A Zwitterionic Hydrogel with Anti-Oxidative and Anti-Inflammatory Properties for the Prevention of Peritoneal Adhesion by Inhibiting Mesothelial-Mesenchymal Transition

A dynamic zwitterionic degradable hydrogel niche for efficient stem cell expansion and recovery

During two-dimensional (2D) culture, stem cells gradually lose their proliferative activity and multipotency due to various physicochemical conditions, which significantly hinder the large-scale clinical applications of stem cell therapy. In recent years, three-dimensional (3D) cell culture has been increasingly utilized in the field of stem cell expansion owing to its unique advantages. The superhydrophilicity of zwitterionic hydrogels ensures the maintenance of stem cells' stemness during their expansion. This study aims to address a key challenge in the large-scale culture of stem cells in vitro: how to sustain their proliferative capacity and multipotency while achieving efficient cell recovery. To this end, we have designed a novel zwitterionic degradable hydrogel based on host-guest interactions as a 3D carrier for the in vitro culture of adipose-derived stem cells (ADSCs). We synthesized the copolymer poly(sulfobetaine-co-cyclodextrin) (p(SBMA-co-CD)) and adamantane-grafted hyaluronic acid (HA-Ada), and a stable hydrogel was rapidly formed by simply mixing solutions of these two polymers. Leveraging the antifouling properties of zwitterionic groups, this hydrogel effectively maintained the long-term stemness expression of ADSCs during culture. More importantly, we utilized the reversibility of host-guest interactions to disrupt the cross-linked structure of the hydrogel by adding competitive monomers, enabling efficient recovery of stem cells under gentle conditions. This process not only achieved a high recovery rate of stem cells but also avoided the damage to cells caused by traditional cell recovery methods. In summary, this study creatively introduced host-guest interactions into a zwitterionic hydrogel and successfully applied it to the 3D culture and recovery of stem cells in vitro. This hydrogel demonstrates functional plasticity in stem cell proliferation, culture, and harvest, holding promise for providing more reliable and efficient solutions in the fields of stem cell therapy and tissue engineering.

Nonfouling Core-Shell Microneedle for Sequential and Sustained Drug Release: Enhancing Synergistic Photothermal Chemotherapy in Melanoma Treatment

Melanoma is a highly aggressive and metastatic malignancy, where current treatment methods often result in damage to healthy tissues, suboptimal therapeutic outcomes, and immune-related side effects. Microneedles, as a drug delivery system, offer advantages such as localized administration, minimal invasiveness, and high delivery efficiency. In this study, we first synthesized tetradecyl-thiol-grafted PAMAM dendrimers, which significantly enhanced cellular uptake and enabled sustained release of doxorubicin (DOX), improving cumulative drug release efficiency. Based on this, we developed a core-shell structured zwitterionic polymer-based microneedle delivery system. The outer shell, loaded with the photothermal agent indocyanine green (ICG), achieved precise photothermal therapy under near-infrared irradiation, effectively targeting melanoma tissues. The inner core, composed of a zwitterionic polymer matrix, encapsulated DOX-loaded dendrimers, enabling controlled and prolonged drug release through gradual polymer swelling and dendrimer expansion. Experiments show that the microneedle drug delivery system based on PAMAM dendrimer grafted with tetradecyl mercaptan and zwitterionic polymer has excellent anti protein adsorption properties, and it can minimize the cytotoxicity of carrier and improve the efficiency of drug delivery. This system effectively inhibited tumor growth through synergistic photothermal-chemotherapy, reducing systemic toxicity and improving drug bioavailability. This microneedle platform provides a promising strategy for targeted and synergistic melanoma therapy, offering a high-efficiency and low-toxicity treatment alternative.

Cell membrane-derived nanovesicles as extracellular vesicle-mimetics in wound healing

Cell membrane-derived nanovesicles (NVs) have emerged as promising alternatives to extracellular vesicles (EVs) for wound healing applications, addressing the limitations of traditional EVs, which include insufficient targeting capability, low production yield, and limited drug-loading capacity. Through mechanical cell extrusion methods, NVs exhibit superior characteristics, demonstrating enhanced yield, stability, and purity compared to natural EVs. These NVs can be derived from various membrane sources, including single cell types (stem cells, blood cells, immune cells, and bacterial membranes), hybrid cell membranes and cell membranes mixed with liposomes, with each offering unique therapeutic properties. The integration of genetic engineering and surface modifications has further enhanced NV functionality, enabling precise targeting and improved drug delivery capabilities. Recent advances in NV-based therapies have demonstrated their potential across multiple biomedical applications. Although challenges persist in terms of standardization, storage stability, and clinical translation, the combination of natural cell-derived functions with artificial modification potential positions NVs as a promising platform for next-generation therapeutic delivery systems, thereby offering new possibilities in wound healing applications. Finally, we explore the challenges and future prospects of translating NV-based therapeutics into clinical practice, providing insights into the future development of this innovative approach in wound healing and tissue repair.

