Robust and Multifunctional Nanoparticles Assembled from Natural Polyphenols and Metformin for Efficient Spinal Cord Regeneration

Biomaterial-based strategies: a new era in spinal cord injury treatment

Enhancing neurological recovery and improving the prognosis of spinal cord injury have gained research attention recently. Spinal cord injury is associated with a complex molecular and cellular microenvironment. This complexity has prompted researchers to elucidate the underlying pathophysiological mechanisms and changes and to identify effective treatment strategies. Traditional approaches for spinal cord injury repair include surgery, oral or intravenous medications, and administration of neurotrophic factors; however, the efficacy of these approaches remains inconclusive, and serious adverse reactions continue to be a concern. With advancements in tissue engineering and regenerative medicine, emerging strategies for spinal cord injury repair now involve nanoparticle-based nanodelivery systems, scaffolds, and functional recovery techniques that incorporate biomaterials, bioengineering, stem cell, and growth factors as well as three-dimensional bioprinting. Ideal biomaterial scaffolds should not only provide structural support for neuron migration, adhesion, proliferation, and differentiation but also mimic the mechanical properties of natural spinal cord tissue. Additionally, these scaffolds should facilitate axon growth and neurogenesis by offering adjustable topography and a range of physical and biochemical cues. The three-dimensionally interconnected porous structure and appropriate physicochemical properties enabled by three-dimensional biomimetic printing technology can maximize the potential of biomaterials used for treating spinal cord injury. Therefore, correct selection and application of scaffolds, coupled with successful clinical translation, represent promising clinical objectives to enhance the treatment efficacy for and prognosis of spinal cord injury. This review elucidates the key mechanisms underlying the occurrence of spinal cord injury and regeneration post-injury, including neuroinflammation, oxidative stress, axon regeneration, and angiogenesis. This review also briefly discusses the critical role of nanodelivery systems used for repair and regeneration of injured spinal cord, highlighting the influence of nanoparticles and the factors that affect delivery efficiency. Finally, this review highlights tissue engineering strategies and the application of biomaterial scaffolds for the treatment of spinal cord injury. It discusses various types of scaffolds, their integrations with stem cells or growth factors, and approaches for optimization of scaffold design.

Neutrophil-like Cell membrane-Coated Molybdenum-based Nanoclusters for Reduced Oxidative Stress and enhanced Neurological Recovery after Intracerebral Hemorrhage

Excessive reactive oxygen species (ROS) are detrimental to the brain that can result in neurological impairment and inhibiting neurological functionals recovery after intracerebral hemorrhage (ICH). However, there is still a lack of effective treatment for ICH, either with medicine or neurosurgery. Nanozymes with excellent superoxide dismutase and catalase properties can scavenge ROS and may provide therapeutic opportunities for ICH patients. However, the ability of nanozymes to non-invasively target cerebral hemorrhage lesions and further antioxidation effect are still unknown. Herein, neutrophile membrane-disguised molybdenum-based polyoxometalate nanozymes (POM@Mem) were developed to alleviate oxidative stress after ICH. Coating with neutrophil membrane allowed POM to target the hemorrhage sites and further inhibit ROS generation. POM@Mem can improve neuroinflammatory microenvironment and promote behavioral improvement of ICH mouse. Combining neutrophile membrane and nanozymes for targeting brain hemorrhage sites provides an effective strategy for the treatment of ICH. STATEMENT OF SIGNIFICANCE: Excessive reactive oxygen species (ROS) are detrimental to the brain and can lead to neurological impairment, hindering the recovery of neurological functions after intracerebral hemorrhage (ICH). Despite this, effective treatments for ICH, whether pharmaceuticals or neurosurgery, remain scarce. In this study, we developed neutrophil membrane-disguised molybdenum-based polyoxometalate nanozymes (POM@Mem) as a novel approach to alleviate oxidative stress following ICH. The neutrophil membrane coating enabled the POM nanozymes to specifically target hemorrhagic sites, thereby inhibiting ROS production. Additionally, POM@Mem improved the neuroinflammatory microenvironment and facilitated behavioral recovery in ICH mice. The combination of neutrophil membranes and nanozymes for targeted delivery to brain hemorrhage sites offers a promising strategy for the treatment of ICH.

