Dextran hydrogels via disulfide-containing Schiff base formation: Synthesis, stimuli-sensitive degradation and release behaviors

Recent advances in smart hydrogels derived from polysaccharides and their applications for wound dressing and healing

Owing to their inherent biocompatibility and biodegradability, hydrogels derived from polysaccharides have emerged as promising candidates for wound management. However, the complex nature of wound healing often requires the development of smart hydrogels---intelligent materials capable of responding dynamically to specific physical or chemical stimuli. Over the past decade, an increasing number of stimuli-responsive polysaccharide-based hydrogels have been developed to treat various types of wounds. While a range of hydrogel types and their versatile functions for wound management have been discussed in the literature, there is still a need for a review of the crosslinking strategies used to create smart hydrogels from polysaccharides. This review provides a comprehensive overview of how stimuli-responsive hydrogels can be designed and made using five key polysaccharides: chitosan, hyaluronic acid, alginate, dextran, and cellulose. Various methods, such as chemical crosslinking, dynamic crosslinking, and physical crosslinking, which are used to form networks within these hydrogels, ultimately determine their ability to respond to stimuli, have been explored. This article further looks at different polysaccharide-based hydrogel wound dressings that can respond to factors such as reactive oxygen species, temperature, pH, glucose, light, and ultrasound in the wound environment and discusses how these responses can enhance wound healing. Finally, this review provides insights into how stimuli-responsive polysaccharide-based hydrogels can be developed further as advanced wound dressings in the future.

Polymer Applied in Hydrogel Wound Dressing for Wound Healing: Modification/Functionalization Method and Design Strategies

Hydrogel wound dressings have emerged as a promising solution for wound healing due to their excellent mechanical and biochemical properties. Over recent years, there has been significant progress in expanding the variety of raw materials used for hydrogel formulation along with the development of advanced modification techniques and design approaches that enhance their performance. However, a comprehensive review encompassing diverse polymer modification strategies and design innovations for hydrogel dressings is still lacking in the literature. This review summarizes the use of natural polymers (e.g., chitosan, gelatin, sodium alginate, hyaluronic acid, and dextran) and synthetic polymers (e.g., poly(vinyl alcohol), polyethylene glycol, Pluronic F-127, poly(N-isopropylacrylamide), polyacrylamide, and polypeptides) in hydrogel wound dressings. We further explore the advantages and limitations of these polymers and discuss various modification strategies, including cationic modification, oxidative modification, double-bond modification, catechol modification, etc. The review also addresses design principles and synthesis methods, aligning polymer modifications with specific requirements in wound healing. Finally, we discuss future challenges and opportunities in the development of advanced hydrogel-based wound dressings.

ROS responsive conductive microspheres loaded with salvianolic acid B as adipose derived stem cell carriers for acute myocardial infarction treatment

Stem cell therapy is currently the most promising strategy for the treatment of myocardial infarction. However, the development of injectable cell carriers that can scavenge reactive oxygen species (ROS) in the infarct zone to improve transplanted cell survival remains a challenge. Here, we developed a ROS responsive conductive microsphere based on chitosan (CS) and dextran (DEX) with 4-formylphenylboronic acid (4-FPBA) as a cross-linking agent and the addition of graphite oxide (GO) and the anti-inflammatory agent salvianolic acid B (SalB), as a cell delivery carrier for myocardial infarction. These microspheres were crosslinked by dual dynamic networks of Schiff base and phenylborate bonds. The relationship between CS concentration and microsphere particle size, as well as the biocompatibility, ROS responsiveness, anti-inflammatory properties, and effects on myogenic differentiation of H9C2 cells were fully investigated. The microspheres exhibit good biocompatibility, proliferation promoting, differentiation promoting, antioxidant, and anti-inflammatory properties. When applied to mice myocardial infarction models, the ROS responsive conductive microspheres loaded with SalB and adipose derived stem cells (ADSC) exhibited excellent in vivo repair ability. In addition, they reduced myocardial fibrosis and promoted ventricular wall regeneration by promoting the expression of Connexin 43 (Cx43) and CD31, ultimately reshaping the infarcted myocardium, suggesting their great potential as cell delivery carriers for myocardial infarction treatment.

The preparation of 3D-printed self-healing hydrogels composed of carboxymethyl chitosan and oxidized dextran via stereolithography for biomedical applications

This study presents a new approach for fabricating 3D-printed self-healing hydrogels via light-assisted 3D printing, utilizing Schiff-base and covalent bonding formations resulting from the reaction between amine and aldehyde functional groups alongside the photopolymerization of methacrylate groups. Two distinct polymers, carboxymethyl chitosan (CMCs) and dextran, were first modified to yield methacrylate-modified carboxymethyl chitosan (CMCs-MA) and oxidized dextran (OD). The structural modifications of these polymers were confirmed using spectroscopic techniques, including 1H NMR and FTIR analyses. Variations in polymer concentration and degree of oxidation resulted in significant differences in the physical properties of resulting hydrogels (e.g., mechanical performance, swelling ratio, and microstructure) and biological responses. The compressive moduli revealed in the range of 14.31 ± 1.38 to 26.20 ± 3.31 kPa. Chondrocytes cultured with various hydrogel formulations exhibited distinct cell morphology and adhesion differences, driven by the interaction between the mechanical and biochemical properties of the hydrogel. We have developed a strategy for fabricating 3D-printed self-healing hydrogels with tunable stiffness, enabling the regulation of chondrocyte morphology and demonstrating significant potential for biomedical applications.

Construction of GOx-loaded metal organic frameworks antibacterial composite hydrogels for skin wound healing

Bacterial infections and inflammation severely impede wound healing. Here, we developed a zwitterionic hydrogel incorporating MOF/GOx for pH-responsive, controlled drug release. The multifunctional hydrogel embedded with MOF/GOx was successfully prepared through the Schiff base reaction between the copolymer poly[(2-methacryloyloxyethyl phosphorylcholine)-co-(4-formylphenyl methacrylate)] (PMF) and the branched polyethylenimine (PEI) modified by the zwitterionic monomer ((4-hydroxyphenyl)sulfonyl)(4-(trimethylammonio)butanoyl)amide (AB), which possessed excellent injectable and self-healing ability, a highly sensitive and reversible responsiveness to pH changes, and good biocompatibility. Moreover, the MOF/GOx-PP composite hydrogel under exposure to a slightly acidic environment would rupture, and the slowly released MOF/GOx triggered a cascade-catalyzed reaction that could inhibit and kill Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and, simultaneously, mouse experiments indicated that the wound healing rate showed 93 % wound closure in 7 days compared to 67 % with controls. The multifunctional antibacterial hydrogel has immense potential as a dressing in the treatment of infected wounds.

