Biofilm microenvironment triggered self-enhancing photodynamic immunomodulatory microneedle for diabetic wound therapy

Bioactive sucralfate-based microneedles promote wound healing through reprogramming macrophages and protecting endogenous growth factors

Impaired wound healing due to insufficient cell proliferation and angiogenesis is a significant physical and psychological burden to patients worldwide. Therapeutic delivery of exogenous growth factors (GFs) at high doses for wound repair is non-ideal as GFs have poor stability in proteolytic wound environments. Here, we present a two-stage strategy using bioactive sucralfate-based microneedle (SUC-MN) for delivering interleukin-4 (IL-4) to accelerate wound healing. In the first stage, SUC-MN synergistically enhanced the effect of IL-4 through more potent reprogramming of pro-regenerative M2-like macrophages via the JAK-STAT pathway to increase endogenous GF production. In the second stage, sucralfate binds to GFs and sterically disfavors protease degradation to increase bioavailability of GFs. The IL-4/SUC-MN technology accelerated wound healing by 56.6 % and 46.5 % in diabetic mice wounds and porcine wounds compared to their respective untreated controls. Overall, our findings highlight the innovative use of molecular simulations to identify bioactive ingredients and their incorporation into microneedles for promoting wound healing through multiple synergistic mechanisms.

L-arginine loading porous PEEK promotes percutaneous tissue repair through macrophage orchestration

Infection and poor tissue repair are the key causes of percutaneous implantation failure. However, there is a lack of effective strategies to cope with due to its high requirements of sterilization, soft tissue healing, and osseointegration. In this work, l-arginine (L-Arg) was loaded onto a sulfonated polyetheretherketone (PEEK) surface to solve this issue. Under the infection condition, nitric oxide (NO) and reactive oxygen species (ROS) are produced through catalyzing L-Arg by inducible nitric oxide synthase (iNOS) and thus play a role in bacteria sterilization. Under the tissue repair condition, L-Arg is catalyzed to ornithine by Arginase-1 (Arg-1), which promotes the proliferation and collagen secretion of L929 and rBMSCs. Notably, L-Arg loading samples could polarize macrophages to M1 and M2 in infection and tissue repair conditions, respectively. The results in vivo show that the L-Arg loading samples could enhance infected soft tissue sealing and bone regeneration. In summary, L-Arg loading sulfonated PEEK could polarize macrophage through metabolic reprogramming, providing multi-functions of antibacterial abilities, soft tissue repair, and bone regeneration, which gives a new idea to design percutaneous implantation materials.

Multifunctional composite soluble microneedle patch based on "one stone, three birds" strategy for promoting the healing of infectious wounds

The colonisation of microorganisms such as bacteria forms a biofilm barrier on the wound's surface, preventing or delaying the penetration of antibacterial drugs. At the same time, continuous bacterial infection can cause oxidative stress and an inflammatory response and hinder angiogenesis, resulting in difficult wound healing. Based on the "one stone, three birds" strategy, a multi-functional nanoparticle composite soluble microneedle was designed and developed to solve this dilemma better. Ginsenoside-liposomes(R-Lipo) were prepared by ginsenoside Rg3, which had the effect of promoting repair, instead of cholesterol, and loaded with berberine (Ber), the antibacterial component of Coptis, together with polydopamine (PDA), which had anti-inflammatory and antioxidant properties, into microneedles based on hyaluronic acid (PDA/R-Lipo@BerMN). PDA/R-Lipo@BerMN tip can penetrate and destroy the integrity of the biofilm, dissolve under the action of hyaluronidase in the skin, and gradually release the drug to achieve rapid antibacterial, anti-inflammatory, antioxidant, and proliferation. As expected, the PDA/R-Lipo@BerMN patch effectively cleared ROS during wound closure, further promoted M2 macrophage polarisation, eradicated bacterial infection, and regulated the immune microenvironment, promoting inflammation suppression, collagen deposition, angiogenesis, and tissue regeneration.

