Polydopamine nanoparticle-dotted food gum hydrogel with excellent antibacterial activity and rapid shape adaptability for accelerated bacteria-infected wound healing

Hyaluronic Acid-Dopamine-NCSN Hydrogel Combined With Extracellular Matrix Promotes Wound Healing

The skin barrier is essential to prevent pathogenic invasion. When injury occurs, multiple biological pathways are promptly activated and wound repair processes are triggered. The effective healing of wounds is essential for survival, and dysfunction could result from aberrant wound repair. Preparation of many hydrogels, which involve the addition of growth/cell factors or mimic extracellular matrix (ECM) components, has not resulted in significant advances in tissue recovery. ECM contains a large number of biologically active molecules that activate a variety of cellular transduction pathways, which are essential for wound repair. Here, this work prepares hyaluronic acid-dopamine-thiourea (HA-DA-NCSN) hydrogels exhibiting ultrafast gelation in situ, following the methods of Xu et al., and subsequently designs a hydrogel containing ECM particles. In addition, the loaded ECM material, specifically decellularized ECM material, not only enhances the strength of the hydrogel network, but also delivers bioactive substances that make it a suitable platform for skin wound repair. The ECM hydrogel has great potential as an efficient bioactive wound dressing. This research suggests that this strategy is likely to improve skin wound closure in rat skin wound models.

Glucose-Responsive Self-Healing Bilayer Drug Microneedles Promote Diabetic Wound Healing Via a Trojan-Horse Strategy

Chronic nonhealing wounds are serious complications of diabetes with a high morbidity, and they can lead to disability or death. Conventional drug therapy is ineffective for diabetic wound healing because of the complex environment of diabetic wounds and the depth of drug penetration. Here, we developed a self-healing, dual-layer, drug-carrying microneedle (SDDMN) for diabetic wound healing. This SDDMN can realize transdermal drug delivery and broad-spectrum sterilization without drug resistance and meets the multiple needs of the diabetic wound healing process. Quaternary ammonium chitosan cografted with dihydrocaffeic acid (Da) and l-arginine and oxidized hyaluronic acid-dopamine are the main parts of the self-healing hydrogel patch. Methacrylated poly(vinyl alcohol) (methacrylated PVA) and phenylboronic acid (PBA) were used as the main part of the MN, and gallium porphyrin modified with 3-amino-1,2 propanediol (POGa) and insulin were encapsulated at its tip. Under hyperglycaemic conditions, the PBA moiety in the MN reversibly formed a glucose-boronic acid complex that promoted the rapid release of POGa and insulin. POGa is disguised as hemoglobin through a Trojan-horse strategy, which is then taken up by bacteria, allowing it to target bacteria and infected lesions. Based on the synergistic properties of these components, SDDMN-POGa patches exhibited an excellent biocompatibility, slow drug release, and antimicrobial properties. Thus, these patches provide a potential therapeutic approach for the treatment of diabetic wounds.

Pathogen-Activated Macrophage Membrane Encapsulated CeO2-TCPP Nanozyme with Targeted and Photo-Enhanced Antibacterial Therapy

Nanozymes with peroxidase-mimic activity have recently emerged as effective strategies for eliminating infections. However, challenges in enhancing catalytic activities and the ability to target bacteria have hindered the broader application of nanozymes in bacterial infections. Herein, a novel nanozyme based on mesoporous CeO2 nanosphere and meso-tetra(4-carboxyphenyl)porphine (TCPP) encapsulated within pathogen-activated macrophage membranes, demonstrates photodynamic capability coupled with photo-enhanced chemodynamic therapy for selective and efficient antibacterial application against infected wounds. Interestingly, the expression of Toll-like receptors accordingly upregulates when macrophages are co-cultured with specific bacteria, thereby facilitating to recognition of the pathogen-associated molecular patterns originating from bacteria. The CeO2 not only serve as carriers for TCPP, but also exhibit intrinsic peroxidase-like catalytic activity. Consequently, Staphylococcus aureus (S. aureus)-activated macrophage membrane-coated CeO2-TCPP (S-MM@CeO2-TCPP) generated singlet oxygen, and simultaneously promoted photo-enhanced chemodynamic therapy, significantly boosting reactive oxygen species (ROS) to effectively eliminate bacteria. S-MM@CeO2-TCPP specifically targeted S. aureus via Toll-like receptor, thereby directly disrupting bacterial structural integrity to eradicate S. aureus in vitro and relieve bacteria-induced inflammation to accelerate infected wound healing in vivo. By selectively targeting specific bacteria and effectively killing pathogens, such strategy provides a more efficient and reliable alternative for precise elimination of pathogens and inflammation alleviation in microorganism-infected wounds.

Multi-Enzyme-Based Superabsorbent Hydrogel for Self-Enhanced NIR-II Photothermal-Catalytic Antibacterial Therapy

The synergistic strategy of nanozyme-based catalytic therapy and photothermal therapy holds great potential for combating bacterial infection. However, challenges such as single and limited enzyme catalytic property, unfavorable catalytic environment, ineffective interaction between nanozymes and bacteria, unsafe laser irradiation ranges, and failed trauma fluid management impede their antibacterial capability and wound healing speed. Herein, for the first time, a PNMn hydrogel is fabricated with multi-enzyme activities and excellent near-infrared (NIR)-II photothermal performance for self-enhanced NIR-II photothermal-catalytic capabilities to efficiently eradicate bacteria. This hydrogel triggers parallel and cascade reactions to generate •OH, •O2 -, and 1O2 radicals from H2O2 and O2 without external energy input. Notably, it provides a suitable catalytic environment while capturing bacteria (≈30.1% of Escherichia coli and ≈29.3% of Staphylococcus aureus) to reinforce antibacterial activity. Furthermore, the PNMn hydrogel expedites skin wound healing by managing excess fluid (swelling rate up to ≈7299%). The PNMn hydrogel possesses remarkable stretching, elasticity, toughness, and adhesive characteristics under any shape of the wound, thus making it suitable for wound dressing. Therefore, the PNMn hydrogel has great potential to be employed as a next-generation wound dressing in the clinical context, providing a non-antibiotic strategy to improve the antibacterial performance and promote wound healing.

Nanoparticles incorporated hydrogels for delivery of antimicrobial agents: developments and trends

The prevention and treatment of microbial infections is an imminent global public health concern due to the poor antimicrobial performance of the existing antimicrobial regime and rapidly emerging antibiotic resistance in pathogenic microbes. In order to overcome these problems and effectively control bacterial infections, various new treatment modalities have been identified. To attempt this, various micro- and macro-molecular antimicrobial agents that function by microbial membrane disruption have been developed with improved antimicrobial activity and lesser resistance. Antimicrobial nanoparticle-hydrogels systems comprising antimicrobial agents (antibiotics, biological extracts, and antimicrobial peptides) loaded nanoparticles or antimicrobial nanoparticles (metal or metal oxide) constitute an important class of biomaterials for the prevention and treatment of infections. Hydrogels that incorporate nanoparticles can offer an effective strategy for delivering antimicrobial agents (or nanoparticles) in a controlled, sustained, and targeted manner. In this review, we have described an overview of recent advancements in nanoparticle-hydrogel hybrid systems for antimicrobial agent delivery. Firstly, we have provided an overview of the nanoparticle hydrogel system and discussed various advantages of these systems in biomedical and pharmaceutical applications. Thereafter, different hybrid hydrogel systems encapsulating antibacterial metal/metal oxide nanoparticles, polymeric nanoparticles, antibiotics, biological extracts, and antimicrobial peptides for controlling infections have been reviewed in detail. Finally, the challenges and future prospects of nanoparticle-hydrogel systems have been discussed.