Smart release injectable hydrogel co-loaded with liposomal combretastatin A4 and doxorubicin nanogel for local combinational drug delivery: A preclinical study

Surgical resection and postoperative adjuvant chemotherapy have enhanced the outlook for breast cancer patients. However, tumor relapse and serious side effects of chemotherapy continue to impact patients' quality of life. Designing injectable composite hydrogel made of biodegradable polymers providing sustained release of antiangiogenic and chemotherapeutic agents might play a vital role in elimination of cancer cells. In this regard, we developed dextran based composite hydrogel incorporating doxorubicin-loaded dual-sensitive pH-redox nanogels (DOX-DSNG) and combretastatin A4 (CA4) loaded liposomes which undergo rapid disassembly in cancer cells. CA4 prevents tubulin polymerization and thus inhibits angiogenesis by binding to vascular endothelial tubulin. The results showed that DOX-DSNGs were negatively charged and 144.8 ± 0.85 nm in size. Besides, the size of CA4 loaded liposomes were 102.35 ± 4.22 nm and were negatively charged. Encapsulation efficiency of DOX-DSNGs and CA4 loaded liposomes were 100 % and 89 %, respectively. After loading into the hydrogel structure, doxorubicin and CA4 were gradually released from the composite hydrogel for up to 21 days. DOX-DSNGs and CA4 loaded liposomes showed a dose-dependent cytotoxic effect against 4 T1 breast cancer cells. Thereafter, the anti-neoplastic effect and survival study of the composite hydrogel was evaluated in vivo in tumor-bearing mice. The composite hydrogel significantly reduced tumor volume (from 116 mm3 to 38 mm3) with negligible organ damage, while showed lower cardiotoxicity in 28 days. In conclusion, our results revealed that injectable composite dextran-based hydrogel incorporated with DOX-DSNG and CA4 loaded liposomes could be used as an efficient delivery platform for combination therapies in treatment of solid tumors.

Pullulan fermented by Aureobasidium melanogenum TZ-FC3 for the preparation of self-healing, adhesive, injectable and antibacterial pullulan/PVA/borax hydrogel

Natural polymer hydrogels, such as pullulan-based hydrogels, offer significant advantages over synthetic materials due to their thermal stability, film-forming capacity, solubility, adhesiveness, and antioxidant properties. In this study, the strain Aureobasidium melanogenum TZ-FC3, which produces a high level of pullulan, was successfully isolated from the mangrove ecosystems of Guangdong Province, China. 66.01 ± 1.10 g/L pullulan without melanin was produced by the TZ-FC3 strain within 120 h at flask level. Pullulan fermented by A. melanogenum TZ-FC3 was added to enhance the hydrogen bond network within the pullulan/PVA/borax hydrogels (P-2, P-3 and P-4 hydrogels) to improve mechanical strength and crosslinking density of PVA/borax hydrogel (P-1 hydrogel). Compared to the P-1 hydrogel, the P-2 hydrogel exhibited a 65.4 % increase in tensile strain, a remarkable 694.03 % increase in tensile strength and improved the degree of internal crosslinking. Additionally, the pullulan/PVA/borax hydrogels demonstrated excellent self-healing properties, adhesion, injectability, and antibacterial activity. The preparation process of pullulan/PVA/borax hydrogels is straightforward and effective, suggesting broad industrial applicability and underscoring their potential as next-generation materials for advanced healthcare solutions.

'Click' hydrogels from renewable polysaccharide resources: Bioorthogonal chemistry for the preparation of alginate, cellulose and other plant-based networks with biomedical applications

Click chemistry refers to a class of highly selective reactions that occur in one pot, are not disturbed by water or oxygen, proceed quickly to high yield and generate only inoffensive byproducts. Since its first definition by Barry Sharpless in 2001, click chemistry has increasingly been used for the preparation of hydrogels, which are water-swollen polymer networks with numerous biomedical applications. Polysaccharides, which can be obtained from renewable resources including plants, have drawn growing attention for use in hydrogels due to the recent focus on the development of a sustainable society and the reduction of the environmental impact of the chemical industry. Importantly, plant-based polysaccharides are often bioresorbable and exhibit excellent biocompatibility and biomimicry. This comprehensive review describes the synthesis, characterization and biomedical applications of hydrogels which combine the renewable and biocompatible aspects of polysaccharides with the chemically and biomedically favorable characteristics of click crosslinking. The manuscript focuses on click hydrogels prepared from alginate and cellulose, the most widely used polysaccharides for this type of hydrogel, but also click hydrogels based on other plant-derived polymers (e.g. pectin) are discussed. In addition, the challenges are described that should be overcome to facilitate translation from academia to the clinic.

Functionalized hydrogels as smart gene delivery systems to treat musculoskeletal disorders

