Preparation of methacrylated hyaluronate/methacrylated collagen sponges with rapid shape recovery and orderly channel for fast blood absorption as hemostatic dressing

Antibacterial Chitin-Based Sponges with Enhanced Water Absorbency and Mechanical Properties for Hemostasis and Wound Healing

The development of antibacterial sponges with both high water-absorbing and mechanical properties is highly desirable for attaining efficient hemostasis and closure of noncompressible wounds, but remains challenging. General methods, such as increasing porosity, to improve the water absorption of sponges inevitably compromise their mechanical properties. Herein, a chitin (CT)/quaternized chitosan (QCS) sponge with the desirable properties was fabricated by freeze-drying the chemically and physically dual cross-linked CT/QCS hydrogel with enhanced hydrophilicity. The obtained CT/QCS sponge possessed improved water (5906%) and blood absorption rates (6374%), robust mechanical strength (compressive stress at 90% strain = 0.52 MPa), and rapid water-triggered shape recovery ability (less than 5.3 s). In addition to good biocompatibility, the CT/QCS sponge also showed high in vitro/in vivo hemostatic efficacy and remarkable bacteriostasis rates against E. coli (85.4%) and S. aureus (91.6%) due to its hydrophilic and positively charged porous structure. The CT/QCS sponge exhibited significant healing efficacy in infected wounds compared to commercial gauze and gelatin sponge. This work demonstrates that the antibacterial CT/QCS sponge with enhanced water-absorbing and mechanical properties is promising for treating noncompressible bleeding and infected wounds.

Co-assembled biomimetic fibrils from collagen and chitosan for performance-enhancing hemostatic dressing

The development of safe and efficient hemostatic materials is medically important to prevent death due to trauma bleeding. Exploiting the synergistic effect between the D-periodic functional domain of collagen fibrils on platelet activation and cationic chitosan on erythrocyte aggregation is expected to develop performance-enhanced hemostatic materials. In this study, we prepared collagen fibrils and chitosan composite hemostatic materials by modulating the self-assembled bionic fibrillation of collagen with different degrees of deacetylation (DD, 50%, 70% and 85%) of chitosan. The findings indicated that chitosan promoted collagen self-assembly, with all the collagen fibrils demonstrating a typical D-periodical structure similar to that of the native collagen. Furthermore, the composite demonstrated enhanced structural integrity and procoagulant capacity along with good biocompatibility. Notably, the fibrillar composites with 70% DD of chitosan exhibited optimal mechanical properties, procoagulant activity, and adhesion of erythrocytes and platelets. Compared to pure collagen fibrils and the commercial hemostatic agent Celox™, the collagen/chitosan fibrillar composite treatment significantly accelerated hemostasis in the rat tail amputation model and liver injury model. This research offers new insights into the development of hemostatic materials and indicates that collagen-chitosan composites hold promising potential for clinical applications.

Serotonin-functionalized starch-based hemostatic sponges enhance platelet activation in the management of non-compressible hemorrhage

Massive hemorrhage poses a serious threat to human health and even life. Access to rapid and potent hemostatic materials is crucial for lowering mortality rates. Starch-based materials exhibit good biocompatibility and are extensively utilized in hemostatic. However, existing starch-based hemostatic products suffer from limited hemostatic efficacy. Serotonin, an indoleamine naturally occurring in the human body, is recognized for its potent platelet-activating properties. Therefore, this study focused on enhancing the procoagulant activity of starch by incorporating serotonin into the starch backbone via esterification and amidation reactions, yielding a novel serotonin-loaded starch-based hemostatic sponge (SLS sponge). The SLS sponges featured exceptional porosity (≥80 %) and water absorption capacity (≥2000 %), which rapidly initiated the coagulation cascade reaction, promoted the adhesion and aggregation of red blood cells and platelets, and intensified platelet activation. This multifaceted approach synergistically enhanced hemostasis via both active and passive coagulation mechanisms. Notably, the SLS sponges adhered firmly to the wound surfaces without pressure. Compared with gelatin sponges, the SLS sponges significantly reduced blood loss by approximately 40.5 % and shortened the time to achieve hemostasis by approximately 28.9 %. These findings indicate that the newly developed SLS sponges are a promising active hemostatic material, particularly effective in managing non-compressible hemorrhages.