Inflamed Tissue-Targeting Polyphenol-Condensed Antioxidant Nanoparticles with Therapeutic Potential

Inflammation is essential for pathogen eradication and tissue repair; However, chronic inflammation can bring on multi-organ dysfunction due to an overproduction of reactive oxygen species (ROS). Among various anti-inflammatory agents, polyphenol-based nanotherapeutics offer potential advantages, including enhanced stability, targeted delivery, multiple therapeutic functions, and personalized therapy tailored to the severity. Despite these advantages, the development of biocompatible nanomedicines capable of selective accumulation in inflamed tissues and efficient inhibition of ROS-induced inflammatory signaling pathways remains a considerable challenge. In this study, a novel anti-inflammatory nanotherapeutic is engineered through the temperature-dependent condensation of polyphenolic catechin facilitated by hydrothermal reactions. The resulting catechin-condensed nanotherapeutic (CCN150), synthesized at a relatively low temperature, retains physicochemical and functional properties akin to its precursor, catechin, but with a marked enhancement in water solubility. CCN150 protects cells from oxidative stress by eliminating intracellular ROS and augmenting antioxidant enzymes. In vivo studies reveal that intravenously administered CCN150 predominantly accumulates in inflamed tissues, with minimal distribution to healthy regions. Furthermore, CCN150 effectively reduces systemic inflammation in mouse models by disrupting the cycles of ROS instigated by a pro-inflammatory oxidative milieu. Exhibiting negligible toxicity, CCN150 holds substantial promise for extensive therapeutic applications in the treatment of various ROS-mediated inflammatory diseases.

Sustainable Pb(II) Removal and Recovery from Wastewater Using a Bioinspired Metal-Phenolic Hybrid Membrane with Efficient Regeneration

High-performance adsorbents often require efficient selectivity in wastewater, recoverability, and ease of multiple regeneration cycles, but achieving this remains a significant challenge. We report a new strategy for the efficient removal of lead (Pb(II)) from contaminated water streams using an innovative tannic acid (TA)-Fe(III)-based metal-phenolic network (MPN) hybrid membrane (MPN-PAM). This novel membrane exploits the tunable pH-sensitive coordination structure of the MPN to achieve selective removal and recovery of Pb(II) while enabling efficient membrane regeneration by filtration. This membrane demonstrates superior selectivity for Pb(II) with a removal efficiency of up to 98 % and an adsorption capacity of approximately 117.58 mg/g, even in the presence of high salinity, as well as coexisting heavy metals. The membrane maintains high Pb(II) removal efficiency over 20 consecutive cycles and 95 % efficiency over 10 regeneration cycles. Under continuous operation, it treats approximately 85 L per m2 of membrane, reducing Pb(II) concentrations to trace levels (~40 μg/L), meeting electroplating wastewater standard (GB21900-2008). Additionally, even low concentrations of Pb(II) (<5 mg/L) are efficiently purified to below WHO drinking water standard (10 μg/L). The operational cost for treating Pb(II)-contaminated wastewater is about $0.13 per ton, highlighting the cost-effectiveness and potential for large-scale application in wastewater treatment.

Metformin's therapeutic potential in spinal cord injury: a systematic review and meta-analysis on locomotor recovery, neuropathic pain alleviation, and modulation of secondary injury mechanisms

OBJECTIVE

To evaluate metformin's efficacy in locomotion recovery, alleviating neuropathic pain, and modulating underlying molecular mechanisms in Spinal Cord Injury (SCI) rodent models through a systematic review and meta-analysis.

METHODS

We conducted a comprehensive literature search across Medline, Embase, Scopus, and Web of Science from inception to May 2024. We included studies that utilized rodent models of traumatic SCI treated with metformin versus untreated controls. Data on locomotor recovery, neuropathic pain, and molecular mechanisms related to secondary injury were extracted. Standardized mean differences (SMDs) were synthesized as the pooled effect sizes.

RESULTS

Twenty-three studies comprising 1,567 animals met the inclusion criteria. Metformin significantly enhanced locomotor function (SMD = 2.23, 95% CI: 1.74, 2.73, p < 0.001) and improved both mechanical allodynia (SMD = 1.18; 95% CI, 0.35 to 2.00; p = 0.005) and thermal hyperalgesia (SMD = 2.40; 95% CI, 1.65 to 3.16; p < 0.001). It reduces inflammation, oxidative stress, microglial activation, and astrogliosis and promotes myelination and autophagy flux via activating the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. This resulted in decreased apoptosis and lesion size and increased tissue preservation and neuronal survival. Subgroup analyses indicated greater locomotor improvements when metformin was administered in the acute (< 3 days of injury) phase of the injury (meta-regression coefficient = 1.65; 95% CI, 0.37 to 2.93; p = 0.011).

CONCLUSION

Metformin shows significant therapeutic benefits for SCI in rodent models, promoting locomotor recovery and alleviating neuropathic pain. These results underscore its translational potential for clinical SCI management.

Catechin-Based Polyphenol Nanoparticles Ameliorated Ferroptosis to Alleviate Brain Injury after Intracerebral Hemorrhage

Spontaneous intracerebral hemorrhagic stroke (ICH) is a highly aggressive disease, with a high incidence and mortality rate. Iron deposition following ICH leads to oxidative damage and motor dysfunction, significantly impacting the overall quality of life for those affected. Here, a polyphenolic nanomedicine, catechin-based polyphenol nanoparticles surface-modified by thiol-terminated poly(ethylene glycol) (CNPs@PEG), was developed through the oxidative polymerization and self-assembly of catechin, a natural compound in tea. Due to its potent antioxidant and metal-chelating properties, CNPs@PEG effectively maintained blood-brain barrier integrity, reduced brain edema, significantly increased the survival rate of mice with cerebral hemorrhage and markedly improved neurological deficits after ICH. Mechanistically, CNPs@PEG accomplishes this by chelating iron, enhancing tissue antioxidant capacity, reducing oxidative stress, and inhibiting iron deposition. This approach holds promise as a targeted therapeutic strategy for addressing cerebral hemorrhage and other conditions associated with iron overload.