Despite critical advances in regenerative medicine, the generation of definitive, reliable treatments for musculoskeletal diseases remains challenging. Gene therapy based on the delivery of therapeutic genetic sequences has strong value to offer effective, durable options to decisively manage such disorders. Furthermore, scaffold-mediated gene therapy provides powerful alternatives to overcome hurdles associated with classical gene therapy, allowing for the spatiotemporal delivery of candidate genes to sites of injury. Among the many scaffolds for musculoskeletal research, hydrogels raised increasing attention in addition to other potent systems (solid, hybrid scaffolds) due to their versatility and competence as drug and cell carriers in tissue engineering and wound dressing. Attractive functionalities of hydrogels for musculoskeletal therapy include their injectability, stimuli-responsiveness, self-healing, and nanocomposition that may further allow to upgrade of them as "intelligently" efficient and mechanically strong platforms, rather than as just inert vehicles. Such functionalized hydrogels may also be tuned to successfully transfer therapeutic genes in a minimally invasive manner in order to protect their cargos and allow for their long-term effects. In light of such features, this review focuses on functionalized hydrogels and demonstrates their competence for the treatment of musculoskeletal disorders using gene therapy procedures, from gene therapy principles to hydrogel functionalization methods and applications of hydrogel-mediated gene therapy for musculoskeletal disorders, while remaining challenges are being discussed in the perspective of translation in patients. STATEMENT OF SIGNIFICANCE: Despite advances in regenerative medicine, the generation of definitive, reliable treatments for musculoskeletal diseases remains challenging. Gene therapy has strong value in offering effective, durable options to decisively manage such disorders. Scaffold-mediated gene therapy provides powerful alternatives to overcome hurdles associated with classical gene therapy. Among many scaffolds for musculoskeletal research, hydrogels raised increasing attention. Functionalities including injectability, stimuli-responsiveness, and self-healing, tune them as "intelligently" efficient and mechanically strong platforms, rather than as just inert vehicles. This review introduces functionalized hydrogels for musculoskeletal disorder treatment using gene therapy procedures, from gene therapy principles to functionalized hydrogels and applications of hydrogel-mediated gene therapy for musculoskeletal disorders, while remaining challenges are discussed from the perspective of translation in patients.

Advances in H2O2-supplying materials for tumor therapy: synthesis, classification, mechanisms, and applications

Hydrogen peroxide (H2O2) as a reactive oxygen species produced by cellular metabolism can be used in antitumor therapy. However, the concentration of intracellular H2O2 limits its application. Some materials could enhance the concentration of intracellular H2O2 to strengthen antitumor therapy. In this review, the recent advances in H2O2-supplying materials in terms of promoting intracellular H2O2 production and exogenous H2O2 supply are summarized. Then the mechanism of H2O2-supplying materials for tumor therapy is discussed from three aspects: reconstruction of the tumor hypoxia microenvironment, enhancement of oxidative stress, and the intrinsic anti-tumor ability of H2O2-supplying materials. In addition, the application of H2O2-supplying materials for tumor therapy is discussed. Finally, the future of H2O2-supplying materials is presented. This review aims to provide a novel idea for the application of H2O2-supplying materials in tumor therapy.

Cell Wall Binding Strategies Based on Cu3SbS3 Nanoparticles for Selective Bacterial Elimination and Promotion of Infected Wound Healing

Utilizing nanomaterials as an alternative to antibiotics, with a focus on maintaining high biosafety, has emerged as a promising strategy to combat antibiotic resistance. Nevertheless, the challenge lies in the indiscriminate attack of nanomaterials on both bacterial and mammalian cells, which limits their practicality. Herein, Cu3SbS3 nanoparticles (NPs) capable of generating reactive oxygen species (ROS) are discovered to selectively adsorb and eliminate bacteria without causing obvious harm to mammalian cells, thanks to the interaction between O of N-acetylmuramic acid in bacterial cell walls and Cu of the NPs. Coupled with the short diffusion distance of ROS in the surrounding medium, a selective antibacterial effect is achieved. Additionally, the antibacterial mechanism is then identified: Cu3SbS3 NPs catalyze the generation of O2•-, which has subsequently been conversed by superoxide dismutase to H2O2. The latter is secondary catalyzed by the NPs to form •OH and 1O2, initiating an in situ attack on bacteria. This process depletes bacterial glutathione in conjunction with the disruption of the antioxidant defense system of bacteria. Notably, Cu3SbS3 NPs are demonstrated to efficiently impede biofilm formation; thus, a healing of MRSA-infected wounds was promoted. The bacterial cell wall-binding nanoantibacterial agents can be widely expanded through diversified design.

Multifunctional hydrogels based on photothermal therapy: A prospective platform for the postoperative management of melanoma

Preventing the recurrence of melanoma after surgery and accelerating wound healing are among the most challenging aspects of melanoma management. Photothermal therapy has been widely used to treat tumors and bacterial infections and promote wound healing. Owing to its efficacy and specificity, it may be used for postoperative management of tumors. However, its use is limited by the uncontrollable distribution of photosensitizers and the likelihood of damage to the surrounding normal tissue. Hydrogels provide a moist environment with strong biocompatibility and adhesion for wound healing owing to their highly hydrophilic three-dimensional network structure. In addition, these materials serve as excellent drug carriers for tumor treatment and wound healing. It is possible to combine the advantages of both of these agents through different loading modalities to provide a powerful platform for the prevention of tumor recurrence and wound healing. This review summarizes the design strategies, research progress and mechanism of action of hydrogels used in photothermal therapy and discusses their role in preventing tumor recurrence and accelerating wound healing. These findings provide valuable insights into the postoperative management of melanoma and may guide the development of promising multifunctional hydrogels for photothermal therapy.

Fast-relaxing hydrogels with reversibly tunable mechanics for dynamic cancer cell culture

The mechanics of the tumor microenvironment (TME) significantly impact disease progression and the efficacy of anti-cancer therapeutics. While it is recognized that advanced in vitro cancer models will benefit cancer research, none of the current engineered extracellular matrices (ECM) adequately recapitulate the highly dynamic TME. Through integrating reversible boronate-ester bonding and dithiolane ring-opening polymerization, we fabricated synthetic polymer hydrogels with tumor-mimetic fast relaxation and reversibly tunable elastic moduli. Importantly, the crosslinking and dynamic stiffening of matrix mechanics were achieved in the absence of a photoinitiator, often the source of cytotoxicity. Central to this strategy was Poly(PEGA-co-LAA-co-AAPBA) (PELA), a highly defined polymer synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. PELA contains dithiolane for initiator-free gel crosslinking, stiffening, and softening, as well as boronic acid for complexation with diol-containing polymers to give rise to tunable viscoelasticity. PELA hydrogels were highly cytocompatible for dynamic culture of patient-derived pancreatic cancer cells. It was found that the fast-relaxing matrix induced mesenchymal phenotype of cancer cells, and dynamic matrix stiffening restricted tumor spheroid growth. Moreover, this new dynamic viscoelastic hydrogel system permitted sequential stiffening and softening to mimic the physical changes of TME.

