Supramolecular chitin-based hydrogels with self-adapting and fast-degradation properties for enhancing wound healing

Physalis peruviana heteropolysaccharide-conjugated selenium nanoparticles: Preparation, characterization, and promising applications in cancer therapy

Selenium nanoparticles (SeNPs) have attracted considerable attention in the field of cancer therapy due to their remarkable biological activities and advantageous nanoscale properties. However, their inherent instability presents a considerable challenge for broader applications. To address this issue, the heteropolysaccharide extracted from golden berries (the fruits of Physalis peruviana), designated as DLG, was utilized to synthesize heteropolysaccharide-conjugated selenium nanoparticles, named DLG-SeNP3. Subsequent characterization showed that the nanoparticles DLG-SeNP3 were spherical, with an average particle size of 77 nm, a zeta potential of -14.4 mV, and excellent stability under physiological pH conditions. Further biological investigations showed that DLG-SeNP3 effectively inhibited tumor cell proliferation, exhibiting an IC50 value of 41.60 μg/mL against A549 cells, and induced apoptosis, with a proportion of 31.30 % at 100 μg/mL. Moreover, in vivo experiments demonstrated that DLG-SeNP3 not only inhibited angiogenesis, resulting in a 26.51 % decrease at 2 μg/mL, but also suppressed tumor growth and invasion, with reductions of 76.90 % and 66.67 % in the intensity and foci of red fluorescence, respectively, at 2 μg/mL. In conclusion, DLG-SeNP3, stabilized with polysaccharides derived from golden berries, shows promising potential for application in cancer treatment.

A highly stretchable, self-healing, self-adhesive polyacrylic acid/chitosan multifunctional composite hydrogel for flexible strain sensors

Conductive hydrogels have emerged as excellent candidates for the design and construction of flexible wearable sensors and have attracted great attention in the field of wearable sensors. However, there are still serious challenges to integrating high stretchability, self-healing, self-adhesion, excellent sensing properties, and good biocompatibility into hydrogel wearable devices through easy and green strategies. In this paper, multifunctional conductive hydrogels (PCGB) with good biocompatibility, high tensile (1694 % strain), self-adhesive, and self-healing properties were fabricated by incorporating boric acid (BA) and glucose (Glu) simultaneously into polyacrylic acid (PAA) and chitosan (CS) polymer networks using a simple one-pot polymerization method. Furthermore, the hydrogel strain sensor constructed from the PCGB assembly had great sensing property including high sensitivity (GF = 5.7), durability and stability (5000 cycles). The hydrogel strain sensor was applied to the detection of human motion, which exhibited accurate detection behavior for both large-scale motions and small activities. A strategy to design and fabricate multifunctional conductive hydrogels integrating high stretchability, self-healing, self-adhesion and good biocompatibility was provided, and the multifunctional conductive hydrogels broadened the application of hydrogel-based wearable sensor.

Antibacterial betaine modified chitosan-based hydrogel with angiogenic property for photothermal enhanced diabetic wound repairing

Chronic diabetes wound repairing is still a huge challenge in clinical practice. High concentration of reactive oxygen species and vascular disfunction are the main factors hindering the recovery of diabetes wounds. This research grafted betaine onto chitosan (CSBT) to enhance the antibacterial property and the CSBT was cross-linked with PEO90 dialdehyde (PEO DA) to prepare hydrogel with Ca2+ loading to promote the coagulation. The polydopamine nanoparticles (PDA NPs) with photothermal property and antioxidant property was composited to the hydrogel and deferoxamine (DFO) was loaded to fabricate the multifunctional CBPCa/PDA/DFO hydrogel to promote vascular regeneration in combination with photothermal antibacterial performance for the diabetes wounds treatment. The CBPCa/PDA/DFO hydrogel showed good mechanical strength, injectability, anti-inflammatory property and coagulation performance. Furthermore, the antibacterial effect of chitosan based hydrogel was enhanced with near infrared (NIR) stimulated photothermal treatment. Combined with the photothermal effect and the angiogenic drug DFO release, the CBPCa/PDA/DFO hydrogel significantly enhanced vascular regeneration and reduced the inflammation in the in vivo wound repairing experiment. As a result, the CBPCa/PDA/DFO hydrogel may provide a promising therapeutic platform for diabetic trauma repairing.

