Fluorescent and Antibacterial Aminobenzeneboronic Acid (ABA)-Modified Gold Nanoclusters for Self-Monitoring Residual Dosage and Smart Wound Care

Advances and applications of biomimetic biomaterials for endogenous skin regeneration

Endogenous regeneration is becoming an increasingly important strategy for wound healing as it facilitates skin's own regenerative potential for self-healing, thereby avoiding the risks of immune rejection and exogenous infection. However, currently applied biomaterials for inducing endogenous skin regeneration are simplistic in their structure and function, lacking the ability to accurately mimic the intricate tissue structure and regulate the disordered microenvironment. Novel biomimetic biomaterials with precise structure, chemical composition, and biophysical properties offer a promising avenue for achieving perfect endogenous skin regeneration. Here, we outline the recent advances in biomimetic materials induced endogenous skin regeneration from the aspects of structural and functional mimicry, physiological process regulation, and biophysical property design. Furthermore, novel techniques including in situ reprograming, flexible electronic skin, artificial intelligence, single-cell sequencing, and spatial transcriptomics, which have potential to contribute to the development of biomimetic biomaterials are highlighted. Finally, the prospects and challenges of further research and application of biomimetic biomaterials are discussed. This review provides reference to address the clinical problems of rapid and high-quality skin regeneration.

Ultrasmall copper nanoclusters as an efficient antibacterial agent for primary peritonitis therapy

The urgent need to develop biocompatible, non-resistant antibacterial agents to effectively combat Gram-negative bacterial infections, particularly for the treatment of peritonitis, presents a significant challenge. In this study, we introduce our water-soluble Cu30 nanoclusters (NCs) as a potent and versatile antibacterial agent tailored for addressing peritonitis. The as-synthesized atomically precise Cu30 NCs demonstrate exceptional broad-spectrum antibacterial performance, and especially outstanding bactericidal activity of 100% against Gram-negative Escherichia coli (E. coli). Our in vivo experimental findings indicate that the Cu30 NCs exhibit remarkable therapeutic efficacy against primary peritonitis caused by E. coli infection. Specifically, the treatment leads to a profound reduction of drug-resistant bacteria in the peritoneal cavity of mice with peritonitis by more than 5 orders of magnitude, along with the resolution of pathological features in the peritoneum and spleen. Additionally, comprehensive in vivo biosafety assessment underscores the remarkable biocompatibility, low biotoxicity, as well as efficient hepatic and renal clearance of Cu30 NCs, emphasizing their potential for in vivo application. This investigation is poised to advance the development of novel Cu NC-based antibacterial agents for in vivo antibacterial treatment and the elimination of abdominal inflammation.

Bacterial Cellulose-Based Bandages with Integrated Antibacteria and Electrical Stimulation for Advanced Wound Management

Bandages for daily wounds are the most common medical supplies, but there are still ingrained defects in their appearance, comfort, functions, as well as environmental pollution. Here, novel bandages based on bacterial cellulose (BC) membrane for wound monitoring and advanced wound management are developed. The BC membrane is combined with silver nanowires (AgNWs) by using vacuum filtration method to achieve transparent, ultrathin (≈7 µm), breathable (389.98-547.79 g m-2  d-1 ), and sandwich-structured BC/AgNWs bandages with superior mechanical properties (108.45-202.35 MPa), antibacterial activities against Escherichia coli and Staphylococcus aureus, biocompatibility, and conductivity (9.8 × 103 -2.0 × 105  S m-1 ). Significantly, the BC/AgNWs bandage is used in the electrical stimulation (direct current, 600  microamperes for 1 h every other day) treatment of full-thickness skin defect in rats, which obviously promotes wound healing by increasing the secretion of vascular endothelial growth factor (VEGF). The BC bandage is used for monitoring wounds and achieve a high accuracy of 94.7% in classifying wound healing stages of hemostasis, inflammation, proliferation, and remodeling, by using a convolutional neural network. The outcomes of this study not only provide two BC-based bandages as multifunctional wound management, but also demonstrate a new strategy for the development of the next generation of smart bandage.

