Gold nanoclusters conjugated berberine reduce inflammation and alleviate neuronal apoptosis by mediating M2 polarization for spinal cord injury repair

Advances in the Treatment of Spinal Cord Injury with Nanozymes

Spinal cord injury (SCI) with increasing incidence can lead to severe disability. The pathological process involves complex mechanisms such as oxidative stress, inflammation, and neuron apoptosis. Current treatment strategies focusing on the relief of oxidative stress and inflammation have achieved good effects, while many problems and challenges remain such as the side effect and short half-life of the therapeutic agents. Nanozymes exhibiting good biocatalytic activities can sustainably scavenge free radicals, inhibit neuroinflammation, and protect the neurons. With high stability in physiological conditions and cost-effectiveness, the nanozymes provide a new strategy for SCI treatment. In this Review, we outline the advances of nanozymes and their enzyme-mimicking activities and highlight the progress in the intervention of SCI-adopting nanozymes. We also propose future directions and clinical translation for the nanozyme strategy against SCI.

Biomaterials for neuroengineering: applications and challenges

Neurological injuries and diseases are a leading cause of disability worldwide, underscoring the urgent need for effective therapies. Neural regaining and enhancement therapies are seen as the most promising strategies for restoring neural function, offering hope for individuals affected by these conditions. Despite their promise, the path from animal research to clinical application is fraught with challenges. Neuroengineering, particularly through the use of biomaterials, has emerged as a key field that is paving the way for innovative solutions to these challenges. It seeks to understand and treat neurological disorders, unravel the nature of consciousness, and explore the mechanisms of memory and the brain's relationship with behavior, offering solutions for neural tissue engineering, neural interfaces and targeted drug delivery systems. These biomaterials, including both natural and synthetic types, are designed to replicate the cellular environment of the brain, thereby facilitating neural repair. This review aims to provide a comprehensive overview for biomaterials in neuroengineering, highlighting their application in neural functional regaining and enhancement across both basic research and clinical practice. It covers recent developments in biomaterial-based products, including 2D to 3D bioprinted scaffolds for cell and organoid culture, brain-on-a-chip systems, biomimetic electrodes and brain-computer interfaces. It also explores artificial synapses and neural networks, discussing their applications in modeling neural microenvironments for repair and regeneration, neural modulation and manipulation and the integration of traditional Chinese medicine. This review serves as a comprehensive guide to the role of biomaterials in advancing neuroengineering solutions, providing insights into the ongoing efforts to bridge the gap between innovation and clinical application.

Periodic Table of Immunomodulatory Elements and Derived Two-Dimensional Biomaterials

Periodic table of chemical elements serves as the foundation of material chemistry, impacting human health in many different ways. It contributes to the creation, growth, and manipulation of functional metallic, ceramic, metalloid, polymeric, and carbon-based materials on and near an atomic scale. Recent nanotechnology advancements have revolutionized the field of biomedical engineering to tackle longstanding clinical challenges. The use of nano-biomaterials has gained traction in medicine, specifically in the areas of nano-immunoengineering to treat inflammatory and infectious diseases. Two-dimensional (2D) nanomaterials have been found to possess high bioactive surface area and compatibility with human and mammalian cells at controlled doses. Furthermore, these biomaterials have intrinsic immunomodulatory properties, which is crucial for their application in immuno-nanomedicine. While significant progress has been made in understanding their bioactivity and biocompatibility, the exact immunomodulatory responses and mechanisms of these materials are still being explored. Current work outlines an innovative "immunomodulatory periodic table of elements" beyond the periodic table of life, medicine, and microbial genomics and comprehensively reviews the role of each element in designing immunoengineered 2D biomaterials in a group-wise manner. It recapitulates the most recent advances in immunomodulatory nanomaterials, paving the way for the development of new mono, hybrid, composite, and hetero-structured biomaterials.

