Advances in Stimuli-Responsive Chitosan Hydrogels for Drug Delivery Systems

Injectable nanocomposite hydrogels for targeted intervention in cancer, wound healing, and bone and myocardial tissue engineering

Despite current medicine's fast-paced advances, many acute and chronic illnesses still lack truly effective and safe therapies. Cancer treatments often lead to off-target healthy tissue damage and poor therapeutic outcomes, wound standard treatments generally demonstrate poor healing efficacy and increased susceptibility to infection, and bone tissue engineering and myocardial tissue engineering can result in immunological rejection and limited availability. To tackle these issues, injectable hydrogels have emerged, and through the incorporation of nanoparticles, nanocomposite hydrogels have appeared as versatile platforms, offering improved biocompatibility, mechanical strength, stability, and precise controlled drug release, as well as targeted delivery with increased drug retention at the site of action, reducing systemic drug distribution to non-target sites. With the ability to deliver a diverse range of therapeutic entities, including low molecular weight drugs, proteins, antibodies, and even isolated cells, injectable nanocomposite hydrogels have revolutionized current therapies, working as multifunctional platforms capable of improving efficacy and safety in cancer treatment, including in chemotherapy, immunotherapy, photothermal therapy, magnetic hyperthermia, photodynamic therapy, chemodynamic therapy, radiotherapy, molecularly targeted therapy, and after tumor surgical removal, and in general, chronic diabetic or tumor-induced wound healing, as well as in bone tissue engineering and myocardial tissue engineering. This review provides a thorough summary and critical insight of current advances on injectable nanocomposite hydrogels as an innovative approach that could bring substantial contributions to biomedical research and clinical practice, with a focus on their applications in cancer therapy, wound healing management, and tissue engineering.

Advanced functionalized chitosan nanocomposites for hyperthermia-based cancer therapy

Chitosan-based nanocomposites have emerged as promising platforms in hyperthermia-mediated cancer therapy due to their unique physicochemical properties, biocompatibility, and functional versatility. This review highlights recent advances in the design and application of chitosan-functionalized nanoparticles (NPs), focusing on their role in enhancing targeted hyperthermic treatment. The integration of chitosan with various nanomaterials-including magnetic nanoparticles, carbon-based structures such as graphene and carbon nanotubes, and gold nanoparticles-offers distinct advantages in thermal conversion efficiency, tumor specificity, and drug delivery potential. Magnetic nanoparticles allow precise thermal ablation of cancer cells under an external magnetic field, while carbon-based materials provide superior thermal conductivity for efficient heat generation. Gold nanoparticles, when conjugated with chitosan, improve biocompatibility and enable surface modification for targeted therapy. Despite promising preclinical outcomes, challenges remain in terms of toxicity, long-term stability, regulatory approval, and scalable synthesis. This review critically examines these aspects and outlines future directions for optimizing chitosan-based nanocomposites toward clinical translation and commercial viability in cancer hyperthermia therapy.

Unidirectional and sustainable release of NGF and BDNF from a chitosan gel-mediated multilayer ordered composite membrane in promoting both spinal cord and sciatic nerve injury repair

To develop a scaffold suitable for simultaneous repair of both spinal cord injury (SCI) and sciatic nerve injury (SNI), we designed a multilayer composite membrane capable of unidirectional and sustained release of two factors: nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). The membrane's morphology, mechanical properties, cytocompatibility, drug release kinetics, swelling, and degradation behavior were thoroughly characterized. Additionally, its ability to promote the differentiation of PC-12 cells was assessed. The findings indicated that the composite membrane featured a tri-layered structure and exhibited robust mechanical strength, enabling it to protect and regulate the release of NGF and BDNF. This regulation ensured the appropriate timing and concentration of the factors necessary for cell differentiation and growth. Moreover, the membrane demonstrated excellent cell compatibility and significantly fostered the differentiation of PC-12 cells into axons. In rat models of SCI and SNI, the composite membrane markedly enhanced axon and neuron regeneration, myelination, neural stem cell proliferation, and nerve fiber clustering, while reducing astrocyte formation. It also improved the integrity of spinal cord tissue and motor function recovery, suggesting that this scaffold holds promise for the repair of both SCI and SNI.

Nanomedicine in cardiology: Precision drug delivery for enhanced patient outcomes

Cardiovascular diseases as a primary driver of global morbidity and mortality. Despite the array of therapeutic avenues in clinical practice, predominantly pharmaceutical and surgical interventions, they often fall short of fully addressing the clinical exigencies of cardiovascular patients. In recent years, nanocarriers have shown great potential in the treatment and diagnose of cardiovascular diseases. They can enhance drug targeting and bioavailability while reducing side effects. Additionally, by improving imaging and detection technologies, they enhance early diagnosis and disease monitoring capabilities. These advancements in technology offer new solutions for precision medicine in cardiovascular diseases, advancing treatment efficacy and disease management. Crafted from biomaterials, metals, or their amalgamations, these nanocarriers approximate the dimensions of biologically active molecules like proteins and DNA. Cardiovascular nanomedicine, in its infancy, has only recently burgeoned. Yet, with continual refinement in nanocarrier architecture, drug delivery mechanisms, and therapeutic outcomes, the potential of nanomedical technologies in clinical contexts becomes increasingly evident. This review aims to consolidate the strides made in nanocarrier research concerning the treatment and diagnose of cardiovascular diseases.