Flexible Accelerated-Wound-Healing Antibacterial Hydrogel-Nanofiber Scaffold for Intelligent Wearable Health Monitoring

Flexible epidermal sensors hold significant potential in personalized healthcare and multifunctional electronic skins. Nonetheless, achieving both robust sensing performance and efficient antibacterial protection, especially in medical paradigms involving electrophysiological signals for wound healing and intelligent health monitoring, remains a substantial challenge. Herein, we introduce a novel flexible accelerated-wound-healing biomaterial based on a hydrogel-nanofiber scaffold (HNFS) via electrostatic spinning and gel cross-linking. We effectively engineer a multifunctional tissue nanoengineered skin scaffold for wound treatment and health monitoring. Key features of HNFS include high tensile strength (24.06 MPa) and elasticity (214.67%), flexibility, biodegradability, and antibacterial properties, enabling assembly into versatile sensors for monitoring human motion and electrophysiological signals. Moreover, in vitro and in vivo experiments demonstrate that HNFS significantly enhances cell proliferation and skin wound healing, provide a comprehensive therapeutic strategy for smart sensing and tissue repair, and guide the development of high-performance "wound healing-health monitoring" bioelectronic skin scaffolds. Therefore, this study provides insights into crafting flexible and repairable skin sensors, holding potential for multifunctional health diagnostics and intelligent medical applications in intelligent wearable health monitoring and next-generation artificial skin fields.

Green, pH-Sensitive, Highly Stretchable, and Hydrogen Bond-Dominated Ionogel for Wound Healing Activity

Traditional hydrogel dressings generally have poor mechanical properties and stability when subjected to external stress due to the undesirable chain entanglement structure of their single valence bond compositions. Therefore, it is particularly important to develop a type of gel dressing with good mechanical strength, stability, and environment-friendly monitoring. In this work, a transparent, pH-sensitive, highly stretchable, and biocompatible anthocyanidin ionogel dressing was prepared, realizing green and accurate detection. Attributed to the antibacterial activity of the ionic liquid, the biocompatibility of the pectin, and the ability to scavenge free radicals of the anthocyanidin, the ionogel dressing exhibited excellent re-epithelialization in the 14 day wound healing process. Besides, changes in pH values monitoring of the ionogel over 3 days coincided with normal wound exudate. The obtained ionogel also showed good water retention, swelling properties, mechanical stretchability, and 5 week stability, illustrating great potential in wound dressings.

Recent advances in nanoantibiotics against multidrug-resistant bacteria

Multidrug-resistant (MDR) bacteria-caused infections have been a major threat to human health. The abuse of conventional antibiotics accelerates the generation of MDR bacteria and makes the situation worse. The emergence of nanomaterials holds great promise for solving this tricky problem due to their multiple antibacterial mechanisms, tunable antibacterial spectra, and low probabilities of inducing drug resistance. In this review, we summarize the mechanism of the generation of drug resistance, and introduce the recently developed nanomaterials for dealing with MDR bacteria via various antibacterial mechanisms. Considering that biosafety and mass production are the major bottlenecks hurdling the commercialization of nanoantibiotics, we introduce the related development in these two aspects. We discuss urgent challenges in this field and future perspectives to promote the development and translation of nanoantibiotics as alternatives against MDR pathogens to traditional antibiotics-based approaches.

hROS-Responsive Behavior for Long-Term Stability of Cellulosic Gold Nanoclusters

Understanding the gold core-ligand interaction in gold nanoclusters (GNCs) is essential for the on-demand tailoring of their photoluminescence properties and long-term stability. Here, inspired by the suckers arranged directionally on the tentacles of octopus, a series of GNCs with regulating ligand structures are grown and stabilized on the cellulose nanocrystals (CNCs). The carboxylated CNCs providing an electron-rich environment to promote the luminescence of GNCs and stabilize it within a long-term of 1 year through anchoring and diluting effects, and the highest quantum yields reaches 31.02% in ultrapure water. Interestingly, this bionic preparation strategy is generally applicable to various ligands for tailoring on-demand hROS-responsive and nonresponsive GNCs to construct tunable-emission wavelength dual GNCs ratiometric probes. The results show that designing a specific ligand structure to inhibit the transformation of Au-Au to Au (I)-ligand in GNCs is crucial to regulate the hROS-responsive characteristics. As expected, the interfacial compatible dual GNCs ratiometric probe with a hROS limit of detection of 0.74 µmol L-1 can diagnose certain diseases through intracellular hROS imaging. This work provides important insights for understanding the gold core-ligand interaction in GNCs during the oxidation process triggered by intracellular hROS.