Overview of chitin dissolution, hydrogel formation and its biomedical applications

Chitin hydrogel and hydrogel-based products are some of the frequently reported biomaterials for biomedical applications. Yet there is a void in understanding chitin's dissolution mechanism and its most suitable solvent system(s). Chitin is a natural polysaccharide polymer which can be dissolved in solvents such as calcium chloride- methanol, sodium hydroxide/urea (NaOH/urea), lithium chloride diacetamide (LiCl/DMAc), ionic liquids and deep eutectic solvents. Among the alkali/urea dissolution systems such as NaOH/urea, KOH/urea, LiOH/urea for dissolution of chitin we will be focussing on NaOH-based system here for ease of comparison with the other systems. Chitin has been used for decades in the biomedical field; however, new solvent systems are still being explored even to this day to identify the most suitable chemical(s) for dissolving it. Chitin, due to its biocompatibility, allows us to use it for multifaceted purposes. Hence, it is important to consolidate the available studies for better understanding about the most sought-after biomaterial. This overview deeply delves into the mechanism of action of the existing solvent systems and highlights its merits and demerits. It discusses the rheological properties of the chitin gel from different solvent systems and puts forth the current biomedical applications of chitin gel in areas such as tissue engineering, drug delivery, biosensing, hemostasis and wound healing. It also outlines recent advances and highlights the potential gaps which need to be addressed in future studies.

Advances of naturally derived biomedical polymers in tissue engineering

The extensive utilization of natural polymers in tissue engineering is attributed to their excellent biocompatibility, degradability, and resemblance to the natural extracellular matrix. These polymers have a wide range of applications such as delivering therapeutic medicine, detecting diseases, sensing biological substances, promoting tissue regeneration, and treating diseases. This is a brief review of current developments in the properties and uses of widely used biomedical polymers derived from nature. Additionally, it explores the correlation between the characteristics and functions of these materials in different biomedical applications and highlights the prospective direction for the advancement of natural polymer materials in tissue engineering.

Development of hybrid polyvinylpyrrolidone/carboxymethyl cellulose/collagen incorporated oregano scaffolds via direct ink write printing for potential wound healing applications

Additive manufacturing can develop regenerative scaffolds for wound healing. 3D printing offers meticulous porosity, mechanical integrity, cell adhesion and cost-effectiveness. Herein, we prepared ink composed of carboxymethyl cellulose (CMC), polyvinylpyrrolidone (PVP), collagen, and oregano extract for the fabrication of tissue constructs. The blend was optimized to form a homogeneous ink and rheological characterization demonstrated shear thinning behavior. The scaffolds were printed using Direct Ink Write (DIW) at a flow speed of 4 mm3/s and a layer height of 0.18 mm. The fabricated scaffolds demonstrated an ultimate tensile strength (UTS) and toughness of 730 KPa and 2.72 MJ/m3, respectively. Scanning Electron Microscopy (SEM) revealed an average pore size of 300 ± 30 μm. Fourier transform infrared spectroscopy (FTIR) analysis confirmed that all materials were present. The contact angle of the composite scaffold was 68° ± 1°. Moreover, the scaffolds presented 82 % mass loss (degradation) in phosphate buffer saline (PBS) over 14 days. The composite scaffold exhibited inhibition zones of 9 mm and 12 mm against Staphylococcus aureus and Escherichia coli, respectively. The PVP/CMC/collagen/oregano 3D printed scaffolds exhibited excellent biocompatibility with the mesenchymal stem cells and humman dermal fibroblast cells, confirmed by water-soluble tetrazolium - 8 (WST-8) assay (test conducted for 7 days). The enhanced angiogenic potential of said scaffold was assesed by release of vascular endothelial growth factor followed by further validation through in-vivo CAM assay. Thus, confirming suitability for the potential wound healing application.