High-Density Dynamic Bonds Cross-Linked Hydrogel with Tissue Adhesion, Highly Efficient Self-Healing Behavior, and NIR Photothermal Antibacterial Ability as Dressing for Wound Repair

Multifunctional hydrogels with tissue adhesion, self-healing behavior, and antibacterial properties have potential in wound healing applications. However, their inefficient self-healing behavior and antibacterial agents can cause long-term cytotoxicity and drug resistance, considerably limiting their clinical use. Herein, we reported a PDA@LA hydrogel constructed by introducing polydopamine nanoparticles (PDA-NPs) into a high-density dynamic bonds cross-linked lipoic acid (LA) hydrogel that was formed by the polymerization of LA. Because of its rich carboxyl groups, the LA hydrogel could adhere firmly to various tissues. Owing to the high-density dynamic bonds, the cut LA hydrogel exhibited highly inefficient self-healing behavior and recovered to its uncut state after self-healing for 10 min. After the introduction of the PDA-NPs, the hydrogel was able to heat up to more than 40 °C to kill approximately 100% of the Escherichia coli and Staphylococcus aureus under near-infrared (NIR) laser, thus resisting wound infections. Because no toxic antibacterial agent was used, the PDA@LA hydrogel caused mild long-term cytotoxicity or drug resistance. Consequently, the adhesive, highly efficient self-healing, and NIR photothermal antibacterial PDA@LA hydrogel exhibits considerable potential for clinical use.

Dual-Delivery Temperature-Sensitive Hydrogel with Antimicrobial and Anti-Inflammatory Brevilin A and Nitric Oxide for Wound Healing in Bacterial Infection

Bacterial infections impede the wound healing process and can trigger local or systemic inflammatory responses. Therefore, there is an urgent need to develop a dressing with antimicrobial and anti-inflammatory properties to promote the healing of infected wounds. In this study, BA/COs/NO-PL/AL hydrogels were obtained by adding brevilin A (BA) camellia oil (CO) submicron emulsion and nitric oxide (NO) to hydrogels consisting of sodium alginate (AL) and Pluronic F127 (PL). The hydrogels were characterized through dynamic viscosity analysis, differential scanning calorimetry, and rheology. They were evaluated through anti-inflammatory, antimicrobial, and wound healing property analyses. The results showed that BA/COs/NO-PL/AL hydrogels were thermo-responsive and had good ex vivo and in vivo anti-inflammatory activity, and they also exhibited strong antimicrobial activity against methicillin-resistant Staphylococcus aureus Pseudomonas aeruginosa (MRPA) and methicillin-resistant Staphylococcus aureus (MRSA). They were able to effectively promote healing of the infected wound model and reduce inflammation and bacterial burden. H&E and Masson's staining showed that BA/COs/NO-PL/AL hydrogels promoted normal epithelial formation and collagen deposition. In conclusion, BA/COs/NO-PL/AL hydrogels are promising candidates for promoting the healing of infected wounds.

Bibliometric analysis of Traditional Chinese Medicine nanoparticles research from 2005 to 2023

To gain a deeper understanding of the current status of research on Traditional Chinese Medicine (TCM) and nanoparticles, we conducted a bibliometric study. We conducted a literature search in the Web of Science (WOS) for publications related to TCM and nanoparticles from 1992 to 2023. The data, including countries of publication, research institutions, journals, citations, and keywords, were analyzed using the Bibliometrix R-4.0 software package. We performed an analysis to identify the co-occurrence of keywords in the documents including their titles and abstracts. From 2005 to 2023, a total of 309 publications were included, with an average annual growth rate of 4.25%. The majority of these publications were published in Q1 journals (72, 47.06%) and Q2 journals (45, 29.41%). Among the 309 publications, 22 articles (7.12%) had an impact factor greater than 10, while 78 articles (25.24%) had an impact factor greater than 5. The analysis of international collaboration networks revealed limited international cooperation, with most collaborations occurring between institutions in China, the United States, and Australia. These 309 publications involved a total of 438 research institutions, with Chinese research institutions being the most prolific contributors. In this study, a total of 309 publications were included, comprising 1142 author keywords and 1175 keywords plus. Factor analysis of the 1175 keywords plus revealed that they could be grouped into five categories: one category included terms such as "oxide" and "zinc," another category included terms like "lipid" and "acid," a third category included terms such as "improve" and "enhance," a fourth category included terms like "silica" and "mesoporous," and the fifth category included terms like "PLGA" and "immune." Research on nanoparticles in TCM has been gradually gaining popularity. Currently, most of the research in this field is conducted in China, with limited international collaboration. The majority of TCM nanoparticle research focuses on individual herbal compounds, while research on nanoparticle formulations of traditional herbal prescriptions is relatively scarce.

2D nanomaterial-based 3D network hydrogels for anti-infection therapy

Two-dimensional nanomaterials (2D NMs) refer to nanomaterials that possess a planar topography with a thickness of one or several atomic layers. Due to their large specific surface areas, atomic thickness, rough edges, and electron confinement in two dimensions, they have emerged as promising antimicrobial agents over antibiotics in combating bacterial infections. However, 2D NMs encounter issues such as low bio-safety, easy aggregation, and limited tissue penetration efficiency. To address these concerns, hydrogels with three-dimensional (3D) networks have been developed to encapsulate 2D NMs, aiming to enhance their biocompatibility, biodegradability, and ability to regulate and remodel the tissue microenvironment at the infected site. This review systematically summarizes the current studies on 2D NM-based antibacterial hydrogels with 3D network structures (named 2N3Hs). Firstly, we introduce the emerging types of 2N3Hs and describe their antibacterial actions. Subsequently, we discuss the applications of 2N3Hs in three biomedical fields, including wound dressing, cancer treatment, and bone regeneration. Finally, we conclude the review with current challenges and future developments for 2N3Hs, highlighting their potential as a promising choice for next-generation biomedical devices, particularly in the field of tissue engineering and regenerative medicine. This review aims to provide a comprehensive and panoramic overview of anti-infective 2N3Hs for various biomedical applications.

Rapid Preparation of Highly Stretchable and Fast Self-Repairing Antibacterial Hydrogels for Promoting Hemostasis and Wound Healing

Hydrogel dressings have emerged as a vital resource in wound management, offering several advantages over conventional wound dressing materials. Their inherent biocompatibility, ability to replicate the native extracellular matrix, and capacity to provide an ideal environment for cell survival make them particularly valuable. Nevertheless, the mechanical properties of many hydrogel dressings are an area that warrants improvement, as it currently constrains their application range. This limitation is especially evident when skin wounds are addressed in highly active or easily scratched areas. In this study, we present the development of a highly stretchable self-repairing hydrogel by cross-linking poly(vinyl alcohol) (PVA) through dynamic boron ester bonds, coupled with the hydrogen bonding of carboxymethyl cellulose sodium (CMC) via an efficient one-pot method without adding any catalyst. This innovative PVA/CMC hydrogel exhibited remarkable antibacterial properties achieved through the incorporation of bergamot oil, which was dispersed in a β-cyclodextrin solution. The hydrogel's elongation at the point of rupture reached an impressive 1910%, and it was capable of rapid self-healing in just 3 min upon bonding. Additionally, the hydrogel demonstrated excellent hemostatic properties, effectively mitigating blood loss and exudation. In vivo wound models have shown that PVA/CMC significantly expedites wound healing by reducing bacterial infections, inflammatory responses, and blood loss and by promoting collagen deposition. In summary, this research provides crucial insights into its potential as an advanced wound dressing material, particularly well-suited for addressing wounds in places with frequent activities or easy scratches.

Tunicate cellulose nanocrystals reinforced modified calcium sulfate bone cement with enhanced mechanical properties for bone repair

Considering the poor mechanical properties of bone cement, its practical application has always been limited. In this study, we introduced tunicate cellulose nanocrystals (TCNCs) into calcium sulfate bone cement for the first time, and multiple enhanced composite bone cement was prepared by the condensation reflux method. Firstly, high-strength modified calcium sulfate hemihydrate (CSH) bone cement was successfully prepared by using tartaric acid, a crystal modifier with a chiral structure. Secondly, the inclusion of TCNCs not only exhibited significant reinforcement and toughening effects but also stimulated the adhesion, proliferation, and differentiation of related osteoblasts. Furthermore, TCNCs encapsulated the CSH particles, overcoming the limitations of excessive degradation rates in bone cement and enabling sustained release of Ca2+, promoting the healing of bone defects. Overall, this study presents novel ideas and methodologies for designing bone cement with exceptional performance. It also provides a new platform for the development of bone tissue engineering and is expected to become a new type of bone regeneration material. The utilization of oceanic resources in this context holds high-value potential, alleviating environmental burdens and providing clinically applicable bone tissue repair materials with broad application prospects.

