The synthesis of bacterial cellulose-chitosan zwitterionic hydrogels with pH responsiveness for drug release mechanism of the naproxen

Bacterial cellulose in transdermal drug delivery systems: Expanding horizons in multi-scale therapeutics and patient-centric approach

This review explores the transformative potential of Bacterial cellulose (BC) in an increasingly vital avenue of transdermal drug delivery systems (TDDS) for multi-scale therapeutic applications with patient-centric approach. In this review, we have not only highlighted the role of BC as the main matrix material for TDDS but emphasized the other possible role that BC can play in TDDS. For this purpose, we have delved into the avenues of the physico-chemical interactions that BC can offer in governing the incorporation of different length-scales of therapeutics as well as tuning their extent of loading. Furthermore, this review underscores BC's potential in developing need-specific drug release profiles and stimuli-responsive release platforms, enabling their application in TDDS for wound healing, pain management, and targeted delivery for chronic diseases. Apart from the existing literature, this review focuses on patient comfort, which is an often-overlooked aspect, and highlights how BC's unique physicochemical properties enhance user experience. Additionally, this review justifies the potential of BC in compliance with the other parameters of the TDDS, including shelf-life, design requirements, and evaluation strategies in ensuring their clinical translation and user acceptance. To harness BC's potential in the new era of personalized TDDS, this review also sheds light on the challenges of standardizing BC production processes with appropriate data disclosure, ensuring adhesion and anti-microbial actions, along with the integration of passive and active technologies.

pH responsive and zwitterionic micelle for enhanced cellular uptake and antitumor performance

The side effects of small molecule chemotherapeutic drugs (SMCD) have brought great pain to the cancer patients. Many nanodrug carriers can relieve the shortcomings of SMCD, but they have complex synthesis processes and lack biodegradability. To overcome both problems, we synthesized a pH responsive biodegradable zwitterionic molecules (EK-D) by linking zwitterionic polypeptide (EK7) and dodecyl acrylate through a simple click reaction. Subsequently, doxorubicin (DOX) was physically encapsulated within the EK-D micelles to produce EK-D-DOX micelles, and polyethylene glycol monooleate (POO) employed as a comparative group for the preparation of POO-DOX micelles. The results show that EK-D-DOX micelles have good aqueous stability and anti-protein non-specific adsorption performance at pH 7.4, but EK-D-DOX micelles aggregate under the condition of pH = 5.5 due to the biodegradability of EK-D. The tumor cell uptake rate of EK-D-DOX micelles is higher than that of POO-DOX micelles and free DOX, which makes EK-D-DOX micelles the highest cytotoxic. Additionally, EK-D-DOX micelles release more DOX in a slightly acidic environment than at pH 7.4, and the release of DOX reaches a significant cumulative value of 75.20 % under pH conditions of 5.5. More importantly, EK-D-DOX micelles exhibit superior in vivo tumor inhibitory efficacy compared to free DOX, resulting in a remarkable tumor inhibition rate of 95.7 %. EK-D-DOX micelles not only have lower biological toxicity to normal tissues than free DOX, but also have a longer blood circulation time in mice. The method of EK-D-DOX micelles preparation represents a new method to prepare biodegradable zwitterionic nanodrug.

A Review of Chitosan-Based Materials for Biomedical, Food, and Water Treatment Applications

Chitosan, a natural biopolymer with excellent biocompatibility, biodegradability, and modifiable structure, has broad applications in regenerative medicine, tissue engineering, food packaging, and environmental technology. Its abundance, solubility in acidic solutions, and capacity for chemical modification make it highly adaptable for creating specialized derivatives with enhanced properties. Recent advances have demonstrated chitosan's efficacy in composite systems for tissue regeneration, drug delivery, and antimicrobial applications. This review examines chitosan's unique properties, with a focus on its antibacterial activity as influenced by factors like pH, concentration, molecular weight, and deacetylation degree. Additionally, chitosan's potential as a sustainable, non-toxic material for eco-friendly packaging and water treatment is explored, highlighting the growing interest in chitosan composites with other polymers and metallic nanoparticles for enhanced biomedical and environmental applications.

