Antioxidant Hydrogels: Antioxidant Mechanisms, Design Strategies, and Applications in the Treatment of Oxidative Stress-Related Diseases

NIR-responsive electrospun nanofiber dressing promotes diabetic-infected wound healing with programmed combined temperature-coordinated photothermal therapy

BACKGROUND

Diabetic wounds present significant challenges, specifically in terms of bacterial infection and delayed healing. Therefore, it is crucial to address local bacterial issues and promote accelerated wound healing. In this investigation, we utilized electrospinning to fabricate microgel/nanofiber membranes encapsulating MXene-encapsulated microgels and chitosan/gelatin polymers.

RESULTS

The film dressing facilitates programmed photothermal therapy (PPT) and mild photothermal therapy (MPTT) under near-infrared (NIR), showcasing swift and extensive antibacterial and biofilm-disrupting capabilities. The PPT effect achieves prompt sterilization within 5 min at 52 °C and disperses mature biofilm within 10 min. Concurrently, by adjusting the NIR power to induce local mild heating (42 °C), the dressing stimulates fibroblast proliferation and migration, significantly enhancing vascularization. Moreover, in vivo experimentation successfully validates the film dressing, underscoring its immense potential in addressing the intricacies of diabetic wounds.

CONCLUSIONS

The MXene microgel-loaded nanofiber dressing employs temperature-coordinated photothermal therapy, effectively amalgamating the advantageous features of high-temperature sterilization and low-temperature promotion of wound healing. It exhibits rapid, broad-spectrum antibacterial and biofilm-disrupting capabilities, exceptional biocompatibility, and noteworthy effects on promoting cell proliferation and vascularization. These results affirm the efficacy of our nanofiber dressing, highlighting its significant potential in addressing the challenge of diabetic wounds struggling to heal due to infection.

Preliminary Investigation of Astragalus arpilobus subsp. hauarensis: LC-MS/MS Chemical Profiling, In Vitro Evaluation of Antioxidant, Anti-Inflammatory Properties, Cytotoxicity, and In Silico Analysis against COX-2

The search results offer comprehensive insights into the phenolic compounds, antioxidant, anti-inflammatory, cytotoxic effects, LC-MS/MS analysis, molecular docking, and MD simulation of the identified phenolic compounds in the Astragalus arpilobus subsp. hauarensis extract (AAH). The analysis revealed substantial levels of total phenolic content (TPC), with a measured value of 191 ± 0.03 mg GAE/g DM. This high TPC was primarily attributed to two key phenolic compounds: total flavonoid content (TFC) and total tannin content (TTC), quantified at 80.82 ± 0.02 mg QE/g DM and 51.91 ± 0.01 mg CE/g DM, respectively. LC-MS/MS analysis identified 28 phenolic compounds, with gallic acid, protocatechuic acid, catechin, and others. In the DPPH scavenging assay, the IC50 value for the extract was determined to be 19.44 ± 0.04 μg/mL, comparable to standard antioxidants like BHA, BHT, ascorbic acid, and α-tocopherol. Regarding anti-inflammatory activity, the extract demonstrated a notably lower IC50 value compared to both diclofenac and ketoprofen, with values of 35.73 µg/mL, 63.78 µg/mL, and 164.79 µg/mL, respectively. Cytotoxicity analysis revealed significant cytotoxicity of the A. arpilobus extract, with an LC50 value of 28.84 µg/mL, which exceeded that of potassium dichromate (15.73 µg/mL), indicating its potential as a safer alternative for various applications. Molecular docking studies have highlighted chrysin as a promising COX-2 inhibitor, with favorable binding energies and interactions. Molecular dynamic simulations further support chrysin's potential, showing stable interactions with COX-2, comparable to the reference ligand S58. Overall, the study underscores the pharmacological potential of A. arpilobus extract, particularly chrysin, as a source of bioactive compounds with antioxidant and anti-inflammatory properties. Further research is warranted to elucidate the therapeutic mechanisms and clinical implications of these natural compounds.

The MnO2/GelMA Composite Hydrogels Improve the ROS Microenvironment of Annulus Fibrosus Cells by Promoting the Antioxidant and Autophagy through the SIRT1/NRF2 Pathway