Cu(II)@MXene based photothermal hydrogel with antioxidative and antibacterial properties for the infected wounds

The regeneration of skin tissue is often impeded by bacterial infection seriously. At the same time, reactive oxygen species (ROS) are often overexpressed in infected skin wounds, causing persistent inflammation that further hinders the skin repair process. All of these make the treatment of infected wounds is still a great challenge in clinic. In this study, we fabricate Cu(II)@MXene photothermal complex based on electrostatic self-assembly between Cu2+ and MXene, which are then introduced into a hyaluronic acid (HA) hydrogel to form an antibacterial dressing. The rapid adhesion, self-healing, and injectability of the dressing allows the hydrogel to be easily applied to different wound shapes and to provide long-term wound protection. More importantly, this easily prepared Cu(II)@MXene complex can act as a photothermal antibacterial barrier, ROS scavenger and angiogenesis promoter simultaneously to accelerate the healing rate of infected wounds. Our in vivo experiments strongly proved that the inflammatory condition, collagen deposition, vessel formation, and the final wound closure area were all improved by the application of Cu(II)@MXene photothermal hydrogel dressing.

Etamsylate loaded oxidized Konjac glucomannan-ε-polylysine injectable hydrogels for rapid hemostasis and wound healing

Uncontrollable bleeding is a crucial factor that can lead to fatality. Therefore, the development of hemostatic dressings that enable rapid hemostasis is of utmost importance. Hydrogels with injectability, self-healing ability, and adhesiveness hold significant potential as effective hemostatic dressings. Herein, a composite hydrogel was fabricated by the oxidized Konjac glucomannan and ε-polylysine. After the encapsulation of a hemostatic drug, etamsylate, an oxidized Konjac glucomannan/ε-polylysine/etamsylate (OKGM/PL/E) composite hydrogel that possesses favorable properties including injectability, self-healing ability, tissue adhesiveness, hemocompatibility and cytocompatibility was fabricated. The OKGM/PL/E hydrogel demonstrated the ability to effectively adhere red blood cells and seal wounds, enabling rapid control of hemorrhaging. In vivo wound healing experiments confirmed the hemostatic and wound healing efficacy of the OKGM/PL/E hydrogel, highlighting its potential as a valuable hemostatic dressing.

Advancement in Biopolymer Assisted Cancer Theranostics

Applications of nanotechnology have increased the importance of research and nanocarriers, which have revolutionized the method of drug delivery to treat several diseases, including cancer, in the past few years. Cancer, one of the world's fatal diseases, has drawn scientists' attention for its multidrug resistance to various chemotherapeutic drugs. To minimize the side effects of chemotherapeutic agents on healthy cells and to develop technological advancement in drug delivery systems, scientists have developed an alternative approach to delivering chemotherapeutic drugs at the targeted site by integrating it inside the nanocarriers like synthetic polymers, nanotubes, micelles, dendrimers, magnetic nanoparticles, quantum dots (QDs), lipid nanoparticles, nano-biopolymeric substances, etc., which has shown promising results in both preclinical and clinical trials of cancer management. Besides that, nanocarriers, especially biopolymeric nanoparticles, have received much attention from researchers due to their cost-effectiveness, biodegradability, treatment efficacy, and ability to target drug delivery by crossing the blood-brain barrier. This review emphasizes the fabrication processes, the therapeutic and theragnostic applications, and the importance of different biopolymeric nanocarriers in targeting cancer both in vitro and in vivo, which conclude with the challenges and opportunities of future exploration using biopolymeric nanocarriers in onco-therapy with improved availability and reduced toxicity.

Injectable antibacterial tissue-adhesive hydrogel based on biocompatible o-phthalaldehyde/amine crosslinking for efficient treatment of infected wounds

Injectable antibacterial hydrogels have attracted considerable attention in wound management. However, the development of injectable hydrogels with excellent antibacterial activity, good biocompatibility, and strong tissue adhesion remains a challenge. In this study, an antibacterial tissue-adhesive hydrogel was developed based on a catalyst-free o-phthalaldehyde (OPA)/amine reaction by simply mixing OPA-terminated four-arm poly(ethylene glycol) (4aPEG-OPA) and ε-poly-l-lysine (ε-PLL) solutions. The hydrogel showed tunable gelation time, storage moduli, and degradation rate depending on the polymer concentration and 4aPEG-OPA/ε-PLL mass ratio. The hydrogel exhibited nearly 100% bacterial inhibition rates in-vitro against Gram-negative E. coli and Gram-positive S. aureus, while maintaining good biocompatibility. The hydrogel matched well in shape and tightly adhered to the tissue after in-situ formation at the wound sites. Following the treatment of rat models of full-thickness skin incisions and round wounds, the hydrogel effectively closed the wounds and promoted wound healing. Moreover, after administering to S. aureus infected full-thickness skin wounds, the hydrogel exhibited remarkable efficacy in inhibiting wound infection with a bacterial inhibition rate over 99.94%, achieving a significantly accelerated wound healing compared with the commercially available Prontosan® gel. Therefore, the hydrogel exhibits great potential as a wound dressing for infection prevention and promotion of healing.

Cascade enzymatic preparation of carboxymethyl chitosan-based multifunctional hydrogels for promoting cutaneous wound healing

Designing wound dressings with inherent multifunctional therapeutic effects is desirable for clinical applications. Herein, a series of multifunctional carboxymethyl chitosan (CMCS)-based hydrogels were fabricated by the facile urate oxidase (UOX)-horseradish peroxidase (HRP) cascade enzymatic crosslinking system. For the first time, the cascade enzymatic crosslinking system was not only used for preparing hydrogel wound dressings but also for accelerating wound healing due to the activity retention of the self-compartmental enzymes. A CMCS derivative (HCMCS-mF) synthesized by successively grafting 4-hydroxybenzaldehyde (H) and 5-methylfurfural (mF) on CMCS and a quaternary ammonium crosslinker (QMal) with terminal grafting maleimide (Mal) groups were combined with enzymatic system for the facile preparation of hydrogels. The mild Diels-Alder (DA) crosslinking reaction between mF and Mal groups constructed the first network of hydrogels. The cascade UOX-HRP system mediated the oxidative crosslinking of phenols thus forming the second gel network. Self-entrapped UOX maintained its enzymatic activity and could continuously catalyze the oxidation of uric acid, generating therapeutic allantoin. These porous, degradable, mechanically stable hydrogels with excellent antioxidant performance and enhanced antibacterial capacity could effectively accelerate skin wound repair by simultaneously reducing oxidative stress, relieving inflammation, promoting collagen deposition and upregulating the expression level of CD31.

Novel neutrophil extracellular trap-related mechanisms in diabetic wounds inspire a promising treatment strategy with hypoxia-challenged small extracellular vesicles

Neutrophil extracellular traps (NETs) have been considered a significant unfavorable factor for wound healing in diabetes, but the mechanisms remain unclear. The therapeutic application of small extracellular vesicles (sEVs) derived from mesenchymal stem cells (MSCs) has received considerable attention for their properties. Hypoxic preconditioning is reported to enhance the therapeutic potential of MSC-derived sEVs in regenerative medicine. Therefore, the aim of this study is to illustrate the detailed mechanism of NETs in impairment of diabetic wound healing and develop a promising NET-targeting treatment based on hypoxic pretreated MSC-derived sEVs (Hypo-sEVs). Excessive NETs were found in diabetic wounds and in high glucose (HG)-induced neutrophils. Further research showed that high concentration of NETs impaired the function of fibroblasts through activating endoplasmic reticulum (ER) stress. Hypo-sEVs efficiently promoted diabetic wound healing and reduced the excessive NET formation by transferring miR-17-5p. Bioinformatic analysis and RNA interference experiment revealed that miR-17-5p in Hypo-sEVs obstructed the NET formation by targeting TLR4/ROS/MAPK pathway. Additionally, miR-17-5p overexpression decreased NET formation and overcame NET-induced impairment in fibroblasts, similar to the effects of Hypo-sEVs. Overall, we identify a previously unrecognized NET-related mechanism in diabetic wounds and provide a promising NET-targeting strategy for wound treatment.