Photocrosslinkable Biomaterials for 3D Bioprinting: Mechanisms, Recent Advances, and Future Prospects

Constructing scaffolds with the desired structures and functions is one of the main goals of tissue engineering. Three-dimensional (3D) bioprinting is a promising technology that enables the personalized fabrication of devices with regulated biological and mechanical characteristics similar to natural tissues/organs. To date, 3D bioprinting has been widely explored for biomedical applications like tissue engineering, drug delivery, drug screening, and in vitro disease model construction. Among different bioinks, photocrosslinkable bioinks have emerged as a powerful choice for the advanced fabrication of 3D devices, with fast crosslinking speed, high resolution, and great print fidelity. The photocrosslinkable biomaterials used for light-based 3D printing play a pivotal role in the fabrication of functional constructs. Herein, this review outlines the general 3D bioprinting approaches related to photocrosslinkable biomaterials, including extrusion-based printing, inkjet printing, stereolithography printing, and laser-assisted printing. Further, the mechanisms, advantages, and limitations of photopolymerization and photoinitiators are discussed. Next, recent advances in natural and synthetic photocrosslinkable biomaterials used for 3D bioprinting are highlighted. Finally, the challenges and future perspectives of photocrosslinkable bioinks and bioprinting approaches are envisaged.

Recent research advances in polysaccharide-based hemostatic materials: A review

Massive bleeding resulting from civil and martial accidents can often lead to shock or even death, highlighting the critical need for the development of rapid and efficient hemostatic materials. While various types of hemostatic materials are currently utilized in clinical practice, they often come with limitations such as poor biocompatibility, toxicity, and biodegradability. Polysaccharides, such as alginate (AG), chitosan (CS), cellulose, starch, hyaluronic acid (HA), and dextran, have exhibit excellent biocompatibility and in vivo biodegradability. Their degradation products are non-toxic to surrounding tissues and can be absorbed by the body. As a result, polysaccharides have been extensively utilized in the development of hemostatic materials and have gained significant attention in the field of in vivo hemostasis. This review offers an overview of the different forms, hemostatic mechanisms, and specific applications of polysaccharides. Additionally, it discusses the future opportunities and challenges associated with polysaccharide-based hemostats.

Preparation and Application of Hemostatic Hydrogels

Hemorrhage remains a critical challenge in various medical settings, necessitating the development of advanced hemostatic materials. Hemostatic hydrogels have emerged as promising solutions to address uncontrolled bleeding due to their unique properties, including biocompatibility, tunable physical characteristics, and exceptional hemostatic capabilities. In this review, a comprehensive overview of the preparation and biomedical applications of hemostatic hydrogels is provided. Particularly, hemostatic hydrogels with various materials and forms are introduced. Additionally, the applications of hemostatic hydrogels in trauma management, surgical procedures, wound care, etc. are summarized. Finally, the limitations and future prospects of hemostatic hydrogels are discussed and evaluated. This review aims to highlight the biomedical applications of hydrogels in hemorrhage management and offer insights into the development of clinically relevant hemostatic materials.

MXene-NH2/chitosan hemostatic sponges for rapid wound healing

Effective control of wound bleeding and sustained promotion of wound healing remain a major challenge for hemostatic materials. In this study, the hemostatic sponge with controllable antibacterial and adjustable continuous promotion of wound healing (CMNCu) was prepared by chitosan, aminated MXene and copper ion. Interestingly, the internal topological point-line-surface interaction endowed the CMN-Cu sponge longitudinal staggered tubular porous microstructure, combined with the lipophilic properties obtained by modified MXene, which greatly improved its flexibility, wet elasticity and blood enrichment capacity. In addition, the sponge achieved controlled release of active ingredients, which made it present highly effective antibacterial activity and long-lasting ability to promote wound healing. In vitro and in vivo experiments confirmed that CMN-Cu sponge presented high-efficient hemostatic performance. Last but not least, a series of cell experiments showed that the CMN-Cu sponge had excellent safety as a hemostatic material.

Clinical Study of Rh-bFGF Combined With Collagen Sponge in the Treatment of Maxillofacial Deep Ⅱ Degree Burn

OBJECTIVES

To observe the clinical effect of recombinant human alkaline fibroblast growth factor (rh-bFGF) combined with collagen sponge in the treatment of maxillofacial deepⅡ degree burn.

METHODS

From January 2019 to January 2022, 96 patients with maxillofacial deep Ⅱ degree burns were randomly divided into a control group (N=48) and an observation group (N=48). The observation group was treated with rh-bFGF and collagen sponge after debridement, whereas the control group was treated with silver sulfadiazine ointment after debridement. The healing rate and healing time of the wounds were observed, interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-10, epidermal growth factor (EGF), endothelial growth factor growth factor (VEGF), and metalloproteinase tissue inhibitor 1 (TIMP-1) were measured. Vancouver Scar Scale (VSS) was used to evaluate the local scar at 6 months after wound healing in both groups.

RESULTS

On the 10th, 14th, and 21st day of treatment, the wound healing rate in the observation group was higher than that in the control group (P<0.05), the wound healing time in the observation group was lower than that in the control group (P<0.05), and on the 14th day of treatment, the levels of TNF-α and IL-6 in the observation group were lower than those in the control group (P<0.05). The levels of IL-10 in the observation group were higher than those in the control group (P<0.05). The levels of EGF, VEGF, and TIMP-1 in the observation group were higher than those in the control group (P<0.05), and the scores of VSS in the observation group were lower than those in the control group (P<0.05).

