Properties of collagen-based hemostatic patch compared to oxidized cellulose-based patch

Development and Evaluation of Thrombin-Loaded Gelatin Hemostatic Sheets for Spinal Surgery Applications

Introduction

During spinal surgery, management of intraoperative bleeding and effective hemostasis are required to clearly visualize the surgical field and to safely perform procedures and positive postoperative outcomes. However, it is challenging to stop bleeding from the venous plexus around the dural sac due to the potential risk of neural tissue damage. We aimed to develop hemostatic sheets with appropriate characteristics for spinal surgery, such as softness, appropriate thickness, biodegradability, thrombin bioactivity, and minimal water-induced expansion.

Methods

Hemostatic sheets were made by dissolving bovine bone-derived gelatin in water and aerating it to form foam, followed by freeze-drying, crosslinking, and thrombin-soaking. Sheets A to H were produced with different gelatin concentrations, foam densities, and crosslinking times by additional heat treatment. The sheets were then soaked in thrombin solution for enhanced hemostasis. Material properties, such as density, tensile strength, biodegradability, and hemostatic capacity, were evaluated. Sheet efficacy was further assessed with liver bleeding and spinal venous plexus bleeding models in a miniature pig.

Results

High-density gelatin sheets showed stable shape retention in wet conditions and robust tensile strength. Sheets with higher density and more crosslinking had prolonged persistence in the pepsin test and lower biodegradability in vivo. Sheet B, produced from a 4% gelatin solution with heating at 155°C for 4 h, showed the best balance of properties, such as no deformation cracks, rapid water absorption, minimal expansion, and faster degradation within 10 weeks, compared with TachoSil and other sheets. In hemostasis models, Sheet B outperformed Avitene and TachoSil, achieving higher success rates in spinal (four out of six sites) and liver bleeding (five out of five sites) models.

Conclusions

A thrombin-loaded hemostatic sheet produced from 4% gelatin solution with a short heating time for crosslinking demonstrated well-balanced material properties, such as shape retention, biodegradability, and wet expansion rate, which resulted in effective hemostasis in in vivo models. These advances may contribute to surgical hemostatic applications.

A Malleable Collagen-Mimic that Undergoes Moisture-Induced Hardening for Gluing Hydrophilic Surfaces

A collagen-inspired helical protein-mimic has been synthesized via topochemical polymerization of a designed tripeptide monomer. In the monomer crystal, molecules arrange in a head-to-tail manner, forming supramolecular helices. The azide and alkyne of adjacent molecules in the supramolecular helix are proximally preorganized in a ready-to-react arrangement. On heating, the monomer crystals undergo regiospecific single-crystal-to-single-crystal azide-alkyne cycloaddition polymerization, yielding triazolyl- polypeptide. Polymerization softens the crystals, making the polymer malleable and mouldable. The polymer grains absorb moisture and form agglomerates through water-bridged adhesion, which hardens over time. The weight-bearing capacity of a mould made from this polymer increased by 50-fold due to moisture-induced hardening. We have demonstrated that this collagen-mimic can glue both biological specimens such as wood and bone and synthetic materials such as glass and paper. In vitro studies established the biocompatibility, making it an attractive bioinspired material for potential application as a bioadhesive.

Evaluation of toxicity, local biocompatibility, biodegradation, and systemic metabolism of cellulose/alginate/strontium apatite membranes implanted subcutaneously in mice

PURPOSE

To evaluate membranes originating from pure or oxidized bacterial cellulose (BC)/alginate/strontium apatite hydrogels regarding toxicity, biocompatibility, biodegradation and metabolism.

METHODS

The toxicity was measured by incubating the materials with Artemia salina for 24 h, and mortality and the 50% lethal concentration were determined in comparison to potassium dichromate by Probit analysis. Local biocompatibility and biodegradation were evaluated by subcutaneous assay in 75 Swiss mice; the test groups were compared to sham and collagen membrane at one, three and nine weeks. The histopathology of tissue irritation followed the ISO 10993-6 standard, and the integrity of the biomaterials scored by quartiles. Metabolic analysis of relative weight and the intensity of catalase, iodine and nitrite were carried out for liver, kidneys and tibias of the tested animals.

RESULTS

All cellulose-based materials were nontoxic, biocompatible, and none presented nitrosative stress. The oxidized BC was more resorbable, and the non-oxidized BC had greater renal biochemical reactivity.

CONCLUSION

The membranes suggest applicability as regenerative barriers. However, long-term studies in bone defects are necessary to elucidate their osteopromoting efficiency.