Microneedle system for tissue engineering and regenerative medicines: a smart and efficient therapeutic approach

The global demand for an enhanced quality of life and extended lifespan has driven significant advancements in tissue engineering and regenerative medicine. These fields utilize a range of interdisciplinary theories and techniques to repair structurally impaired or damaged tissues and organs, as well as restore their normal functions. Nevertheless, the clinical efficacy of medications, materials, and potent cells used at the laboratory level is always constrained by technological limitations. A novel platform known as adaptable microneedles has been developed to address the abovementioned issues. These microneedles offer a solution for the localized distribution of various cargos while minimizing invasiveness. Microneedles provide favorable patient compliance in clinical settings due to their effective administration and ability to provide a painless and convenient process. In this review article, we summarized the most recent development of microneedles, and we started by classifying various microneedle systems, advantages, and fundamental properties. Subsequently, it provides a comprehensive overview of different types of microneedles, the material used to fabricate microneedles, the fundamental properties of ideal microneedles, and their applications in tissue engineering and regenerative medicine, primarily focusing on preserving and restoring impaired tissues and organs. The limitations and perspectives have been discussed by concluding their future therapeutic applications in tissue engineering and regenerative medicines.

Structurally Oriented Carbon Dots as ROS Nanomodulators for Dynamic Chronic Inflammation and Infection Elimination

The selective elimination of cytotoxic ROS while retaining essential ones is pivotal in the management of chronic inflammation. Co-occurring bacterial infection further complicates the conditions, necessitating precision and an efficacious treatment strategy. Herein, the dynamic ROS nanomodulators are rationally constructed through regulating the surface states of herbal carbon dots (CDs) for on-demand inflammation or infection elimination. The phenolic OH containing CDs derived from honeysuckle (HOCD) and dandelion (DACD) demonstrated appropriate redox potentials, ensuring their ability to scavenge cytotoxic ROS such as ·OH and ONOO-, while invalidity toward essential ones such as O2·-, H2O2, and NO. This enables efficient treatment of chronic inflammation without affecting essential ROS signal pathways. The surface C-N/C═N of CDs derived from taxus leaves (TACD) and DACD renders them with suitable band structures, facilitating absorption in the red region and efficient generation of O2·- upon light irradiation for sterilization. Specifically, the facilely prepared DACD demonstrates fascinating dynamic ROS modulating ability, making it highly suitable for addressing concurrent chronic inflammation and infection, such as diabetic wound infection. This dynamic ROS regulation strategy facilitates the realization of the precise and efficient treatment of chronic inflammation and infection with minimal side effects, holding immense potential for clinical practice.

M2 macrophage-polarized anti-inflammatory microneedle patch for accelerating biofilm-infected diabetic wound healing via modulating the insulin pathway

Macrophages play a pivotal role in the healing of diabetic ulcers. The sustained elevation of glucose levels damages the insulin signaling pathway in macrophages, leading to dysfunctional macrophages that struggle to transition from pro-inflammatory (M1) to reparative (M2) states. Therefore, modulating macrophage inflammatory responses via the insulin pathway holds promise for diabetic ulcer treatment. Additionally, the presence of biofilm impedes drug penetration, and the resulting immunosuppressive microenvironment exacerbates the persistent infiltration of pro-inflammatory M1 macrophages. Therefore, we designed an array of dissolvable microneedle (denoted as NPF@MN) loaded with self-assembled nanoparticles that could deliver NPF nanoparticles, acid-sensitive NPF-releasing Protocatechualdehyde (PA) with hypoglycemic and insulin-like effects, regulating macrophage polarization to an anti-inflammatory M2 phenotype. Additionally, this study extensively examined the mechanism by which NPF@MN accelerates the healing of diabetic ulcers through the activation of the insulin signaling pathway. Through RNA-seq and GSEA analysis, we identified a reduction in the expression of pathway-related factors such as IR, IRS-1, IRS-2, and SHC. Our work presents an innovative therapeutic approach targeting the insulin pathway in diabetic ulcers and underscores its translational potential for clinical management.