Developing hydrogels for gene therapy and tissue engineering

Hydrogels are a class of highly absorbent and easily modified polymer materials suitable for use as slow-release carriers for drugs. Gene therapy is highly specific and can overcome the limitations of traditional tissue engineering techniques and has significant advantages in tissue repair. However, therapeutic genes are often affected by cellular barriers and enzyme sensitivity, and carrier loading of therapeutic genes is essential. Therapeutic gene hydrogels can well overcome these difficulties. Moreover, gene-therapeutic hydrogels have made considerable progress. This review summarizes the recent research on carrier gene hydrogels for the treatment of tissue damage through a summary of the most current research frontiers. We initially introduce the classification of hydrogels and their cross-linking methods, followed by a detailed overview of the types and modifications of therapeutic genes, a detailed discussion on the loading of therapeutic genes in hydrogels and their characterization features, a summary of the design of hydrogels for therapeutic gene release, and an overview of their applications in tissue engineering. Finally, we provide comments and look forward to the shortcomings and future directions of hydrogels for gene therapy. We hope that this article will provide researchers in related fields with more comprehensive and systematic strategies for tissue engineering repair and further promote the development of the field of hydrogels for gene therapy.

Advancements in hydrogel-based drug delivery systems for the treatment of inflammatory bowel disease: a review

Inflammatory bowel disease (IBD) is a chronic disorder that affects millions of individuals worldwide. However, current drug therapies for IBD are plagued by significant side effects, low efficacy, and poor patient compliance. Consequently, there is an urgent need for novel therapeutic approaches to alleviate IBD. Hydrogels, three-dimensional networks of hydrophilic polymers with the ability to swell and retain water, have emerged as promising materials for drug delivery in the treatment of IBD due to their biocompatibility, tunability, and responsiveness to various stimuli. In this review, we summarize recent advancements in hydrogel-based drug delivery systems for the treatment of IBD. We first identify three pathophysiological alterations that need to be addressed in the current treatment of IBD: damage to the intestinal mucosal barrier, dysbiosis of intestinal flora, and activation of inflammatory signaling pathways leading to disequilibrium within the intestines. Subsequently, we discuss in depth the processes required to prepare hydrogel drug delivery systems, from the selection of hydrogel materials, types of drugs to be loaded, methods of drug loading and drug release mechanisms to key points in the preparation of hydrogel drug delivery systems. Additionally, we highlight the progress and impact of the hydrogel-based drug delivery system in IBD treatment through regulation of physical barrier immune responses, promotion of mucosal repair, and improvement of gut microbiota. In conclusion, we analyze the challenges of hydrogel-based drug delivery systems in clinical applications for IBD treatment, and propose potential solutions from our perspective.

Overcoming the Dilemma of In Vivo Stable Adhesion and Sustained Degradation by the Molecular Design of Polyurethane Adhesives for Bone Fracture Repair

Bone adhesive is a promising candidate to revolutionize the clinical treatment of bone repairs. However, several drawbacks have limited its further clinical application, such as unreliable wet adhesive performance leading to fixation failure and poor biodegradability inhibiting bone tissue growth. By incorporating catechol groups and disulfide bonds into polyurethane (PU) molecules, an injectable and porous PU adhesive is developed with both superior wet adhesion and biodegradability to facilitate the reduction and fixation of comminuted fractures and the subsequent regeneration of bone tissue. The bone adhesive can be cured within a reasonable time acceptable to a surgeon, and then the wet bone adhesive strength is near 1.30 MPa in 1 h. Finally, the wet adhesive strength to the cortical bone will achieve about 1.70 MPa, which is also five times more than nonresorbable poly(methyl methacrylate) bone cement. Besides, the cell culture experiments also indicate that the adhesives show excellent biocompatibility and osteogenic ability in vitro. Especially, it can degrade in vivo gradually and promote fracture healing in the rabbit iliac fracture model. These results demonstrate that this ingenious bone adhesive exhibits great potential in the treatment of comminuted fractures, providing fresh insights into the development of clinically applicable bone adhesives.

Injectable multifunctional chitosan/dextran-based hydrogel accelerates wound healing in combined radiation and burn injury

Clinical wound management of combined radiation and burn injury (CRBI) remains a huge challenge due to serious injuries induced by redundant reactive oxygen species (ROS), the accompanying hematopoietic, immunologic suppression and stem cell reduction. Herein, the injectable multifunctional Schiff base cross-linked with gallic acid modified chitosan (CSGA)/oxidized dextran (ODex) hydrogels were rationally designed to accelerate wound healing through elimination of ROS in CRBI. CSGA/ODex hydrogels, fabricated by mixing solutions of CSGA and Odex, displayed good self-healing ability, excellent injectability, strong antioxidant activity, and favorable biocompatibility. More importantly, CSGA/ODex hydrogels exhibited excellent antibacterial properties, which is facilitated for wound healing. Furthermore, CSGA/ODex hydrogels significantly suppressed the oxidative damage of L929 cells in an H₂O₂-induced ROS microenvironment. The recovery of mice with CRBI in mice demonstrated that CSGA/ODex hydrogels significantly reduced the hyperplasia of epithelial cells and the expression of proinflammatory cytokine, and accelerated wound healing which was superior to the treatment with commercial triethanolamine ointment. In conclusion, the CSGA/ODex hydrogels as a wound dressing could accelerate the wound healing and tissue regeneration of CRBI, which provides great potential in clinical treatment of CRBI.

Dynamic Hydrogels with Viscoelasticity and Tunable Stiffness for the Regulation of Cell Behavior and Fate

The extracellular matrix (ECM) of natural cells typically exhibits dynamic mechanical properties (viscoelasticity and dynamic stiffness). The viscoelasticity and dynamic stiffness of the ECM play a crucial role in biological processes, such as tissue growth, development, physiology, and disease. Hydrogels with viscoelasticity and dynamic stiffness have recently been used to investigate the regulation of cell behavior and fate. This article first emphasizes the importance of tissue viscoelasticity and dynamic stiffness and provides an overview of characterization techniques at both macro- and microscale. Then, the viscoelastic hydrogels (crosslinked via ion bonding, hydrogen bonding, hydrophobic interactions, and supramolecular interactions) and dynamic stiffness hydrogels (softening, stiffening, and reversible stiffness) with different crosslinking strategies are summarized, along with the significant impact of viscoelasticity and dynamic stiffness on cell spreading, proliferation, migration, and differentiation in two-dimensional (2D) and three-dimensional (3D) cell cultures. Finally, the emerging trends in the development of dynamic mechanical hydrogels are discussed.