Polydopamine-containing nano-systems for cancer multi-mode diagnoses and therapies: A review

Polydopamine (PDA) has fascinating properties such as inherent biocompatibility, simple preparation, strong near-infrared absorption, high photothermal conversion efficiency, and strong metal ion chelation, which have catalyzed extensive research in PDA-containing multifunctional nano-systems particularly for biomedical applications. Thus, it is imperative to overview synthetic strategies of various PDA-containing nanoparticles (NPs) for state-of-the-art cancer multi-mode diagnoses and therapies applications, and offer a timely and comprehensive summary. In this review, we will focus on the synthetic approaches of PDA NPs, and summarize the construction strategies of PDA-containing NPs with different structure forms. Additionally, the application of PDA-containing NPs in bioimaging such as photoacoustic imaging, fluorescence imaging, magnetic resonance imaging and other imaging modalities will be reviewed. We will especially offer an overview of their therapeutic applications in tumor chemotherapy, photothermal therapy, photodynamic therapy, photocatalytic therapy, sonodynamic therapy, radionuclide therapy, gene therapy, immunotherapy and combination therapy. At the end, the current trends, limitations and future prospects of PDA-containing nano-systems will be discussed. This review aims to provide guidelines for new scientists in the field of how to design PDA-containing NPs and what has been achieved in this area, while offering comprehensive insights into the potential of PDA-containing nano-systems used in cancer diagnosis and treatment.

Engineering a platelet-rich plasma-based multifunctional injectable hydrogel with photothermal, antibacterial, and antioxidant properties for skin regeneration

Wound healing remains a significant challenge worldwide, necessitating the development of new wound dressings to aid in the healing process. This study presents a novel photothermally active hydrogel that contains platelet-rich plasma (PRP) for infected wound healing. The hydrogel was formed in a one pot synthesis approach by mixing alginate (Alg), gelatin (GT), polydopamine (PDA), and PRP, followed by the addition of CaCl2 as a cross-linker to prepare a multifunctional hydrogel (AGC-PRP-PDA). The hydrogel exhibited improved strength and good swelling properties. PDA nanoparticles (NPs) within the hydrogel endowed them with high photothermal properties and excellent antibacterial and antioxidant activities. Moreover, the hydrogels sustained the release of growth factors due to their ability to protect PRP. The hydrogels also exhibited good hemocompatibility and cytocompatibility, as well as high hemostatic properties. In animal experiments, the injectable hydrogels effectively filled irregular wounds and promoted infected wound healing by accelerating re-epithelialization, facilitating collagen deposition, and enhancing angiogenesis. The study also indicated that near-infrared light improved the healing process. Overall, these hydrogels with antibacterial, antioxidant, and hemostatic properties, as well as sustained growth factor release, show significant potential for skin regeneration in full-thickness, bacteria-infected wounds.

Multifunctional chondroitin sulfate based hydrogels for promoting infected diabetic wounds healing by chemo-photothermal antibacterial and cytokine modulation

Diabetic foot (DF) is difficult to heal due to the formation of drug-resistant bacterial biofilms and dysregulation of the wound microenvironment. To solve this problem, multifunctional hydrogels were prepared by in situ or spraying with 3-aminophenylboronic acid modified oxidized chondroitin sulfate (APBA-g-OCS), polyvinyl alcohol (PVA) and black phosphorus/bismuth oxide/ε-polylysine (BP/Bi₂O₃/ε-PL) as precursors for promoting infected diabetic wounds healing. The hydrogels display multiple stimulus responsiveness, strong adhesion and rapid self-healing ability owing to the dynamic borate ester bonds, hydrogen bonds and π-π conjugation cross-link points, remain synergistic chemo-photothermal antibacterial effect and anti-biofilm formation ability due to the doping of BP/ Bi₂O₃/ε-PL into the hydrogel by dynamic imine bonds crosslinking and possess anti-oxidation and inflammatory chemokine adsorption ability attributing to the presence of APBA-g-OCS. Most importantly, as a result of the above functions, the hydrogels can not only respond to the wound microenvironment to conduct combined PTT and chemotherapy for efficient anti-inflammation, but also improve the wound microenvironment by scavenging ROS and regulating the expression of cytokines, thus further accelerating collagen deposition, promoting granulation tissue formation and angiogenesis, finally promoting the healing of infected wounds in diabetic rats.

Facile and eco-friendly fabrication of biocompatible hydrogel containing CuS@Ser NPs with mechanical flexibility and photothermal antibacterial activity to promote infected wound healing

Bacterial infections can significantly impede wound healing and pose a serious threat to the patient's life. The excessive use of antibiotics to combat bacterial infections has led to the emergence of multi-drug-resistant bacteria. Therefore, there is a pressing need for alternative approaches, such as photothermal therapy (PTT), to address this issue. In this study, for the first time, CuS NPs with photothermal properties were synthesized using sericin as a biological template, named CuS@Ser NPs. This method is simple, green, and does not produce toxic and harmful by-products. These nanoparticles were incorporated into a mixture (XK) of xanthan gum and konjac glucomannan (KGM) to obtain XK/CuS NPs composite hydrogel, which could overcome the limitations of current wound dressings. The composite hydrogel exhibited excellent mechanical flexibility, photothermal response, and biocompatibility. It also demonstrated potent antibacterial properties against both Gram-positive and negative bacteria via antibacterial experiments and accelerated wound healing in animal models. Additionally, it is proved that the hydrogel promoted tissue regeneration by stimulating collagen deposition, angiogenesis, and reducing inflammation. In summary, the XK/CuS NPs composite hydrogel presents a promising alternative for the clinical management of infected wounds, offering a new approach to promote infected wound healing.

Adhesive Composite Microspheres with Dual Antibacterial Strategies for Infected Wound Healing

Skin damage and infection pose a severe challenge to human health. Construction of a novel versatile dressing with good anti-infection and healing-promoting abilities is greatly expected. In this paper, nature-source-based composite microspheres with dual antibacterial mechanisms and bioadhesive features by microfluidics electrospray for infected wound healing is developed. The microspheres enable sustained release of copper ions, which not only show long-term antibacterial properties, but also play important role in wound-healing-related angiogenesis. Additionally, the microspheres are coated with polydopamine via self-polymerization, which renders the microspheres adhesive to the wound surface, and further enhance the antibacterial ability through photothermal energy conversion. Based on the dual antibacterial strategies provided by copper ions and polydopamine as well as the bioadhesive property, the composite microspheres exhibit excellent anti-infection and wound healing performances in a rat wound model. These results, along with the nature-source-based composition and biocompatibility, indicate the great potential of the microspheres in clinical wound repair.

Tailoring Food Biopolymers into Biogels for Regenerative Wound Healing and Versatile Skin Bioelectronics

An increasing utilization of wound-related therapeutic materials and skin bioelectronics urges the development of multifunctional biogels for personal therapy and health management. Nevertheless, conventional dressings and skin bioelectronics with single function, mechanical mismatches, and impracticality severely limit their widespread applications in clinical. Herein, we explore a gelling mechanism, fabrication method, and functionalization for broadly applicable food biopolymers-based biogels that unite the challenging needs of elastic yet injectable wound dressing and skin bioelectronics in a single system. We combine our biogels with functional nanomaterials, such as cuttlefish ink nanoparticles and silver nanowires, to endow the biogels with reactive oxygen species scavenging capacity and electrical conductivity, and finally realized the improvement in diabetic wound microenvironment and the monitoring of electrophysiological signals on skin. This line of research work sheds light on preparing food biopolymers-based biogels with multifunctional integration of wound treatment and smart medical treatment.