Acidic biofilm microenvironment-responsive ROS generation via a protein nanoassembly with hypoxia-relieving and GSH-depleting capabilities for efficient elimination of biofilm bacteria

Reactive oxygen species (ROS) are widely considered to the effective therapeutics for fighting bacterial infections especially those associated with biofilm. However, biofilm microenvironments including hypoxia, limited H2O2, and high glutathione (GSH) level seriously limit the therapeutic efficacy of ROS-based strategies. Herein, we have developed an acidic biofilm microenvironment-responsive antibacterial nanoplatform consisting of copper-dopped bovine serum albumin (CBSA) loaded with copper peroxide (CuO2) synthesized in situ and indocyanine green (ICG). The three-in-one nanotherapeutics (CuO2/ICG@CBSA) are capable of releasing Cu2+ and H2O2 in a slightly acidic environment, where Cu2+ catalyzes the conversion of H2O2 into hydroxyl radical (•OH) and consumes the highly expressed GSH to disrupt the redox homeostasis. With the assistance of an 808 nm laser, the loaded ICG not only triggers the production of singlet oxygen (1O2) by a photodynamic process, but also provides photonic hyperpyrexia that further promotes the Fenton-like reaction for enhancing •OH production and induces thermal decomposition of CuO2 for the O2-self-supplying 1O2 generation. The CuO2/ICG@CBSA with laser irradiation demonstrates photothermal-augmented multi-mode synergistic bactericidal effect and is capable of inhibiting biofilm formation and eradicating the biofilm bacteria. Further in vivo experiments suggest that the CuO2/ICG@CBSA can effectively eliminate wound infections and accelerate wound healing. The proposed three-in-one nanotherapeutics with O2/H2O2-self-supplied ROS generating capability show great potential in treating biofilm-associated bacterial infections. STATEMENT OF SIGNIFICANCE: Here, we have developed an acidic biofilm microenvironment-responsive nanoplatform consisting of copper-dopped bovine serum albumin (CBSA) loaded with copper peroxide (CuO2) synthesized in situ and indocyanine green (ICG). The nanotherapeutics (CuO2/ICG@CBSA) are capable of releasing Cu2+ and H2O2 in an acidic environment, where Cu2+ catalyzes the conversion of H2O2 into •OH and consumes the overexpressed GSH to improve oxidative stress. With the aid of an 808 nm laser, ICG provides photonic hyperpyrexia for enhancing •OH production, and triggers O2-self-supplying 1O2 generation. CuO2/ICG@CBSA with laser irradiation displays photothermal-augmented multi-mode antibacterial and antibiofilm effect. Further in vivo experiments prove that CuO2/ICG@CBSA effectively eliminates wound infection and promotes wound healing. The proposed three-in-one nanotherapeutics show great potential in treating biofilm-associated bacterial infections.

Wireless Intelligent Patch for Closed-loop In Situ Wound Management

Wound infections pose a major healthcare issue, affecting the well-being of millions of patients worldwide. Effective intervention and on-site detection are important in wound management. However, current approaches are hindered by time-consuming analysis and a lack of technology for real-time monitoring and prompt therapy delivery. In this study, a smart wound patch system (SWPS) designed for wireless closed-loop and in-situ wound management is presented. The SWPS integrates a microfluidic structure, an organic electrochemical transistor (OECT) based sensor, an electrical stimulation module, and a miniaturized flexible printed circuit board (FPCB). The OECT incorporates a bacteria-responsive DNA hydrogel-coated gate for continuous monitoring of bacterial virulence at wound sites. Real-time detection of OECT readings and on-demand delivery of electrical cues to accelerate wound healing is facilitated by a mobile phone application linked with an FPCB containing low-power electronics equipped with parallel sensing and stimulation circuitry. In this proof-of-concept study, the functionality of the SWPS is validated and its application both in vitro and in vivo is demonstrated. This proposed system expands the arsenal of tools available for effective wound management and enables personalized treatment.