Two birds with one stone: natural polyphenols boosted periodontitis treatment of chlorhexidine via reducing toxicity and regulating microenvironments

Chlorhexidine (CHX) is considered the gold standard for controlling periodontal plaque and has been extensively used as a topical agent in treating periodontitis. Nevertheless, the practical clinical application of CHX is still constrained by the inherent limitations of its properties, including toxicity, inadequate biofilm scavenging capacity, and single biological effect. In this study, polyphenolic epigallocatechin gallate (EGCG) has been employed to integrate with CHX to form an EGCG-CHX nanoplatform via a facile one-pot method. Due to the dynamic bonding between EGCG and CHX, the EGCG-CHX nanoparticles (NPs) show reduced toxicity and excellent response release behavior. Moreover, a series of in vitro and in vivo studies demonstrated that the EGCG-CHX NPs significantly enhanced the antibiofilm, antioxidative, anti-inflammatory, and autophagic flux activation effects of CHX, ultimately achieving an improved therapeutic effect on periodontitis. This study successfully developed a strategy boosting the efficiency of CHX for periodontitis treatment.

A natural polyphenolic nanoparticle--knotted hydrogel scavenger for osteoarthritis therapy

Exploring highly efficient and cost-effective biomaterials for osteoarthritis (OA) treatment remains challenging, as current therapeutic strategies are difficult to eradicate the excessive reactive oxygen species (ROS) and nitric oxide (NO) at damaged sites. Tea polyphenol (TP) nanoparticles (NPs), a nature-inspired antioxidant in combination with 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), a NO scavenger, could provide maximized positive therapeutic effects on OA by eradicating both ROS and NO. Notably, this combination not only improves the half-life of the TP monomer and the drug loading efficiency of carboxy-PTIO but also prevents nitrite from being harmful to tissue. Moreover, the protonation ability of carboxy-PTIO allows smart acid-responsive release in response to environmental pH, which provides conditioned treatment strategies for OA. In in vitro experiments, TP/PTIO NPs downregulated proinflammatory cytokine release via synergistic removal of ROS and NO and suppression of ROS/NF-κB and iNOS/NO/Caspase-3 signaling. For in vivo experiments, NPs were cross-linked with 4-arm-PEG-SH to form an injectable hydrogel system. The release of TP and carboxy-PTIO from the system efficiently prevents cartilage inflammation and damage via similar signaling pathways. Overall, the proposed system provides an efficient approach for OA therapy.

Isosteviol Sodium Promotes Neurological Function Recovery in a Model of Spinal Cord Injury in Rats

BACKGROUND

Traumatic spinal cord injury (SCI) is an incurable condition that is the largest cause of disability. In previous studies, Isosteviol sodium (STVNa) has been shown to protect rats against acute focal cerebral ischemia; however, the effects of STVNa on SCI recovery in rats remain unknown.

METHODS

STVNa was given intraperitoneally after SCI to see if it had any neuroprotective benefits. On Days 7, 14, 21, and 28 post-SCI, functional recovery was measured using the Basso, Beattie, and Bresnahan (BBB) scoring system along with the oblique plate test. Following these evaluations, spinal cord tissues were harvested for analysis. All behavioral testing occurred between 8 a.m. and 3 p.m.

RESULTS

We found that STVNa improved spinal cord functional recovery in rats, as evidenced by enhanced BBB locomotor rating scale, angle of inclination, decreased cavity of spinal cord damage, and neuron death in vivo. In addition, STVNa reduced inflammation in rats following SCI, as demonstrated by a reduction in proinflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, and interleukin (IL)-1β. STVNa also reduced oxidative damage in SCI rats by lowering ROS while raising SOD levels.

CONCLUSION

These findings suggest that STVNa protects SCI rats through a variety of pathways. STVNa, in particular, may benefit the recovery of SCI by reducing oxidative stress and inflammation, leading to enhanced locomotor activity in rats with SCI.