Fabrication and evaluation of antimicrobial cellulose/Arabic gum hydrogels as potential drug delivery vehicle

This article aims to assess the highly potent antimicrobial hydrogels composed of cellulose and Arabic gum containing sulfadiazine drug (sulfadiazine-loaded Cel/AG) as drug-targeting carriers. ATR-IR, SEM/ EDS, XRD, and XPS methods were used to investigate the hydrogel. The highest water absorption % was 489.93 ± 4.5 at pH 7.4. Pseudo-second order and Fickian diffusion govern the swelling behavior. The maximal sulfadiazine loading percent was 82.291 ± 74. The in-vitro drug release exhibited significant responses in physiologically simulated pH values. The maximum cumulative release percent was 66.42 ± 0.6 % at pH 7.4. The drug release is predicted by the first order and Korsmeyer-Peppas models. The first diffusion coefficient was (D_i = 9.207 ± 47 × 10^-3 cm²/h) and the late one was (D_L = 5.64 ± 9.0 × 10^-2 cm²/h) at pH 7.4. That hydrogel is well-thought-out a potential drug delivery vehicle. The thermal stability of the Cel/AG hydrogel drug carrier has been enhanced by the incorporation of sulfadiazine which is evidenced by increasing the total activation approximately two-fold. The total activation energy of Cel/AG and sulfadiazine-loaded Cel/AG hydrogels were -0.07362 and -0.2092 J/mol. The sulfadiazine medication's inhibitory effect was markedly enhanced when it was incorporated into the Cel/AG hydrogel films.

Injectable Zn2+ and Paeoniflorin Release Hydrogel for Promoting Wound Healing

As more and more superbugs emerge, wounds are struggling to heal due to the inflammation that accompanies infection. Therefore, there is an urgent need to reduce the abuse of antibiotics and find nonantibiotic antimicrobial methods to counter infections to accelerate wound healing. In addition, common wound dressings struggle to cover irregular wounds, causing bacterial invasion or poor drug release, which reduces the wound healing rate. In this study, Chinese medicinal monomer paeoniflorin which can inhibit inflammation is loaded in mesoporous zinc oxide nanoparticles (mZnO), while Zn²⁺ released from mZnO degradation can kill bacteria and facilitate wound healing. The drug-loaded mZnO was encapsulated by a hydrogel formed from oxidized konjac glucomannan and carboxymethyl chitosan via rapid Schiff base reaction to obtain an injectable drug-releasing hydrogel wound dressing. The immediate-formation hydrogel allows the dressing to cover any wound shape. In vitro and in vivo studies have demonstrated that the dressing has good biocompatibility and superior antibacterial properties, which can promote wound healing and tissue regeneration by promoting angiogenesis and collagen production, providing a promising perspective for the further development of multifunctional wound dressings.

Salvianolic-Acid-B-Loaded HA Self-Healing Hydrogel Promotes Diabetic Wound Healing through Promotion of Anti-Inflammation and Angiogenesis

Inflammatory dysfunction and angiogenesis inhibition are two main factors leading to the delayed healing of diabetic wounds. Hydrogels with anti-inflammatory and angiogenesis-promoting effects have been considered as promising wound care materials. Herein, a salvianolic acid B (SAB)-loaded hyaluronic acid (HA) self-healing hydrogel (HA/SAB) with anti-inflammatory and pro-angiogenesis capacities for diabetic wound healing is reported. The HA hydrogel was prepared via the covalent cross-linking of aldehyde groups in oxidized HA (OHA) and hydrazide groups in adipic dihydrazide (ADH)-modified HA (HA-ADH) with the formation of reversible acylhydrazone bonds. The obtained HA hydrogel exhibited multiple favorable properties such as porous structures, excellent self-healing properties, a sustainable release capacity of SAB, as well as excellent cytocompatibility. In addition, the effects of the SAB-loaded HA self-healing hydrogel were investigated via a full-thickness skin defect model using diabetic rats. The HA/SAB hydrogel showed enhanced skin regeneration effects with accelerated wound closure, shorter remaining dermal space length, thicker granulation tissue formation, and more collagen deposition. Furthermore, reduced inflammatory response and enhanced vascularization were found with HA/SAB2.5 hydrogel-treated wounds, indicating that the hydrogel promotes diabetic wound healing through the promotion of anti-inflammation and angiogenesis. Our results suggest that the fabricated SAB-loaded HA self-healing hydrogel is promising as a wound dressing for the treatment of diabetic wounds.

Versatile Hydrogel Dressing with Skin Adaptiveness and Mild Photothermal Antibacterial Activity for Methicillin-Resistant Staphylococcus Aureus-Infected Dynamic Wound Healing

Bacterial infection often induces chronic repair of wound healing owing to aggravated inflammation. Hydrogel dressing exhibiting intrinsic antibacterial activity may substantially reduce the use of antibiotics for infected wound management. Hence, a versatile hydrogel dressing (rGB/QCS/PDA-PAM) exhibiting skin adaptiveness on dynamic wounds and  mild photothermal antibacterial activity is developed for safe and efficient infected wound treatment. Phenylboronic acid-functionalized graphene (rGB) and oxadiazole-decorated quaternary carboxymethyl chitosan (QCS) are incorporated into a polydopamine-polyacrylamide (PDA-PAM) network with multiple covalent and noncovalent bonds, which conferred the hydrogel with flexible mechanical properties, strong tissue adhesion and excellent self-healing ability on the dynamic wounds. Moreover, the glycocalyx-mimicking phenylboronic acid on the surface of rGB enables the hydrogel to specifically capture bacteria. The enhanced membrane permeability of QCS enhanced bacterial vulnerability to photothermal therapy（PTT）, which is demonstrated by efficient mild PTT antibacteria against methicillin-resistant Staphylococcus aureus in vitro and in vivo at temperatures of <49.6 °C. Consequently, the hydrogel demonstrate accelerated tissue regeneration on MRSA-infected wound in vivo, with an intact epidermis, abundant collagen deposition and prominent angiogenesis. Therefore, rGB/QCS/PDA-PAM is a versatile hydrogel dressing exhibiting inherent antibacterial activity and has considerable potential in treating wounds infected with drug-resistant bacteria.

Ultralow Charge Voltage Triggering Exceptional Post-Charging Antibacterial Capability of Co3 O4 /MnOOH Nanoneedles for Skin Infection Treatment

The post-charging antibacterial therapy is highly promising for treatment of Gram-negative bacterial wound infections. However, the therapeutic efficacy of the current electrode materials is yet unsatisfactory due to their low charge storage capacity and limited reactive oxygen species (ROS) yields. Herein, the design of MnOOH decorated Co₃ O₄ nanoneedles (MCO) with exceptional post-charging antibacterial effect against Gram-negative bacteria at a low charge voltage and their implementation as a robust antibacterial electrode for skin wound treatment are reported. Taking advantaging of the increased active sites and enhanced OH^- adsorption capability, the charge storage capacity and ROS production of the MCO electrode are remarkably boosted. As a result, the MCO electrode after charging at an ultralow voltage of 1.4 V gives a 5.49 log and 5.82 log bacterial reduction in Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) within an incubation time of only 5 min, respectively. More importantly, the antibacterial efficiency of the MCO electrode against multi-drug resistant (MDR) bacteria including Klebsiella pneumoniae (K. pneumoniae) and Acinetobacter baumannii (A. baumannii) also reaches 99.999%. In addition, the MCO electrode exhibits excellent reusability, and the role of extracellular ROS in enhancing post-charging antibacterial activity is also unraveled.