Hydroxypropyl chitosan/ε-poly-l-lysine based injectable and self-healing hydrogels with antimicrobial and hemostatic activity for wound repair

The biggest obstacle to treating wound healing continues to be the production of simple, inexpensive wound dressings that satisfy the demands associated with full process of repair at the same time. Herein, a series of injectable composite hydrogels were successfully prepared by a one-pot method by utilizing the Schiff base reaction as well as hydrogen bonding forces between hydroxypropyl chitosan (HCS), ε-poly-l-lysine (EPL), and 2,3,4-trihydroxybenzaldehyde (TBA), and multiple cross-links formed by the reversible coordination between iron (III) and pyrogallol moieties. Notably, hydrogel exhibits excellent physicochemical properties, including injectability, self-healing, water retention, and adhesion, which enable to fill irregular wounds for a long period, providing a suitable moist environment for wound healing. Interestingly, the excellent hemostatic properties of the hydrogel can quickly stop bleeding and avoid the serious sequelae of massive blood loss in acute trauma. Moreover, the powerful antimicrobial and antioxidant properties also protect against bacterial infections and reduce inflammation at the wound site, thus promoting healing at all stages of the wound. The study of biohydrogel with multifunctional integration of wound treatment and smart medical treatment is clarified by this line of research.

Dual cross-linked self-healing hydrogel enhanced by dopamine nanoparticles and raffinose for wound healing

A series of intricate and dynamic physiological healing processes are involved in the healing of skin wounds. Herein, a multifunctional hydrogel is firstly designed and constructed by L-arginine-grafted O-carboxymethyl chitosan (CMCA), catechol-modified oxidized hyaluronic acid (DOHA), and dopamine nanoparticles (pDA-NPs). pDA-NPs were loaded in hydrogel for inherently powerful antimicrobial properties and could be as a cross-linking agent to construct hydrogels. Raffinose (Raf) was further incorporated to obtain CMCA-DOHA-pDA2@Raf hydrogel for its function of modulating epidermal differentiation. The hydrogel has good physicochemical properties and could promote cell proliferation and migration, which shows superior hemostatic capabilities in animal models of hemorrhage. The hydrogel significantly promoted wound healing on rat skin defect models by upregulating VEGF and CD31 and decreasing IL-6 and TNF-α, stimulating neovascularization and collagen deposition in epithelial structures. This multifunctional hydrogel implies the potential to be a dynamic wound dressing.

Metal-ion-controlled hydrogel dressing with enhanced adhesive and antibacterial properties for accelerated wound healing

In order to improve the wound repair environment, this research has successfully developed a new multifunctional hydrogel dressing, which has strong adaptability and can accelerate wound healing. Pioneering the development of metal-ion-controlled hydrogel dressings, this research integrates dopamine and imidazole double crosslinked networks with metal-ion coordination. The resulting hydrogel dressing exhibits a notable antibacterial effect and exceptional mechanical properties, withstanding pressures of up to 12 kPa, tensions of 25 kPa, and maintaining skin adhesion at 6 kPa. Furthermore, the dressing can self-heal within only 7-8 s post-injection. Impressively, the hydrogel achieves complete biodegradation within a short timeframe (37 h). Notably, the use of various metal ions facilitates painless peeling during the degradation period, perfectly aligning with the requirements of an ideal wound dressing. This study has made significant progress in the fields of trauma repair and materials, providing strong solutions for dealing with harsh post-traumatic environments.

Insights of biopolymeric blended formulations for diabetic wound healing

Diabetic wounds (DWs) pose a significant health burden worldwide, with their management presenting numerous challenges. Biopolymeric formulations have recently gained attention as promising therapeutic approaches for diabetic wound healing. These formulations, composed of biocompatible and biodegradable polymers, offer unique properties such as controlled drug release, enhanced wound closure, and reduced scarring. In this review, we aim to provide a comprehensive overview of the current state of research and future prospects regarding the application of biopolymeric formulations for diabetic wound healing. The review begins by highlighting the underlying pathophysiology of DWs, including impaired angiogenesis, chronic inflammation, and compromised extracellular matrix (ECM) formation. It further explores the key characteristics of biopolymeric materials, such as their biocompatibility, biodegradability, and tunable physicochemical properties, which make them suitable for diabetic wound healing applications. The discussion further delves into the types of biopolymeric formulations utilized in the treatment of DWs. These include hydrogels, nanoparticles (NP), scaffolds, films, and dressings. Furthermore, the review addresses the challenges associated with biopolymeric formulations for diabetic wound healing. In conclusion, biopolymeric formulations present a promising avenue for diabetic wound healing. Their unique properties and versatility allow for tailored approaches to address the specific challenges associated with DWs. However, further research and developments are required to optimize their therapeutic efficacy, stability, manufacturing processes, and regulatory considerations. With continued advancements in biopolymeric formulations, the future holds great promise for improving the management and outcomes of DWs.