Regulation of dynamic spatiotemporal inflammation by nanomaterials in spinal cord injury

Spinal cord injury (SCI) is a common clinical condition of the central nervous system that can lead to sensory and motor impairment below the injury level or permanent loss of function in severe cases. Dynamic spatiotemporal neuroinflammation is vital to neurological recovery, which is collectively constituted by the dynamic changes in a series of inflammatory cells, including microglia, neutrophils, and astrocytes, among others. Immunomodulatory nanomaterials can readily improve the therapeutic effects and simultaneously overcome various drawbacks associated with treatment, such as the off-target side effects and loss of bioactivity of immune agents during circulation. In this review, we discuss the role of dynamic spatiotemporal inflammation in secondary injuries after SCI, elaborate on the mechanism of action and effect of existing nanomaterials in treating SCI, and summarize the mechanism(s) whereby they regulate inflammation. Finally, the challenges and prospects associated with using nanotechnology to modulate immunotherapy are discussed to provide new insights for future treatment. Deciphering the intricate spatiotemporal mechanisms of neuroinflammation in SCI requires further in-depth studies. Therefore, SCI continues to represent a formidable challenge.

Nanotechnology Approaches for Prevention and Treatment of Chemotherapy-Induced Neurotoxicity, Neuropathy, and Cardiomyopathy in Breast and Ovarian Cancer Survivors

Nanotechnology has emerged as a promising approach for the targeted delivery of therapeutic agents while improving their efficacy and safety. As a result, nanomaterial development for the selective targeting of cancers, with the possibility of treating off-target, detrimental sequelae caused by chemotherapy, is an important area of research. Breast and ovarian cancer are among the most common cancer types in women, and chemotherapy is an essential treatment modality for these diseases. However, chemotherapy-induced neurotoxicity, neuropathy, and cardiomyopathy are common side effects that can affect breast and ovarian cancer survivors quality of life. Therefore, there is an urgent need to develop effective prevention and treatment strategies for these adverse effects. Nanoparticles (NPs) have extreme potential for enhancing therapeutic efficacy but require continued research to elucidate beneficial interventions for women cancer survivors. In short, nanotechnology-based approaches have emerged as promising strategies for preventing and treating chemotherapy-induced neurotoxicity, neuropathy, and cardiomyopathy. NP-based drug delivery systems and therapeutics have shown potential for reducing the side effects of chemotherapeutics while improving drug efficacy. In this article, the latest nanotechnology approaches and their potential for the prevention and treatment of chemotherapy-induced neurotoxicity, neuropathy, and cardiomyopathy in breast and ovarian cancer survivors are discussed.

Research Progress on Treating Spinal Cord Injury by Modulating the Phenotype of Microglia

Spinal cord injury (SCI) is a severe central nervous system disorder with no currently available effective treatment. Microglia are immune cells in the central nervous system that play crucial roles in the SCI occurrence, development, and recovery stages. They exhibit dynamic polarization over time and can switch between classical activation (M1) and alternative activation (M2) phenotypes to respond to environmental stimuli. The M1 phenotype is involved in initiating and sustaining inflammatory responses, while the M2 phenotype exerts anti-inflammatory effects and promotes tissue repair in damaged areas. Inhibiting M1 polarization and promoting M2 polarization have become hotspots in regulating neuroinflammation and treating SCI. This article provides a comprehensive review centered on modulating microglial polarization phenotypes for SCI treatment.

Enhancing mitophagy by ligustilide through BNIP3-LC3 interaction attenuates oxidative stress-induced neuronal apoptosis in spinal cord injury

Mitophagy selectively eliminates damaged or dysfunctional mitochondria, playing a crucial role in maintaining mitochondrial quality control. However, it remains unclear whether mitophagy can be fully activated and how it evolves after SCI. Our RNA-seq analysis of animal samples from sham and 1, 3, 5, and 7 days post-SCI indicated that mitophagy was indeed inhibited during the acute and subacute early stages. In vitro experiments showed that this inhibition was closely related to excessive production of reactive oxygen species (ROS) and the downregulation of BNIP3. Excessive ROS led to the blockage of mitophagy flux, accompanied by further mitochondrial dysfunction and increased neuronal apoptosis. Fortunately, ligustilide (LIG) was found to have the ability to reverse the oxidative stress-induced downregulation of BNIP3 and enhance mitophagy through BNIP3-LC3 interaction, alleviating mitochondrial dysfunction and ultimately reducing neuronal apoptosis. Further animal experiments demonstrated that LIG alleviated oxidative stress and mitophagy inhibition, rescued neuronal apoptosis, and promoted tissue repair, ultimately leading to improved motor function. In summary, this study elucidated the state of mitophagy inhibition following SCI and its potential mechanisms, and confirmed the effects of LIG-enhanced mitophagy through BNIP3-LC3, providing new therapeutic targets and strategies for repairing SCI.