Phenylboronic Acid-Modified Gold Nanoclusters as a Nanoantibiotic to Treat Vancomycin-Resistant Enterococcus faecalis-Caused Infections

Vancomycin is one of the last lines of defense against certain drug-resistant bacteria-caused infections. However, the high susceptibility to drug resistance and high toxicity seriously limit the application of vancomycin. Nanoantibiotics provide opportunities to solve these problems. Herein, we present mercaptophenylboronic acid (MBA)-modified gold nanoclusters with well-defined molecular formulas and structure (Au44(MBA)18) and excellent antibacterial activities against various drug-resistant bacteria such as vancomycin-resistant Enterococcus faecalis (VRE). Au44(MBA)18 interacts with bacteria by first attaching to teichoic-acid and destroying the cell wall and subsequently binding to the bacterial DNA. Au44(MBA)18 could be administered via multiple routes and has a high biosafety (500 mg/kg, no ototoxicity), overcoming the two major shortcomings of vancomycin (sole administration route and high ototoxicity). Our study is insightful for curing infections caused by multidrug-resistant bacteria using nanoantibiotics with high biosafety.

Recent advances in bacterial cellulose-based antibacterial composites for infected wound therapy

Wound infection arising from pathogenic bacteria brought serious trouble to the patient and medical system. Among various wound dressings that are effective in killing pathogenic bacteria, antimicrobial composites based on bacterial cellulose (BC) are becoming the most popular materials due to their success in eliminating pathogenic bacteria, preventing wound infection, and promoting wound healing. However, as an extracellular natural polymer, BC is not inherently antimicrobial, which means that it must be combined with other antimicrobials to be effective against pathogens. BC has many advantages over other polymers, including nano-structure, significant moisture retention, non-adhesion to the wound surface, which has made it superior to other biopolymers. This review introduces the recent advances in BC-based composites for the treatment of wound infection, including the classification and preparation methods of composites, the mechanism of wound treatment, and commercial application. Moreover, their wound therapy applications include hydrogel dressing, surgical sutures, wound healing bandages, and patches are summarized in detail. Finally, the challenges and future prospects of BC-based antibacterial composites for the treatment of infected wounds are discussed.

Multifunctional Gold-Silver-Carbon Quantum Dots Nano-Hybrid Composite: Advancing Antibacterial Wound Healing and Cell Proliferation

The urgent need for innovative materials that effectively eliminate bacteria while promoting cell growth to accelerate wound healing has led to the exploration of new options, as current antimicrobial nanoparticles often exhibit high cytotoxicity, which hinders wound closure. In this study, a nano-hybrid composite, named gold-silver-carbon quantum dots (AuAg-CDs), was prepared by embedding gold and silver nanoclusters into carbon dots. The AuAg-CDs nano-hybrid composite demonstrates remarkable biocompatibility, displays potent antibacterial activity, and possesses a unique capability to promote cell proliferation. By physically disrupting bacterial membranes and promoting mammalian cell proliferation, this composite emerges as a highly promising material for wound healing applications. The underlying mechanism of the multifunctional AuAg-CDs was investigated through comprehensive analyses encompassing cell morphology, bacterial membrane potential, levels of reactive oxygen species (ROS), and adenosine triphosphate (ATP) production in both bacterial and mammalian cells. Additionally, AuAg-CDs were incorporated into alginate to create a hydrogel wound dressing, which underwent evaluation using animal models. The results underscore the remarkable potential of the AuAg-CDs wound dressing in facilitating the proliferation of wound fibroblasts and combating bacterial infections. The significance of designing multifunctional nanomaterials to address the challenges associated with pathogenic bacterial infections and regenerative medicine is highlighted by this study, paving the way for future advancements in these fields.

Engineering Au44 Nanoclusters for NIR-II Luminescence Imaging-Guided Photoactivatable Cancer Immunotherapy