High-throughput screening-based design of multifunctional natural polyphenol nano-vesicles to accelerate diabetic wound healing

Oxidative stress is a major pathological factor that impedes the diabetic wound healing process. Procyanidins (PC) form nanoparticle-vesicles (PPNs) through hydrogen bonding and exhibit good drug delivery capability; however, their application in diabetic wounds is unsatisfactory. To meet the antioxidant needs for treating, high-throughput screening in the natural product library (NPL) under in vitro oxidative stress conditions was conducted to enhance the antioxidant activity of PPNs. HUVECs treated with tert-Butyl Hydroperoxide (TBHP) were established as screening model in vitro. Baicalein (BAI) was identified from over 600  products in the library as the most effective one to combat oxidative stress. Further study showed that PC and BAI may react in equal proportions to synthesize new vesicles, named BAI-PC Polyphenolic nanovesicles (BPPNs), which possess reactive oxygen species (ROS) responsive and antioxidant effects. Network pharmacology indicated that in diabetic wounds, the target genes of PC are mainly enriched in the vascular endothelial growth factor (VEGF)-related pathways, while BAI primarily regulates tyrosine phosphorylation. The complementarity between the two has been validated in both in vitro and in vivo experiments. In summary, the antioxidant drug BAI, identified through high-throughput screening of NPL, could optimize the biological function of PPNs; the newly-synthesized BPPNs may accelerate diabetic wound healing through dual mechanisms of promoting angiogenesis and combating oxidative stress.

Highly Efficient Synergistic Chemotherapy and Magnetic Resonance Imaging for Targeted Ovarian Cancer Therapy Using Hyaluronic Acid-Coated Coordination Polymer Nanoparticles

The diagnosis and treatment of ovarian cancer (OC) are still a grand challenge, more than 70% of patients are diagnosed at an advanced stage with a dismal prognosis. Magnetic resonance imaging (MRI) has shown superior results to other examinations in preoperative assessment, while cisplatin-based chemotherapy is the first-line treatment for OC. However, few previous studies have brought together the two rapidly expanding fields. Here a technique is presented using cisplatin prodrug (Pt-COOH), Fe3+, and natural polyphenols (Gossypol) to construct the nanoparticles (HA@PFG NPs) that have a stable structure, controllable drug release behavior, and high drug loading capacity. The acidic pH values in tumor sites facilitate the release of Fe3+, Pt-COOH, and Gossypol from HA@PFG NPs. Pt-COOH with GSH consumption and cisplatin-based chemotherapy plus Gossypol with pro-apoptotic effects displays a synergistic effect for killing tumor cells. Furthermore, the release of Fe3+ at the tumor sites promotes ferroptosis and enables MRI imaging of OC. In the patient-derived tumor xenograft (PDX) model, HA@PFG NPs alleviate the tumor activity. RNA sequencing analysis reveals that HA@PFG NPs ameliorate OC symptoms mainly through IL-6 signal pathways. This work combines MRI imaging with cisplatin-based chemotherapy, which holds great promise for OC diagnosis and synergistic therapy.

Natural Polyphenol Delivered Methylprednisolone Achieve Targeted Enrichment for Acute Spinal Cord Injury Therapy

The strong anti-inflammatory effect of methylprednisolone (MP) is a necessary treatment for various severe cases including acute spinal cord injury (SCI). However, concerns have been raised regarding adverse effects from MP, which also severely limits its clinical application. Natural polyphenols, due to their rich phenolic hydroxyl chemical properties, can form dynamic structures without additional modification, achieving targeted enrichment and drug release at the disease lesion, making them a highly promising carrier. Considering the clinical application challenges of MP, a natural polyphenolic platform is employed for targeted and efficient delivery of MP, reducing its systemic side effects. Both in vitro and SCI models demonstrated polyphenols have multiple advantages as carriers for delivering MP: (1) Achieved maximum enrichment at the injured site in 2 h post-administration, which met the desires of early treatment for diseases; (2) Traceless release of MP; (3) Reducing its side effects; (4) Endowed treatment system with new antioxidative properties, which is also an aspect that needs to be addressed for diseases treatment. This study highlighted a promising prospect of the robust delivery system based on natural polyphenols can successfully overcome the barrier of MP treatment, providing the possibility for its widespread clinical application.

Microenvironment-responsive nanomedicines: a promising direction for tissue regeneration

Severe tissue defects present formidable challenges to human health, persisting as major contributors to mortality rates. The complex pathological microenvironment, particularly the disrupted immune landscape within these defects, poses substantial hurdles to existing tissue regeneration strategies. However, the emergence of nanobiotechnology has opened a new direction in immunomodulatory nanomedicine, providing encouraging prospects for tissue regeneration and restoration. This review aims to gather recent advances in immunomodulatory nanomedicine to foster tissue regeneration. We begin by elucidating the distinctive features of the local immune microenvironment within defective tissues and its crucial role in tissue regeneration. Subsequently, we explore the design and functional properties of immunomodulatory nanosystems. Finally, we address the challenges and prospects of clinical translation in nanomedicine development, aiming to propose a potent approach to enhance tissue regeneration through synergistic immune modulation and nanomedicine integration.