Gelatin/heparin coated bio-inspired polyurethane composite fibers to construct small-caliber artificial blood vessel grafts

Long-term patency and ability for revascularization remain challenges for small-caliber blood vessel grafts to treat cardiovascular diseases clinically. Here, a gelatin/heparin coated bio-inspired polyurethane composite fibers-based artificial blood vessel with continuous release of NO and biopeptides to regulate vascular tissue repair and maintain long-term patency is fabricated. A biodegradable polyurethane elastomer that can catalyze S-nitrosothiols in the blood to release NO is synthesized (NPU). Then, the NPU core-shell structured nanofiber grafts with requisite mechanical properties and biopeptide release for inflammation manipulation are fabricated by electrospinning and lyophilization. Finally, the surface of tubular NPU nanofiber grafts is coated with heparin/gelatin and crosslinked with glutaraldehyde to obtain small-caliber artificial blood vessels (ABVs) with the ability of vascular revascularization. We demonstrate that artificial blood vessel grafts promote the growth of endothelial cells but inhibit the growth of smooth muscle cells by the continuous release of NO; vascular grafts can regulate inflammatory balance for vascular tissue remodel without excessive collagen deposition through the release of biological peptides. Vascular grafts prevent thrombus and vascular stenosis to obtain long-term patency. Hence, our work paves a new way to develop small-caliber artificial blood vessel grafts that can maintain long-term patency in vivo and remodel vascular tissue successfully.

Nanomaterials as Microglia Modulators in the Treatment of Central Nervous System Disorders

Microglia play a pivotal role in the central nervous system (CNS) homeostasis, acting as housekeepers and defenders of the surrounding environment. These cells can elicit their functions by shifting into two main phenotypes: pro-inflammatory classical phenotype, M1, and anti-inflammatory alternative phenotype, M2. Despite their pivotal role in CNS homeostasis, microglia phenotypes can influence the development and progression of several CNS disorders such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, ischemic stroke, traumatic brain injuries, and even brain cancer. It is thus clear that the possibility of modulating microglia activation has gained attention as a therapeutic tool against many CNS pathologies. Nanomaterials are an unprecedented tool for manipulating microglia responses, in particular, to specifically target microglia and elicit an in situ immunomodulation activity. This review focuses the discussion on two main aspects: analyzing the possibility of using nanomaterials to stimulate a pro-inflammatory response of microglia against brain cancer and introducing nanostructures able to foster an anti-inflammatory response for treating neurodegenerative disorders. The final aim is to stimulate the analysis of the development of new microglia nano-immunomodulators, paving the way for innovative and effective therapeutic approaches for the treatment of CNS disorders.

Advances in electroactive bioscaffolds for repairing spinal cord injury

Spinal cord injury (SCI) is a devastating neurological disorder, leading to loss of motor or somatosensory function, which is the most challenging worldwide medical problem. Re-establishment of intact neural circuits is the basis of spinal cord regeneration. Considering the crucial role of electrical signals in the nervous system, electroactive bioscaffolds have been widely developed for SCI repair. They can produce conductive pathways and a pro-regenerative microenvironment at the lesion site similar to that of the natural spinal cord, leading to neuronal regeneration and axonal growth, and functionally reactivating the damaged neural circuits. In this review, we first demonstrate the pathophysiological characteristics induced by SCI. Then, the crucial role of electrical signals in SCI repair is introduced. Based on a comprehensive analysis of these characteristics, recent advances in the electroactive bioscaffolds for SCI repair are summarized, focusing on both the conductive bioscaffolds and piezoelectric bioscaffolds, used independently or in combination with external electronic stimulation. Finally, thoughts on challenges and opportunities that may shape the future of bioscaffolds in SCI repair are concluded.