Evaluation of Different Commercial Sealing Hemostatic Patches for Their Selection as Reservoirs for Localized Intraperitoneal Chemotherapy

Peritoneal carcinomatosis (PC) is typically treated by cytoreductive surgery (CRS) and subsequent chemotherapy. Sealing hemostatic patches (HP) are often used during these surgeries to prevent complications such as uncontrolled bleeding. These HP are made of biomaterials like oxidized cellulose or collagen with a binding agent, and beyond their usual function, they could also be used as drug delivery systems (DDS) for localized intraperitoneal chemotherapy in the tissue attached. Our first aim was to characterize and compare three different commercial HP (TachoSil®, Hemopatch®, and VerisetTM). Hemopatch® emerged as the most suitable candidate due to its combination of properties, including slow degradation, high hydrophilicity, excellent biological fluid absorption capacity, and moderate adhesive capacity alongside hemostasis. Utilizing Hemopatch® as a scaffold, we developed a new device incorporating a hyaluronic acid hydrogel loaded with cisplatin or olaparib. This approach facilitated sustained drug release for over 6 days, maintaining the anticancer efficacy of these agents on OVCAR-3 cells. In conclusion, integrating a DDS into HP shows potential for precisely delivering chemotherapeutic agents to any residual microscopic disease in PC following CRS.

Efficacy of a novel polyoxazoline-based hemostatic patch in liver and spleen surgery

BACKGROUND

A new hemostatic sealant based on a N-hydroxy-succinimide polyoxazoline (NHS-POx) polymer was evaluated to determine hemostatic efficacy and long-term wound healing and adverse effects in a large animal model of parenchymal organ surgical bleeds.

METHODS

Experiment 1 included 20 pigs that were treated with two NHS-POx patch prototypes [a gelatin fibrous carrier (GFC) with NHS-POx and an oxidized regenerated cellulose (ORC) with poly(lactic-co-glycolic acid)-NHS-POx:NU-POx (nucleophilically activated polyoxazoline)], a blank gelatin patch (GFC Blank), TachoSil^® and Veriset™ to stop moderate liver and spleen punch bleedings. After various survival periods (1-6 weeks), pigs were re-operated to evaluate patch degradation and parenchymal healing. During the re-operation, experiment 2 was performed: partial liver and spleen resections with severe bleeding, and hemostatic efficacy was evaluated under normal and heparinized conditions of the two previous prototypes and one additional NHS-POx patch. In the third experiment an improved NHS-POx patch (GATT-Patch; GFC-NHS-POx and added 20% as nucleophilically activated polyoxazoline; NU-POx) was compared with TachoSil^®, Veriset™ and GFC Blank on punch bleedings and partial liver and spleen resections for rapid (10s) hemostatic efficacy.

RESULTS

NHS-POx-based patches showed better (GFC-NHS-POx 83.1%, ORC-PLGA-NHS-POx: NU-POx 98.3%) hemostatic efficacy compared to TachoSil^® (25.0%) and GFC Blank (43.3%), and comparable efficacy with Veriset™ (96.7%) on moderate standardized punch bleedings on liver and spleen. All patches demonstrated gradual degradation over 6 weeks with a reduced local inflammation rate and an improved wound healing. For severe bleedings under non-heparinized conditions, hemostasis was achieved in 100% for Veriset™, 40% for TachoSil and 80-100% for the three NHS-POx prototypes; similar differences between patches remained for heparinized conditions. In experiment 3, GATT-Patch, Veriset™, TachoSil and GFC Blank reached hemostasis after 10s in 100%, 42.8%, 7.1% and 14.3%, respectively, and at 3 min in 100%, 100%, 14.3% and 35.7%, respectively, on all liver and spleen punctures and resections.

CONCLUSIONS

NHS-POx-based patches, and particularly the GATT-Patch, are fast in achieving effective hemostatic sealing on standardized moderate and severe bleedings without apparent long-term adverse events.

Effect of naturally derived surgical hemostatic materials on the proliferation of A549 human lung adenocarcinoma cells