Smart Mesoporous Silica Nanoparticles Loading Curcumin Inhibit Liver Cancer

Curcumin (CUR) as one of the natural edible pigments is approved by the World Health Organization due to its nontoxic and anticancer effect. However, the utility of CUR is restricted due to its low oral bioavailability. Nanoparticle drug delivery systems like mesoporous silica nanoparticles (MSNs) have been extensively used due to their high specific surface area, high loading rate, and ease of modification. This study developed lactobionic acid (LA)-modified carboxymethyl chitosan (CMCS)-coated MSNs to deliver CUR specifically targeting hepatocellular carcinoma. Among these nanoparticles, LA targets liver cancer cells. CMCS utilizes pH-responsive release of CUR. The LA-CMCS-MSN@CUR (MSN@CUR) were evaluated using several methods, including Fourier transform infrared spectroscopy, transmission electron microscopy, and zeta potential measurements. Liver cellular uptake of MSN@CUR depends on a specific LA receptor-mediated endocytosis mechanism. Additionally, MSN@CUR performed with a better antitumor effect than Cur in H22 orthotopic transplantation of liver cancer and H22 solid tumor mouse models. Treatment with MSN@CUR significantly reduced the protein of VEGF, p-PI3K, and AKT, increased the protein of caspases 3 and 8, ultimately inhibited tumor migration, and promoted apoptosis. This study provides a new path for delivery of natural active ingredients with excellent bioavailability in the antitumor field.

Preparation of ternary hybridized chitosan microspheres with photothermal effect for pH-sensitive long-lasting controlled release system and its release mechanism

To enhance the effective utilization of drugs and diminish the number of medications for patients, it is vital to investigate controlled long-acting drug release systems and their release mechanisms. In this study, chitosan microspheres were synthesized by cross-linking pH-sensitive Schiff bases, and Zif-8, a pH-sensitive component, was encapsulated within them. Furthermore, MXene was incorporated as a third component to augment the strength and photothermal synergistic characteristics of the microspheres. By adjusting the ratio of each component, the optimal ternary heterogeneous functional pH-controllable long-lasting drug release system was obtained. The optimal coating and the most effective adsorption-release effect were achieved. The release mechanism was examined under varying pH and temperature conditions. The release process was found to be divided into three stages. The initial phase was predominantly governed by the Fick diffusion mechanism, whereas the subsequent phases were primarily regulated by the pH-induced co-decomposition of CS and Zif-8, and the individual decomposition of CS, respectively. The drug was observed to be released in a linear manner during the latter two stages of the experiment. This was evidenced by the persistent release of ciprofloxacin hydrochloride in response to pH changes, and further supported by the results of tests on its antimicrobial properties. The drug release persisted for over three days at pH 5.4 and could be utilized repeatedly, exhibiting promising applications in drug delivery. Moreover, the drug's photothermal properties offer the possibility of developing synergistic therapeutic programs.

Self-healing and injectable chitosan/konjac glucomannan hydrogel with pH response for controlled protein release

Dynamic hydrogels with the features of injection, self-healing, and remodeling at the target site have been developed as smart multifunctional biomaterials for drug delivery. However, most self-healing injectable hydrogels are difficult to control protein release after implantation, owing to the deficiency of pH responsiveness, which reduces the bioavailability of proteins. Herein, we propose a facile strategy to endow pH responsiveness into a dynamic hydrogel with both self-healing and injectable capabilities, by crosslinking biomacromolecular backbones via dual pH sensitive dynamic covalent bond. Particularly, oxidized konjac glucomannan (OKGM) can be crosslinked with poly (aspartic hydrazide) (PAHy) and N-carboxyethyl chitosan (CEC) to form dynamic acylhydrazone bonds and imide bonds, respectively, endowing the hydrogel with pH responsiveness and dynamic behaviors. Specifically, PAHy facilitates the formation of acylhydrazone bonds, improving the mechanical properties and pH sensitivity while reducing the degradation behavior of the hydrogels under physiological conditions. Kinetics indicate that the release of bovine serum albumin follows Fick diffusion under different pH conditions. The pH responsive hydrogel with self-healing injectable capabilities has the potential to be used as a controllable and sustain release carrier for protein drugs.