A poly (lactic-co-glycolic acid) self-pumping Janus dressing with bidirectional biofluid transport for diabetic wound healing via anti-bacteria and pro-angiogenesis

Diabetic wound healing poses a substantial challenge owing to bacterial infections, insufficient angiogenesis, and excessive exudates. Currently, most of the clinical dressings used for diabetic wounds are still conventional dressings such as gauze. In this study, a three-layer Janus dressing was developed via continuous electrostatic spinning. The top-layer was composed of polylactic acid-glycolic acid and hydroxyapatite doped with silver ions and silicate. The hydrophobic top-layer prevented the adhesion of foreign bacteria. The mid-layer was composed of polyethylene glycol, polylactic acid-glycolic acid and hydroxyapatite doped with silver ions and silicate facilitated exudate absorption and bioactive ion release. The modified sub-layer containing polylactic acid-glycolic acid, hydroxyapatite doped with silver ions and silicate and sodium alginate microspheres enabled both the transport of wound exudate from the wound bed to dressing and the backflow of bioactive silver ions and silicate to the wound bed, thereby reducing infection and stimulating angiogenesis. Through in vivo and in vivo experiments, the Janus dressing showed to have antimicrobial, angiogenic, and exudate-control properties that accelerate healing in diabetic wounds. As a novel dressing, the multifunctional, self-pumping Janus wound dressing with bi-directional biofluidic transport offers a new approach to diabetic wound healing.

Mechanical biomimetic silk nano fiber-magnesium ion complex/hydroxyethylcellulose/glycerol hydrogel dressing with angiogenic capacity for accelerating scarless diabetic wound healing

Quick scarless healing remains a key issue for diabetic wounds. Here, a stretchable elastomeric hydrogel dressing composed of hydroxyethylcellulose (HEC), silk nano fiber-magnesium ion complex (Mg2+-SNF) and glycerol (Gly) was developed to optimize mechanical niche, anti-inflammatory and angiogenic behavior simultaneously. The composite hydrogel dressing exhibited skin-like elasticity (175.1 ± 23.9 %) and modulus (156.7 ± 2.5 KPa) while Mg2+-SNF complex endowed the dressing with angiogenesis, both favoring quick scarless skin regeneration. In vitro cell studies revealed that the hydrogel dressing stimulated fibroblast proliferation, endothelial cell migration and vessel-like tube formation, and also induced anti-inflammatory behavior of macrophages. In vivo results revealed accelerated healing of diabetic wounds. The improved granulation ingrowth and collagen deposition suggested high quality repair. Both thinner epidermal layer and low collagen I/III ratio of the regenerated skin confirmed scarless tissue formation. This bioactive hydrogel dressing has promising potential to address the multifaceted challenges of diabetic wound management.

Plant-Derived Chinese Herbal Hydrogel Microneedle Patches for Wound Healing

Several natural Chinese herbal medicines have demonstrated considerable potential in facilitating wound healing, while the primary concern remains centered around optimizing formulation and structure to maximize their efficacy. To address this, a natural microneedles drug delivery system is proposed that harnesses gelatinized starch and key Chinese herbal ingredients-aloe vera and berberine. After gelatinized and aged in a well-designed mold, the starch-based microneedles are fabricated with suitable mechanical strength to load components. The resulting Chinese herbal hydrogel microneedles, enriched with integrated berberine and aloe, exhibit antibacterial, anti-inflammatory, and fibroblast growth-promoting properties, thereby facilitating wound healing in the whole process. In vivo experimental results underscore the notable achievements of the microneedles in early-stage antibacterial effects and subsequent tissue reconstruction, contributing significantly to the overall wound healing process. These results emphasize the advantageous combination of traditional Chinese medicine with microneedles, presenting a novel strategy for wound repair and opening new avenues for the application of traditional Chinese medicine.