Immunotherapy is an advanced therapeutic strategy of cancer treatment but suffers from the issues of off-target adverse effects, lack of real-time monitoring techniques, and unsustainable response. Herein, an ultrasmall Au nanocluster (NC)-based theranostic probe is designed for second near-infrared window (NIR-II) photoluminescence (PL) imaging-guided phototherapies and photoactivatable cancer immunotherapy. The probe (Au44MBA26-NLG for short) is composed of atomically precise and NIR-II emitting Au44MBA26 NCs (here MBA denotes water-soluble 4-mercaptobenzoic acid) conjugated with immune checkpoint inhibitor 1-cyclohexyl-2-(5H-imidazo[5,1-a]isoindol-5-yl)ethanol (NLG919) via a singlet oxygen (1O2)-cleavable linker. Upon NIR photoirradiation, the Au44MBA26-NLG not only enables NIR-II PL imaging of tumors in deep tissues for guiding tumor therapy but also allows the leverage of photothermal property for cancer photothermal therapy (PTT) and the photogenerated 1O2 for photodynamic therapy (PDT) and releasing NLG919 for cancer immunotherapy. Such a multiple effect modulated by Au44MBA26-NLG prompts the proliferation and activation of effector T cells, upshifts systemic antitumor T-lymphocyte (T cell) immunity, and finally suppresses the growth of both primary and distant tumors in living mice. Overall, this study may provide a promising theranostic nanoplatform toward NIR-II PL imaging-guided phototherapies and photoactivatable cancer immunotherapy.

Lattice Strain Engineering of Ti3C2 Narrows Band Gap for Realizing Extraordinary Sonocatalytic Bacterial Killing

The rapid development of sonodynamic therapy (SDT) provides a promising strategy for treating deep-seated multidrug-resistant (MDR) bacterial infection. However, the extreme scarcity of biologically functional and highly efficient sonosensitizers severely limits the further clinical practice of SDT. Herein, the lattice-strain-rich Ti3C2 (LS-Ti3C2) with greatly improved sonosensitizing effect is one-step synthesized using Ti3C2 and meso-tetra(4-carboxyphenyl)porphine (TCPP) by the solvothermal method for realizing extraordinary SDT. The intervention of TCPP causes all the Ti-O chemical bonds and most of the Ti-F chemical bonds on the surface layer of Ti3C2 to break down. The amino groups of TCPP are then recombined with these exposed Ti atoms to perturb the order of the Ti atoms, resulting in displacement of the Ti atoms and final lattice structural distortion of Ti3C2. The inherent lattice strain narrows the band gap of Ti3C2, which mainly facilitates the electron-hole pair separation and electron transfer under ultrasound irradiation, thereby resulting in US-mediated reactive oxygen species (ROS) production and the subsequent robust bactericidal capability (99.77 ± 0.16%) against methicillin-resistant Staphylococcus aureus (MRSA). Overall, this research offers a perspective into the development of Ti-familial sonosensitizers toward SDT practice.

Visual Multifunctional Aggregation-Induced Emission-Based Bacterial Cellulose for Killing of Multidrug-Resistant Bacteria

Multidrug-resistant (MDR) bacteria-related wound infections are a thorny issue. It is urgent to develop new antibacterial wound dressings that can not only prevent wounds from MDR bacteria infection but also promote wound healing. Herein, an aggregation-induced emission (AIE) molecule BITT-composited bacterial cellulose (BC) is presented as wound dressings. BC-BITT composites have good transparency, making it easy to monitor the wound healing process through the composite membrane. The BC-BITT composites retain the advantages of biocompatible BC, and display photodynamic and photothermal synergistic antibacterial effects under irradiation of a 660 nm laser. Furthermore, the BC-BITT composites show excellent wound healing performance in a mouse full-thickness skin wound model infected by MDR bacteria, simultaneously with negligible toxicity. This work paves a way for treating clinically troublesome wound infections.

Photodynamic activity enhanced by in situ biosynthetic BC/CQDs@PCN-224 membranes through FRET strategy

Porphyrin-based metal organic frameworks (MOFs) with efficient bactericidal performance have increasingly attracted attention in photodynamic inactivation materials. However, low reactive oxygen species (ROS) yield and drug residue hazards of current porphyrin-MOFs materials lead to unsatisfactory clinical therapeutic effects. In this paper, carbon quantum dots (CQDs) were encapsulated into PCN-224, which enhanced the photodynamic activity of the MOFs through fluorescence resonance energy transfer (FRET) process. Singlet oxygen (¹O₂) detection confirmed that the photodynamic activity of CQDs-doped PCN-224 (CQDs@PCN-224) was enhanced than that of pristine PCN-224 under illumination. Furthermore, the CQDs@PCN-224 were firmly embedded into bacterial cellulose (BC) nanofibrous membranes by using an eco-friendly biosynthetic approach, efficiently preventing MOFs leakage during use. The results of bactericidal assays demonstrated that BC/CQDs@PCN-224 membrane with higher photodynamic activity causes more severe disruption to bacterial structure and possesses better antibacterial efficiency (>99.99 % reduction of both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli O157:H7 within 30 min) than BC/PCN-224 membrane under visible light illumination (500 W, 15 cm height, λ ≥ 420 nm). In addition, the biosynthesized BC/CQDs@PCN-224 membrane showed good hemocompatibility and low cytotoxicity, revealing that the BC- and MOFs-based material with enhanced PDI efficiency and satisfying safety has great potential in medical fields.