An injectable hydrogel based on hyaluronic acid prepared by Schiff base for long-term controlled drug release

Drug-loaded injectable hydrogels have been studied widely in biomedical technology while the stable long-term controlled drug release and cytotoxicity are challenges. In this work, an injectable hydrogel with good swelling resistance was in situ synthetized using aminated hyaluronic acid (NHA) and aldehyde β-cyclodextrin (ACD) via Schiff-base reaction. The composition, morphology and mechanical property were characterized with FTIR, ¹³C NMR, SEM and rheology test, respectively. Voriconazole (VCZ) and Endophthalmitis was selected as a model drug and disease, respectively. The drug release, cytotoxicity and antifungal properties were detected in vitro. The results showed a long-term (> 60 days) drug release was realized, the NHA/ACD2/VCZ presented a zero-order release in the later stage. The cytotoxicity of NHA/ACD was detected by live/dead staining assay and Cell Counting Kit-8 (CCK-8). The survival rate of adult retina pigment epithelial cell line-19 (ARPE-19) was over 100 % after 3 d, it indicated a good cytocompatibility. The antifungal experiment presented samples had antifungal property. Biocompatibility in vivo proved NHA/ACD2 had no adverse effects on ocular tissues. Consequently, the injectable hydrogel based on hyaluronic acid prepared by Schiff base reaction provides a new option for long-term controlled drug release in the course of disease treatment from a material perspective.

β-Cyclodextrin/chitosan-based (polyvinyl alcohol-co-acrylic acid) interpenetrating hydrogels for oral drug delivery

Gallic acid is an important phenolic compound with extensive applications in the food and pharmaceutical industries due to its health-promoting properties. However, due to its poor solubility and bioavailability, it is rapidly excreted from the body. Therefore, β-cyclodextrin/chitosan-based (polyvinyl alcohol-co-acrylic acid) interpenetrating controlled release hydrogels were developed to improve its dissolution and bioavailability. pH, polymer ratios, dynamic and equilibrium swelling, porosity, sol-gel, FTIR, XRD, TGA, DSC, SEM and structural parameters like an average molecular weight between crosslinks, solvent interaction parameters, and diffusion coefficient affecting release behavior were investigated. The highest swelling and release were observed at pH 7.4. Furthermore, hydrogels showed good antioxidant and antibacterial properties. Hydrogels improved the bioavailability of gallic acid in a pharmacokinetics study in rabbits. In vitro biodegradation showed that hydrogels were more stable in blank PBS than lysozyme and collagenase. Hydrogels were safe for rabbits (3500 mg/kg) without causing hematological or histopathological changes. The hydrogels showed good biocompatibility, and no adverse reactions were observed. Moreover, the developed hydrogels can be used to improve the bioavailability of various other drugs.

Tissue engineering modalities in skeletal muscles: focus on angiogenesis and immunomodulation properties

Muscular diseases and injuries are challenging issues in human medicine, resulting in physical disability. The advent of tissue engineering approaches has paved the way for the restoration and regeneration of injured muscle tissues along with available conventional therapies. Despite recent advances in the fabrication, synthesis, and application of hydrogels in terms of muscle tissue, there is a long way to find appropriate hydrogel types in patients with congenital and/or acquired musculoskeletal injuries. Regarding specific muscular tissue microenvironments, the applied hydrogels should provide a suitable platform for the activation of endogenous reparative mechanisms and concurrently deliver transplanting cells and therapeutics into the injured sites. Here, we aimed to highlight recent advances in muscle tissue engineering with a focus on recent strategies related to the regulation of vascularization and immune system response at the site of injury.

Dynamic and Wearable Electro-responsive Hydrogel with Robust Mechanical Properties for Drug Release

Electro-responsive dynamic hydrogels, which possess robust mechanical properties and precise spatiotemporal resolution, have a wide range of applications in biomedicine and energy science. However, it is still challenging to design and prepare electro-responsive hydrogels (ERHs) which have all of these properties. Here, we report one such class of ERHs with these features, based on the direct current voltage (DCV)-induced rearrangement of sodium dodecyl sulfate (SDS) micelles, where the rearrangement can tune the hydrogel networks that are originally maintained by the SDS micelle-assisted hydrophobic interactions. An enlarged mesh size is demonstrated for these ERHs after DCV treatment. Given the unique structure and properties of these ERHs, hydrophobic cargo (thiostrepton) has been incorporated into the hydrogels and is released upon DCV loading. Additionally, these hydrogels are highly stretchable (>6000%) and tough (507 J/m²), showing robust mechanical properties. Moreover, these hydrogels have a high spatiotemporal resolution. As the cross-links within our ERHs are enabled by the non-covalent (i.e., hydrophobic) interactions, these hydrogels are self-healing and malleable. Considering the robust mechanical properties, precise spatiotemporal resolution, dynamic nature (e.g., injectable and self-healing), and on-demand drug delivery ability, this class of ERHs will be of great interest in the fields of wearable bioelectronics and smart drug delivery systems.

A Smart Benzothiazole-Based Conjugated Polymer Nanoplatform with Multistimuli Response for Enhanced Synergistic Chemo-Photothermal Cancer Therapy

The combination of chemotherapy and phototherapy has received tremendous attention in multimodal cancer therapy. However, satisfactory therapeutic outcomes of chemo-photothermal therapy (chemo-PTT) still remain challenging. Herein, a biocompatible smart nanoplatform based on benzothiazole-linked conjugated polymer nanoparticles (CPNs) is rationally designed, for effectively loading doxorubicin (DOX) and Mo-based polyoxometalate (POM) through both dynamic chemical bond and intermolecular interactions, with an expectation to obtain new anticancer drugs with multiple stimulated responses to the tumor microenvironment (TME) and external laser irradiation. Controlled drug release of DOX from the obtained nanoformulation (CPNs-DOX-PEG-cRGD-BSA@POM) triggered by both endogenous stimulations (GSH and low pH) and exogenous laser irradiation has been well demonstrated by pharmacodynamics investigations. More intriguingly, incorporating POM into the nanoplatform not only enables the nanomedicine to achieve mild hyperthermia but also makes it exhibit self-assembly behavior in acidic TME, producing enhanced tumor retention. Benefiting from the versatile functions, the prepared CPNs-DOX-PEG-cRGD-BSA@POM exhibited excellent tumor targeting and therapeutic effects in murine xenografted models, showing great potential in practical cancer therapy.