Injectable Chitosan Hydrogels Doped with 2D Peptide Nanosheet-Drug Conjugates for Glutathione-Responsive Sustained Drug Delivery

The development of novel and effective drug delivery systems aimed at enhancing therapeutic profile and efficacy of therapeutic agents is a critical challenge in modern medicine. This study presents an intelligent drug delivery system based on self-assembled two-dimensional peptide nanosheets (2D PNSs). Leveraging the tunable properties of amino acid structures and sequences, we design a peptide with the sequence of Fmoc-FKKGSHC, which self-assembles into 2D PNSs with uniform structure, high biocompatibility, and excellent degradability. Covalent attachment of thiol-modified doxorubicin (DOX) drugs to 2D PNSs via disulfide bond results in the peptide-drug conjugates (PDCs), which is denoted as PNS-SS-DOX. Subsequently, the PDCs are encapsulated within the injectable, thermosensitive chitosan (CS) hydrogels for drug delivery. The designed drug delivery system demonstrates outstanding pH-responsiveness and sustained drug release capabilities, which are facilitated by the characteristics of the CS hydrogels. Meanwhile, the covalently linked disulfide bond within the PNS-SS-DOX is responsive to intracellular glutathione (GSH) within tumor cells, enabling controlled drug release and significantly inhibiting the cancer cell growth. This responsive peptide-drug conjugate based on a 2D peptide nanoplatform paves the way for the development of smart drug delivery systems and has bright prospects in the future biomedicine field.

ECM-inspired calcium/zinc laden cellulose scaffold for enhanced bone regeneration

Cellulose-based polymer scaffolds are highly diverse for designing and fabricating artificial bone substitutes. However, realizing the multi-biological functions of cellulose-based scaffolds has long been challenging. In this work, inspired by the structure and function of the extracellular matrix (ECM) of bone, we developed a novel yet feasible strategy to prepare ECM-like scaffolds with hybrid calcium/zinc mineralization. The 3D porous structure was formed via selective oxidation and freeze drying of bacterial cellulose. Following the principle of electrostatic interaction, calcium/zinc hybrid hydroxyapatite nucleated, crystallized, and precipitated on the 3D scaffold in simulated physiological conditions, which was well confirmed by morphology and composition analysis. Compared with alternative scaffold cohorts, this hybrid ion-loaded cellulose scaffold exhibited a pronounced elevation in alkaline phosphatase (ALP) activity, osteogenic gene expression, and cranial defect regeneration. Notably, the hybrid ion-loaded cellulose scaffold effectively fostered an M2 macrophage milieu and had a strong immune effect in vivo. In summary, this study developed a hybrid multifunctional cellulose-based scaffold that appropriately simulates the ECM to regulate immunomodulatory and osteogenic differentiation, setting a measure for artificial bone substitutes.

Biomedical Trends in Stimuli-Responsive Hydrogels with Emphasis on Chitosan-Based Formulations

Biomedicine is constantly evolving to ensure a significant and positive impact on healthcare, which has resulted in innovative and distinct requisites such as hydrogels. Chitosan-based formulations stand out for their versatile utilization in drug encapsulation, transport, and controlled release, which is complemented by their biocompatibility, biodegradability, and non-immunogenic nature. Stimuli-responsive hydrogels, also known as smart hydrogels, have strictly regulated release patterns since they respond and adapt based on various external stimuli. Moreover, they can imitate the intrinsic tissues' mechanical, biological, and physicochemical properties. These characteristics allow stimuli-responsive hydrogels to provide cutting-edge, effective, and safe treatment. Constant progress in the field necessitates an up-to-date summary of current trends and breakthroughs in the biomedical application of stimuli-responsive chitosan-based hydrogels, which was the aim of this review. General data about hydrogels sensitive to ions, pH, redox potential, light, electric field, temperature, and magnetic field are recapitulated. Additionally, formulations responsive to multiple stimuli are mentioned. Focusing on chitosan-based smart hydrogels, their multifaceted utilization was thoroughly described. The vast application spectrum encompasses neurological disorders, tumors, wound healing, and dermal infections. Available data on smart chitosan hydrogels strongly support the idea that current approaches and developing novel solutions are worth improving. The present paper constitutes a valuable resource for researchers and practitioners in the currently evolving field.