Smart microneedle patches for wound healing and management

The number of patients with non-healing wounds is generally increasing globally, placing a huge social and economic burden on every country. The complexity of the wound-healing process remains a major health challenge despite the numerous studies that have been reported on conventional wound dressings. Therefore, a therapeutic system that combines diagnostic and therapeutic modalities is essential to monitor wound-related biomarkers and facilitate wound healing in real time. Microneedles, as a multifunctional platform, are promising for transdermal diagnostics and drug delivery. Their advantages are mainly reflected in painless transdermal drug delivery, good biocompatibility, and ease of self-administration. In this work, we review recent advances in the use of microneedle patches for wound healing and monitoring. The paper first provides a brief overview of the skin structure and the wound healing process, and then discusses the current state of research and prospects for the development of wound-related biomarkers and their real-time monitoring based on microneedle sensors. It summarizes the current state of research based on the unique design of microneedle patches, including biomimetic, conductive, and environmentally responsive, to achieve wound healing. It further summarizes the prospects for the application of different microneedle-based drug delivery modalities and drug delivery substances for wound healing, due to their superior transdermal drug delivery advantages. It concludes with challenges and expectations for the use of smart microneedle patches for wound healing and management.

Smart bioadhesives for wound healing and closure

The high demand for rapid wound healing has spurred the development of multifunctional and smart bioadhesives with strong bioadhesion, antibacterial effect, real-time sensing, wireless communication, and on-demand treatment capabilities. Bioadhesives with bio-inspired structures and chemicals have shown unprecedented adhesion strengths, as well as tunable optical, electrical, and bio-dissolvable properties. Accelerated wound healing has been achieved via directly released antibacterial and growth factors, material or drug-induced host immune responses, and delivery of curative cells. Most recently, the integration of biosensing and treatment modules with wireless units in a closed-loop system yielded smart bioadhesives, allowing real-time sensing of the physiological conditions (e.g., pH, temperature, uric acid, glucose, and cytokine) with iterative feedback for drastically enhanced, stage-specific wound healing by triggering drug delivery and treatment to avoid infection or prolonged inflammation. Despite rapid advances in the burgeoning field, challenges still exist in the design and fabrication of integrated systems, particularly for chronic wounds, presenting significant opportunities for the future development of next-generation smart materials and systems.

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Rational material engineering of bioadhesives with optimized mechanical and curative properties.

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Incorporation of biosensing allows real-time and precise evaluation of the healing stage.

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Closed-loop, smart bioadhesives that integrate wireless sensing and treatment hold great potential for chronic wound healing.

Nanosized Shikonin-Fe(III) Coordination Material for Synergistic Wound Treatment: An Initial Explorative Study

Shikonin (Shik), a natural pigment, has received growing interest in various biomedical fields due to its anti-inflammatory, antitumor, antimicrobial, and antioxidant ability. However, some inherent characteristics of Shik, such as its virulence, low bioavailability, and poor solubility, have limited its biomedical applicability. Here, we reported a facile synthetic method to produce the Shik-iron (III) nanoparticles (Shik-Fe NPs), which could overcome these limitations of Shik. The synthesized Shik-Fe NPs possessed a uniform size range of 110 ± 10 nm, negative surface charges, good water dispersity, and high safety. Iron distributed uniformly inside Shik-Fe NPs, and iron constituted 20% of total mass in PEGylated Shik-Fe NPs. When interacting with activated macrophages, Shik-Fe NPs significantly reduced the level of cellular inflammatory factors, for example, iNOS, IL-1β, and TNF-α. Furthermore, the Shik-Fe NPs demonstrated synergistic anti-inflammation and anti-bacterial properties in vivo, since they could release Fe³⁺ and Shik to eradicate bacteria (Staphylococcus aureus and P. aeruginosa were used as model microbes here) during wound infections and provide full recovery for scald wounds. Collectively, the study established a dual-functional Shik-derived nanoplatform, which could be useful for the treatment of various inflammation-involved diseases.