Intervertebral disc degeneration (IVDD) is a worldwide disease that causes low back pain and reduces quality of life. Biotherapeutic strategies based on tissue engineering alternatives, such as intervertebral disc scaffolds, supplemented by drug-targeted therapy have brought new hope for IVDD. In this study, to explore the role and mechanism of MnO2/GelMA composite hydrogels in alleviating IVDD, we prepared composite hydrogels with MnO2 and methacrylate gelatin (GelMA) and characterized them using compression testing and transmission electron microscopy (TEM). Annulus fibrosus cells (AFCs) were cultured in the composite hydrogels to verify biocompatibility by live/dead and cytoskeleton staining. Cell viability assays and a reactive oxygen species (ROS) probe were used to analyze the protective effect of the composite hydrogels under oxidative damage. To explore the mechanism of improving the microenvironment, we detected the expression levels of antioxidant and autophagy-related genes and proteins by qPCR and Western blotting. We found that the MnO2/GelMA composite hydrogels exhibited excellent biocompatibility and a porous structure, which promoted cell proliferation. The addition of MnO2 nanoparticles to GelMA cleared ROS in AFCs and induced the expression of antioxidant and cellular autophagy through the common SIRT1/NRF2 pathway. Therefore, the MnO2/GelMA composite hydrogels, which can improve the disc microenvironment through scavenging intracellular ROS and resisting oxidative damage, have great application prospects in the treatment of IVDD.

Prosopis africana exerts neuroprotective activity against quaternary metal mixture-induced memory impairment mediated by oxido-inflammatory response via Nrf2 pathway

The beneficial effects of Prosopis africana (PA) on human health have been demonstrated; however, its protective effects against heavy metals (HM) are not yet understood. This study evaluated the potential neuroprotective effects of PA in the cerebral cortex and cerebellum. To accomplish this, we divided 35 albino Sprague Dawley rats into five groups. Group I did not receive either heavy metal mixture (HMM) or PA. Group II received a HMM of PbCl2 (20 mg/kg), CdCl2 (1.61 mg/kg), HgCl2 (0.40 mg/kg), and NaAsO3 (10 mg/kg) orally for a period of two months. Groups III, IV, and V received HMM along with PA at doses of 500, 1000, and 1500 mg/kg, respectively. PA caused decreased levels of HM accumulation in the cerebral cortex and cerebellum and improved performance in the Barnes maze and rotarod tests. PA significantly reduced levels of IL-6 and TNF-α. PA increased concentrations of SOD, CAT, GSH, and Hmox-1 and decreased the activities of AChE and Nrf2. In addition, levels of MDA and NO decreased in groups III, IV, and V, along with an increase in the number of live neurons. In conclusion, PA demonstrates a complex neuroprotective effect with the potential to alleviate various aspects of HM-induced neurotoxicity.

pH-responsive CuS/DSF/EL/PVP nanoplatform alleviates inflammatory bowel disease in mice via regulating gut immunity and microbiota

The clinical treatment of inflammatory bowel disease (IBD) is challenging. We developed copper sulfate (CuS)/disulfiram (DSF)/methacrylic acid-ethyl acrylate copolymer (EL)/polyvinylpyrrolidone (PVP) nanoplatform (CuS/DSF/EL/PVP) and evaluated its efficiency for treating IBD. After oral administration, the pH-sensitive EL protected the CuS/DSF/EL/PVP against degradation by acidic gastric juices. Once the colon was reached, EL was dissolved, releasing DSF and Cu2+. Further, the main in vivo metabolite of DSF can bind to Cu2+ and form copper (II) N, N-diethyldithiocarbamate (CuET), which significantly alleviated acute colitis in mice. Notably, CuS/DSF/EL/PVP outperformed CuS/EL/PVP and DSF/EL/PVP nanoplatforms in reducing colonic pathology and improving the secretion of inflammation-related cytokines (such as IL-4 and IL-10) in the colonic mucosa. RNA-seq analysis revealed that the nanoplatform reduced colonic inflammation and promoted intestinal mucosal repair by upregulating C-type lectin receptor (CLR)-related genes and signaling pathways. Furthermore, CuS/DSF/EL/PVP showed potential for improving colitis Th1/Th17 cells through innate immunity stimulation, down-regulation of inflammatory cytokines, and upregulation of anti-inflammatory cytokines. Additionally, the intervention with CuS/DSF/EL/PVP led to increased intestinal flora diversity, decreased Escherichia-Shigella abundance, and elevated levels of short-chain fatty acid (SCFA)-producing bacteria Prevotella, Lactobacillus, and Bifidobacterium, indicating their potential to modulate the dysregulated intestinal flora and suppress inflammation. STATEMENT OF SIGNIFICANCE: Our study introduces the CuS/DSF/EL/PVP nanoplatform as a therapeutic strategy for treating inflammatory bowel disease (IBD). This approach demonstrates significant efficacy in targeting the colon and alleviating acute colitis in mice. It uniquely modulates gut immunity and microbiota, exhibiting a notable impact on inflammation-related cytokines and promoting intestinal mucosal repair. The nanoplatform's ability to regulate gut flora diversity, combined with its cost-effective and scalable production, positions it as a potentially transformative treatment for IBD, offering new avenues for personalized medical interventions.