Biogenic derived nanoparticles modulate mitochondrial function in cardiomyocytes

Preservation of mitochondrial functionality is essential for heart hemostasis and cardiovascular diseases treatment. However, the current nanomedicines including liposomes, polymers and inorganic nanomaterials are severely hindered by poor stability, high manufacturing costs and potential biotoxicity. In this research, we present novel polyphenolic nanoparticles (NPs) derived from naturally occurring pomegranate peel (PP, labelled as PPP NPs), which exhibit potent antioxidative and anti-inflammatory properties, serving as a modulator of mitochondrial function. PPP NPs have been identified to improve survival rates in models of mitochondrial depletion through enhancement of cardiomyocyte proliferation and the reduction of DNA damage. Moreover, PPP NPs can effectively inhibit the production of reactive oxygen species and inflammatory mediators in lipopolysaccharide (LPS)-induced mitochondrial damage. Utilizing human engineered heart tissue and mice models, PPP NPs were found to significantly improve contractile function and alleviate inflammation activities after LPS treatment. Mechanically, PPP NPs regulated inflammatory responses via a m6A dependent manner, as determined using RNA-seq and MeRIP-seq analyses. Collectively, these insights underscore the potential of PPP NPs as a novel therapeutic approach for mitochondrial dysfunction.

Advances in Novel Biomaterial-Based Strategies for Spinal Cord Injury Treatment

Spinal cord injury (SCI) is a highly disabling neurological disorder. Its pathological process comprises an initial acute injury phase (primary injury) and a secondary injury phase (subsequent chronic injury). Although surgical, drug, and cell therapies have made some progress in treating SCI, there is no exact therapeutic strategy for treating SCI and promoting nerve regeneration due to the complexity of the pathological SCI process. The development of novel drug delivery systems to treat SCI is expected to significantly impact the individualized treatment of SCI due to its unique and excellent properties, such as active targeting and controlled release. In this review, we first describe the pathological progression of the SCI response, including primary and secondary injuries. Next, we provide a concise overview of newly developed nanoplatforms and their potential application in regulating and treating different pathological processes of SCI. Then, we introduce the existing potential problems and future clinical application perspectives of biomedical engineering-based therapies for SCI.

Current multi-scale biomaterials for tissue regeneration following spinal cord injury

Spinal cord injury (SCI) may cause loss of motor and sensory function, autonomic dysfunction, and thus disrupt the quality of life of patients, leading to severe disability and significant psychological, social, and economic burden. At present, existing therapy for SCI have limited ability to promote neural function recovery, and there is an urgent need to develop innovative regenerative approaches to repair SCI. Biomaterials have become a promising strategy to promote the regeneration and repair of damaged nerve tissue after SCI. Biomaterials can provide support for nerve tissue by filling cavities, and improve local inflammatory responses and reshape extracellular matrix structures through unique biochemical properties to create the optimal microenvironment at the SCI site, thereby promoting neurogenesis and reconnecting damaged spinal cord tissue. Considering the importance of biomaterials in repairing SCI, this article reviews the latest progress of multi-scale biomaterials in SCI treatment and tissue regeneration, and evaluates the relevant technologies for manufacturing biomaterials.

ROS-responsive hydrogels: from design and additive manufacturing to biomedical applications

Hydrogels with intricate 3D networks and high hydrophilicity have qualities resembling those of biological tissues, making them ideal candidates for use as smart biomedical materials. Reactive oxygen species (ROS) responsive hydrogels are an innovative class of smart hydrogels, and are cross-linked by ROS-responsive modules through covalent interactions, coordination interactions, or supramolecular interactions. Due to the introduction of ROS response modules, this class of hydrogels exhibits a sensitive response to the oxidative stress microenvironment existing in organisms. Simultaneously, due to the modularity of the ROS-responsive structure, ROS-responsive hydrogels can be manufactured on a large scale through additive manufacturing. This review will delve into the design, fabrication, and applications of ROS-responsive hydrogels. The main goal is to clarify the chemical principles that govern the response mechanism of these hydrogels, further providing new perspectives and methods for designing responsive hydrogel materials.

Metformin enhances endogenous neural stem cells proliferation, neuronal differentiation, and inhibits ferroptosis through activating AMPK pathway after spinal cord injury

BACKGROUND

Inadequate nerve regeneration and an inhibitory local microenvironment are major obstacles to the repair of spinal cord injury (SCI). The activation and differentiation fate regulation of endogenous neural stem cells (NSCs) represent one of the most promising repair approaches. Metformin has been extensively studied for its antioxidative, anti-inflammatory, anti-aging, and autophagy-regulating properties in central nervous system diseases. However, the effects of metformin on endogenous NSCs remains to be elucidated.

METHODS

The proliferation and differentiation abilities of NSCs were evaluated using CCK-8 assay, EdU/Ki67 staining and immunofluorescence staining. Changes in the expression of key proteins related to ferroptosis in NSCs were detected using Western Blot and immunofluorescence staining. The levels of reactive oxygen species, glutathione and tissue iron were measured using corresponding assay kits. Changes in mitochondrial morphology and membrane potential were observed using transmission electron microscopy and JC-1 fluorescence probe. Locomotor function recovery after SCI in rats was assessed through BBB score, LSS score, CatWalk gait analysis, and electrophysiological testing. The expression of the AMPK pathway was examined using Western Blot.