Multifunctional polypeptide-based hydrogel bio-adhesives with pro-healing activities and their working principles

Wound healing is a complex physiological process involving hemostasis, inflammation, proliferation, and tissue remodeling. Therefore, there is an urgent need for suitable wound dressings for effective and systematical wound management. Polypeptide-based hydrogel bio-adhesives offer unique advantages and are ideal candidates. However, comprehensive reviews on polypeptide-based hydrogel bio-adhesives for wound healing are still lacking. In this review, the physiological mechanisms and evaluation parameters of wound healing were first described in detail. Then, the working principles of hydrogel bio-adhesives were summarized. Recent advances made in multifunctional polypeptide-based hydrogel bio-adhesives involving gelatin, silk fibroin, fibrin, keratin, poly-γ-glutamic acid, ɛ-poly-lysine, serum albumin, and elastin with pro-healing activities in wound healing and tissue repair were reviewed. Finally, the current status, challenges, developments, and future trends of polypeptide-based hydrogel bio-adhesives were discussed, hoping that further developments would be stimulated to meet the growing needs of their clinical applications.

Chemical Design of Supramolecular Reversible Adhesives for Promising Applications

Supramolecular reversible adhesives have garnered significant attention due to their potential applications in various fields. These adhesives exhibit remarkable properties such as reversible adhesion, self-healing, and high flexibility. This concept aims to present a comprehensive overview of the current research progress in developing supramolecular reversible adhesives. Firstly, the fundamentals of supramolecular chemistry and the principles underlying the design and synthesis of reversible adhesive systems are discussed. Next, the concept focuses on characterizing the reversible adhesion strength of supramolecular adhesive systems that have been developed. The adhesion performance of supramolecular reversible adhesives is summarized, highlighting their unique characteristics and promising applications. Finally, the challenges and future perspectives in the field of supramolecular reversible adhesives are discussed. The comprehensive overview provided in this concept aims to inspire further research and innovation in this exciting field.

Injectable hydrogels as promising in situ therapeutic platform for cartilage tissue engineering

Injectable hydrogels are gaining prominence as a biocompatible, minimally invasive, and adaptable platform for cartilage tissue engineering. Commencing with their synthesis, this review accentuates the tailored matrix formulations and cross-linking techniques essential for fostering three-dimensional cell culture and melding with complex tissue structures. Subsequently, it spotlights the hydrogels' enhanced properties, highlighting their augmented functionalities and broadened scope in cartilage tissue repair applications. Furthermore, future perspectives are advocated, urging continuous innovation and exploration to surmount existing challenges and harness the full clinical potential of hydrogels in regenerative medicine. Such advancements are crucial for validating the long-term efficacy and safety of hydrogels, positioning them as a promising direction in regenerative medicine to address cartilage-related ailments.

Engineered cyclodextrin-based supramolecular hydrogels for biomedical applications

Cyclodextrin (CD)-based supramolecular hydrogels are polymer network systems with the ability to rapidly form reversible three-dimensional porous structures through multiple cross-linking methods, offering potential applications in drug delivery. Although CD-based supramolecular hydrogels have been increasingly used in a wide range of applications in recent years, a comprehensive description of their structure, mechanical property modulation, drug loading, delivery, and applications in biomedical fields from a cross-linking perspective is lacking. To provide a comprehensive overview of CD-based supramolecular hydrogels, this review systematically describes their design, regulation of mechanical properties, modes of drug loading and release, and their roles in various biomedical fields, particularly oncology, wound dressing, bone repair, and myocardial tissue engineering. Additionally, this review provides a rational discussion on the current challenges and prospects of CD-based supramolecular hydrogels, which can provide ideas for the rapid development of CD-based hydrogels and foster their translation from the laboratory to clinical medicine.