Nanozymes for the Therapeutic Treatment of Diabetic Foot Ulcers

Diabetic foot ulcers (DFU) are chronic, refractory wounds caused by diabetic neuropathy, vascular disease, and bacterial infection, and have become one of the most serious and persistent complications of diabetes mellitus because of their high incidence and difficulty in healing. Its malignancy results from a complex microenvironment that includes a series of unfriendly physiological states secondary to hyperglycemia, such as recurrent infections, excessive oxidative stress, persistent inflammation, and ischemia and hypoxia. However, current common clinical treatments, such as antibiotic therapy, insulin therapy, surgical debridement, and conventional wound dressings all have drawbacks, and suboptimal outcomes exacerbate the financial and physical burdens of diabetic patients. Therefore, development of new, effective and affordable treatments for DFU represents a top priority to improve the quality of life of diabetic patients. In recent years, nanozymes-based diabetic wound therapy systems have been attracting extensive interest by integrating the unique advantages of nanomaterials and natural enzymes. Compared with natural enzymes, nanozymes possess more stable catalytic activity, lower production cost and greater maneuverability. Remarkably, many nanozymes possess multienzyme activities that can cascade multiple enzyme-catalyzed reactions simultaneously throughout the recovery process of DFU. Additionally, their favorable photothermal-acoustic properties can be exploited for further enhancement of the therapeutic effects. In this review we first describe the characteristic pathological microenvironment of DFU, then discuss the therapeutic mechanisms and applications of nanozymes in DFU healing, and finally, highlight the challenges and perspectives of nanozyme development for DFU treatment.

Near-Infrared Triggered Biodegradable Microneedle Patch for Controlled Macromolecule Drug Release

Transdermal drug delivery of macromolecule drugs attracts significant attention due to the advantage of convenience and biocompatibility. However, the practical usage of it is limited by the low delivery efficiency and poor drug absorption. To develop an efficient, safe, and controllable transdermal delivery method, the near-infrared (NIR) triggered calcium sulfate and gelatin biodegradable composite microneedle (MN) patches are developed. The MN patches are fabricated by polydimethylsiloxane (PDMS) molds, and the structure data can be adjusted by changing the molds. Such an MN patch can release both macro and micro molecule drugs. After loading with photothermal converter IR780, which can transfer energy of light to heat, the release of macromolecule drugs in MNs can be controlled by applying NIR irradiation. The control effect can be enhanced by spraying 1-tetradecanol (TD) coating and optimizing the ratio (weight) of gelatin and calcium sulfate to 2:6. Besides, the MN patch can deliver drugs through the skin barrier, and the process can be controlled by NIR. Moreover, the insulin-loaded MN patch exhibits some therapeutic effects on healthy mice. This work suggests that biodegradable MNs can achieve controllable drug delivery and potentially be applied in individual treatment via transdermal ingestion.

Enzyme-Like Photocatalytic Octahedral Rh/Ag2MoO4 Accelerates Diabetic Wound Healing by Photo-Eradication of Pathogen and Relieving Wound Hypoxia

The harsh environment of diabetic wounds, including bacterial infection and wound hypoxia, is not conducive to wound healing. Herein, an enzyme-like photocatalytic octahedral Rh/Ag2MoO4 is developed to manage diabetic-infected wounds. The introduction of Rh nanoparticles with catalase-like catalytic activity can enhance the photothermal conversion and photocatalytic performance of Rh/Ag2MoO4 by improving near-infrared absorbance and promoting the separation of electron-hole pairs, respectively. Rh/Ag2MoO4 can effectively eliminate pathogens through a combination of photothermal and photocatalytic antibacterial therapy. After bacteria inactivation, Rh/Ag2MoO4 can catalyze hydrogen peroxide to produce oxygen to alleviate the hypoxic environment of diabetic wounds. The in vivo treatment effect demonstrated the excellent therapeutic performance of Rh/Ag2MoO4 on diabetic infected wounds by removing infectious pathogens and relieving oxygen deficiency, confirming the potential application of Rh/Ag2MoO4 in the treatment of diabetic infected wounds.

Ta4C3 Nanosheets as a Novel Therapeutic Platform for Photothermal-Driven ROS Scavenging and Immune Activation against Antibiotic-Resistant Infections in Diabetic Wounds

The accumulation of excessive reactive oxygen species (ROS) and recurrent infections with drug-resistant bacteria pose significant challenges in diabetic wound infections, often leading to impediments in wound healing. Addressing this, there is a critical demand for novel strategies dedicated to treating and preventing diabetic wounds infected with drug-resistant bacteria. Herein, 2D tantalum carbide nanosheets (Ta4C3 NSs) have been synthesized through an efficient and straightforward approach, leading to the development of a new, effective nanoplatform endowed with notable photothermal properties, biosafety, and diverse ROS scavenging capabilities, alongside immunogenic attributes for diabetic wound treatment and prevention of recurrent drug-resistant bacterial infections. The Ta4C3 NSs exhibit remarkable photothermal performance, effectively eliminating methicillin-resistant Staphylococcus aureus (MRSA) and excessive ROS, thus promoting diabetic wound healing. Furthermore, Ta4C3 NSs enhance dendritic cell activation, further triggering T helper 1 (TH1)/TH2 immune responses, leading to pathogen-specific immune memory against recurrent MRSA infections. This nanoplatform, with its significant photothermal and immunomodulatory effects, holds vast potential in the treatment and prevention of drug-resistant bacterial infections in diabetic wounds.