Dynamic and photodegradable dextran/gelatin hydrogel niche crosslinked with disulfide bonds: Promoting growth and release of stem cells

Due to the utilization of well-defined artificial niches, stem cell culture in a three-dimensional hydrogel matrix has been a promising method for obtaining sufficient seed cells. Although various hydrogels can support desirable cell proliferation, establishing a normalized hydrogel that adequately mimics the extracellular matrix (ECM), maintains stemness and allows for controlled release of stem cells remains a significant challenge. Herein, we report a hydrogel composed of sulfobetaine-modified dextran and gelatin to maintain stemness and enable the rapid release of adipose-derived stem cells (ADSCs). Dextran can effectively maintain multipotent phenotype of ADSCs by grafting zwitterionic groups. Gelatin can significantly improve the proliferation of ADSCs. The hydrogel network they form effectively mimics the ECM microenvironment, providing an advantage when used as a three-dimensional niche to promote cell proliferation. Most importantly, the disulfide-crosslinked hydrogels show specific photodegradation capability, which precisely enables the system to achieve controlled release and efficient harvest of ADSCs. The cell viability (90 %) and harvest ratio (64 %) were well maintained by light degradation compared with GSH and collagenase degradation. Overall, this study offers a universal stem cell niche based on photodegradable hydrogel that shows great promise in the field of ADSCs proliferation and harvest.

The Safety and Efficacy of Dietary Epigallocatechin Gallate Supplementation for the Management of Obesity and Non-Alcoholic Fatty Liver Disease: Recent Updates

Epigallocatechin gallate (EGCG) is the predominant bioactive catechin in green tea, and it has been ascribed a range of beneficial health effects. Current increases in obesity and non-alcoholic fatty liver disease (NAFLD) rates represent a persistent and burdensome threat to global public health. While many clinical studies have demonstrated that EGCG is associated with positive effects on various health parameters, including metabolic biomarkers, waist circumference, and body weight when consumed by individuals affected by obesity and NAFLD, there are also some reports suggesting that it may entail some degree of hepatotoxicity. The present review provides a comprehensive summary of the extant clinical findings pertaining to the safety and effectiveness of EGCG in managing obesity and NAFLD, with a particular focus on how treatment duration and dose level affect the bioactivity of this compound.

Organism-Inspired Antioxidant Bioadhesive with Strong Sealing Ability to Prevent Epidural Adhesion

Epidural adhesion or epidural fibrosis is the major reason for postoperative pain, which remains a clinically challenging problem. Current physical barriers fail to provide a satisfactory therapeutic outcome mainly due to their lack of adhesion, inability to prevent fluid leakage, and exhibiting limited antioxidant properties. Herein, we fabricated a cysteine-modified bioadhesive (SECAgel) with improved sealing and antioxidant properties for epidural adhesion prevention, inspired by the organism's antioxidant systems. The resulting SECAgel showed good injectability and in situ adhesion ability, effectively covering every corner of the irregular wound. Besides, it possessed efficient sealing properties (395.2 mmHg), effectively stopping blood leakage in the rabbit carotid artery transection model. The antioxidant experiments demonstrated that the SECAgel effectively scavenged various radicals and saved the cells from oxidative stress. Two animal models were used to show that the SECAgel effectively inhibited adhesion in both situations with and without cerebrospinal fluid leakage. The RNA sequencing analysis showed that SECAgel treatment effectively inhibited the expression of key genes related to adhesion development, inflammatory response, and oxidative stress. The SECAgel, together with good biocompatibility, can be a good candidate for preventing epidural adhesion in the clinic.

Nonswellable Hydrogel Patch with Tissue-Mimetic Mechanical Characteristics Remodeling In Vivo Microenvironment for Effective Adhesion Prevention

Postoperative adhesion is a common complication after abdominal surgery, but current clinical products have unsatisfactory therapeutic effects. Here, we present a hydrogel patch formed in a single step through dialysis. The exchange of DMSO into water facilitates hydrophobic aggregate in situ formation and the formation of hydrogen bonds within the hydrogel. Thanks to the optimized component ratio and precise structural design. The hydrogel patch has soft-tissue-like mechanical characteristics, including high strength, high toughness, low modulus similar to the abdominal wall, good fatigue resistance, and fast self-recovery properties. The nonswellable hydrogel patch retains over 80% of its original mechanical properties after 7 days of immersion in physiological saline, with a maximum swelling ratio of 5.6%. Moreover, the hydrophobic biomultifunctionality of benzyl isothiocyanate can self-assemble onto the hydrogel patch during the sol-gel transition process, enabling it to remodel the inflammatory microenvironment through synergistic antibacterial, antioxidant, and anti-inflammatory effects. The hydrogel patch prevents postsurgical adhesion in a rat sidewall defect-cecum abrasion model and outperforms the leading commercial Interceed. It holds promising potential for clinical translation, considering that FDA-approved raw materials (PVA and gelatin) form the backbone of this effective hydrogel patch.

