Redox/pH-Responsive Biodegradable Thiol-Hyaluronic Acid/Chitosan Charge-Reversal Nanocarriers for Triggered Drug Release

Hyaluronic acid as a versatile building block for the development of biofunctional hydrogels: In vitro models and preclinical innovations

Hyaluronic acid (HyA) is a non-sulphated linear polysaccharide found abundantly in the extracellular matrix, known for its biocompatibility and versatility in tissue engineering. Chemical modifications of HyA, including methacrylate, acrylate, click chemistry, norbornene, or host-guest chemistry, are necessary for the formation of stable hydrogels with tuneable biophysical characteristics. These modifications enable precise control over stiffness, swelling, degradation, and advanced functionalities such as shear-thinning, self-healing, and injectability. Functionalisation further enhances hydrogel bioactivity, enabling controlled cell adhesion, modulation of cell behaviour, hydrogel degradation, and release profiles, as well as inflammation modulation or bacterial growth inhibition. These are achieved by conjugating proteins, peptides, antibodies, or reactive chemical groups. HyA hydrogels find broad applications both in vitro and in vivo. In vitro, HyA-based hydrogels can support the development of models to understand fundamental processes in health and mechanisms behind disease progression, serving as highly tuneable extracellular matrix mimetics. As therapeutic interventions, injectable or implantable HyA-based hydrogels have been developed to repair a range of tissues, including cartilage, bone, muscle, and skin defects. However, issues remain to be addressed before widespread adoption of HyA-based hydrogels as clinical options. Future innovations for HyA hydrogels include its establishment as an enabling technology for the delivery of novel therapeutics, with a particular focus on immunomodulatory molecules, and the development of more dynamic, tissue-mimetic HyA-based hydrogels.

Stimuli-responsive delivery systems using carbohydrate polymers: A review

Carbohydrate polymers, including Chitosan, Cellulose, Starch, Dextran, Pectin, Alginate, and Hyaluronic Acid, have been considered as stimuli-responsive biopolymers demonstrating significant potential for drug delivery approaches. Relying on the specific design and fabrication, such biopolymers are able to respond to fluctuations in pH, temperature, or enzymatic activity. This review investigates stimuli-responsive biopolymers, known as carbohydrate polymers, mainly chitosan, cellulose, and alginate, utilized as drug delivery approaches, emphasizing that these stimuli-responsive biopolymers accelerate controlled drug release. The pH-responsive delivery systems selectively target acidic tumor microenvironments, while temperature-responsive materials provide precise control for drug release produced by hyperthermia. Light-responsive biopolymers provide spatial and temporal control, providing appropriate for targeted therapy. Redox-responsive structures are especially efficient in responding to elevated glutathione (GSH) in tumor microenvironment, facilitating targeted drug release. Electro- and magnetic-responsive systems provide remote control functionalities, improving the accuracy of drug administration. The incorporation of multi-stimuli-responsive mechanisms implies a remarkable progression in drug delivery, providing a more versatile and adaptable framework for therapeutic applications. Accordingly, the future research on carbohydrate polymer-based stimuli-responsive delivery systems should focus on improving the responsiveness and targeting efficacy through complicated optimization of features and performance of carbohydrate polymers, where the integration of multifunctional moieties facilitates transformation of targeted drugs for broader biological functions.

Effective Strategies in Designing Chitosan-hyaluronic Acid Nanocarriers: From Synthesis to Drug Delivery Towards Chemotherapy

The biomedical field faces an ongoing challenge in developing more effective anti-cancer medication due to the significant burden that cancer poses on human health. Extensive research has been conducted on the utilization of natural polysaccharides in nanomedicine owing to their properties of biocompatibility, biodegradability, non-immunogenicity, and non-toxicity. These characteristics make them a potent drug delivery system for cancer therapy. The chitosan hyaluronic acid nanoparticle (CSHANp) system, consisting of chitosan and hyaluronic acid nanoparticles, has exhibited considerable potential as a nanocarrier for various cancer drugs, rendering it one of the most auspicious systems presently accessible. The CSHANps demonstrate remarkable drug loading capacity, precise control over drug release, and exceptional selectivity towards cancer cells. These properties enhance the therapeutic effectiveness against cancerous cells. This article aims to provide a comprehensive analysis of CSHANp, focusing on its characteristics, production techniques, applications, and future prospects.