Biomaterials-based anti-inflammatory treatment strategies for Alzheimer's disease

The current therapeutic drugs for Alzheimer's disease only improve symptoms, they do not delay disease progression. Therefore, there is an urgent need for new effective drugs. The underlying pathogenic factors of Alzheimer's disease are not clear, but neuroinflammation can link various hypotheses of Alzheimer's disease; hence, targeting neuroinflammation may be a new hope for Alzheimer's disease treatment. Inhibiting inflammation can restore neuronal function, promote neuroregeneration, reduce the pathological burden of Alzheimer's disease, and improve or even reverse symptoms of Alzheimer's disease. This review focuses on the relationship between inflammation and various pathological hypotheses of Alzheimer's disease; reports the mechanisms and characteristics of small-molecule drugs (e.g., nonsteroidal anti-inflammatory drugs, neurosteroids, and plant extracts); macromolecule drugs (e.g., peptides, proteins, and gene therapeutics); and nanocarriers (e.g., lipid-based nanoparticles, polymeric nanoparticles, nanoemulsions, and inorganic nanoparticles) in the treatment of Alzheimer's disease. The review also makes recommendations for the prospective development of anti-inflammatory strategies based on nanocarriers for the treatment of Alzheimer's disease.

Current Advances in Nanotechnology-Mediated Delivery of Herbal and Plant-Derived Medicines

Phytomedicine has been used by humans since ancient times to treat a variety of diseases. However, herbal medicines face significant challenges, including poor water and lipid solubility and instability, which lead to low bioavailability and insufficient therapeutic efficacy. Recently, it has been shown that nanotechnology-based drug delivery systems are appropriate to overcome the above-mentioned limitations. The present review study first discusses herbal medicines and the challenges involved in the formulation of these drugs. The different types of nano-based drug delivery systems used in herbal delivery and their potential to improve therapeutic efficacy are summarized, and common techniques for preparing nanocarriers used in herbal drug delivery are also discussed. Finally, a list of nanophyto medicines that have entered clinical trials since 2010, as well as those that the FDA has approved, is presented.

Electroacupuncture Relieves HuR/KLF9-Mediated Inflammation to Enhance Neurological Repair after Spinal Cord Injury

Electroacupuncture (EA) is widely applied in clinical therapy for spinal cord injury (SCI). However, the associated molecular mechanism has yet to be elucidated. The current study aimed to investigate the underlying mechanism of EA in neurologic repair after SCI. First, we investigated the role of EA in the neurologic repair of the SCI rat model. The expression levels of human antigen R (HuR) and Krüppel-like factor 9 (KLF9) in spinal cord tissues were quantified after treatment. Second, we conducted bioinformatics analysis, RNA pull-down assays, RNA immunoprecipitation, and luciferase reporter gene assay to verify the binding of HuR and KLF9 mRNA for mRNA stability. Last, HuR inhibitor CMLD-2 was used to verify the enhanced effect of EA on neurologic repair after SCI via the HuR/KLF9 axis. Our data provided convincing evidence that EA facilitated the recovery of neuronal function in SCI rats by reducing apoptosis and inflammation of neurons. We found that EA significantly diminished the SCI-mediated upregulation of HuR, and HuR could bind to the 3' untranslated region of KLF9 mRNA to protect its decay. In addition, a series of in vivo experiments confirmed that CMLD-2 administration increased EA-mediated pain thresholds and motor function in SCI rats. Collectively, the present study showed that EA improved pain thresholds and motor function in SCI rats via impairment of HuR-mediated KLF9 mRNA stabilization, thus providing a better understanding of the regulatory mechanisms regarding EA-mediated neurologic repair after SCI.