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.

Self-cross-linked starch/chitosan hydrogel as a biocompatible vehicle for controlled release of drug

A facile one-pot approach was adopted to prepare a polysaccharide-based hydrogel of oxidized starch (OS)-chitosan. The synthetic monomer-free, eco-friendly hydrogel was prepared in an aqueous solution and employed for controlled drug release application. The starch was first oxidized under mild conditions to prepare its bialdehydic derivative. Subsequently, the amino group-containing a modified polysaccharide, "chitosan" was introduced on the backbone of OS via a dynamic Schiff-base reaction. The bio-based hydrogel was obtained via a one-pot in-situ reaction, where functionalized starch acts as a macro-cross-linker that contributes structural stability and integrity to the hydrogel. The introduction of chitosan contributes stimuli-responsive properties and thus pH-sensitive swelling behavior was obtained. The hydrogel showed its potential as a pH-dependent controlled drug release system and a maximum of 29 h sustained release period was observed for ampicillin sodium salt drug. In vitro studies confirmed that the prepared drug-loaded hydrogels showed excellent antibacterial ability. Most importantly, the hydrogel could find potential use in the biomedical field due to its facile reaction conditions, biocompatibility along with the controlled releasing ability of the encapsulated drug.

Polyacrylamide Hydrogel Containing Calendula Extract as a Wound Healing Bandage: In Vivo Test

Hydrogel is a biomaterial widely used in several areas of industry due to its great biocompatibility and adaptability to biological tissues. In Brazil, the Calendula plant is approved by the Ministry of Health as a medicinal herb. It was chosen to be incorporated in the hydrogel formulation because of its anti-inflammatory, antiseptic and healing effects. This study synthesized polyacrylamide hydrogel containing calendula extract and evaluated its efficiency as a bandage for wound healing. The hydrogels were prepared using free radical polymerization and characterized by Scanning Electron Microscopy, swelling analysis and mechanical properties by texturometer. The morphology of the matrices showed large pores and foliaceous structure. In vivo testing, as well as the evaluation of acute dermal toxicity, was conducted using male Wistar rats. The tests indicated efficient collagen fiber production, improved skin repair and no signs of dermal toxicity. Thus, the hydrogel presents compatible properties for the controlled release of calendula extract used as a bandage to promote cicatrization.

Preparation of new hydrogels by visible light cross-linking of dextran methacrylate and poly(ethylene glycol)-maleic acid copolymer

In this work, a series of new biodegradable and biocompatible hydrogels were synthesized by photopolymerization of dextran-methacrylate (DXM) with poly(ethylene glycol)-maleic acid copolymer (poly(PEG-co-MA, PEGMA)) using (-)-riboflavin as a visible light photoinitiator and L-arginine as a co-photoinitiator. DXM was prepared by acylation of dextran (DX) with methacryloyl chloride (MAC), and PEGMA was synthesized by polycondensation of poly(ethylene glycol) (PEG) and maleic acid (MA). The DXM and PEGMA were characterized by FT-IR and ¹HNMR spectroscopy. Different types of hydrogels from various ratios of DXM and PEGMA were prepared and characterized by SEM. The results showed that the prepared hydrogel by photo-cross-linking of DXM (DPHG0) was transparent and flexible, and its physical shape was excellent, but it was sticky. The stickiness was reduced by increasing the PEGMA contents, and different types of DXM/PEGMA hydrogels (DPHG1-4) with various properties were prepared. For example, DPHG2 (PEGMA content was 0.25 g) was transparent and flexible, its physical shape was excellent, and it was not sticky. The prepared hydrogels showed excellent cytocompatibility, and their tensile and compressive strength were also evaluated. Additionally, the in vitro degradation and swelling ratios of the prepared hydrogels were studied in buffer solution at different pHs.

Dextran Formulations as Effective Delivery Systems of Therapeutic Agents

Dextran is by far one of the most interesting non-toxic, bio-compatible macromolecules, an exopolysaccharide biosynthesized by lactic acid bacteria. It has been extensively used as a major component in many types of drug-delivery systems (DDS), which can be submitted to the next in-vivo testing stages, and may be proposed for clinical trials or pharmaceutical use approval. An important aspect to consider in order to maintain high DDS' biocompatibility is the use of dextran obtained by fermentation processes and with a minimum chemical modification degree. By performing chemical modifications, artefacts can appear in the dextran spatial structure that can lead to decreased biocompatibility or even cytotoxicity. The present review aims to systematize DDS depending on the dextran type used and the biologically active compounds transported, in order to obtain desired therapeutic effects. So far, pure dextran and modified dextran such as acetalated, oxidised, carboxymethyl, diethylaminoethyl-dextran and dextran sulphate sodium, were used to develop several DDSs: microspheres, microparticles, nanoparticles, nanodroplets, liposomes, micelles and nanomicelles, hydrogels, films, nanowires, bio-conjugates, medical adhesives and others. The DDS are critically presented by structures, biocompatibility, drugs loaded and therapeutic points of view in order to highlight future therapeutic perspectives.

In situ self-assembly of amphiphilic dextran micelles and superparamagnetic iron oxide nanoparticle-loading as magnetic resonance imaging contrast agents

Polymeric micelles have long been considered as promising nanocarrier for hydrophobic drugs and imaging probes, due to their nanoscale particle size, biocompatibility and ability to loading reasonable amount of cargoes. Herein, a facile method for dextran micelles preparation was developed and their performance as carriers of superparamagnetic iron oxide (SPIO) nanocrystals was evaluated. Amphiphilic dextran (Dex-g-OA) was synthesized via the Schiff base reactions between oxidized dextran and oleylamine, and self-assembled in situ into nano-size micelles in the reaction systems. The self-assembling behaviors of the amphiphilic dextran were identified using fluorescence resonance energy transfer technique by detection the energy transfer signal between the fluorophore pairs, Cy5 and Cy5.5. Hydrophobic SPIO nanoparticles (Fe₃O₄ NPs) were successfully loaded into the dextran micelles via the in situ self-assembly process, leading to a series of Fe₃O₄ NPs-loaded micelle nanocomposites (Fe₃O₄@Dex-g-OA) with good biocompatibility, superparamagnetism and strongly enhanced T ₂ relaxivity. At the magnetic field of 0.5 T, the Fe₃O₄@Dex-g-OA nanocomposite with particle size of 116.2 ± 53.7 nm presented a higher T ₂ relaxivity of 327.9 mM Fe - 1 ·s^-1. The prepared magnetic nanocomposites hold the promise to be used as contrast agents in magnetic resonance imaging.