Facile Synthesis of Thermoresponsive Alternating Copolymers with Tunable Phase-Transition Temperatures

A series of novel amphiphilic alternating CPEG copolymers were synthesized through an amine-epoxy click reaction comprising aliphatic amine and polyethylene glycol diglycidyl ether (PEGDE). These polymers were characterized in detail via nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) to confirm the successful synthesis. Due to their amphiphilic structure, these polymers display thermoresponsiveness, with tunable cloud points (Tcps) that are adjustable from 20.8 °C to 46.8 °C by altering the side-chain length of the aliphatic amine, varying the mixing ratios of copolymers, the solution's pH, and salt additions. This tunable thermoresponsive behavior positions CPEG copolymers as promising candidates for a range of functional material applications.

A review on exploring the potential of PVA and chitosan in biomedical applications: A focus on tissue engineering, drug delivery and biomedical sensors

Polymers have been integral to the advancement of biomedicine, owing to their exceptional versatility and functionality. Among these, polyvinyl alcohol (PVA) and chitosan both natural polymers stand out for their remarkable biocompatibility, biodegradability, and unique properties. This review article provides a comprehensive examination of the diverse applications of PVA and chitosan in three pivotal areas: tissue engineering, drug delivery, and biosensors. In tissue engineering, the discussion centres on how PVA and chitosan are engineered into scaffolds that not only support cell growth and differentiation but also promote tissue regeneration by closely mimicking the extracellular matrix. These scaffolds offer the necessary mechanical strength and adaptability for various biomedical applications. For drug delivery, the article delves into the development of sophisticated controlled release systems and targeted drug carriers, highlighting the polymers' customizable properties and their mucoadhesive nature, which make them highly effective across multiple drug delivery methods. Furthermore, the potential of PVA and chitosan in biosensor technology is explored, particularly their ability to interact with biomolecules and their intrinsic conductivity attributes that are essential for creating sensitive, reliable, and biocompatible sensors for medical diagnostics. By synthesizing recent research findings and suggesting future research directions, this review underscores the versatility and critical role of PVA and chitosan in pushing the boundaries of biomedical innovation. It offers valuable insights for researchers and scientists dedicated to advancing healthcare through the application of these natural polymers.

Stimuli-responsive chitosan based nanoparticles in cancer therapy and diagnosis: A review

Chitosan, obtained through deacetylation of chitin, has been shown to a promising biopolymer for the development of nano- and micro-particles. In spite of inherent anti-cancer activity of chitosan, the employment of this carbohydrate polymer for the synthesis of nanoparticles opens a new gate in disease therapy. The properties of chitosan including biocompatibility, biodegradability, and modifiability are vital in enhancing these nanoparticles, allowing for improved solubility and interaction with cellular targets. Among the pathological events, cancer has demonstrated an increase in incidence rate and therefore, the chitosan nanoparticles have been significantly utilized in cancer therapy. The present review emphasizes on the role of stimuli-responsive chitosan nanoparticles in the field of cancer therapy. The stimuli-responsive nanoparticles can release the cargo in the tumor site that not only improves the anti-cancer activity of chemotherapy drugs, but also diminishes their systemic toxicity. The stimuli-responsive chitosan nanoparticles can respond to endogenous and exogenous stimuli including pH, redox and light to release cargo. This improves the specificity towards tumor cells and enhances accumulation of drugs and/or drugs. The light-responsive chitosan nanoparticles can cause photothermal and photodynamic therapy in tumor ablation and provide theranostic feature that is cancer diagnosis and therapy simultaneously.