Translational Challenges in Drug Therapy and Delivery Systems for Treating Chronic Lower Extremity Wounds

Despite several promising preclinical studies performed over the past two decades, there remains a paucity of market-approved drugs to treat chronic lower extremity wounds in humans. This translational gap challenges our understanding of human chronic lower extremity wounds and the design of wound treatments. Current targeted drug treatments and delivery systems for lower extremity wounds rely heavily on preclinical animal models meant to mimic human chronic wounds. However, there are several key differences between animal preclinical wound models and the human chronic wound microenvironment, which can impact the design of targeted drug treatments and delivery systems. To explore these differences, this review delves into recent new drug technologies and delivery systems designed to address the chronic wound microenvironment. It also highlights preclinical models used to test drug treatments specific for the wound microenvironments of lower extremity diabetic, venous, ischemic, and burn wounds. We further discuss key differences between preclinical wound models and human chronic wounds that may impact successful translational drug treatment design.

Alloy nanozyme-reinforced hyaluronic acid-based hydrogel with wound environment-responsive properties for synergistically accelerating infectious wound healing

The recovery of infectious wound tissues presents a significant global health challenge due to the impediments posed by the harsh healing microenvironment, which includes ongoing bacterial invasion, high oxidative stress, inflammatory response, and impaired angiogenesis. To overcome the above issues, we propose a composite hydrogel based on the multiple-crosslinked mechanism involving the covalent network of CC bonds within catechol and maleic-modified HA (CMHA), the self-assembly network of glycyrrhizic acid (GA), and the metal-polyphenol coordination induced by ZHMCe for accelerating infectious wound healing. The resulting CMHA/GA/ZHMCe hydrogels demonstrate enhanced mechanical, adhesive, antioxidative, and antibacterial properties. Importantly, the hydrogel system possesses wound environment-responsive properties that allow it to adapt to the specific therapeutic requirements of different stages by regulating various enzyme activities in the healing of infected wounds. Furthermore, the biocompatible CMHA/GA/ZHMCe shows the ability to promote cell migration and angiogenesis in vitro while reprogramming macrophages toward an anti-inflammatory phenotype due to the effective release of active ingredients. In vivo experiments confirm that the CMHA/GA/ZHMCe hydrogel significantly enhances infectious wound healing by accelerating re-epithelialization, promoting collagen deposition, regulating inflammation, and contributing to vascularization. These findings underscore the therapeutic potential of our hydrogel dressings for the treatment of bacterially infected cutaneous wound healing.

Eugenol-loaded polyurethane gelatin dressing for efficient angiogenesis and antibacterial effects in refractory diabetic wound defect healing

The amelioration of refractory diabetic ulcers presents a formidable conundrum on a global scale, attributable to the elevated peril of contagion and protracted convalescence durations. Within the purlieus of this reparative epoch, the deployment of efficacious wound coverings endowed with both angiogenesis and antibacterial attributes is of paramount significance. Hydrogel wound dressings are distinguished by their elevated biocompatibility, adhesive tenacity, and innate regenerative capacity. Eugenol, a substance distilled from the blossoms of the lilac, serves as a precursor to metformin and is known to impede the genesis of reactive oxygen species. Although its antibacterial effects have been extensively chronicled, the angiogenic ramifications of eugenol within the context of wound remediation remain under-investigated. This research aimed to evaluate the effectiveness of eugenol-infused hydrogel as a wound dressing material. In this context, polyurethane gelatin (PG) was combined with eugenol at concentrations of 0.5% and 1%, creating PG-eugenol hydrogel mixtures with specific mass ratios for both in vivo and in vitro assessments. The in vivo studies indicated that hydrogels infused with eugenol expedited diabetic wound healing by fostering angiogenesis. Enhanced healing was noted, attributed to improved antibacterial and angiogenic properties, increased cell proliferation, tissue regeneration, and re-epithelialization. The in vitro analyses revealed that eugenol-enriched hydrogels stimulated the growth of fibroblasts (HFF-1) and human umbilical vein endothelial cells (HUVECs) and exhibited antibacterial characteristics. This investigation confirms the potential of eugenol-laden hydrogels in effectively treating diabetic wound defects.