Insights into the Role of Natural Polysaccharide-Based Hydrogel Wound Dressings in Biomedical Applications

Acute skin damage caused by burns or cuts occurs frequently in people's daily lives. Such wounds are difficult to heal normally and have persistent inflammation. Wound dressings not only improve the speed of wound healing, but also protect and cover the wound well. Hydrogels have the characteristics of good flexibility, high water content, and good biocompatibility, and are widely used in biomedicine and other fields. Common hydrogels are mainly natural hydrogels and synthetic hydrogels. Hydrogels cross-linked using different raw materials and different methods have different performance characteristics. Natural hydrogels prepared using polysaccharides are simple to obtain and have good biocompatibility, but are inferior to synthetic hydrogels in terms of mechanical properties and stability, and a single polysaccharide hydrogel cannot meet the component requirements for wound healing. Therefore, functional composite hydrogels with high mechanical properties, high biocompatibility, and high antibacterial properties are the current research hotspots. In this review, several common polysaccharides for hydrogel synthesis and the synthesis methods of polysaccharide hydrogels are introduced, and functional composite hydrogel dressings from recent years are classified. It is hoped that this can provide useful references for relevant research in this field.

Multifunctional all-in-one adhesive hydrogel for the treatment of perianal infectious wounds

Postoperative wound of perianal infectious disease represents a common but unique refractory wound in clinical practice. The reasons that hinder the wound healing process include not only the severe bacterial infection of the wound itself and the narrow and deep shape of the wound, but also its frequent bacterial contact. Therefore, the development of biofunctional dressings to aid in therapy is essential. In this study, we synthesized a new type of dressing comprising a hydrogel host based on the Schiff base principle and catechol groups between polydopamine, oxidized dextran, and quaternized chitosan, and then loaded it with traditional Chinese medicine molecules. These formed an integrated hydrogel for accelerated wound repair in a perianal infection model. The prepared hydrogels exhibited excellent wet tissue adhesion, antifouling, morphological variability, suitable swelling properties, and complete degradability, as well as remarkable contact antibacterial ability and the ability to rapidly scavenge free radicals. Hemostatic experiments showed excellent hemostatic properties, as the integrated hydrogel could instantly gel to seal the hemorrhage. Hemocompatibility and in vitro cell experiments showed that the integrated hydrogel had good biosafety and significantly promoted cell proliferation, which in turn accelerated the repair of infected whole cortexes in rats. A histomorphological evaluation showed that the integrated hydrogel promoted the recovery of normal anatomical tissue in rats by promoting the formation of collagen fibers and inhibiting inflammation. The results showed that this multifunctional integrated hydrogel has great potential for the treatment of continuously infected skin regeneration, providing a promising therapeutic strategy for postoperative wound healing in perianal infectious diseases.

Antibacterial Conductive UV-Blocking Adhesion Hydrogel Dressing with Mild On-Demand Removability Accelerated Drug-Resistant Bacteria-Infected Wound Healing

The on-demand replacement of multifunctional hydrogel wound dressings helps to avoid bacterial colonization, and the on-demand painless peeling of tissue adhesive hydrogels on the wound site remains a major challenge to be solved. In this work, we design and develop a series of multifunctional dynamic Schiff base network hydrogels composed of cystamine-modified hyaluronic acid, benzaldehyde-functionalized poly(ethylene glycol)-co-poly(glycerol sebacate), and polydopamine@polypyrrole nanocomposite (PDA@PPy) with mild on-demand removability to enhance drug-resistant bacteria-infected wound healing. These hydrogels exhibited ideal injectable and self-healing properties, excellent tissue adhesion, in vivo hemostasis, good antioxidation, and conductivity. PDA@PPy inspired by melanin endows hydrogels with excellent antioxidant capacity, UV-blocking ability, and photothermal anti-infection ability. Based on the dynamic oxidation-reduction response of disulfide bonds inspired by the dissociation of the tertiary spatial structure transformation of poly-polypeptide chains, these hydrogels can achieve rapid painless on-demand removal under mild conditions by adding dithiothreitol. These multifunctional hydrogels significantly promoted collagen deposition and angiogenesis in the MRSA-infected full-thickness skin repair experiment. All the results showed that these multifunctional hydrogels with painless on-demand removal property showed great potential in clinical treatment of infected wounds.

Fabrication, GSH-responsive drug release, and anticancer properties of thioctic acid-based intelligent hydrogels

Injectable hydrogels are potential local drug delivery systems since they contain plenty of water and soft like biological tissues. Such hydrogels could be injected directly into the tumor site where the drug is released under the tumor microenvironment. However, drug loaded hydrogels for cancer treatment based on lipoic acid (natural small molecule) have not been exploited. Here, a novel poly(lipoic acid)-poly(ethylene glycol) (PEG-PTA) hydrogels were prepared through a two-step reaction. The hydrogels contained disulfide bonds, so they could be degraded via the thiol exchange reaction with the abundant GSH in the tumor microenvironment, and subsequently release the drug. The results in vitro and at cellular level showed that the hydrogels were degraded and released the drugs only in the presence of GSH. Therefore, the injectable GSH-responsive hydrogels are promising to be served as an intelligent drug delivery system for cancer treatment.