A review of recent advances of cellulose-based intelligent-responsive hydrogels as vehicles for controllable drug delivery system

To realize the maximum therapeutic activity of medicine and protect the body from the adverse effects of active ingredients, drug delivery systems (DDS) featured with targeted transportation sites and controllable release have captured extensive attention over the past decades. Hydrogels with unique three-dimensional (3D) porous structures present tunable capacity, controllable degradation, various stimuli sensitivity, therapeutic agents encapsulation, and loaded drugs protection properties, which endow hydrogels with bred-in-the-bone advantages as vehicles for drug delivery. In recent years, with the impressive consciousness of the "back-to-nature" concept, biomass materials are becoming the 'rising star' as the hydrogels building blocks for controlled drug release carriers due to their biodegradability, biocompatibility, and non-toxicity properties. In particular, cellulose and its derivatives are promising candidates for fabricating hydrogels as their rich sources and high availability, and various smart cellulose-based hydrogels as targeted carriers under exogenous such as light, electric field, and magnetic field or endogenous such as pH, temperature, ionic strength, and redox gradients. In this review, we summarized the main synthetic strategies of smart cellulose-based hydrogels including physical and chemical cross-linking, and illustrated the detailed intelligent-responsive mechanism of hydrogels in DDS under external stimulus. Additionally, the ongoing development and challenges of cellulose-based hydrogels in the biomedical field are also presented.

Bifunctional lignocellulose nanofiber hydrogel possessing intriguing pH-responsiveness and self-healing capability towards wound healing applications

Lignocellulose nanofibers (LCNF) obtained from agricultural waste are potential candidates for enhancing composite materials because of their excellent mechanical properties, abundant groups and high biocompatibility. However, the application of LCNF has received limited attention to date from researchers in the healthcare field. Herein, based on the bifunctional group (carboxyl and aldehyde groups) modified LCNF (DCLCNF) and chitosan (CS), we developed a multifunctional bio-based hydrogel (CS-DCLCNF). The addition of lignin-containing DCLCNF strengthened the internal crosslinking and the intermolecular interaction of hydrogels, and the presence of lignin and carboxyl groups increased the mechanical strength of the hydrogel and the adsorption of aromatic drugs. Results revealed that the hydrogels exhibited self-healing, injectable, and high swelling rates. The hydrogels had favorable mechanical strength (G'max of ~16.60 kPa), and the maximum compressive stress was 24 kPa. Moreover, the entire tetracycline hydrochloride (TH) release process was slow and pH-responsive, because of the rich noncovalent and π-π interactions between DCLCNF and TH. The hydrogels also exhibited excellent biocompatibility and antibacterial properties. Notably, the wound healing experiment showed that the hydrogels were beneficial in accelerating wounds healing, which could heal completely in 13 days. Therefore, CS-DCLCNF hydrogels may have promising applications in drug delivery for wound healing.

Promising cellulose-based functional gels for advanced biomedical applications: A review

Novel biomedical materials provide a new horizon for the diagnosis/treatment of diseases and tissue repair in medical engineering. As the most abundant biomass polymer on earth, cellulose is characterized by natural biocompatibility, good mechanical properties, and structure-performance designability. Owing to these outstanding features, cellulose as a biomacromolecule can be designed as functional biomaterials via hydrogen bonding (H-bonding) interaction or chemical modification for human tissue repair, implantable tissue organs, and controlling drug release. Moreover, cellulose can also be used to construct medical sensors for monitoring human physiological signals. In this study, the structural characteristics, functionalization approaches, and advanced biomedical applications of cellulose are reviewed. The current status and application prospects of cellulose and its functional materials for wound dressings, drug delivery, tissue engineering, and electronic skin (e-skin) are discussed. Finally, the key technologies and methods used for designing cellulosic biomaterials and broadening their application prospects in biomedical fields are highlighted.