pH-sensitive docetaxel-loaded chitosan/thiolated hyaluronic acid polymeric nanoparticles for colorectal cancer

Aim: This study aimed to develop and evaluate pH-sensitive docetaxel-loaded thiolated hyaluronic acid (HA-SH) nanoparticles (NPs) for targeted treatment of colon cancer. Materials & methods: HA-SH, synthesized via oxidation and subsequent covalent linkage to cysteamine, served as the precursor for developing HA-SH NPs through polyelectrolyte complexation involving chitosan and thiol-bearing HA. Results & conclusion: HA-SH NPs displayed favorable characteristics, with small particle sizes (184-270 nm), positive zeta potential (15.4-18.6 mV) and high entrapment efficiency (91.66-95.02%). In vitro, NPs demonstrated potent mucoadhesion and enhanced cytotoxicity compared with free docetaxel. In vivo assessments confirmed safety and biocompatibility, suggesting HA-SH NPs as promising pH-sensitive drug carriers with enhanced antitumor activity for colorectal cancer treatments.

Stimuli-responsive hydrogel based on natural polymers for breast cancer

Aims: Breast cancer is the most common malignancy among women in both high- and low-resource settings. Conventional breast cancer therapies were inefficient and had low patient compliance. Stimuli-responsive hydrogels possessing similar physicochemical features as soft tissue facilitate diagnostic and therapeutic approaches for breast cancer subtypes. Scope: Polysaccharides and polypeptides are major natural polymers with unique biocompatibility, biodegradability, and feasible modification approaches utilized frequently for hydrogel fabrication. Alternating the natural polymer-based hydrogel properties in response to external stimuli such as pH, temperature, light, ultrasonic, enzyme, glucose, magnetic, redox, and electric have provided great potential for the evolution of novel drug delivery systems (DDSs) and various advanced technologies in medical applications. Stimuli-responsive hydrogels are triggered by specific cancer tissue features, promote target delivery techniques, and modify release therapeutic agents at localized sites. This narrative review presented innovation in preparing and characterizing the most common stimuli-responsive natural polymer-based hydrogels for diagnostic and therapeutic applications in the breast cancer area. Conclusion: Stimuli-responsive hydrogels display bioinspiration products as DDSs for breast cancer subtypes, protect the shape of breast tissue, provide modified drug release, enhance therapeutic efficacy, and minimize chemotherapy agents' side effects. The potential benefits of smart natural polymer-based hydrogels make them an exciting area of practice for breast cancer diagnosis and treatment.

Chitosan-functionalized bioplatforms and hydrogels in breast cancer: immunotherapy, phototherapy and clinical perspectives

Breast cancer is the most common and malignant tumor among women. Chitosan (CS)-based nanoparticles have been introduced into breast cancer therapy as a way to increase the targeted delivery of drugs and genes to the tumor site. CS nanostructures suppress tumorigenesis by enhancing both the targeted delivery of cargo (drug and gene) and its accumulation in tumor cells. The tumor cells internalize CS-based nanoparticles through endocytosis. Moreover, chitosan nanocarriers can also induce phototherapy-mediated tumor ablation. Smart and multifunctional types of CS nanoparticles, including pH-, light- and redox-responsive nanoparticles, can be used to improve the potential for breast cancer removal. In addition, the acceleration of immunotherapy by CS nanoparticles has also been achieved, and there is potential to develop CS-nanoparticle hydrogels that can be used to suppress tumorigenesis.