Ferrocene-Based Antioxidant Self-Healing Hydrogel via the Biginelli Reaction for Wound Healing

The development of antioxidant wound dressings to remove excessive free radicals around wounds is essential for wound healing. In this study, we developed an efficient strategy to prepare antioxidant self-healing hydrogels as wound dressings by combining multicomponent reactions (MCRs) and postpolymerization modification. A polymer containing ferrocene and phenylboronic acid groups was developed via the Biginelli reaction, followed by efficient modification. This polymer is antioxidant due to its ferrocene moieties and can rapidly cross-link poly(vinyl alcohol) to realize an antioxidant self-healing hydrogel through dynamic borate ester linkages. This hydrogel has low cytotoxicity and is biocompatible. In in vivo experiments, this hydrogel is superior to existing clinical dressings in promoting wound healing. This study demonstrates the value of the Biginelli reaction in exploring biomaterials, potentially offering insights into the design of other multifunctional polymers and related materials using different MCRs.

PEGylated chitosan-coated nanophotosensitizers for effective cancer treatment by photothermal-photodynamic therapy combined with glutathione depletion

The combination of photothermal therapy (PTT) and photodynamic therapy (PDT) has emerged as a promising strategy for cancer treatment. However, the poor photostability and photothermal conversion efficiency (PCE) of organic small-molecule photosensitizers, and the intracellular glutathione (GSH)-mediated singlet oxygen scavenging largely decline the antitumor efficacy of PTT and PDT. Herein, a versatile nanophotosensitizer (NPS) system is developed by ingenious incorporation of indocyanine green (ICG) into the PEGylated chitosan (PEG-CS)-coated polydopamine (PDA) nanoparticles via multiple π-π stacking, hydrophobic and electrostatic interactions. The PEG-CS-covered NPS showed prominent colloidal and photothermal stability as well as high PCE (ca 62.8 %). Meanwhile, the Michael addition between NPS and GSH can consume GSH, thus reducing the GSH-induced singlet oxygen scavenging. After being internalized by CT26 cells, the NPS under near-infrared laser irradiation produced massive singlet oxygen with the aid of thermo-enhanced intracellular GSH depletion to elicit mitochondrial damage and lipid peroxide formation, thus leading to ferroptosis and apoptosis. Importantly, the combined PTT and PDT delivered by NPS effectively inhibited CT26 tumor growth in vivo by light-activated intense hyperthermia and redox homeostasis disturbance. Overall, this work presents a new tactic of boosting antitumor potency of ICG-mediated phototherapy by PEG-CS-covered NPS.

Kirigami-inspired artificial spidroin microneedles for wound patches

Intelligent wound management has important potential for promoting the recovery of chronic wounds caused by diabetes. Here, inspired by the field of kirigami, smart patterned high-stretch microneedle dressings (KPMDs) based on gene-modified spider silk proteins were developed to achieve sensitive biochemical and physiological sensing. The spider silk protein (spidroin) has excellent tensile properties, ductility, toughness and biocompatibility. Notably, the kirigami method-prepared kirigami structure of the spidroin MN dressing had a high tensile strength , while its ductility reached approximately 800 %. Moreover, the unique optical properties of photonic crystals allow for fluorescence enhancement, providing KPMD with color-sensitive properties suitable for wound management and clinical guidance. Furthermore, to improve the sensitivity of KPMD-s to motion monitoring, a microelectronic matrix was integrated on its surface. These distinct material properties suggest that this research lays the foundation for a new generation of high-performance biomimetic diatomaceous earth materials for application.