Multifunctional Gold Nanoclusters for Effective Targeting, Near-Infrared Fluorescence Imaging, Diagnosis, and Treatment of Cancer Lymphatic Metastasis

Developing effective lymph-node (LN) targeting and imaging probes is crucial for the early detection and diagnosis of tumor metastasis to improve patient survival. Most current clinical LN imaging probes are based on small organic dyes (e.g., indocyanine green) or radioactive ^99mTc-complexes, which often suffer from limitations, such as rapid photobleaching, poor signal contrast, and potential biosafety issues. Moreover, these probes cannot easily incorporate therapeutic functions to realize beneficial theranostics without affecting their LN-targeting ability. Herein, we have developed dual-ligand-/multiligand-capped gold nanoclusters (GNCs) for specific targeting, near-infrared (NIR) fluorescence imaging, diagnosis, and treatment of LN cancer metastasis in in vivo mouse models. By optimizing the surface ligand coating, we have prepared Au₂₅(SR₁)_n(SR₂)_18-n (where SR₁ and SR₂ are different functional thiol ligands)-type GNCs, which display highly effective LN targeting, excellent stability and biocompatibility, and optimal body-retention time. Moreover, they can provide continuous NIR fluorescence imaging of LNs for >3 h from a single dose, making them well-suited for fluorescence-guided surgery. Importantly, we have further incorporated methotrexate, a chemotherapeutic drug, into the GNCs without affecting their LN-targeting ability. Consequently, they can significantly improve the efficiency of methotrexate delivery to target LNs, achieving excellent therapeutic efficacy with up to 4-fold lower hepatotoxicity. Thus, the GNCs are highly effective and safe theranostic nanomedicines against cancer lymphatic metastasis.

Breathable and Stretchable Dressings for Accelerating Healing of Infected Wounds

Multidrug-resistant (MDR) bacteria-infected wounds are challenging issues that threaten human health. Herein, L-thioproline (T) and Boc-capped L-thioproline (BT)-decorated gold nanoparticles (TBT-GNPs) with potent antibacterial activity against MDR bacteria are reported. The TBT-GNPs are composited with bacterial cellulose to form wound dressings which show excellent antimicrobial performance both in vitro and in vivo. Moreover, this dressing is both breathable and stretchable which is favorable for gas exchange to accelerate the wound healing. This work is insightful for developing multifunctional dressings to satisfy the clinical requirements.

Porous synthetic hydrogel carrying basic fibroblast growth factor with controllable and rapid degradation rate to promote wound healing

Porous hydrogel dressings show breathability and possibility to carry and release basic fibroblast growth factor (bFGF) to promote wound healing. However, the difficult replacement may lead to the secondary damage. Thus, there is an urgent need to develop a method platform to control the degradation rate of hydrogel, so as to realize the on-demand replacement. The present study fabricated a porous hydrogel from co-polymized N,N′-bis(acryloyl) cystamine (BAC), allyl polyethylene glycol 500 (APEG500) and acrylic acid (AA) with the presence of polycaprolactone (PCL). BAC contains disulfide bond, which crosslinked the hydrogel. The pore size of the porous hydrogel was 400–600 μm. Higher content of BAC indicated higher crosslinking density, which reduced swelling ratio of hydrogel, while promoted hydrogel storage modulus. At the same time, the presence of PCL reduced swelling ratio of hydrogel, while promoted hydrogel mechanical properties, endowing hydrogel with tough feature. Porous hydrogels that crosslinked by disulfide bonds immersed in glutathione solution were found to degrade spontaneously and quickly due to the response to glutathione. Both crosslinking density and PCL content affected the degradation rate. The porous hydrogel carrying bFGF was applied to wound, promoting angiogenesis, thus accelerating wound healing within 12 d. Due to the spontaneous and rapid degradation of optimized porous hydrogel on wound within 3 days, there was no operation of removing dressing during treatment, avoiding damage during dressing replacement.

Nanobiotechnology: Applications in Chronic Wound Healing

Wounds occur when skin integrity is broken and the skin is damaged. With progressive changes in the disease spectrum, the acute wounds caused by mechanical trauma have been become less common, while chronic wounds triggered with aging, diabetes and infection have become more frequent. Chronic wounds now affect more than 6 million people in the United States, amounting to 10 billion dollars in annual expenditure. However, the treatment of chronic wounds is associated with numerous challenges. Traditional remedies for chronic wounds include skin grafting, flap transplantation, negative-pressure wound therapy, and gauze dressing, all of which can cause tissue damage or activity limitations. Nanobiotechnology — which comprises a diverse array of technologies derived from engineering, chemistry, and biology — is now being applied in biomedical practice. Here, we review the design, application, and clinical trials for nanotechnology-based therapies for chronic wound healing, highlighting the clinical potential of nanobiotechnology in such treatments. By summarizing previous nanobiotechnology studies, we lay the foundation for future wound care via a nanotech-based multifunctional smart system.