CD44 tagged hyaluronic acid - chitosan liposome carrier for the delivery of berberine and doxorubicin into lung cancer cells

Liposomes are unique biomolecular, capable of loading both hydrophilic and hydrophobic molecules and delivered into the biological system. Liposomes (L) coated with hyaluronic acid (HA) and chitosan (CS) carrier system was fabricated. Berberine (BER) and doxorubicin (DOX) were encapsulated to enhance drug proliferation and therapeutic effect in lung cancer cells. The FTIR, XRD, SEM, and TEM techniques were carried out for functional group identification, crystallinity, and surface morphology analysis, respectively. In-vitro drug release confirms the sustained release of BER and DOX in various physiological environments. HA-CS@BER&DOX-L has good penetration ability and higher cytotoxicity effect in the A549 cells, and the IC50 value of HA-CS@BER&DOX-L is 89.19 μg/300 μL. The pure liposome showed a negligible cytotoxicity effect, and the HA-CS@BER&DOX-L could efficiently induce the apoptosis of A549 cells. The cellular uptake analysis of the HA-CS@BER&DOX-L effectively targeted and entered the A549 cells and clearly observed C. elegans images. Hence, the proposed system will be a potential treatment methodology to enhance the cytotoxicity of the A549 cancer cells and be useful to future drug administration methodology development.

3D printed scaffolds based on hyaluronic acid bioinks for tissue engineering: a review

Hyaluronic acid (HA) is widely distributed in human connective tissue, and its unique biological and physicochemical properties and ability to facilitate biological structure repair make it a promising candidate for three-dimensional (3D) bioprinting in the field of tissue regeneration and biomedical engineering. Moreover, HA is an ideal raw material for bioinks in tissue engineering because of its histocompatibility, non-immunogenicity, biodegradability, anti-inflammatory properties, anti-angiogenic properties, and modifiability. Tissue engineering is a multidisciplinary field focusing on in vitro reconstructions of mammalian tissues, such as cartilage tissue engineering, neural tissue engineering, skin tissue engineering, and other areas that require further clinical applications. In this review, we first describe the modification methods, cross-linking methods, and bioprinting strategies for HA and its derivatives as bioinks and then critically discuss the strengths, shortcomings, and feasibility of each method. Subsequently, we reviewed the practical clinical applications and outcomes of HA bioink in 3D bioprinting. Finally, we describe the challenges and opportunities in the development of HA bioink to provide further research references and insights.

Preparation of pH-sensitive chitosan-deoxycholic acid-sodium alginate nanoparticles loaded with ginsenoside Rb1 and its controlled release mechanism

Ginsenoside is a natural extract of the genus ginseng, which has tumor preventive and inhibiting effects. In this study, ginsenoside loaded nanoparticles were prepared by an ionic cross-linking method with sodium alginate to enable a sustained slow release effect of ginsenoside Rb₁ in the intestinal fluid through an intelligent response. Chitosan grafted hydrophobic group deoxycholic acid was used to synthesize CS-DA, providing loading space for hydrophobic Rb₁. Scanning electron microscopy (SEM) showed that the nanoparticles was spherical with smooth surfaces. The encapsulation rate of Rb₁ enhanced with the increase of sodium alginate concentration and could reach to 76.62 ± 1.78 % when concentration was 3.6 mg/mL. It was found that the release process of CDA-NPs was most consistent with the primary kinetic model which is a diffusion-controlled release mechanism. CDA-NPs exhibited good pH sensitivity and controlled release properties in buffer solutions of different pH's at 1.2 and 6.8. The cumulative release of Rb₁from CDA-NPs in simulated gastric fluid was <20 % within 2 h, while could release completely around 24 h in the simulated gastrointestinal fluid release system. It was demonstrated that CDA_3.6-NPs can effectively control release and intelligently deliver ginsenoside Rb₁, which is a promising alternative way for oral delivery.