Berberine-loaded MSC-derived sEVs encapsulated in injectable GelMA hydrogel for spinal cord injury repair

After spinal cord injury (SCI), local inflammatory response and fibrous scar formation severely hinder nerve regeneration. Berberine (Ber) has a powerful regulatory effect on the local microenvironment, but its limited solubility and permeability through the blood-brain barrier severely limit its systemic efficacy. Human umbilical cord mesenchymal stem cells (hUC-MSCs)-derived small extracellular vesicles (sEVs) are natural nanocarriers with high cargo loading capacity, and can cross the blood-brain barrier. Most importantly, sEVs can improve drug solubility and drug utilization. Therefore, they can overcome many defects of Ber application. This experiment aimed to design a Ber-carrying hUC-MSCs-derived sEVs and GelMA hydrogel. Ber was loaded into sEVs (sEVs-Ber) by ultrasonic co-incubation with a drug loading capacity (LC) of 15.07%. The unhindered release of up to 80% of sEVs-Ber from GelMA hydrogel was accomplished for up to 14 days. And they could be directly absorbed by local cells of injury, allowing for direct local delivery of the drug and enhancing its efficacy. The experimental results confirmed injecting GelMA-sEVs-Ber into spinal cord defects could exert anti-inflammatory effects by regulating the expression of inflammatory factors. It also demonstrated the anti-fibrotic effect of Ber in SCI for the first time. The modulatory effects of sEVs and Ber on the local microenvironment significantly promoted nerve regeneration and recovery of motor function in post-SCI rats. These results demonstrated that the GelMA-sEVs-Ber dual carrier system is a promising therapeutic strategy for SCI repair.

Bioactive fibrous scaffolds with programmable release of polypeptides regulate inflammation and extracellular matrix remodeling

Inflammation manipulation and extracellular matrix (ECM) remodeling for healthy tissue regeneration are critical requirements for tissue engineering scaffolds. To this end, the bioactive polycaprolactone (PCL)-based scaffolds are fabricated to release aprotinin and thymosin β4 (Tβ4) in a programmable manner. The core part of the fiber is composed of hyaluronic acid and Tβ4, and the shell is PCL, which is further coated with heparin/gelatin/aprotinin to enhance biocompatibility. The in vitro assay demonstrates that the controlled release of aprotinin prevents initial excessive inflammation. The subsequent release of Tβ4 after 3 days induces the transition of macrophages from M1 into M2 polarization. The manipulation of inflammatory response further controls the expression of transforming growth factor-β and fibroblast activation, which oversee the quantity and quality of ECM remodeling. In addition, the gradual degradation of the scaffold allows cells to proliferate within the platform. In vivo implant evaluation convinces that PCL-based scaffolds possess the high capability to control the inflammatory response and restore the ECM to normal conditions. Hence, our work paves a new way to develop tissue engineering scaffolds for inflammation manipulation and ECM remodeling with peptide-mediated reactions.

Recent advances in nanomaterials for the treatment of spinal cord injury

Spinal cord injuries (SCIs) are devastating. In SCIs, a powerful traumatic force impacting the spinal cord results in the permanent loss of nerve function below the injury level, leaving the patient paralyzed and wheelchair-bound for the remainder of his/her life. Unfortunately, clinical treatment that depends on surgical decompression appears to be unable to handle damaged nerves, and high-dose methylprednisolone-based therapy is also associated with problems, such as infection, gastrointestinal bleeding, femoral head necrosis, obesity, and hyperglycemia. Nanomaterials have opened new avenues for SCI treatment. Among them, performance-based nanomaterials derived from a variety of materials facilitate improvements in the microenvironment of traumatic injury and, in some cases, promote neuron regeneration. Nanoparticulate drug delivery systems enable the optimization of drug effects and drug bioavailability, thus contributing to the development of novel treatments. The improved efficiency and accuracy of gene delivery will also benefit the exploration of SCI mechanisms and the understanding of key genes and signaling pathways. Herein, we reviewed different types of nanomaterials applied to the treatment of SCI and summarized their functions and advantages to provide new perspectives for future clinical therapies.

