In addition, superior conductivity imparts them with the capacity to realize continuous and steady monitoring of motion sensing. The practical performance further demonstrated that the versatile MMN dressing showed obvious therapeutic efficacy in vivo animal wound models. Thus, it is believed that MMN dressings with biomimetic structures, controllable drug release, and conductive pathways will open a new chapter for wound management and widen other practical applications in biomedical fields, such as artificial tendons and soft robotics. STATEMENT OF SIGNIFICANCE: MXene-based materials have been demonstrated as critical tools in advancing our understanding of wound healing. However, the rapid crack propagation is a constraint on their tensile properties. Here, inspired by the intestinal wrinkles and villi structure, a single-step method has also been discussed to present a MXene-based microneedle dressing composed of unitary MXene elastic film and superfine microneedle arrays. At the same time, the dressing with biomimetic structures, controllable drug release, and conductive pathways has prospects in intelligent wound management and varieties of related biomedical fields.

Mesoporous Materials Make Hydrogels More Powerful in Biomedicine

Scientists have been attempting to improve the properties of mesoporous materials and expand their application since the 1990s, and the combination with hydrogels, macromolecular biological materials, is one of the research focuses currently. Uniform mesoporous structure, high specific surface area, good biocompatibility, and biodegradability make the combined use of mesoporous materials more suitable for the sustained release of loaded drugs than single hydrogels. As a joint result, they can achieve tumor targeting, tumor environment stimulation responsiveness, and multiple therapeutic platforms such as photothermal therapy and photodynamic therapy. Due to the photothermal conversion ability, mesoporous materials can significantly improve the antibacterial ability of hydrogels and offer a novel photocatalytic antibacterial mode. In bone repair systems, mesoporous materials remarkably strengthen the mineralization and mechanical properties of hydrogels, aside from being used as drug carriers to load and release various bioactivators to promote osteogenesis. In hemostasis, mesoporous materials greatly elevate the water absorption rate of hydrogels, enhance the mechanical strength of the blood clot, and dramatically shorten the bleeding time. As for wound healing and tissue regeneration, incorporating mesoporous materials can be promising for enhancing vessel formation and cell proliferation of hydrogels. In this paper, we introduce the classification and preparation methods of mesoporous material-loaded composite hydrogels and highlight the applications of composite hydrogels in drug delivery, tumor therapy, antibacterial treatment, osteogenesis, hemostasis, and wound healing. We also summarize the latest research progress and point out future research directions. After searching, no research reporting these contents was found.

The Use of Proteins, Lipids, and Carbohydrates in the Management of Wounds

Despite the fact that skin has a stronger potential to regenerate than other tissues, wounds have become a serious healthcare issue. Much effort has been focused on developing efficient therapeutical approaches, especially biological ones. This paper presents a comprehensive review on the wound healing process, the classification of wounds, and the particular characteristics of each phase of the repair process. We also highlight characteristics of the normal process and those involved in impaired wound healing, specifically in the case of infected wounds. The treatments discussed here include proteins, lipids, and carbohydrates. Proteins are important actors mediating interactions between cells and between them and the extracellular matrix, which are essential interactions for the healing process. Different strategies involving biopolymers, blends, nanotools, and immobilizing systems have been studied against infected wounds. Lipids of animal, mineral, and mainly vegetable origin have been used in the development of topical biocompatible formulations, since their healing, antimicrobial, and anti-inflammatory properties are interesting for wound healing. Vegetable oils, polymeric films, lipid nanoparticles, and lipid-based drug delivery systems have been reported as promising approaches in managing skin wounds. Carbohydrate-based formulations as blends, hydrogels, and nanocomposites, have also been reported as promising healing, antimicrobial, and modulatory agents for wound management.

Biomedical materials for wound dressing: recent advances and applications

Wound healing is vital to maintain the physiological functions of the skin. The most common treatment is the use of a dressing to cover the wound and reduce infection risk and the rate of secondary injuries. Modern wound dressings have been the top priority choice for healing various types of wounds owing to their outstanding biocompatibility and biodegradability. In addition, they also maintain temperature and a moist environment, aid in pain relief, and improve hypoxic environments to stimulate wound healing. Due to the different types of wounds, as well as the variety of advanced wound dressing products, this review will provide information on the clinical characteristics of the wound, the properties of common modern dressings, and the in vitro, in vivo as well as the clinical trials on their effectiveness. The most popular types commonly used in producing modern dressings are hydrogels, hydrocolloids, alginates, foams, and films. In addition, the review also presents the polymer materials for dressing applications as well as the trend of developing these current modern dressings to maximize their function and create ideal dressings. The last is the discussion about dressing selection in wound treatment and an estimate of the current development tendency of new materials for wound healing dressings.