Deploying Gold Nanomaterials in Combating Multi-Drug-Resistant Bacteria

Antibiotic resistance has become a serious threat to human health due to the overuse of antibiotics. Different antibiotics are being developed to treat resistant bacteria, but the development cycle of antibiotics is hard to keep up with the high incidence of antibiotic resistance. Recent advances in antimicrobial nanomaterials have made nanotechnology a powerful solution to this dilemma. Among these nanomaterials, gold nanomaterials have excellent antibacterial efficacy and biosafety, making them alternatives to antibiotics. This review presents strategies that use gold nanomaterials to combat drug-resistant bacteria. We focus on the influence of physicochemical factors such as surface chemistry, size, and shape of gold nanomaterials on their antimicrobial properties and describe the antimicrobial applications of gold nanomaterials in medical devices. Finally, the existing challenges and future directions are discussed.

Antibacterial metal nanoclusters

Combating bacterial infections is one of the most important applications of nanomedicine. In the past two decades, significant efforts have been committed to tune physicochemical properties of nanomaterials for the development of various novel nanoantibiotics. Among which, metal nanoclusters (NCs) with well-defined ultrasmall size and adjustable surface chemistry are emerging as the next-generation high performance nanoantibiotics. Metal NCs can penetrate bacterial cell envelope more easily than conventional nanomaterials due to their ultrasmall size. Meanwhile, the abundant active sites of the metal NCs help to catalyze the bacterial intracellular biochemical processes, resulting in enhanced antibacterial properties. In this review, we discuss the recent developments in metal NCs as a new generation of antimicrobial agents. Based on a brief introduction to the characteristics of metal NCs, we highlight the general working mechanisms by which metal NCs combating the bacterial infections. We also emphasize central roles of core size, element composition, oxidation state, and surface chemistry of metal NCs in their antimicrobial efficacy. Finally, we present a perspective on the remaining challenges and future developments of metal NCs for antibacterial therapeutics.

Boronic Acid-Decorated Multivariate Photosensitive Metal-Organic Frameworks for Combating Multi-Drug-Resistant Bacteria

Metal-organic frameworks (MOFs) are promising photosensitized materials that have displayed great advantages in antibacterial application. However, their bactericidal activity is still limited by the ultrashort diffusion distance of biocidal reactive oxygen species (ROS). Herein, we integrate the bacterial-binding boronic acid ligand and photosensitized porphyrin into one single MOF, synergistically boosting antibiotic capability. The introduction of the boronic acid group with a closed physical gap makes multivariate MOFs more powerful for eradicating multi-drug-resistant (MDR) bacteria. The MOFs that are decorated with boronic acid possess antibacterial efficiencies (10-20 times) higher than those without the targeting ligand. Moreover, the MOFs exhibit excellent biocompatibility. They significantly decrease the inflammatory responses and accelerate the healing of chronic wounds infected with MDR bacteria (nearly 2 times faster). This work provides a strategy to develop multivariate MOFs that target bacteria, which will further inspire specific bacterial-binding therapy in the future.

Aminophenol-Decorated Gold Nanoparticles for Curing Bacterial Infections

Nanomaterials usually kill bacteria via multiple mechanisms which are not explicit to the same degree as those of conventional antibiotics. This situation may hinder the development of novel nanoscale antibiotics. Here, we present aminophenol (AP) to modify gold nanoparticles (AP_Au NPs) which show a broad antibacterial spectrum and potent antibacterial effects against multidrug-resistant (MDR) bacteria with clear antibacterial mechanisms. AP_Au NPs can not only damage bacterial cell walls but also bind to the 16S rRNA to block bacterial protein synthesis. Moreover, AP_Au NPs show excellent performance in curing abdominal bacterial infections in an in vivo model. AP_Au NPs thus have the potential to become a novel antibacterial agent for clinical applications.

Extraction of Au(iii) from hydrochloric acid media using a novel amide-based ionic liquid

A study on the performance of selective extraction of Au(iii) using a novel amide-based IL.