RESULTS

Metformin promoted the proliferation and neuronal differentiation of NSCs both in vitro and in vivo. Furthermore, a ferroptosis model of NSCs using erastin treatment was established in vitro, and metformin treatment could reverse the changes in the expression of key ferroptosis-related proteins, increase glutathione synthesis, reduce reactive oxygen species production and improve mitochondrial membrane potential and morphology. Moreover, metformin administration improved locomotor function recovery and histological outcomes following SCI in rats. Notably, all the above beneficial effects of metformin were completely abolished upon addition of compound C, a specific inhibitor of AMP-activated protein kinase (AMPK).

CONCLUSION

Metformin, driven by canonical AMPK-dependent regulation, promotes proliferation and neuronal differentiation of endogenous NSCs while inhibiting ferroptosis, thereby facilitating recovery of locomotor function following SCI. Our study further elucidates the protective mechanism of metformin in SCI, providing new mechanistic insights for its candidacy as a therapeutic agent for SCI.

Sonochemical Synthesis of Natural Polyphenolic Nanoparticles for Modulating Oxidative Stress

Natural polyphenolic compounds play a vital role in nature and are widely utilized as building blocks in the fabrication of emerging functional nanomaterials. Although diverse fabrication methodologies are developed in recent years, the challenges of purification, uncontrollable reaction processes and additional additives persist. Herein, a modular and facile methodology is reported toward the fabrication of natural polyphenolic nanoparticles. By utilizing low frequency ultrasound (40 kHz), the assembly of various natural polyphenolic building blocks is successfully induced, allowing for precise control over the particle formation process. The resulting natural polyphenolic nanoparticles possessed excellent in vitro antioxidative abilities and in vivo therapeutic effects in typical oxidative stress models including wound healing and acute kidney injury. This study opens new avenues for the fabrication of functional materials from naturally occurring building blocks, offering promising prospects for future advancements in this field.

Green Nanoengineered Fabrics: Waste-Derived Polyphenol-Zinc@ Silica Core-Shell Reactive Janus Nanoparticles for Functional Fabrics

Fabricating Janus nanoparticle-functionalized fabrics with UV protection, strength enhancement, self-cleaning properties, and wash durability, with a biocompatible nature, is crucial in modern functional fabrics engineering. Particularly, tailoring multifunctional nanoparticles capable of exhibiting several distinct properties, utilizing low-cost raw materials, and adhering to green chemistry principles is pivotal. A fabrication strategy for developing multifunctional reactive Janus nanoparticles, utilizing waste-derived natural polyphenol (quercetin-3-glucuronide, myricetin-3-galactoside, gossypin, phlorizin, kaempferol, myricetin-3-arabinoside)-integrated zinc-silica core-shell Janus nanoparticles with UV protection, strength enhancement, and self-cleaning properties, is proposed. Polyphenols were utilized as sustainable precursors for synthesizing zinc-polyphenol complexes, which were then encapsulated within a silica shell to form a core-shell structure. Furthermore, Janus particles were created by introducing a bifunctional layer with half amine/carboxylic acid and half methyl terminals, imparting reactive hydrophilic and hydrophobic properties. Janus-coated textiles and leather exhibited significant attenuation of harmful UV radiation, with water contact angle measurements confirming improved water repellency. The coexistence of natural phenols and bifunctional groups within a material bolstered textile strength, fostering superior adhesion and markedly enhancing wash durability. This eco-friendly approach, utilizing waste-derived materials, presents a promising solution for sustainable textile engineering with enhanced performance in UV protection and water resistance, thereby contributing to the advancement of green nanotechnology in textile applications.

Acid Neutralization by Composite Lysine Nanoparticles for Spinal Cord Injury Recovery through Mitigating Mitochondrial Dysfunction

After spinal cord injury (SCI), significant alterations in the tissue microenvironment lead to mitochondrial dysfunction, inducing apoptosis and inhibiting the remodeling of neural circuits, thereby impeding recovery. Although previous studies have demonstrated a marked decrease in pH at the injury site, creating an acidic microenvironment, the impact of improving this acidic microenvironment on SCI recovery has not been investigated. This study prepared a lysine@hollow mesoporous silica nanoparticle/gelatin methacrylate (GelMA) (L@H/G) composite hydrogel. The L@H/G composite hydrogel was demonstrated to release lysine and efficiently improve the acidic microenvironment slowly. Significantly, the composite hydrogel reduced cell apoptosis, promoted nerve regeneration, inhibited glial scar formation, and ultimately enhanced motor function recovery in mice with SCI. Mechanistically, the L@H/G hydrogel improved the mitochondrial tricarboxylic acid (TCA) cycle and fatty acid metabolism, restoring energy supply and facilitating mitochondrial function recovery. To the best of our knowledge, this is the first report confirming that improving the acidic microenvironment could promote SCI repair, providing a potential therapeutic strategy for SCI.