Recent Nanotechnologies to Overcome the Bacterial Biofilm Matrix Barriers

Bacterial biofilm-related infectious diseases severely influence human health. Under typical situations, pathogens can colonize inert or biological surfaces and form biofilms. Biofilms are functional aggregates that coat bacteria with extracellular polymeric substances (EPS). The main reason for the failure of biofilm infection treatment is the low permeability and enrichment of therapeutic agents within the biofilm, which results from the particular features of biofilm matrix barriers such as negatively charged biofilm components and highly viscous compact EPS structures. Hence, developing novel therapeutic strategies with enhanced biofilm penetrability is crucial. Herein, the current progress of nanotechnology methods to improve therapeutic agents' penetrability against biofilm matrix, such as regulating material morphology and surface properties, utilizing the physical penetration of nano/micromotors or microneedle patches, and equipping nanoparticles with EPS degradation enzymes or signal molecules, is first summarized. Finally, the challenges, perspectives, and future implementations of engineered delivery systems to manage biofilm infections are presented in detail.

Amylase degradation enhanced NIR photothermal therapy and fluorescence imaging of bacterial biofilm infections

Effective treatment of bacterial biofilm-related infections is a great challenge for the medical community. During the formation of biofilms, bacteria excrete extracellular polymeric substances (EPS), including polysaccharides, proteins, nucleic acids, etc., to encapsulate themselves and form a "fort-like" structure, which greatly reduces the efficiency of therapeutic agents. Herein, we prepared a nanoagent (MnO₂-amylase-PEG-ICG nanosheets, MAPI NSs) with biofilm degradation capability for efficient photothermal therapy and fluorescence imaging of methicillin-resistant Staphylococcus aureus (MRSA) biofilm infections. MAPI NSs were constructed by sequentially modifying α-amylase, polyethylene glycol (PEG), and indocyanine green (ICG) on manganese dioxide nanosheets (MnO₂ NSs). Experimental results exhibited that MAPI NSs could accumulate in infected tissues after intravenous injection, degrade in the acidic biofilm microenvironment, and release the loaded ICG for near-infrared (NIR) fluorescence imaging of the infected tissues. Importantly, MAPI NSs could efficiently eliminate MRSA biofilm infections in mice by α-amylase enhanced photothermal therapy. In addition, MAPI NSs exhibited neglectable toxicity towards mice. Given the superior properties of MAPI NSs, the enzyme-degradation enhanced therapeutic strategy presented in this work offers a promising solution for effectively combating biofilm infectious diseases.

Advances in image-guided drug delivery for antibacterial therapy

The emergence of antibiotic-resistant bacterial strains is seriously endangering the global healthcare system. There is an urgent need for combining imaging with therapies to realize the real-time monitoring of pathological condition and treatment progress. It also provides guidance on exploring new medicines and enhance treatment strategies to overcome the antibiotic resistance of existing conventional antibiotics. In this review, we provide a thorough overview of the most advanced image-guided approaches for bacterial diagnosis (e.g., computed tomography imaging, magnetic resonance imaging, photoacoustic imaging, ultrasound imaging, fluorescence imaging, positron emission tomography, single photon emission computed tomography imaging, and multiple imaging), and therapies (e.g., photothermal therapy, photodynamic therapy, chemodynamic therapy, sonodynamic therapy, immunotherapy, and multiple therapies). This review focuses on how to design and fabricate photo-responsive materials for improved image-guided bacterial theranostics applications. We present a potential application of different image-guided modalities for both bacterial diagnosis and therapies with representative examples. Finally, we highlighted the current challenges and future perspectives image-guided approaches for future clinical translation of nano-theranostics in bacterial infections therapies. We envision that this review will provide for future development in image-guided systems for bacterial theranostics applications.

Nanomaterials-Functionalized Hydrogels for the Treatment of Cutaneous Wounds

Hydrogels have been utilized extensively in the field of cutaneous wound treatment. The introduction of nanomaterials (NMs), which are a big category of materials with diverse functionalities, can endow the hydrogels with additional and multiple functions to meet the demand for a comprehensive performance in wound dressings. Therefore, NMs-functionalized hydrogels (NMFHs) as wound dressings have drawn intensive attention recently. Herein, an overview of reports about NMFHs for the treatment of cutaneous wounds in the past five years is provided. Firstly, fabrication strategies, which are mainly divided into physical embedding and chemical synthesis of the NMFHs, are summarized and illustrated. Then, functions of the NMFHs brought by the NMs are reviewed, including hemostasis, antimicrobial activity, conductivity, regulation of reactive oxygen species (ROS) level, and stimulus responsiveness (pH responsiveness, photo-responsiveness, and magnetic responsiveness). Finally, current challenges and future perspectives in this field are discussed with the hope of inspiring additional ideas.