Granular Disulfide-Crosslinked Hyaluronic Hydrogels: A Systematic Study of Reaction Conditions on Thiol Substitution and Injectability Parameters

Granular polymer hydrogels based on dynamic covalent bonds are attracting a great deal of interest for the design of injectable biomaterials. Such materials generally exhibit shear-thinning behavior and properties of self-healing/recovery after the extrusion that can be modulated through the interactions between gel microparticles. Herein, bulk macro-hydrogels based on thiolated-hyaluronic acid were produced by disulphide bond formation using oxygen as oxidant at physiological conditions and gelation kinetics were monitored. Three different thiol substitution degrees (SD%: 65%, 30% and 10%) were selected for hydrogel formation and fully characterized as to their stability in physiological medium and morphology. Then, extrusion fragmentation technique was applied to obtain hyaluronic acid microgels with dynamic disulphide bonds that were subsequently sterilized by autoclaving. The resulting granular hyaluronic hydrogels were able to form stable filaments when extruded through a syringe. Rheological characterization and cytotoxicity tests allowed to assess the potential of these materials as injectable biomaterials. The application of extrusion fragmentation for the formation of granular hyaluronic hydrogels and the understanding of the relation between the autoclaving processes and the resulting particle size and rheological properties should expand the development of injectable materials for biomedical applications.

Colloidal Polyelectrolyte Complexes from Hyaluronic Acid: Preparation and Biomedical Applications

Hyaluronic acid (HA) is a naturally occurring polysaccharide which has been extensively exploited in biomedical fields owing to its outstanding biocompatibility. Self-assembly of HA and polycations through electrostatic interactions can generate colloidal polyelectrolyte complexes (PECs), which can offer a wide range of applications while being relatively simple to prepare with rapid and "green" processes. The advantages of colloidal HA-based PECs stem from the combined benefits of nanomedicine, green chemistry, and the inherent properties of HA, namely high biocompatibility, biodegradability, and biological targeting capability. Accordingly, colloidal PECs from HA have received increasing attention in the recent years as high-performance materials for biomedical applications. Considering their potential, this review is aimed to provide a comprehensive understanding of colloidal PECs from HA in complex with polycations, from the most fundamental aspects of the preparation process to their various biomedical applications, notably as nanocarriers for delivering small molecule drugs, nucleic acids, peptides, proteins, and bioimaging agents or the construction of multifunctional platforms.

Chitin, Chitosan, and Nanochitin: Extraction, Synthesis, and Applications

Crustacean shells are a sustainable source of chitin. Extracting chitin from crustacean shells is ongoing research, much of which is devoted to devising a sustainable process that yields high-quality chitin with minimal waste. Chemical and biological methods have been used extensively for this purpose; more recently, methods based on ionic liquids and deep eutectic solvents have been explored. Extracted chitin can be converted into chitosan or nanochitin. Once chitin is obtained and modified into the desired form, it can be used in a wide array of applications, including as a filler material, in adsorbents, and as a component in biomaterials, among others. Describing the extraction of chitin, synthesis of chitosan and nanochitin, and applications of these materials is the aim of this review. The first section of this review summarizes and compares common chitin extraction methods, highlighting the benefits and shortcomings of each, followed by descriptions of methods to convert chitin into chitosan and nanochitin. The second section of this review discusses some of the wide range of applications of chitin and its derivatives.

Chitosan-Hyaluronic Acid Nanoparticles for Active Targeting in Cancer Therapy

Cancer is the most common cause of death worldwide; therefore, there is a need to discover novel treatment modalities to combat it. One of the cancer treatments is nanoparticle technology. Currently, nanoparticles have been modified to have desirable pharmacological effects by using chemical ligands that bind with their specific receptors on the surface of malignant cells. Chemical grafting of chitosan nanoparticles with hyaluronic acid as a targeted ligand can become an attractive alternative for active targeting. Hence, these nanoparticles can control drug release with pH- responsive stimuli, and high selectivity of hyaluronic acid to CD44 receptors makes these nanoparticles accumulate more inside cells that overexpress these receptors (cancer cells). In this context, we discuss the benefits and recent findings of developing and utilizing chitosan–hyaluronic acid nanoparticles against distinct forms of cancer malignancy. From here we know that chitosan–hyaluronic acid nanoparticles (CHA-Np) can produce a nanoparticle system with good characteristics, effectiveness, and a good active targeting on various types of cancer cells. Therefore, this system is a good candidate for targeted drug delivery for cancer therapy, anticipating that CHA-Np could be further developed for various cancer therapy applications.