Constructing a novel humidity sensor using acrylic acid/bagasse cellulose porous hydrogel combining graphene oxide and citral for antibacterial and intelligent fruit preservation

A novel hydrogel humidity sensor was developed using acrylic acid/bagasse cellulose (AA/BC) porous hydrogel triggered by cold plasma (CP) combining graphene oxide (GO) and embedding citral for antibacterial and intelligent fruit preservation. Results showed that both GO and citral were loaded in AA/BC and had strong hydrogen bond interaction with hydrogel. Acrylic acid/bagasse cellulose/graphene oxide (AA/BC/GO) showed the highest humidity response when the compound concentration of GO was 1.0 mg/mL and the test frequency was 1 kHz, and exhibited high electrical conductivity (-2.6 mS/cm). In addition, in continuous and cyclic relative humidity (RH) tests, the response time of AA/BC/GO from 33.70 % RH to 75.30 % RH was about 177.4 s and the recovery time was about 150.6 s, with excellent sensitivity and durability. The sensors also revealed remarkable antibacterial properties against Escherichia coli and Staphylococcus aureus, among which acrylic acid/bagasse cellulose/graphene oxide-citral (AA/BC/GO-C) was the most prominent, and could extend the shelf life of mangoes for about 8 days. By intuitively judging the appearances and total color difference (TCD) of the hydrogel sensors, it could play the role of intelligent preservation by connecting their water absorption and the release of citral. Therefore, this work provided innovative strategies for the application of hydrogel sensors in food preservation.

Bacterial cellulose microfiber reinforced hollow chitosan beads decorated with cross-linked melamine plates for the removal of the Congo red

In this epoch, the disposal of multipollutant wastewater inevitably compromises life on Earth. In this study, the inclusion of Bacterial cellulose microfilaments reinforced chitosan adorned with melamine 2D plates creates a unique 3D bead structure for anionic dye removal. The establishment of an imine network between melamine and chitosan, along with the quantity of inter- and intra‑hydrogen bonds, boosts the specific surface area to 106.68 m2.g-1. Removal efficiency and in-depth comprehension of synthesized adsorbent characteristics were assessed using batch adsorption experiments and characterization methods. Additionally, pH, adsorbent quantity, time, beginning concentration of solution, and temperature were analyzed and optimized as adsorption essential factors. Owing to the profusion of hydroxyl, amine, imine functional groups and aromatic rings, the synthesized adsorbent intimated an astonishing maximum adsorption capacity of 3168 mg.g-1 in Congo red dye removal at pH 5.5. Based on the kinetic evaluation, pseudo-second-order (R2 = 0.999), pseudo-first-order (R2 = 0.964), and Avrami (R2 = 0.986) models were well-fitted with the kinetic results among the seven investigated models. The isothermal study reveals that the adsorption mechanism predominantly follows the Redlich-Peterson (R2 = 0.996), Koble-Carrigan, and Hill isotherm models (R2 = 0.994). The developed semi-natural sorbent suggests high adsorption capacity, which results from its exceptional structure, presenting promising implications for wastewater treatment.

Stimulus-Responsive Hydrogels as Drug Delivery Systems for Inflammation Targeted Therapy

Deregulated inflammations induced by various factors are one of the most common diseases in people's daily life, while severe inflammation can even lead to death. Thus, the efficient treatment of inflammation has always been the hot topic in the research of medicine. In the past decades, as a potential biomaterial, stimuli-responsive hydrogels have been a focus of attention for the inflammation treatment due to their excellent biocompatibility and design flexibility. Recently, thanks to the rapid development of nanotechnology and material science, more and more efforts have been made to develop safer, more personal and more effective hydrogels for the therapy of some frequent but tough inflammations such as sepsis, rheumatoid arthritis, osteoarthritis, periodontitis, and ulcerative colitis. Herein, from recent studies and articles, the conventional and emerging hydrogels in the delivery of anti-inflammatory drugs and the therapy for various inflammations are summarized. And their prospects of clinical translation and future development are also discussed in further detail.