Hemostatic materials are generally applied in surgical operations for cancer, but their effects on the growth and recurrence of tumors are unclear. Herein, three commonly used naturally derived hemostatic materials, gelatin sponge, Surgicel (oxidized regenerated cellulose), and biopaper (mixture of sodium hyaluronate and carboxymethyl chitosan), were cocultured with A549 human lung adenocarcinoma cells in vitro. Furthermore, the performance of hemostatic materials and the tumorigenicity of the materials with A549 ​cells were observed after subcutaneous implantation into BALB/c mice. The in vitro results showed that biopaper was dissolved quickly, with the highest cell numbers at 2 and 4 days of culture. Gelatin sponges retained their structure and elicited the least cell infiltration during the 2- to 10-day culture. Surgicel partially dissolved and supported cell growth over time. The in vivo results showed that biopaper degraded rapidly and elicited an acute Th1 lymphocyte reaction at 3 days after implantation, which was decreased at 7 days after implantation. The gelatin sponge resisted degradation and evoked a hybrid M1/M2 macrophage reaction at 7–21 days after implantation, and a protumor M2d subset was confirmed. Surgicel resisted early degradation and caused obvious antitumor M2a macrophage reactions. Mice subjected to subcutaneous implantation of A549 ​cells and hemostatic materials in the gelatin sponge group had the largest tumor volumes and the shortest overall survival (OS), while the Surgicel and the biopaper group had the smallest volumes and the longest OS. Therefore, although gelatin sponges exhibited cytotoxicity to A549 ​cells in vitro, they promoted the growth of A549 ​cells in vivo, which was related to chronic M2d macrophage reaction. Surgicel and biopaper inhibited A549 ​cell growth in vivo, which is associated with chronic M2a macrophage reaction or acute Th1 lymphocyte reaction.

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The gelatin sponge, Surgicel and biopaper had different effects on A549 ​cell growth and proliferation.

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Biopaper degraded rapidly in vivo and elicited an antitumor Th1 lymphocyte reaction at acute inflammatory phase.

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The gelatin sponge resisted degradation and evoked a protumor M2d macrophage reactions.

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Surgicel resisted early degradation and caused obvious antitumor M2a macrophage reactions.

Hemostats in Spine Surgery: Literature Review and Expert Panel Recommendations

Bleeding in spine surgery is a common occurrence but when bleeding is uncontrolled the consequences can be severe due to the potential for spinal cord compression and damage to the central nervous system. There are many factors that influence bleeding during spine surgery including patient factors and those related to the type of surgery and the surgical approach to bleeding. There are a range of methods that can be employed to both reduce the risk of bleeding and achieve hemostasis, one of which is the adjunct use of hemostatic agents. Hemostatic agents are available in a variety of forms and materials and with considerable variation in cost, but specific evidence to support their use in spine surgery is sparse. A literature review was conducted to identify the pre-, peri-, and postsurgical considerations around bleeding in spine surgery. The review generated a set of recommendations that were discussed and ratified by a wider expert group of spine surgeons. The results are intended to provide a practical guide to the selection of hemostats for specific bleeding situations that may be encountered in spine surgery.

Evaluation of the safety and effectiveness of a sealant hemostatic patch for preventing cerebrospinal fluid leaks in cranial surgery

BACKGROUND

Cerebrospinal fluid (CSF) leak remains a significant source of morbidity after neurosurgical procedures. The objective is to evaluate the effectiveness and safety of a polyethylene glycol-coated collagen patch (PCC) in different neurosurgical procedures.

METHODS

A retrospective, single-center cohort study in patients who underwent a cranial neurosurgical procedure. After collecting multiple data variables, patients were divided into two groups depending on the use of PCC as sealant on dural closure following procedures.

RESULTS

Data from 230 patients were collected (PCC, 128; control group, 102). Incidence of CSF leakage was significantly lower in the PCC group (p < .001). Complications that were significantly lower in PCC than the control group included surgical infection (p = .022), and hydrocephalus (p = .017), as well as reduced rates of reintervention (p < .001) and shorter hospital stays (p = .028). Factors associated with a higher incidence of CSF leakage included posterior fossa procedures, reinterventions, and the need for CSF drainage placement. PCC reduced the risk of suffering CSF leakage by more than 75% (p = .002) once adjusted for age, surgical approach, type of cranial opening, reintervention, CSF drainage, dural substitute, and dural defect coverage.

CONCLUSIONS

Our findings confirm PCC as an effective means of preventing CSF leakage following cranial neurosurgery with fewer associated complications.

Emerging Functional Biomaterials as Medical Patches

Medical patches have been widely explored and applied in various medical fields, especially in wound healing, tissue engineering, and other biomedical areas. Benefiting from emerging biomaterials and advanced manufacturing technologies, great achievements have been made on medical patches to evolve them into a multifunctional medical device for diverse health-care purposes, thus attracting extensive attention and research interest. Here, we provide up-to-date research concerning emerging functional biomaterials as medical patches. An overview of the various approaches to construct patches with micro- and nanoarchitecture is presented and summarized. We then focus on the applications, especially the biomedical applications, of the medical patches, including wound healing, drug delivery, and real-time health monitoring. The challenges and prospects for the future development of the medical patches are also discussed.