Polydopamine Nanoparticles-Based Photothermal Effect Against Adhesion Formation in a Rat Model of Achilles Tendon Laceration Repair

Background

Adhesion formation after tendon surgery is a major obstacle to repair of tendon ruptures, and there is still no effective clinical anti-adhesion method. Myofibroblasts expressing α-smooth muscle actin (α-SMA) play a crucial role in adhered fibrous tissue. Heat shock protein (Hsp) 72 can selectively prevent the activation of c-Jun N-terminal kinase (JNK), which mediates the conversion from fibroblasts to myofibroblasts. The purpose of this study was to investigate for the first time whether polydopamine nanoparticles (PDA NPs)-based photothermal effect would attenuate adhesion formation in a rat model of Achilles tendon laceration repair.

Materials and Methods

Forty-five adult male Sprague-Dawley rats were randomly assigned to the photothermal group, the control group and the PDA NPs group (n = 15 per group). The primary outcome measure was the adhesion scores at two weeks after surgery according to the grading of Tang et al. The secondary outcomes included the expressions of Hsp 72, JNK, phosphorylated JNK and α-SMA, which were measured by immunohistochemistry or Western blot.

Results

The average adhesion score was significantly lower in the photothermal group (4.25 ± 0.21) than that in the control group (5.29 ± 0.12) (p = 0.005) and the PDA NPs group (5.29 ± 0.20) (p = 0.005). Relative to the control group and PDA NPs group, Hsp 72 in the photothermal group was significantly increased whereas α-SMA and p-JNK was significantly decreased, but JNK was not found to be different across the three groups.

Conclusion

The photothermal effect produced by PDA NPs could reduce tendon adhesion formation in rats by inhibiting myocyte fibrosis, which may have potential in developing endogenous heating for postsurgical tissue adhesions.

Rational design of porous structure-based sodium alginate/chitosan sponges loaded with green synthesized hybrid antibacterial agents for infected wound healing

An ideal wound dressing should have excellent antimicrobial properties and provide a suitable microenvironment for regenerating damaged skin tissue. In this study, we utilized sericin to biosynthesize silver nanoparticles in situ and introduced curcumin to obtain Sericin-AgNPs/Curcumin (Se-Ag/Cur) antimicrobial agent. The hybrid antimicrobial agent was then encapsulated in a physically double cross-linking 3D structure network (Sodium alginate-Chitosan, SC) to obtain the SC/Se-Ag/Cur composite sponge. The 3D structural networks were constructed through electrostatic interactions between sodium alginate and chitosan and ionic interactions between sodium alginate and calcium ions. The prepared composite sponges have excellent hygroscopicity (contact angle 51.3° ± 5.6°), moisture retention ability, porosity (67.32 % ± 3.37 %), and mechanical properties (>0.7 MPa) and exhibit good antibacterial ability against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). In addition, in vivo experiments have shown that the composite sponge promotes epithelial regeneration and collagen deposition in wounds infected with S. aureus or P. aeruginosa. Tissue immunofluorescence staining analysis confirmed that the SC/Se-Ag/Cur complex sponge stimulated upregulated expression of CD31 to promote angiogenesis while downregulating TNF-α expression to reduce inflammation. These advantages make it an ideal candidate for infectious wound repair materials, providing an effective repair strategy for clinical skin trauma infections.

Mucoadhesive Hydrogel with Anti-gastric Acid and Sustained-Release Functions for Amelioration of DSS-Induced Ulcerative Colitis

Mucoadhesive hydrogels with multifunctional properties such as gastric acid resistance and sustained drug release in the intestinal tract are highly desirable for the oral treatment of inflammatory bowel diseases (IBDs). Polyphenols are proven to have great efficacies compared with the first-line drugs for IBD treatments. We recently reported that gallic acid (GA) was capable of forming a hydrogel. However, this hydrogel is prone to easy degradation and poor adhesion in vivo. To tackle this problem, the current study introduced sodium alginate (SA) to form a gallic acid/sodium alginate hybrid hydrogel (GAS). As expected, the GAS hydrogel showed excellent antiacid, mucoadhesive, and sustained degradation properties in the intestinal tract. In vitro studies demonstrated that the GAS hydrogel significantly alleviated ulcerative colitis (UC) in mice. The colonic length of the GAS group (7.75 ± 0.38 cm) was significantly longer than that of the UC group (6.12 ± 0.25 cm). The disease activity index (DAI) value of the UC group was (5.5 ± 0.57), which was markedly higher than that of the GAS group (2.5 ± 0.65). The GAS hydrogel also could inhibit the expression of inflammatory cytokines, regulating macrophage polarization and improving the intestinal mucosal barrier functions. All these results indicated that the GAS hydrogel was an ideal candidate for oral treatment of UC.

Injectable spontaneous hydrogen-releasing hydrogel for long-lasting alleviation of osteoarthritis

Excessive production of reactive oxygen species (ROS) amplifies pro-inflammatory pathways and exacerbates immune responses, and is a key factor in the progression of osteoarthritis (OA). Therapeutic hydrogen gas (H₂) with antioxidative and anti-inflammatory effects, has a potential for OA alleviation, but the targeted delivery and sustained release of H₂ are still challenging. Herein, we develop an injectable calcium boride nanosheets (CBN) loaded hydrogel platform (CBN@GelDA hydrogel) as a high-payload and sustainable H₂ precursor for OA treatment. The CBN@GelDA hydrogel could maintain constant physiological pH conditions which further promotes more H₂ release than the CBN alone and lasts more than one week. The biocompatibility of this hydrogel with macrophages and chondrocytes is effectively enhanced. The experiments show that the CBN@GelDA hydrogel holds the ROS scavenging ability, reducing the expression of related inflammatory cytokines, lessening M1 macrophages but stimulating M2 phenotype, and thereby decreasing chondrocyte apoptosis, which facilitates to breaking of the vicious circle of OA progression. Furthermore, a single-time injection of the CBN@GelDA hydrogel markedly reduces joint destruction in OA rats. From what has been discussed above, this injectable spontaneous H₂-releasing hydrogel is promising for OA treatment. STATEMENT OF SIGNIFICANCE: Oxidative stress and inflammation play the key role in the occurrence and development of osteoarthritis (OA). The system of a hydrogel loaded with H₂ precursor calcium boride nanosheet (CBN), which is the first to use as an H₂ precursor, integrates superior injectable and biocompatible of hydrogel and the selection of antioxidant properties of H₂. This system can improve H₂ release behavior and achieve a single injection into the articular cavity to alleviate the progression of OA in rats. This study of the combination of a convenient long-acting injectable hydrogel and a safe therapeutic gas is of great value for improving the quality of life of clinical patients.

Atomically precise Au nanocluster-embedded carrageenan for single near-infrared light-triggered photothermal and photodynamic antibacterial therapy

In this study, we report atomically precise gold nanoclusters-embedded natural polysaccharide carrageenan as a novel hydrogel platform for single near-infrared light-triggered photothermal (PTT) and photodynamic (PDT) antibacterial therapy. Briefly, atomically precise captopril-capped Au nanoclusters (Au₂₅Capt₁₈) prepared by an alkaline NaBH₄ reduction method and then embedded them into the biosafe carrageenan to achieve superior PTT and PDT dual-mode antibacterial effect. In this platform, the embedded Au₂₅Capt₁₈, as simple-component phototherapeutic agents, exhibit superior thermal effects and singlet oxygen generation under a single near-infrared (NIR, 808 nm) light irradiation, which enables rapid elimination of bacteria. Carrageenan endows the hydrogel platform with superior gelation characteristics and wound microenvironmental regulation. The Au₂₅Capt₁₈-embedded hydrogels exhibited good water retention, hemostasis, and breathability, providing a favorable niche environment for promoting wound healing. In vitro experiments confirmed the excellent antibacterial activity of the Au₂₅Capt₁₈ hydrogels against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The antibacterial effect and promoting wound healing function were further validated in a S. aureus-infected wound model. Biosafety evaluation showed that the Au₂₅Capt₁₈ hydrogel has excellent biocompatibility. This PTT/PDT dual-mode therapy offers an alternative strategy for battling bacterial infections without antibiotics. More importantly, this hydrogel is facile to prepare which is helpful for expanding applications.