Hyaluronic Acid within Self-Assembling Nanoparticles: Endless Possibilities for Targeted Cancer Therapy

Self-assembling nanoparticles (SANPs) based on hyaluronic acid (HA) represent unique tools in cancer therapy because they combine the HA targeting activity towards cancer cells with the advantageous features of the self-assembling nanosystems, i.e., chemical versatility and ease of preparation and scalability. This review describes the key outcomes arising from the combination of HA and SANPs, focusing on nanomaterials where HA and/or HA-derivatives are inserted within the self-assembling nanostructure. We elucidate the different HA derivatization strategies proposed for this scope, as well as the preparation methods used for the fabrication of the delivery device. After showing the biological results in the employed in vivo and in vitro models, we discussed the pros and cons of each nanosystem, opening a discussion on which approach represents the most promising strategy for further investigation and effective therapeutic protocol development.

Nanoparticles as Physically- and Biochemically-Tuned Drug Formulations for Cancers Therapy

Simple Summary

Conventional antitumor drugs have limitations, including poor water solubility and lack of targeting capability, with consequent non-specific distribution, systemic toxicity, and low therapeutic index. Nanotechnology promises to overcome these drawbacks by exploiting the physical properties of diverse nanocarriers that can be linked to moieties with binding selectivity for cancer cells. The use of nanoparticles as therapeutic formulations allows a targeted delivery and a slow, controlled release of the drug(s), making them tunable modules for applications in precision medicine. In addition, nanoparticles are also being developed as cancer vaccines, offering an opportunity to increase both cellular and humoral immunity, thus providing a new weapon to beat cancer.

Abstract

Malignant tumors originate from a combination of genetic alterations, which induce activation of oncogenes and inactivation of oncosuppressor genes, ultimately resulting in uncontrolled growth and neoplastic transformation. Chemotherapy prevents the abnormal proliferation of cancer cells, but it also affects the entire cellular network in the human body with heavy side effects. For this reason, the ultimate aim of cancer therapy remains to selectively kill cancer cells while sparing their normal counterparts. Nanoparticle formulations have the potential to achieve this aim by providing optimized drug delivery to a pathological site with minimal accumulation in healthy tissues. In this review, we will first describe the characteristics of recently developed nanoparticles and how their physical properties and targeting functionalization are exploited depending on their therapeutic payload, route of delivery, and tumor type. Second, we will analyze how nanoparticles can overcome multidrug resistance based on their ability to combine different therapies and targeting moieties within a single formulation. Finally, we will discuss how the implementation of these strategies has led to the generation of nanoparticle-based cancer vaccines as cutting-edge instruments for cancer immunotherapy.

Single and Multiple Stimuli-Responsive Polymer Particles for Controlled Drug Delivery

Polymers that can change their properties in response to an external or internal stimulus have become an interesting platform for drug delivery systems. Polymeric nanoparticles can be used to decrease the toxicity of drugs, improve the circulation of hydrophobic drugs, and increase a drug’s efficacy. Furthermore, polymers that are sensitive to specific stimuli can be used to achieve controlled release of drugs into specific areas of the body. This review discusses the different stimuli that can be used for controlled drug delivery based on internal and external stimuli. Internal stimuli have been defined as events that evoke changes in different characteristics, inside the body, such as changes in pH, redox potential, and temperature. External stimuli have been defined as the use of an external source such as light and ultrasound to implement such changes. Special attention has been paid to the particular chemical structures that need to be incorporated into polymers to achieve the desired stimuli response. A current trend in this field is the incorporation of several stimuli in a single polymer to achieve higher specificity. Therefore, to access the most recent advances in stimuli-responsive polymers, the focus of this review is to combine several stimuli. The combination of different stimuli is discussed along with the chemical structures that can produce it.