Nanofiber Hydrogel Drug Delivery System for Prevention of Postsurgical Intestinal Adhesion

Intestinal adhesion is one of the complications that occurs more frequently after abdominal surgery. Postsurgical intestinal adhesion (PIA) can lead to a series of health problems, including abdominal pain, intestinal obstruction, and female infertility. Currently, hydrogels and nanofibrous films as barriers are often used for preventing PIA formation; however, these kinds of materials have their intrinsic disadvantages. Herein, we developed a dual-structure drug delivery patch consisting of poly lactic-co-glycolic acid (PLGA) nanofibers and a chitosan hydrogel (NHP). PLGA nanofibers loaded with deferoxamine mesylate (DFO) were incorporated into the hydrogel; meanwhile, the hydrogel was loaded with anti-inflammatory drug dexamethasone (DXMS). The rapid degradation of the hydrogel facilitated the release of DXMS at the acute inflammatory stage of the early injury and provided effective anti-inflammatory effects for wound sites. Moreover, PLGA composite nanofibers could provide sustained and stable release of DFO for promoting the peritoneal repair by the angiogenesis effects of DFO. The in vivo results indicated that NHP can effectively prevent PIA formation by restraining inflammation and vascularization, promoting peritoneal repair. Therefore, we believe that our NHP has a great potential application in inhibition of PIA.

Hemoadhican-Based Bioabsorbable Hydrogel for Preventing Postoperative Adhesions

Postoperative peritoneal adhesions are a prevalent clinical issue following abdominal and pelvic surgery, frequently resulting in heightened personal and societal health burdens. Traditional biomedical barriers offer limited benefits because of practical challenges for doctors and their incompatibility with laparoscopic surgery. Hydrogel materials, represented by hyaluronic acid gels, are receiving increasing attention. However, existing antiadhesive gels still have limited effectiveness or carry the risk of complications in clinical applications. Herein, we developed a novel hydrogel using polysaccharide hemoadhican (HD) as the base material and polyethylene glycol diglycidyl ether (PEGDE) as the cross-linking agent. The HD hydrogels exhibit appropriate mechanical properties, injectability, and excellent cytocompatibility. We demonstrate resistance to protein adsorption and L929 fibroblast cell adhesion to the HD hydrogel. The biodegradability and efficacy against peritoneal adhesion are further evaluated in C57BL/6 mice. Our results suggest a potential strategy for anti-postoperative tissue adhesion barrier biomaterials.

A comprehensive review on the inherent and enhanced antifouling mechanisms of hydrogels and their applications

Biofouling remains a persistent challenge within the domains of biomedicine, tissue engineering, marine industry, and membrane separation processes. Multifunctional hydrogels have garnered substantial attention due to their complex three-dimensional architecture, hydrophilicity, biocompatibility, and flexibility. These hydrogels have shown notable advances across various engineering disciplines. The antifouling efficacy of hydrogels typically covers a range of strategies to mitigate or inhibit the adhesion of particulate matter, biological entities, or extraneous pollutants onto their external or internal surfaces. This review provides a comprehensive review of the antifouling properties and applications of hydrogels. We first focus on elucidating the fundamental principles for the inherent resistance of hydrogels to fouling. This is followed by a comprehensive investigation of the methods employed to enhance the antifouling properties enabled by the hydrogels' composition, network structure, conductivity, photothermal properties, release of reactive oxygen species (ROS), and incorporation of silicon and fluorine compounds. Additionally, we explore the emerging prospects of antifouling hydrogels to alleviate the severe challenges posed by surface contamination, membrane separation and wound dressings. The inclusion of detailed mechanistic insights and the judicious selection of antifouling hydrogels are geared toward identifying extant gaps that must be bridged to meet practical requisites while concurrently addressing long-term antifouling applications.

Injectable Asymmetric Adhesive-Antifouling Bifunctional Hydrogel for Peritoneal Adhesion Prevention

Peritoneal adhesion is a common problem after abdominal surgery and can lead to various medical problems. In response to the lack of in situ retention and pro-wound healing properties of existing anti-adhesion barriers, this work reports an injectable adhesive-antifouling bifunctional hydrogel (AAB-hydrogel). This AAB-hydrogel can be constructed by "two-step" injection. The tissue adhesive hydrogel based on gallic acid-modified chitosan and aldehyde-modified dextran is prepared as the bottom hydrogel (B-hydrogel) by Schiff base reaction. The aldehyde-modified zwitterionic dextran/carboxymethyl chitosan-based hydrogel is formed on the B-hydrogel surface as the antifouling top hydrogel (T-hydrogel). The AAB-hydrogel exhibits good bilayer binding and asymmetric properties, including tissue adhesive, antifouling, and antimicrobial properties. To evaluate the anti-adhesion effect in vivo, the prepared hydrogels are injected onto the wound surface of a mouse abdominal wall abrasion-cecum defect model. Results suggest that the AAB-hydrogel has antioxidant capacity and can reduce the postoperative inflammatory response by modulating the macrophage phenotype. Moreover, the AAB-hydrogel could effectively inhibit the formation of postoperative adhesions by reducing protein deposition, and resisting fibroblast adhesions and bacteria attacking. Therefore, AAB-hydrogel is a promising candidate for the prevention of postoperative peritoneal adhesions.