Bacterial cellulose/gum Arabic composite production by in-situ modification from lavender residue hydrolysate

In this study, bacterial cellulose/gum Arabic composite (BC/GA) was synthesized by in-situ modification from lavender residue hydrolysate for the first time. The in-situ modification with GA adding showed great beneficial effect for BC/GA synthesis. Both the product (BC or BC/GA) yield and the product (BC or BC/GA) production per sugars consumption increased greatly by the in-situ modification when compared with the fermentation without GA adding (2.90 g/L vs. 0.91 g/L, and 0.461 g/g vs. 0.138 g/g). It is hypothesized that the combination of BC and GA is the main mechanism for the beneficial effect of the in-situ modification, and the scanning electron microscope (SEM) images confirmed this hypothesis. GA adding showed little effect on the rheological properties of lavender residue hydrolysate, and this environment was suitable for the combination of BC and GA. The in-situ modification had an obvious influence on the crystallinity index and the thermal stability of BC/GA, but affected little on its functional groups and cellulose structural framework. Besides BC/GA synthesis and structure, the in-situ modification could also alter the texture properties of BC/GA. Overall, this study can offer some useful information for the biochemical conversion from green and cost-effective lavender residue hydrolysate to attractive biomaterial BC/GA.

Advances in drug delivery applications of modified bacterial cellulose-based materials

Bacterial cellulose (BC) is generated by certain species of bacteria and comprises polysaccharides with unique physical, chemical, and mechanical characteristics. Due to its outstanding biocompatibility, high purity, excellent mechanical strength, high water absorption, and highly porous structure, bacterial cellulose has been recently investigated for biomedical application. However, the pure form of bacterial cellulose is hardly used as a biomedical material due to some of its inherent shortcomings. To extend its applications in drug delivery, modifications of native bacterial cellulose are widely used to improve its properties. Usually, bacterial cellulose modifications can be carried out by physical, chemical, and biological methods. In this review, a brief introduction to bacterial cellulose and its production and fabrication is first given, followed by up-to-date and in-depth discussions of modification. Finally, we focus on the potential applications of bacterial cellulose as a drug delivery system.

Recent advances in cellulose, pectin, carrageenan and alginate-based oral drug delivery systems

Polymers-based drug delivery systems constitute one of the highly explored thrust areas in the field of the medicinal and pharmaceutical industries. In the past years, the properties of polymers have been modified in context to their solubility, release kinetics, targeted action site, absorption, and therapeutic efficacy. Despite the availability of diverse synthetic polymers for the bioavailability enhancement of drugs, the use of natural polymers is still highly recommended due to their easy availability, accessibility, and non-toxicity. The aim of the review is to provide the available literature of the last five years on oral drug delivery systems based on four natural polymers i.e., cellulose, pectin, carrageenan, and alginate in a concise and tabulated manner. In this review, most of the information is in tabulated form to provide easy accessibility to the reader. The data related to active pharmaceutical ingredients and supported components in different formulations of the mentioned polymers have been made available.

Novel Double Cross-Linked Acrylic Acid/Bagasse Cellulose Porous Hydrogel for Controlled Release of Citral and Bacteriostatic Effects

In this study, double cross-linked acrylic acid/bagasse cellulose (AA/BC) porous hydrogels were first prepared using cold plasma (CP) technology instead of chemical initiators. The structure and properties of porous hydrogels, as well as the controlled release and bacteriostatic application as functional carriers, were investigated. Results showed that a novel double cross-linked hydrogel had been successfully synthesized by utilizing ^•OH and H⁺ produced during plasma discharge. The acrylic acid (AA) monomers were successfully grafted onto the main chains of bagasse cellulose (BC), forming a porous three-dimensional network structure. The AA/BC porous hydrogels showed excellent swelling levels and intelligent responses. The release of citral in hydrogel inclusion compounds embedded with citral was controlled by adjusting the pH, and the slow release period was about 2 days. The inclusion compounds presented strong bacteriostatic effects against Escherichia coli and Staphylococcus aureus, extending the shelf life of fruits for about 4 days. Therefore, it can be concluded that CP technology is considered to be an efficient and environmental-friendly initiation technology for preparing hydrogels. The potential application of hydrogel inclusion compounds in the food field is expanded.

pH-sensitive gallol-rich chitosan hydrogel beads for on-off controlled drug delivery