Synthesis of magnetic/pH dual responsive dextran hydrogels as stimuli-sensitive drug carriers

Hydrogels loaded with magnetic nanoparticles have been widely researched recently as biomaterials, due to their good biocompatibility and unique magnetic characteristics. In this study, water-soluble superparamagnetic iron oxide nanoparticles (Fe₃O₄) prepared by coprecipitation were physically doped into the dextran hydrogels which were formed via Schiff base reactions between ethylenediamine and oxidized dextran. The combination of magnetic nanoparticles and chemical cross-linked hydrogels leads to magnetic/pH dual-sensitive hydrogels which can be used as stimuli-responsive carrier. Magnetic properties, swelling, and rheology behaviors of the resulted magnetic hydrogels were strongly affected by the Fe₃O₄ nanoparticle content. Moreover, doxorubicin (DOX⋅HCl) was embedded into the magnetic hydrogels and pH/magnetic sensitive release profiles were identified. The release mechanism analysis indicated that the release behaviors of DOX⋅HCl were controlled by the diffusion, swelling, and erosion processes simultaneously. The prepared hydrogel/Fe₃O₄ composites with dual magnetic/pH stimuli-responsiveness hold the promise to be used in various applications such as drug release.

High-resolution 3D printing of xanthan gum/nanocellulose bio-inks

The current study provides a comprehensive rheology study and a survey on direct ink writing of xanthan gum/cellulose nanocrystal (XG/CNC) bio-inks for developing 3D geometries that mimic soft tissue engineering scaffolds' physical and mechanical properties. The presence of CNC was found to be a critical prerequisite for the printability of XG bio-inks; accordingly, the hybrid XG/CNC bio-inks revealed the excellent viscoelastic properties that enabled precise control of hydrogel shaping and printing of lattice structures composed of up to eleven layers with high fidelity and fair resolution without any deformation after printing. The lyophilized 3D scaffolds presented a porous structure with open and interconnected pores and a porosity higher than 70%, vital features for tissue engineering scaffolds. Moreover, they showed a relatively high swelling of approximately 11 g/g, facilitating oxygen and nutrient exchange. Furthermore, the elastic and compressive moduli of the scaffolds that enhanced significantly upon increasing CNC content were in the range of a few kPa, similar to soft tissues. Finally, no significant cell cytotoxicity was observed against human liver cancer cells (HepG2), highlighting the potential of these developed 3D printed scaffolds for soft tissue engineering applications.

Injectable Hydrogel Based on Defect-Rich Multi-Nanozymes for Diabetic Wound Healing via an Oxygen Self-Supplying Cascade Reaction

Diabetic wound healing remains challenging owing to the risk for bacterial infection, hypoxia, excessive glucose levels, and oxidative stress. Glucose-activated cascade reactions can consume glucose and eradicate bacteria, avoiding the direct use of hydrogen peroxide (H₂ O₂ ) and wound pH restriction on peroxidase-like activity. However, the anoxic microenvironment in diabetic wounds impedes the cascade reaction due to the oxygen (O₂ ) dependence of glucose oxidation. Herein, defect-rich molybdenum disulfide nanosheets loaded with bovine serum albumin-modified gold nanoparticle (MoS₂ @Au@BSA NSs) heterostructures are designed and anchored onto injectable hydrogels to promote diabetic wound healing through an O₂ self-supplying cascade reaction. BSA decoration decreases the particle size of Au, increasing the activity of multiple enzymes. Glucose oxidase-like Au catalyzes the oxidation of glucose into gluconic acid and H₂ O₂ , which is transformed into a hydroxyl radical (•OH) catalyzed by peroxidase-like MoS₂ @Au@BSA to eradicate bacteria. When the wound pH reaches an alkalescent condition, MoS₂ @Au@BSA mimicks superoxide dismutase to transform superoxide anions into O₂ and H₂ O₂ , and decomposes endogenous and exogenous H₂ O₂ into O₂ via catalase-like mechanisms, reducing oxidative stress, alleviating hypoxia, and facilitating glucose oxidation. The MoS₂ @Au@BSA nanozyme-anchored injectable hydrogel, composed of oxidized dextran and glycol chitosan crosslinked through a Schiff base, significantly accelerates diabetic wound healing.

Dual stimuli-responsive nanocarriers based on polyethylene glycol-mediated schiff base interactions for overcoming tumour chemoresistance

Multifunctional and stimulus-sensitive intelligent nanodrug delivery systems (NDDSs) can significantly optimize the effectiveness of theranostic agents for cancer treatment. In this study, redox and pH dual-responsive nanocarriers (CPNPs) were prepared through molecular assembly by utilizing the Schiff base interactions of cystamine (Cys), PEG-NH₂ and formaldehyde (FA) under aqueous conditions with a one-pot, one-step technique. First, the degradation products of CPNPs exhibited good biocompatibility, and the high concentration of intact CPNPs (200 µg/mL) could inhibit the growth of cells. In addition, doxorubicin (DOX) was encapsulated in CPNPs simply by changing the pH (DOX@CPNPs), and pH/GSH-responsive release behaviour was confirmed. In vitro, CPNPs significantly increased the uptake of DOX and enhanced the cytotoxicity of DOX to tumour cells. More importantly, DOX@CPNPs strongly reversed drug resistance in three different types of cancer cells, exhibiting significant anticancer effects. Collectively, this study presents the easy preparation of nanomedicines that respond to multiple stimuli, which highlights the advantages of Schiff base-based nanomedicines for cancer therapy and reversing chemoresistance.

Comparison of dialdehyde polysaccharides as crosslinkers for hydrogels: The case of poly(vinyl alcohol)

A little is known about the link between the macromolecular architecture of dialdehyde polysaccharides (DAPs), their crosslinking capabilities, and the properties of resulting hydrogels. Here, DAPs based on cellulose, dextrin, dextran, and hyaluronate were compared as crosslinkers for poly(vinyl alcohol), PVA. The swelling, network parameters, viscoelastic properties, porosity, and cytotoxicity of PVA/DAP hydrogels were investigated concerning the crosslinker structure, molecular weight, aldehyde group density per macromolecule, and the size of spontaneously formed crosslinker nano-assemblies. Generally, crosslinkers based on linear polysaccharides (cellulose, hyaluronate) performed more reliably, while the presence of branching could be both beneficial (dextran) but also detrimental (dextrin) at lower crosslinker concentrations. For example, the hydrogel swelling differed by up to one-third (600 vs. 400%) and storage modulus even by up to one half (~7000 vs. ~3500 Pa) depending on crosslinker structure and properties. These differences were rationalized by variances in crosslinking modes derived based on obtained data.