Locally controlled release of immunosuppressive promotes survival of transplanted adult spinal cord tissue

Transplantation of adult spinal cord tissue (aSCT) is a promising treatment for spinal cord injury (SCI) basing on various types of neural cells and matrix components inside aSCT. However, long-term systemic administration of immunosuppressors (e.g. tacrolimus, TAC) is required for the survival of allogeneic tissue, which often associated with severe side effects such as infection, liver damageand renal failure. In this study, a triglycerol monostearate (TGM)-based TAC delivery system (e.g. TAC@TGM) with high drug loading concentration was developed, which possessed injectable properties as well as sustainable and immune-responsive drug release behaviors. In complete transected SCI model, locally injected TAC@TGM could reduce the infiltration of inflammation cells, enhance the survival of transplanted aSCT (e.g. Tuj-1⁺ and NF⁺ neurons) and promote the recovery of locomotor function. Moreover, controlled release of TAC by TAC@TGM attenuated side effects of TAC on liver and kidneys compared with traditional systemic administration. More importantly, the developed TAC@TGM system provided a facile single dose of long-term immunosuppressive effect not just for aSCT transplantation, but also for other tissue/organ and cell transplantations.

Recent advances in regenerative biomaterials

Nowadays, biomaterials have evolved from the inert supports or functional substitutes to the bioactive materials able to trigger or promote the regenerative potential of tissues. The interdisciplinary progress has broadened the definition of 'biomaterials', and a typical new insight is the concept of tissue induction biomaterials. The term 'regenerative biomaterials' and thus the contents of this article are relevant to yet beyond tissue induction biomaterials. This review summarizes the recent progress of medical materials including metals, ceramics, hydrogels, other polymers and bio-derived materials. As the application aspects are concerned, this article introduces regenerative biomaterials for bone and cartilage regeneration, cardiovascular repair, 3D bioprinting, wound healing and medical cosmetology. Cell-biomaterial interactions are highlighted. Since the global pandemic of coronavirus disease 2019, the review particularly mentions biomaterials for public health emergency. In the last section, perspectives are suggested: (i) creation of new materials is the source of innovation; (ii) modification of existing materials is an effective strategy for performance improvement; (iii) biomaterial degradation and tissue regeneration are required to be harmonious with each other; (iv) host responses can significantly influence the clinical outcomes; (v) the long-term outcomes should be paid more attention to; (vi) the noninvasive approaches for monitoring in vivo dynamic evolution are required to be developed; (vii) public health emergencies call for more research and development of biomaterials; and (viii) clinical translation needs to be pushed forward in a full-chain way. In the future, more new insights are expected to be shed into the brilliant field-regenerative biomaterials.

Gold nanoclusters-loaded hydrogel formed by dimeric hydrogen bonds crosslinking: A novel strategy for multidrug-resistant bacteria-infected wound healing

Restoring skin integrity after wound infection remains a tougher health challenge due to the uncontrolled antibiotic-resistant pathogens caused by antibiotic abuse. Herein, an injectable hydrogel with dual antibacterial and anti-inflammatory activities composed of gold nanoclusters (GNCs) and carbomer (CBM) is developed for wound dressing to overcome multidrug-resistant infection. Firstly, both experimental investigations and molecular dynamics simulation validate the protonation state of 6-mercaptohexanoic acid (MHA) ligands play an important role in its antibacterial action of GNCs. The self-organizing GNCs-CBM composite hydrogel is then spontaneously cross-linked by the dimeric hydrogen bonds (H-bonds) between the MHA ligands and the acrylic acid groups of CBM. Benefitting from the dimeric H-bonds, the hydrogel becomes thickening enough as an ideal wound dressing and the GNCs exist in the hydrogel with a high protonation level that contributes to the enhanced bactericidal function. In all, by combining bactericidal and immunomodulatory actions, the GNCs-CBM hydrogel demonstrated excellent synergy in accelerating wound healing in animal infection models. Hence, the dimeric H-bonds strengthening strategy makes the GNCs-CBM hydrogel hold great potential as a safe and effective dressing for treating infected wounds.