CONCLUSIONS

Rh-bFGF combined with collagen sponge can decrease the levels of TNF-α and IL-6 and increase the levels of IL-10, which can control the inflammation effectively, at the same time, it can increase the level of EGF, VEGF, and TIMP-1, promote wound healing, and reduce scar hyperplasia. The treatment protocol is simple, safe, effective, and suitable for clinical application.

Dual green hemostatic sponges constructed by collagen fibers disintegrated from Halocynthia roretzi by a shortcut method

Recently, biomacromolecules have received considerable attention in hemostatic materials. Collagen, an ideal candidate for hemostatic sponges due to its involvement in the clotting process, has been facing challenges in extraction from raw materials, which is time-consuming, expensive, and limited by cultural and religious restrictions associated with traditional livestock and poultry sources. To address these issues, this study explored a new shortcut method that using wild Halocynthia roretzi (HR), a marine fouling organism, as a raw material for developing HR collagen fiber sponge (HRCFs), which employed urea to disrupt hydrogen bonds between collagen fiber aggregates. This method simplifies traditional complex manufacturing processes while utilized marine waste, thus achieving dual green in terms of raw materials and manufacturing processes. FTIR results confirmed that the natural triple-helical structure of collagen was preserved. HRCFs exhibit a blood absorption ratio of 2000-3500 %, attributed to their microporous structure, as demonstrated by kinetic studies following a capillary model. Remarkably, the cytotoxicity and hemolysis ratio of HRCFs are negligible. Furthermore, during in vivo hemostasis tests using rabbit ear and kidney models, HRCFs significantly reduce blood loss and shorten hemostasis time compared to commercial gelatin sponge and gauze, benefiting from the capillary effect and collagen's coagulation activity. This study provides new insights into the design of collagen-based hemostatic biomaterials, especially in terms of both raw material and green manufacturing processes.

Human urine-derived stem cell exosomes delivered via injectable GelMA templated hydrogel accelerate bone regeneration

The key to critical bone regeneration in tissue engineering relies on an ideal bio-scaffold coated with a controlled release of growth factors. Gelatin methacrylate (GelMA) and Hyaluronic acid methacrylate (HAMA) have been a novel topic of interest in bone regeneration while introducing appropriate nano-hydroxyapatite (nHAP) to improve its mechanical properties. And the exosomes derived from human urine-derived stem cells (human USCEXOs) have also been reported to promote osteogenesis in tissue engineering. The present study aimed to design a new GelMA-HAMA/nHAP composite hydrogel as a drug delivery system. The USCEXOs were encapsulated and slow-released in the hydrogel for better osteogenesis. The characterization of the GelMA-based hydrogel showed excellent controlled release performance and appropriate mechanical properties. The in vitro studies showed that the USCEXOs/GelMA-HAMA/nHAP composite hydrogel could promote the osteogenesis of bone marrow mesenchymal stem cells (BMSCs) and the angiogenesis of endothelial progenitor cells (EPCs), respectively. Meanwhile, the in vivo results confirmed that this composite hydrogel could significantly promote the defect repair of cranial bone in the rat model. In addition, we also found that USCEXOs/GelMA-HAMA/nHAP composite hydrogel can promote the formation of H-type vessels in the bone regeneration area, enhancing the therapeutic effect. In conclusion, our findings suggested that this controllable and biocompatible USCEXOs/GelMA-HAMA/nHAP composite hydrogel may effectively promote bone regeneration by coupling osteogenesis and angiogenesis.

Evaluating the Degradation Process of Collagen Sponge and Acellular Matrix Implants In Vivo Using the Standardized HPLC-MS/MS Method

The purpose of this study was to establish a collagen determination method based on an isotope-labeled collagen peptide as an internal reference via high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS), and using the established method to evaluate the degradation process of collagen-based implants in vivo. The specific peptide (GPAGPQGPR) of bovine type I collagen was identified with an Orbitrap mass spectrometer. Then, the quantification method based on the peptide detection with HPLC-MS/MS was established and validated, and then further used to analyze the degradation trend of the collagen sponge and acellular matrix (ACM) in vivo at 2, 4, 6, 8, 12, 16, and 18 weeks after implantation. The results indicate that the relative standard deviation (RSD) of the detection precision and repeatability of the peptide-based HPLC-MS/MS quantification method were 3.55% and 0.63%, respectively. The limitations of quantification and detection were 2.05 × 10−3 μg/mL and 1.12 × 10−3 μg/mL, respectively. The collagen sponge and ACM were completely degraded at 10 weeks and 18 weeks, respectively. Conclusion: A specific peptide (GPAGPQGPR) of bovine type I collagen was identified with an Orbitrap mass spectrometer, and a standardized HPLC-MS/MS-based internal reference method for the quantification of bovine type I collagen was established. The method can be used for the analysis of the degradation of collagen-based implants in vivo.