Recent advances in chitosan-based smart hydrogel for drug delivery systems

Achieving sustainable and controllable drug delivery is a highly effective disease treatment approach. Chitosan hydrogels, with their unique three-dimensional (3D) porous structures, offer tunable capacity, controllable degradation, various stimuli sensitivities, and the ability to encapsulate therapeutic agents. These characteristics provide chitosan hydrogels with inherent advantages as vehicles for drug delivery systems. In recent years, there has been a notable shift toward embracing the "back-to-nature" ethos, with biomass materials emerging as promising candidates for constructing chitosan hydrogels used in controlled drug release applications. This trend is sustained by their biodegradability, biocompatibility, and non-toxic properties, emphasizing their unique benefits and innovative features. These hydrogels exhibit sensitivity to various factors such as temperature, pH, ion concentration, light, magnetic fields, redox, ultrasound, and multi-responsiveness, offering opportunities for finely tuned drug release mechanisms. This review comprehensively outlines fabrication methods, properties, and biocompatibility of chitosan hydrogel, as well as modification strategies and stimuli-responsive mechanisms. Furthermore, their potential applications in subcutaneous (wound dressing), parental (transdermal drug delivery), oral (gastrointestinal tract), and facial (ophthalmic and brain) drug delivery are briefly discussed. The challenges in clinical application and the future outlook of chitosan-based smart hydrogel are also highlighted.

Recent advances on chitosan/hyaluronic acid-based stimuli-responsive hydrogels and composites for cancer treatment: A comprehensive review

Cancer, as leading cause of death, has a high rate of mortality worldwide. Although there is a wide variety of conventional approaches for the treatment of cancer (such as surgery and chemotherapy), they have considerable drawbacks in terms of practicality, treatment efficiency, and cost-effectiveness. Therefore, there is a fundamental requirement for the development of safe and efficient treatment modalities based on breakthrough technologies to suppress cancer. Chitosan (CS) and hyaluronic acid (HA) polysaccharides, as FDA-approved biomaterials for some biomedical applications, are potential biopolymers for the efficient treatment of cancer. CS and HA have high biocompatibility, bioavailability, biodegradability, and immunomodulatory function which guarantee their safety and non-toxicity. CS-/HA-based hydrogels (HGs)/composites stand out for their potential anticancer function, versatile preparation and modification, ease of administration, controlled/sustained drug release, and active and passive drug internalization into target cells which is crucial for efficient treatment of cancer compared with conventional treatment approaches. These HGs/composites can respond to external (magnetic, ultrasound, light, and thermal) and internal (pH, enzyme, redox, and ROS) stimuli as well which further paves the way to their manipulation, targeted drug delivery, practicality, and efficient treatment. The above-mentioned properties of CS-/HA-based HGs/composites are unique and practical in cancer treatment which can ignore the deficiencies of conventional approaches. The present manuscript comprehensively highlights the advances in the practical application of stimuli-responsive HGs/composites based on CS/HA polysaccharides.

Antioxidative, Anti-Inflammatory, Antibacterial, Photo-Cross-Linkable Hydrogel of Gallic Acid-Chitosan Methacrylate: Synthesis, In Vitro, and In Vivo Assessments

Chitosan (CS)-based photo-cross-linkable hydrogels have gained increasing attention in biomedical applications. In this study, we grafted CS with gallic acid (GA) by carbodiimide chemistry to prepare the GA-CS conjugate, which was subsequently modified with methacrylic anhydride (MA) modification to obtain the methacrylated GA-CS conjugate (GA-CS-MA). Our results demonstrated that the GA-CS-MA hydrogel not only exhibited improved physicochemical properties but also showed antibacterial, antioxidative, and anti-inflammatory capacity. It showed moderate antibacterial activity and especially showed a more powerful inhibitory effect against Gram-positive bacteria. It modulated macrophage polarization, downregulated pro-inflammatory gene expression, upregulated anti-inflammatory gene expression, and significantly reduced reactive oxygen species (ROS) and nitric oxide (NO) production under lipopolysaccharide (LPS) stimulation. Subcutaneously implanted GA-CS-MA hydrogels induced significantly lower inflammatory responses, as evidenced by less inflammatory cell infiltration, thinner fibrous capsule, and predominately promoted M2 polarization. This study provides a feasible strategy to prepare CS-based photo-cross-linkable hydrogels with improved physicochemical properties for biomedical applications.