Electrospun organic/inorganic hybrid nanofibers for accelerating wound healing: a review

Electrospun nanofiber membranes hold great promise as scaffolds for tissue reconstruction, mirroring the natural extracellular matrix (ECM) in their structure. However, their limited bioactive functions have hindered their effectiveness in fostering wound healing. Inorganic nanoparticles possess commendable biocompatibility, which can expedite wound healing; nevertheless, deploying them in the particle form presents challenges associated with removal or collection. To capitalize on the strengths of both components, electrospun organic/inorganic hybrid nanofibers (HNFs) have emerged as a groundbreaking solution for accelerating wound healing and maintaining stability throughout the healing process. In this review, we provide an overview of recent advancements in the utilization of HNFs for wound treatment. The review begins by elucidating various fabrication methods for hybrid nanofibers, encompassing direct electrospinning, coaxial electrospinning, and electrospinning with subsequent loading. These techniques facilitate the construction of micro-nano structures and the controlled release of inorganic ions. Subsequently, we delve into the manifold applications of HNFs in promoting the wound regeneration process. These applications encompass hemostasis, antibacterial properties, anti-inflammatory effects, stimulation of cell proliferation, and facilitation of angiogenesis. Finally, we offer insights into the prospective trends in the utilization of hybrid nanofiber-based wound dressings, charting the path forward in this dynamic field of research.

MgO@polydopamine Nanoparticle-Loaded Photothermal Microneedle Patches Combined with Chitosan Gel Dressings for the Treatment of Infectious Wounds

As for wound drug delivery, microneedles (MNs) have attracted wide attention. However, while effective at increasing the depth of drug delivery, traditional MNs often have limited drug loads and have difficulty penetrating scabs on wounds. Herein, we develop a drug delivery system combining MgO@polydopamine (MgO@PDA) nanoparticle-loaded photothermal MN patches and chitosan (CS) gel to inhibit the formation of scabs and deliver sufficient drugs into deep tissue. When inserted into the wound, the MN system can keep the wound bed moist and weakly acidic to inhibit the formation of scabs and accelerate wound closure. The released MgO@PDA nanoparticles from both the tips and the backing layer, which immensely increase the drug load, continuously release Mg2+ in the moist, weakly acidic wound bed, promoting tissue migration and the formation of microvessels. MgO@PDA nanoparticles show excellent antibacterial activity under near-infrared irradiation synergized with the CS gel, and the PDA coating can also overcome the adverse effects of oxidative stress. Through in vitro and in vivo experiments, the MN system showed remarkable antibacterial, antioxidant, anti-inflammatory, and pro-angiogenic effects, indicating its potential in the treatment of infectious wounds.

GSH/pH Cascade-Responsive Nanoparticles Eliminate Methicillin-Resistant Staphylococcus aureus Biofilm via Synergistic Photo-Chemo Therapy

Bacterial biofilm infection threatens public health, and efficient treatment strategies are urgently required. Phototherapy is a potential candidate, but it is limited because of the off-targeting property, vulnerable activity, and normal tissue damage. Herein, cascade-responsive nanoparticles (NPs) with a synergistic effect of phototherapy and chemotherapy are proposed for targeted elimination of biofilms. The NPs are fabricated by encapsulating IR780 in a polycarbonate-based polymer that contains disulfide bonds in the main chain and a Schiff-base bond connecting vancomycin (Van) pendants in the side chain (denoted as SP-Van@IR780 NPs). SP-Van@IR780 NPs specifically target bacterial biofilms in vitro and in vivo by the mediation of Van pendants. Subsequently, SP-Van@IR780 NPs are decomposed into small size and achieve deep biofilm penetration due to the cleavage of disulfide bonds in the presence of GSH. Thereafter, Van is then detached from the NPs because the Schiff base bonds are broken at low pH when SP@IR780 NPs penetrate into the interior of biofilm. The released Van and IR780 exhibit a robust synergistic effect of chemotherapy and phototherapy, strongly eliminate the biofilm both in vitro and in vivo. Therefore, these biocompatible SP-Van@IR780 NPs provide a new outlook for the therapy of bacterial biofilm infection.