An Antibiotic Nanobomb Constructed from pH-Responsive Chemical Bonds in Metal-Phenolic Network Nanoparticles for Biofilm Eradication and Corneal Ulcer Healing

In the treatment of refractory corneal ulcers caused by Pseudomonas aeruginosa, antibacterial drugs delivery faces the drawbacks of low permeability and short ocular surface retention time. Hence, novel positively-charged modular nanoparticles (NPs) are developed to load tobramycin (TOB) through a one-step self-assembly method based on metal-phenolic network and Schiff base reaction using 3,4,5-trihydroxybenzaldehyde (THBA), ε-poly-ʟ-lysine (EPL), and Cu2+ as matrix components. In vitro antibacterial test demonstrates that THBA-Cu-TOB NPs exhibit efficient instantaneous sterilization owing to the rapid pH responsiveness to bacterial infections. Notably, only 2.6 µg mL-1 TOP is needed to eradicate P. aeruginosa biofilm in the nano-formed THBA-Cu-TOB owing to the greatly enhanced penetration, which is only 1.6% the concentration of free TOB (160 µg mL-1). In animal experiments, THBA-Cu-TOB NPs show significant advantages in ocular surface retention, corneal permeability, rapid sterilization, and inflammation elimination. Based on molecular biology analysis, the toll-like receptor 4 and nuclear factor kappa B signaling pathways are greatly downregulated as well as the reduction of inflammatory cytokines secretions. Such a simple and modular strategy in constructing nano-drug delivery platform offers a new idea for toxicity reduction, physiological barrier penetration, and intelligent drug delivery.

Polyphenols-based intelligent oral barrier membranes for periodontal bone defect reconstruction

Periodontitis-induced periodontal bone defects significantly impact patients' daily lives. The guided tissue regeneration and guided bone regeneration techniques, which are based on barrier membranes, have brought hope for the regeneration of periodontal bone defects. However, traditional barrier membranes lack antimicrobial properties and cannot effectively regulate the complex oxidative stress microenvironment in periodontal bone defect areas, leading to unsatisfactory outcomes in promoting periodontal bone regeneration. To address these issues, our study selected the collagen barrier membrane as the substrate material and synthesized a novel barrier membrane (PO/4-BPBA/Mino@COL, PBMC) with an intelligent antimicrobial coating through a simple layer-by-layer assembly method, incorporating reactive oxygen species (ROS)-scavenging components, commercial dual-functional linkers and antimicrobial building blocks. Experimental results indicated that PBMC exhibited good degradability, hydrophilicity and ROS-responsiveness, allowing for the slow and controlled release of antimicrobial drugs. The outstanding antibacterial, antioxidant and biocompatibility properties of PBMC contributed to resistance to periodontal pathogen infection and regulation of the oxidative balance, while enhancing the migration and osteogenic differentiation of human periodontal ligament stem cells. Finally, using a rat periodontal bone defect model, the therapeutic effect of PBMC in promoting periodontal bone regeneration under infection conditions was confirmed. In summary, the novel barrier membranes designed in this study have significant potential for clinical application and provide a reference for the design of future periodontal regenerative functional materials.

Application and advances of biomimetic membrane materials in central nervous system disorders

Central nervous system (CNS) diseases encompass spinal cord injuries, brain tumors, neurodegenerative diseases, and ischemic strokes. Recently, there has been a growing global recognition of CNS disorders as a leading cause of disability and death in humans and the second most common cause of death worldwide. The global burdens and treatment challenges posed by CNS disorders are particularly significant in the context of a rapidly expanding global population and aging demographics. The blood-brain barrier (BBB) presents a challenge for effective drug delivery in CNS disorders, as conventional drugs often have limited penetration into the brain. Advances in biomimetic membrane nanomaterials technology have shown promise in enhancing drug delivery for various CNS disorders, leveraging properties such as natural biological surfaces, high biocompatibility and biosafety. This review discusses recent developments in biomimetic membrane materials, summarizes the types and preparation methods of these materials, analyzes their applications in treating CNS injuries, and provides insights into the future prospects and limitations of biomimetic membrane materials.