Malignant tumors have emerged as a serious health issue, and the interest in developing pH-sensitive polymers for site-specific drug delivery has increased. The physical and/or chemical properties of pH-sensitive polymers depend on the pH, and thus, drugs can be released by cleaving dynamic covalent and/or noncovalent bonds. In this study, gallic acid (GA) was conjugated to chitosan (CS) to prepare self-crosslinked hydrogel beads containing Schiff base (imine bond) crosslinks. The CS-GA hydrogel beads were formed by the dropwise addition of the CS-GA conjugate solution into a Tris-HCl buffer solution (TBS, pH 8.5). The pH-sensitivity of pristine CS was significantly enhanced following the introduction of GA moiety, and as a result, the CS-GA hydrogel beads swelled more than approximately 5000 % at pH 4.0, indicating an excellent swelling/deswelling ability of the beads at different pH (pH 4.0 and 8.5). The reversible breakage/recovery of the imine crosslinks in the CS-GA hydrogel beads was confirmed through X-ray photoelectron spectroscopic and rheological studies. Finally, Rhodamine B was loaded onto the hydrogel beads as a model drug to investigate the pH-sensitive drug release behavior. At pH 4, the drug was released up to approximately 83 % within 12 h. The findings indicate that the CS-GA hydrogel beads have great potential as a drug delivery system that is sensitive to acidic tumor sites in the body.

Recent Development of Functional Chitosan-Based Hydrogels for Pharmaceutical and Biomedical Applications

Chitosan is a promising naturally derived polysaccharide to be used in hydrogel forms for pharmaceutical and biomedical applications. The multifunctional chitosan-based hydrogels have attractive properties such as the ability to encapsulate, carry, and release the drug, biocompatibility, biodegradability, and non-immunogenicity. In this review, the advanced functions of the chitosan-based hydrogels are summarized, with emphasis on fabrications and resultant properties reported in literature from the recent decade. The recent progress in the applications of drug delivery, tissue engineering, disease treatments, and biosensors are reviewed. Current challenges and future development direction of the chitosan-based hydrogels for pharmaceutical and biomedical applications are prospected.

Smart stimuli-responsive chitosan hydrogel for drug delivery: A review

Smart stimuli-responsive materials can respond to different signals (pH, temperature, light, electricity, etc.), and they have become a hot research topic for drug delivery. As a polysaccharide polymer with excellent biocompatibility, chitosan can be obtained from diverse natural sources. Chitosan hydrogels with different stimuli-response capabilities are widely applied in the drug delivery field. This review highlights and discusses the research progress on chitosan hydrogels concerning their stimuli-responsive capabilities. The feature of various stimuli-responsive kinds of hydrogels is outlined, and their potential use of drug delivery is summarized. Furthermore, the questions and future development chances of stimuli-responsive chitosan hydrogels are analyzed by comparing the current published literature, and the directions for the intelligent development of chitosan hydrogels are discussed.

Hypoglycemic Activity of Self-Assembled Gellan Gum-Soybean Isolate Composite Hydrogel-Embedded Active Substance-Saponin

In order to avoid hemolysis caused by direct dietary of kidney tea saponin, complex gels based on gellan gum (GG) and soybean isolate protein (SPI) loaded with saponin were created in the present study by using a self-assembly technique. Studies were conducted on the rheological characteristics, encapsulation effectiveness, molecular structure, microstructure, and hypoglycemic activity of GG/SPI-saponin gels. Increasing the concentration of SPI helped to enhance the strength and energy storage modulus (G') of the gels, and the incorporation of high acylated saponin allowed the whole gel to undergo sol-gel interconversion. The encapsulation efficiency showed that GG/SPI-saponin was 84.52 ± 0.78% for saponin. Microstructural analysis results suggested that GG and SPI were bound by hydrogen bonds. The in vitro digestion results also indicated that saponin could be well retained in the stomach and subsequently released slowly in the intestine. In addition, the in vitro hypoglycemic activity results showed that the IC₅₀ of encapsulated saponin against α-glucosidase and α-amylase were at 2.4790 mg/mL and 1.4317 mg/mL, respectively, and may be used to replace acarbose for hypoglycemia.