Polydopamine/tannic acid/chitosan/poloxamer 407/188 thermosensitive hydrogel for antibacterial and wound healing

The design and development of smart shape-adaptable wound dressings with superior antimicrobial ability remain a challenge in therapeutic and clinical application. Herein, polydopamine/tannic acid/chitosan/poloxamer 407/188 hydrogel (PTCPP) was prepared with the aim of developing an in situ-formed antibacterial wound dressing with temperature stimulation and near-infrared radiation (NIR) responsive ability. PTCPP possessed injectability, photothermal stability, sustained release properties and cytocompatibility. In vitro antibacterial results showed that the bactericidal rates of PTCPP against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) under NIR irradiation were 99.994 % and 99.91 %, respectively. In vivo experiments, PTCPP can adapt to shape of the wound, showing good adhesion, while promoting wound healing in bacterial infections. Therefore, PTCPP has potential application in the treatment of infectious wounds, and provides a strategic choice for developing antibacterial wound dressing combined with photothermal therapy.

Anti-oxidant anti-inflammatory and antibacterial tannin-crosslinked citrate-based mussel-inspired bioadhesives facilitate scarless wound healing

The revolutionary role of tissue adhesives in wound closure, tissue sealing, and bleeding control necessitates the development of multifunctional materials capable of effective and scarless healing. In contrast to the use of traditionally utilized toxic oxidative crosslinking initiators (exemplified by sodium periodate and silver nitrate), herein, the natural polyphenolic compound tannic acid (TA) was used to achieve near instantaneous (<25s), hydrogen bond mediated gelation of citrate-based mussel-inspired bioadhesives combining anti-oxidant, anti-inflammatory, and antimicrobial activities (3A-TCMBAs). The resulting materials were self-healing and possessed low swelling ratios (<60%) as well as considerable mechanical strength (up to ∼1.0 MPa), elasticity (elongation ∼2700%), and adhesion (up to 40 kPa). The 3A-TCMBAs showed strong in vitro and in vivo anti-oxidant ability, favorable cytocompatibility and cell migration, as well as photothermal antimicrobial activity against both Staphylococcus aureus and Escherichia coli (>90% bacterial death upon near-infrared (NIR) irradiation). In vivo evaluation in both an infected full-thickness skin wound model and a rat skin incision model demonstrated that 3A-TCMBAs + NIR treatment could promote wound closure and collagen deposition and improve the collagen I/III ratio on wound sites while simultaneously inhibiting the expression of pro-inflammatory cytokines. Further, phased angiogenesis was observed via promotion in the early wound closure phases followed by inhibition and triggering of degradation & remodeling of the extracellular matrix (ECM) in the late stage (supported by phased CD31 (platelet endothelial cell adhesion molecule-1) PDGF (platelet-derived growth factor) and VEGF (vascular endothelial growth factor) expression as well as elevated matrix metalloprotein-9 (MMP-9) expression on day 21), resulting in scarless wound healing. The significant convergence of material and bioactive properties elucidated above warrant further exploration of 3A-TCMBAs as a significant, new class of bioadhesive.

•

Citrate-based mussel-inspired bioadhesive prepolymers were crosslinked with tannic acid via hydrogen bonding (3A-TCMBAs).

•

3A-TCMBAs showed good tissue adhesiveness, self-healing and elastic properties.

•

3A-TCMBAs exhibited photothermal antibacterial, antioxidant and anti-inflammatory efficiency.

•

3A-TCMBAs could promote scarless wound healing by enabling phased angiogenesis.

Photothermal Hydrogels for Promoting Infected Wound Healing

Photothermal therapies (PTT), with spatiotemporally controllable antibacterial capabilities without inducing resistance, have shown encouraging prospects in the field of infected wound treatments. As an important platform for PTT, photothermal hydrogels exhibit attractive advantages in the field of infected wound treatment due to their excellent biochemical properties and have been intensively explored in recent years. This review summarizes the progress of the photothermal hydrogels for promoting infected wound healing. Three major elements of photothermal hydrogels, i.e., photothermal materials, hydrogel matrix, and construction methods, are introduced. Furthermore, different strategies of photothermal hydrogels in the treatment of infected wounds are summarized. Finally, the challenges and prospects in the clinical treatment of photothermal hydrogels are discussed.

Polymeric Gel Scaffolds and Biomimetic Environments for Wound Healing

Infected wounds that do not heal are a worldwide problem that is worsening, with more people dying and more money being spent on care. For any disease to be managed effectively, its root cause must be addressed. Effective wound care becomes a bigger problem when various traditional wound healing methods and products may not only fail to promote good healing. Still, it may also hinder the healing process, causing wounds to stay open longer. Progress in tissue regeneration has led to developing three-dimensional scaffolds (3D) or constructs that can be leveraged to facilitate cell growth and regeneration while preventing infection and accelerating wound healing. Tissue regeneration uses natural and fabricated biomaterials that encourage the growth of tissues or organs. Even though the clinical need is urgent, the demand for polymer-based therapeutic techniques for skin tissue abnormalities has grown quickly. Hydrogel scaffolds have become one of the most imperative 3D cross-linked scaffolds for tissue regeneration because they can hold water perfectly and are porous, biocompatible, biodegradable, and biomimetic. For damaged organs or tissues to heal well, the porosity topography of the natural extracellular matrix (ECM) should be imitated. This review details the scaffolds that heal wounds and helps skin tissue to develop. After a brief overview of the bioactive and drug-loaded polymeric hydrogels, the discussion moves on to how the scaffolds are made and what they are made of. It highlights the present uses of in vitro and in-vivo employed biomimetic scaffolds. The prospects of how well bioactiveloaded hydrogels heal wounds and how nanotechnology assists in healing and regeneration have been discussed.

A CS-based composite scaffold with excellent photothermal effect and its application in full-thickness skin wound healing

The development of natural polymer-based scaffolds with excellent biocompatibility, antibacterial activity, and blood compatibility, able to facilitate full-thickness skin wound healing, remains challenging. In this study, we have developed three chitosan (CS)-based porous scaffolds, including CS, CS/CNT (carbon nanotubes) and CS/CNT/HA (nano-hydroxyapatite, n-HA) using a freeze-drying method. All three scaffolds have a high swelling ratio, excellent antibacterial activity, outstanding cytocompatibility and blood compatibility in vitro. The introduction of CNTs exhibited an obvious increase in mechanical properties and exerts excellent photothermal response, which displays excellent healing performance as a wound dressing in mouse full-thickness skin wound model when compared to CS scaffolds. CS/CNT/HA composite scaffolds present the strongest ability to promote full-thickness cutaneous wound closure and skin regeneration, which might be ascribed to the synergistic effect of photothermal response from CNT and excellent bioactivity from n-HA. Overall, the present study indicated that CNT and n-HA can be engineered as effective constituents in wound dressings to facilitate full-thickness skin regeneration.

Polysaccharide-based hydrogel with photothermal effect for accelerating wound healing

Polysaccharide-based hydrogel has excellent biochemical function, abundant sources, good biocompatibility and other advantages, and has a broad application prospect in biomedical fields, especially in the field of wound healing. With its inherent high specificity and low invasive burden, photothermal therapy has shown great application prospect in preventing wound infection and promoting wound healing. Combining polysaccharide-based hydrogel with photothermal therapy (PTT), multifunctional hydrogel with photothermal, bactericidal, anti-inflammatory and tissue regeneration functions can be designed, so as to achieve better therapeutic effect. This review first focuses on the basic principles of hydrogel and PTT, and the types of polysaccharides that can be used to design hydrogels. In addition, according to the different materials that produce photothermal effects, the design considerations of several representative polysaccharide-based hydrogels are emphatically introduced. Finally, the challenges faced by polysaccharide-based hydrogels with photothermal properties are discussed, and the future prospects of this field are put forward.