Application and outlook of topical hemostatic materials: a narrative review

Bleeding complications can cause significant morbidities and mortalities in both civilian and military conditions. The formation of stable blood clots or hemostasis is essential to prevent major blood loss and death from excessive bleeding. However, the body's self-coagulation process cannot accomplish timely hemostasis without the assistance of hemostatic agents under some conditions. In the past two decades, topical hemostatic materials and devices containing platelets, fibrin, and polysaccharides have been gradually developed and introduced to induce faster or more stable blood clot formation, updating or iterating traditional hemostatic materials. Despite the various forms and functions of topical hemostatic materials that have been developed for different clinical conditions, uncontrolled hemorrhage still causes over 30% of trauma deaths across the world. Therefore, it is important to fabricate fast, efficient, safe, and ready-to-use novel hemostatic materials. It is necessary to understand the coagulation process and the hemostatic mechanism of different materials to develop novel topical hemostatic agents, such as tissue adhesives and sealants from various natural and synthetic materials. This review discusses the structural features of topical hemostatic materials related to the stimulation of hemostasis, summarizes the commercially available products and their applications, and reviews the ongoing clinical trials and recent studies concerning the development of different hemostatic materials.

Versatility and clinical effectiveness of a synthetic sealing hemostatic patch as alternative to parenchyma suturing in laparoscopic partial nephrectomy

BACKGROUND

Improvements in laparoscopic partial nephrectomy (LPN) in order to minimize perioperative warm ischemia time (WIT), complications, and consequently patient outcome are desirable. Veriset™ is a ready-to-use hemostatic patch of absorbable oxidized cellulose and hydrogel components that has earlier been implemented in vascular and hepatic surgery. We report our experience using this device in LPN.

METHODS

Patients with a solitary malignant renal mass suspicious for renal cancer underwent LPN with either the use of Veriset™ hemostatic patch (n = 40) or conventional suture technique (n = 40). Patient characteristics, operation time and WIT, postoperative course and complications were recorded retrospectively. Tumor complexity was calculated according to the R.E.N.A.L. score. Outcome was determined according to the "trifecta" criteria (negative surgical margin, WIT < 25 min, no complications within 30 days).

RESULTS

No significant differences with regard to clinical parameters and median R.E.N.A.L. score (6) were observed between both groups. Operation time (mean 127.1 min vs. 162. 8 min; p = 0.001) and WIT were both lower in the Veriset™ group (14.6 min vs. 20.6 min; p = 0.01). No differences in surgical margins (p = 0.602) and overall complication rates at 30 (p = 0.599) and 90 days (p = 0.611) postoperatively were noticed. The surgical outcome according to "trifecta" was achieved in 65% of patients using Veriset™ and in 57.5% of patients by suture closure, respectively.

CONCLUSION

The hemostatic Veriset™ patch can successfully be implemented in LPN. Handling and application appear favorable, thereby reducing operation time and WIT. The present results suggest that the device may represent an alternative to parenchyma suturing in LPN.

Oxidized cellulose-based hemostatic materials

The application of hemostatic agents is essential to prevent significant blood loss and death from excessive bleeding in surgical or emergency scenarios. Oxidized cellulose is an excellent biodegradable and biocompatible derivate of cellulose, which has become one of the most important hemostatic agents used in surgical procedures. However, to date, there has been no comprehensive report assessing oxidized cellulose-based hemostatic materials. Hence, this paper first reviewed the oxidation preparation, cellulose origin and structure, as well as biodegradability and safety of oxidized cellulose. Then a comprehensive review regarding the hemostatic mechanisms, various forms, modification, and current commercially available products of oxidized cellulose is discussed, which emphatically presents the most significant developments in the recent scientific literature. In conclusion, this paper summarizes the latest developments in oxidized cellulose-based hemostatic materials and provides a reference for further research and development in this field.

Degradable and Bioadhesive Alginate-Based Composites: An Effective Hemostatic Agent

The perfect hemostatic material should be capable of rapidly controlling substantial hemorrhaging from visceral organs, veins, and arteries. Ideally, it should be biodegradable, biocompatible, easily applied, and inexpensive. Herein, taking advantages of sodium alginate (SA), carboxymethyl chitosan (CMC), and collagen, a degradable powdery hemostatic composite (SACC) was synthesized using emulsification and cross-linking technology. The morphology and structure of SACC were determined using Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). This hemostatic material exhibited a typical generic sphere shape with narrow size distribution, rough surface, and satisfactory water absorption. Using in vitro bleeding and in vivo bleeding models (rat liver injury model and rat tail amputation model), it was shown that SACC had superior hemostatic actions compared to CMC and SA. Excellent cytocompatibility was proven during cytotoxicity tests and SEM observations. Histomorphological evaluation during the wound healing process proved the superior biocompatibility of SACC in a rat liver injury model. Biodegradability of SACC was demonstrated by immunofluorescence techniques both in vitro and in vivo. In summary, we have demonstrated the enormous potential of SACC, which has excellent hemostatic activity, biodegradability, and biocompatibility properties for use in clinical hemostasis applications.