On-Demand Changeable Theranostic Hydrogels and Visual Imaging-Guided Antibacterial Photodynamic Therapy to Promote Wound Healing

Antibacterial wound dressings are confronted with the challenges in real-time imaging of infected wounds and effective removal of bacterial debris after sterilization to promote the healing process. Herein, injectable theranostic hydrogels were constructed from antimicrobial peptide ε-polylysine (ePL) and polydopamine (PDA) nanoparticles for real-time diagnosis of infected wounds, imaging-guided antibacterial photodynamic therapy (PDT), and on-demand removal of bacterial debris. Ureido-pyrimidinone was conjugated on ePL to produce PLU hydrogels through quadruple hydrogen bonding, and the inoculation of tetrakis(4-carboxyphenyl)porphyrin (TCPP)-loaded PDA (PTc) nanoparticles introduced Schiff base linkages in PLU@PTc hydrogels. The double-cross-linked networks enhance mechanical performance, adhesion strength, and self-healing properties of hydrogels, and the dynamic cross-linking enables their photothermal removal. The injection of PLU precursors and PTc NPs generates in situ sol-gel transformation, and the acid-triggered release of TCPP restores fluorescence emissions for real-time imaging of infected wounds under 410 nm illumination. Then, the released TCPP in the infected wounds is illuminated at 660 nm to launch a precise antibacterial PDT, which is strengthened by the bacterial capture on hydrogels. Hydrogels with wrapped bacterial debris are removed under illumination at 808 nm, and the hydrogel dressing change accelerates healing of infected wounds through simultaneous relief of oxidative stress, regulation of inflammatory factors, acceleration of collagen deposition, and promotion of angiogenesis. Thus, this study demonstrates a feasible strategy for wound infection theranostics through bacterial infection-triggered visual imaging, efficient nonantibiotic sterilization, and on-demand dressing change and bacterial debris removal.

Co-Delivery of Dihydroartemisinin and Indocyanine Green by Metal-Organic Framework-Based Vehicles for Combination Treatment of Hepatic Carcinoma

Dihydroartemisinin (DHA), a widely used antimalarial agent, has clinical potential for the treatment of hepatic carcinoma. Although chemotherapy is indispensable for tumor therapy, it is generally limited by poor solubility, low efficiency, rapid clearance, and side effects. As an emerging treatment method, photothermal therapy (PTT) has many outstanding properties, but suffers from poor photostability of photosensitizer and incomplete ablation. Multimodal therapies could combine the advantages of different therapy methods to improve antitumor efficiency. Hence, we designed a nano-delivery system (ICG&DHA@ZIF-8) using zeolitic imidazolate framework-8 (ZIF-8) with a high porous rate and pH sensitivity property, to co-load DHA and indocyanine green (ICG). Dynamic light scattering and transmission electron microscopy were used to characterize the prepared nanoparticles. The photothermal conversion and drug release performances of ICG&DHA@ZIF-8 were investigated. In vitro antitumor efficacy and cellular uptake were studied. The mechanism of the combination treatment was studied by reactive oxygen species level detection and western blot assays. In vivo antitumor assays were then studied with the guidance of ex vivo imaging. The results showed that the ICG&DHA@ZIF-8 based combination therapy could efficiently kill hepatic carcinoma cells and suppress tumor growth. This research provides a potential nanodrug for the treatment of hepatic carcinoma.

Stimuli-responsive therapeutic systems for the treatment of diabetic infected wounds

Diabetic wound infection is a common disease that has significantly reduced people's quality of life. Although tremendous achievements have been made in clinical treatment, the crucial challenge in diabetic infected wound management stems from the detrimental diabetic wound environment and the emergence of bacterial resistance after long-term medication, which result in a reduced efficacy, an increased dosage of medication, and severe side effects. To tackle these issues, it is of great significance to develop an innovative treatment strategy for diabetic wound infection therapy. Currently, the exploitation of nanobiomaterial-based therapeutic systems for diabetic infected wounds is booming, and therapeutic systems with a stimuli-responsive performance have received extensive attention. These therapeutic systems are able to accelerate diabetic infected wound healing due to the on-demand release of therapeutic agents in diabetic infected wounds in response to stimulating factors. Based on the characteristics of diabetic infected wounds, many endogenous stimuli-responsive (e.g., glucose, enzyme, hypoxia, and acidity) therapeutic systems have been employed for the targeted treatment of infected wounds in diabetic patients. Additionally, exogenous stimulants, including light, magnetism, and temperature, are also capable of achieving on-demand drug release and activation. In this review, the characteristics of diabetic infected wounds are presented, and then exogenous/endogenous stimuli therapeutic systems for the treatment of diabetic infected wounds are summarized. Finally, the current challenges and future outlook of stimuli-responsive therapeutic systems are also discussed.

Self-Powered Electrodeposition System for Sub-10-nm Silver Nanoparticles with High-Efficiency Antibacterial Activity

Recently, silver nanoparticles (AgNPs) have been widely applied in sterilization due to their excellent antibacterial properties. However, AgNPs require rigorous storage conditions because their antibacterial performances are significantly affected by environmental conditions. Instant fabrication provides a remedy for this drawback. In this study, we propose a self-powered electrodeposition system to synthesize sub-10-nm AgNPs, consisting of a triboelectric nanogenerator (TENG) as the self-powered source, a capacitor for storing electrical energy from the TENG, and an electrochemical component for electrodeposition. The self-powered system with larger capacitance and discharging voltage tends to deliver smaller AgNPs due to the nucleation mechanism dominated by current density. Furthermore, antibacterial tests reveal that compared to direct current (DC) electrodeposition, the TENG-based electrodeposition can synthesize finer-sized AgNPs (<10 nm) with overwhelming antibacterial effect against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) (with 100% efficiency at 2 h). This work provides a new strategy for the self-powered, instant, and controllable electrodeposition of nanoparticles.