Functional Polyphenol-Based Nanoparticles Boosted the Neuroprotective Effect of Riluzole for Acute Spinal Cord Injury

Riluzole is commonly used as a neuroprotective agent for treating traumatic spinal cord injury (SCI), which works by blocking the influx of sodium and calcium ions and reducing glutamate activity. However, its clinical application is limited because of its poor solubility, short half-life, potential organ toxicity, and insufficient bioabilities toward upregulated inflammation and oxidative stress levels. To address this issue, epigallocatechin gallate (EGCG), a natural polyphenol, was employed to fabricate nanoparticles (NPs) with riluzole to enhance the neuroprotective effects. The resulting NPs demonstrated good biocompatibility, excellent antioxidative properties, and promising regulation effects from the M1 to M2 macrophages. Furthermore, an in vivo SCI model was successfully established, and NPs could be obviously aggregated at the SCI site. More interestingly, excellent neuroprotective properties of NPs through regulating the levels of oxidative stress, inflammation, and ion channels could be fully demonstrated in vivo by RNA sequencing and sophisticated biochemistry evaluations. Together, the work provided new opportunities toward the design and fabrication of robust and multifunctional NPs for oxidative stress and inflammation-related diseases via biological integration of natural polyphenols and small-molecule drugs.

Polyphenolic Platform Ameliorated Sanshool for Skin Photoprotection

Natural evolution has nurtured a series of active molecules that play vital roles in physiological systems, but their further applications have been severely limited by rapid deactivation, short cycle time, and potential toxicity after isolation. For instance, the instability of structures and properties has greatly descended when sanshool is derived from Zanthoxylum xanthoxylum. Herein, natural polyphenols are employed to boost the key properties of sanshool by fabricating a series of nanoparticles (NPs). The intracellular evaluation and in vivo animal model are conducted to demonstrate the decreased photodamage score and skin-fold thickness of prepared NPs, which can be attributed to the better biocompatibility, improved free radical scavenging, down-regulated apoptosis ratios, and reduced DNA double-strand breaks compared to naked sanshool. This work proposes a novel strategy to boost the key properties of naturally occurring active molecules with the assistance of natural polyphenol-based platforms.

Modified ZIF-8 Nanoparticles for Targeted Metabolic Treatment of Acute Spinal Cord Injury

The activation of proinflammatory M1-type macrophages in the injured lesion accelerates the progression of a spinal cord injury (SCI). However, adverse side effects during systemic treatments targeting M1 macrophages have limited their applications. Nanoplatforms are novel carriers of traditional Chinese medicine because of their great efficiency to deliver and accumulation in the lesion. Herein, we synthesized a modified zeolitic imidazolate framework-8 (ZIF-8) nanoplatform for internalization and accumulation in the injured spinal cord and effective administration for SCI. In vitro and in vivo experiments suggested that Prussian blue and Schisandrin B modified ZIF-8 effectively accumulated in M1 macrophages, inhibited reactive oxygen species (ROS), and polarized the macrophage from proinflammatory M1 to anti-inflammatory M2 for rapid tissue infiltration by reprogramming the metabolic macrophages phenotype. This nanoplatform achieves a synergistic therapeutic effect of immunomodulation and neuroprotection, thereby shedding new light on the application of ZIF-8, and provides great potential for SCI.

In Situ Reaction-Generated Aldehyde-Scavenging Polypeptides-Curcumin Conjugate Nanoassemblies for Combined Treatment of Spinal Cord Injury

The microenvironment after traumatic spinal cord injury (SCI) involves complex pathological processes, including elevated oxidative stress, accumulated reactive aldehydes from lipid peroxidation, excessive immune cell infiltration, etc. Unfortunately, most of current neuroprotection therapies cannot cope with the intricate pathophysiology of SCI, leading to scant treatment efficacies. Here, we developed a facile in situ reaction-induced self-assembly method to prepare aldehyde-scavenging polypeptides (PAH)-curcumin conjugate nanoassemblies (named as PFCN) for combined neuroprotection in SCI. The prepared PFCN could release PAH and curcumin in response to oxidative and acidic SCI microenvironment. Subsequently, PFCN exhibited an effectively neuroprotective effect through scavenging toxic aldehydes as well as reactive nitrogen and oxygen species in neurons, modulating microglial M1/M2 polarization, and down-regulating the expression of inflammation-related cytokines to inhibit neuroinflammation. The intravenous administration of PFCN could significantly ameliorate the malignant microenvironment of injured spinal cord, protect the neurons, and promote the motor function recovery in the contusive SCI rat model.

Multifunctional Carbon Quantum Dots: Iron Clearance and Antioxidation for Neuroprotection in Intracerebral Hemorrhage Mice

Iron overload and oxidative stress are pivotal in the pathogenesis of brain injury secondary to intracerebral hemorrhage (ICH). There is a compelling need for agents that can chelate iron and scavenge free radicals, particularly those that demonstrate substantial brain penetration, to mitigate ICH-related damage. In this study, we have engineered an amine-functionalized aspirin-derived carbon quantum dot (NACQD) with a nominal diameter of 6-13 nm. The NACQD possesses robust iron-binding and antioxidative capacities. Through intrathecal administration, NACQD therapy substantially reduced iron deposition and oxidative stress in brain tissue, alleviated meningeal inflammatory responses, and improved the recovery of neurological function in a murine ICH model. As a proof of concept, the intrathecal injection of NACQD is a promising therapeutic strategy to ameliorate the ICH injury.