Mussel-inspired "all-in-one" sodium alginate/carboxymethyl chitosan hydrogel patch promotes healing of infected wound

Hydrogels have been widely used as wound dressings to accelerate wound healing. However, due to the impaired skin barrier at the wound site, external bacteria can easily invade the wound and cause infection. In this study, we designed a dopamine-modified sodium alginate/carboxymethyl chitosan/polyvinylpyrrolidone (CPD) hydrogel, which was able to promote wound healing while preventing wound infection. Due to the high content of catechol groups, the CPD hydrogel exhibited good tissue adhesion ability and a significant scavenging ability for DPPH• and PTIO• radicals. Under near-infrared laser irradiation, the temperature of CPD hydrogel increased significantly, which significantly killed the Staphylococcus aureus and Escherichia coli. The cell migration test confirmed that CPD hydrogel could promote the cell migration ratio. In the in vivo wound healing test for infected full-thickness skin defect, CPD hydrogel significantly inhibited bacterial proliferation and enhanced wound healing rate. Therefore, the multifunctional hydrogel is expected to be applied to wound healing.

New Insights into Antioxidant Peptides: An Overview of Efficient Screening, Evaluation Models, Molecular Mechanisms, and Applications

Antioxidant peptides are currently a hotspot in food science, pharmaceuticals, and cosmetics. In different fields, the screening, activity evaluation, mechanisms, and applications of antioxidant peptides are the pivotal areas of research. Among these topics, the efficient screening of antioxidant peptides stands at the forefront of cutting-edge research. To this end, efficient screening with novel technologies has significantly accelerated the research process, gradually replacing the traditional approach. After the novel antioxidant peptides are screened and identified, a time-consuming activity evaluation is another indispensable procedure, especially in in vivo models. Cellular and rodent models have been widely used for activity evaluation, whilst non-rodent models provide an efficient solution, even with the potential for high-throughput screening. Meanwhile, further research of molecular mechanisms can elucidate the essence underlying the activity, which is related to several signaling pathways, including Keap1-Nrf2/ARE, mitochondria-dependent apoptosis, TGF-β/SMAD, AMPK/SIRT1/PGC-1α, PI3K/Akt/mTOR, and NF-κB. Last but not least, antioxidant peptides have broad applications in food manufacture, therapy, and the cosmetics industry, which requires a systematic review. This review introduces novel technologies for the efficient screening of antioxidant peptides, categorized with a new vision. A wide range of activity evaluation assays, encompassing cellular models, as well as rodent and non-rodent models, are provided in a comprehensive manner. In addition, recent advances in molecular mechanisms are analyzed with specific cases. Finally, the applications of antioxidant peptides in food production, therapy, and cosmetics are systematically reviewed.

Citric Acid Loaded Hydrogel-Coated Stent for Dissolving Pancreatic Duct Calculi

In recent years, the incidence of chronic pancreatitis has increased significantly. Pancreatic calculi obstruct the pancreatic duct and induce abdominal pain in the patients. Pancreatic duct stenting is the major treatment option for chronic pancreatitis with calculi. In this study, a new kind of drug-eluting stent, a pancreatic stent coated by methacrylated gelatin (GelMA) hydrogel loaded with citric acid (CA), was designed for the interventional treatment of pancreatic duct calculi. The CA loading capacity reached up to 0.7 g CA/g hydrogel-coated stent. The GelMA hydrogel coating has higher mechanical strength and lower swelling performance after loading with CA. The in vitro experiments of stents exhibited good performance in CA sustained release and the calculi can be dissolved in almost 3 days. The stents also showed good blood compatibility and cell compatibility. This research has important clinical value in the treatment of chronic pancreatitis with pancreatic calculi.

Hydrogel-Transformable Antioxidant Poly-γ-Glutamic Acid/Polyethyleneimine Hemostatic Powder for Efficient Wound Hemostasis

Hemostatic powder, which can absorb large amounts of water and tends to produce repeated hydration with tissue, has been clinically proven as an ideal engineering material for treating wounds and tissues. We herein designed a polypeptide-based hemostatic powder. A water-soluble polypeptide, γ-polyglutamic acid (γ-PGA), was mixed with the polyethyleneimine (PEI), N-hydroxysuccinimide, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide. The solution of these polymers was lyophilized to harvest the γ-PGA/PEI powder (PP hemostatic powder). When deposited on a bleeding wound, the PP hemostatic powder can quickly absorb a large amount of blood and interstitial fluid, concentrate coagulation factors, coagulate blood cells, and eventually form a stable mechanical hydrogel. The wound bleeding time of the PP hemostatic powder group was 1.8 ± 0.4 min, significantly lower than that of the commercial chitosan hemostatic powder group (2.8 ± 0.4 min). The PP hemostatic powder was endowed with antioxidant capacity by introducing protocatechuic aldehyde, which can effectively inhibit inflammation and promote wound healing. Therefore, via preparation through a facile lyophilization method, the PP hemostatic powder is expected to find a wide application prospect as a qualified hemostatic powder.