Current Progress and Outlook of Nano-Based Hydrogel Dressings for Wound Healing

Wound dressing is an important tool for wound management. Designing wound dressings by combining various novel materials and drugs to optimize the peri-wound environment and promote wound healing is a novel concept. Hydrogels feature good ductility, high water content, and favorable oxygen transport, which makes them become some of the most promising materials for wound dressings. In addition, nanomaterials exhibit superior biodegradability, biocompatibility, and colloidal stability in wound healing and can play a role in promoting healing through their nanoscale properties or as carriers of other drugs. By combining the advantages of both technologies, several outstanding and efficient wound dressings have been developed. In this paper, we classify nano-based hydrogel dressings into four categories: hydrogel dressings loaded with a nanoantibacterial drug; hydrogel dressings loaded with oxygen-delivering nanomedicines; hydrogel dressings loaded with nanonucleic acid drugs; and hydrogel dressings loaded with other nanodelivered drugs. The design ideas, advantages, and challenges of these nano-based hydrogel wound dressings are reviewed and analyzed. Finally, we envisaged possible future directions for wound dressings in the context of relevant scientific and technological advances, which we hope will inform further research in wound management.

Molecular Dynamics Simulations of Polydopamine Nanosphere's Structure Based on Experimental Evidence

In this work, we show how to obtain internal monodispersed gold nanoparticles inside polydopamine (PDA) nanospheres that are also externally decorated with gold. The number of internal nanoparticles is affected by the size of the PDA nanosphere used, and the lower limit in the number of gold nanoparticles in the center of decorated nanospheres, one single gold nanoparticle, has been reached. In addition, extensive molecular dynamics simulations of PDA nanospheres based on four different chemical motifs, in the presence of water and with different sizes, have been performed to gain insight into the arrangements capable of accommodating cavities. In particular, PDA nanospheres based on pyranoacridinotrione (PYR) units provide good agreement with the experimental attainment of internal metal nanoparticles. In these, the stacking of PYR units leads to a particular morphology, with large portions of space occupied by the solvent, that would explain the observed formation of gold nanoparticles inside the PDA nanosphere.

Alginate/pectin dressing with niosomal mangosteen extract for enhanced wound healing: evaluating skin irritation by structure-activity relationship

Most modern wound dressings assist the wound-healing process. In contrast, conventional wound dressings have limited antibacterial activity and promote sporadic fibroblast growth. Therefore, wound dressings with prolonged substance release must be improved. This research aimed to develop hydrogel films. These were synthesized from alginate and pectin, incorporated with mangosteen extract (ME), and encapsulated in niosomes (ME-loaded niosomes). Subsequently, we examined the in vitro release and physical characteristics of ME-loaded niosomes. These characteristics included particle pH, size, charge, polydispersity index (PDI), and drug loading properties. These properties included drug loading content (DLC), entrapment efficiency (EE), and yield (Y). Additionally, we examined the swelling ratio and biological characteristics of the hydrogel film. These characteristics included antibacterial activity, cytotoxicity (L929), cell attachment to the tested materials, cell migration, hemocompatibility, and in vivo irritation. Significant results were obtained using a 2:1 niosome preparation containing Span60 and cholesterol. Ratio influenced size, charge, PDI, DLC, EE, and Y. The results were 225.5 ± 5.83 nm, negatively charged, 0.38, 16.2 ± 0.87%, 64.8 ± 3.49%, and 87.3 ± 3.09%, respectively. Additionally, the release of encapsulated ME was pH sensitive because 85% of the ME can be released at a pH of 5.5 within seven days and decrease to 70% at a pH of 7.4. The maximum swelling ratios of patches with 0.5% and 1% Ca²⁺ crosslinking were 867 wt% and 1,025 wt%, respectively, after 30 min. These results suggested that a medium dose (15 mg) of niosomal ME incorporated in a hydrogel film provided better bacterial inhibition, cell migration, and cell adhesion in an in vitro model. Additionally, no toxicity was observed in the fibroblasts and red blood cells. Therefore, given the above-mentioned advantages, this product can be a promising candidate for wound dressing applications.

Design of Near-Infrared-Triggered Cellulose Nanocrystal-Based In Situ Intelligent Wound Dressings for Drug-Resistant Bacteria-Infected Wound Healing

Postoperative infected wound complications caused by residual tumor cells, bacterial biofilms, and drug-resistant bacteria have become the main challenge in postsurgical skin regeneration. Herein, a bionic cellulose nanocrystal (CNC)-based in situ intelligent wound dressing with near-infrared (NIR)-, temperature-, and pH-responsive functions was designed by using NIR-responsive CNC as the network skeleton, dynamic imine bonds between dialdehyde cellulose nanocrystals and doxorubicin, chitosan oligosaccharide as the pH-responsive switch, and temperature-sensitive poly(N-isopropyl acrylamide) as the temperature-responsive in situ formation switch. The as-prepared wound dressing with the intertwining three-dimensional (3D) network structure possessed high drug loadability of indocyanine green (30 mg/g) and doxorubicin (420 mg/g) simultaneously. The temperature-, NIR-, and pH-responsive switches endowed the wound dressing with controllable on-demand drug release behavior. In particular, the temperature switch endowed the dressing with a shape-adaptable ability on irregularly infected wounds. Interestingly, the wound dressing showed excellent antitumor activity for A375 tumor cells, antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and bacterial biofilm removal ability. Therefore, the developed wound dressing can provide an ideal synergistic treatment strategy combined with chemotherapy and photodynamic and photothermal therapy for postoperative drug-resistant bacteria-infected wound healing.

Debonding-On-Demand Polymeric Wound Patches for Minimal Adhesion and Clinical Communication

Herein, a multifunctional bilayer wound patch is developed by integrating a debonding-on-demand polymeric tissue adhesive (DDPTA) with an ionic conducting elastomer (ICE). As a skin adhesive layer, the DDPTA is soft and adherent at skin temperature but hard and non-tacky when cooled, so it provides unique temperature-triggered quick adhesion and non-forced detachment from the skin. During use, the dense surface of the DDPTA prevents blood infiltration and reduces unnecessary blood loss with gentle pressing. Moreover, its hydrophobic matrix helps to repel blood and prevents the formation of clots, thus precluding wound tearing during its removal. This unique feature enables the DDPTA to avoid the severe deficiencies of hydrophilic adhesives, providing a reliable solution for a wide range of secondary wound injuries. The DDPTA is versatile in that it can be covered with ICE to configure a DDPTA@ICE patch for initiating non-verbal communication systems by the fingers, leading toward sign language recognition and a remote clinical alarm system. This multifunctional wound patch with debonding-on-demand can promote a new style of tissue sealant for convenient clinical communication.

pH-Responsive Hyperbranched Polymer Nanoparticles to Combat Intracellular Infection by Disrupting Bacterial Wall and Regulating Macrophage Polarization

Intracellular bacterial infections pose a serious threat to public health. Macrophages are a heterogeneous population of immune cells that play a vital role in intracellular bacterial infection. However, bacteria that survive inside macrophages could subvert the cell signaling and eventually reduce the antimicrobial activity of macrophages. Herein, dual pH-responsive polymer (poly[(3-phenylprop-2-ene-1,1-diyl)bis(oxy)bis(enthane-2,1-diyl)diacrylate-co-N-aminoethylpiperazine] (PCA)) nanoparticles were developed to clear intracellular bacteria by activating macrophages and destructing bacterial walls. The presence of acid-labile acetal linkages and tertiary amine groups in the polymer's backbone endow hyperbranched PCA dual pH-response activity that shows acid-induced positive charge increase and cinnamaldehyde release properties. The biodegraded PCA nanoparticles could significantly inhibit the growth of bacteria by damaging the bacterial walls. Meanwhile, PCA nanoparticles could uptake by macrophages, generate reactive oxygen species (ROS), and remodel the immune response by upregulating M1 polarization, leading to the reinforced antimicrobial capacity. Furthermore, PCA nanoparticles could promote bacteria-infected wound healing in vivo. Therefore, these dual pH-responsive PCA nanoparticles enabling bacteria-killing and macrophage activation provide a novel outlook for treating intracellular infection.