Coagulant Protein-Free Blood Coagulation Using Catechol-Conjugated Adhesive Chitosan/Gelatin Double Layer.

Since the discovery of polyphenolic underwater adhesion in marine mussels, researchers strive to emulate this natural phenomenon in the development of adhesive hemostatic materials. In this study, bio-inspired hemostatic materials that lead to pseudo-active blood coagulation, utilizing traditionally passive polymer matrices of chitosan and gelatin are developed. The two-layer configuration, consisting of a thin, blood-clotting catechol-conjugated chitosan (CHI-C) layer and a thick, barrier-functioning gelatin (Geln) ad-layer, maximizes hemostatic capability and usability. The unique combination of coagulant protein-free condition with CHI-C showcases not only coagulopathy-independent blood clotting properties (efficacy) but also exceptional clinical potential, meeting all necessary biocompatibility evaluation (safety) without inclusion of conventional coagulation triggering proteins such as thrombin or fibrinogen. As a result, the CHI-C/Geln is approved by the Ministry of Food and Drug Safety (MFDS, Republic of Korea) as a class II medical device. Hemostatic efficacy observed in multiple animal models further demonstrates the superiority of CHI-C/Geln sponges in achieving quick hemostasis compared to standard treatments. This study not only enriches the growing body of research on mussel-inspired materials but also emphasizes the potential of biomimicry in developing advanced medical materials, contributing a promising avenue toward development of readily accessible and affordable hemostatic materials.

A multicenter, prospective, randomized clinical trial of marine mussel-inspired adhesive hemostatic materials, InnoSEAL Plus.

PURPOSE: InnoSEAL Plus is an adhesive, coagulant-free hemostatic material that mimics the adhesion mechanism of marine mussels. This study reports on the safety and efficacy of InnoSEAL Plus for patients with hemorrhage after hepatectomy despite first-line hemostasis treatments. METHODS: This is a multicenter, prospective, single-blinded, randomized clinical trial involving 96 hepatectomy patients. TachoSil was used as a comparator group. Three-minute and 10-minute hemostatic success rates were monitored. Rebleeding rates were also observed. Safety was assessed by recording all novel undesirable symptoms. RESULTS: InnoSEAL Plus showed a 3-minute hemostasis rate of 100%, while TachoSil had a rate of 98.0% (48 of 49 patients), demonstrating that the 2 had similar hemostatic efficacies. The difference in efficacy between the test and comparator group was 2.04%, and the lower limit of the one-sided 97.5% confidence interval was -1.92%; as this is greater than the noninferiority limit of -23.9%, the 2 treatments were equivalent. Meanwhile, the 10-minute hemostatic success rate was the same in both groups (100%). No rebleeding occurred in either group. In the safety evaluation, 89 patients experienced adverse events (45 in the test group and 44 in the comparator group). The difference between the 2 groups was not significant. No death occurred after application of the test or comparator group product. CONCLUSION: Given that InnoSEAL Plus is a coagulation factor-free product, the hemostasis results are encouraging, especially considering that TachoSil contains a coagulation factor. InnoSEAL Plus was found to be a safe and effective hemostatic material for control of bleeding in hepatectomy patients.

Self-sealing hyaluronic acid-coated 30-gauge intravitreal injection needles for preventing vitreous and drug reflux through needle passage.

Self-sealing hyaluronic acid (HA)-coated self-sealing 30-gauge needles exhibiting instant leakage prevention of intravitreal humor and injected drug were developed in this study. Ninety New Zealand rabbits were used in this study. We assessed dye regurgitation in intravitreal ICG dye injections using HA-coated needles (HA needle group) and conventional needles (control group). Vitreous humor levels of anti-vascular endothelial growth factor (VEGF) were compared between groups one, three, and seven days after intravitreal bevacizumab (0.016 mL) injections. Expression levels of inflammatory cytokines in the aqueous humor and vitreous humor, including prostaglandin E2 (PGE2), interferon-γ, tumor necrosis factor-α, interleukin (IL)-1ß, IL-4, IL-6, IL-17, and IL-8, were compared between HA needle, control, and normal (in which intravitreal injection was not performed) groups following 12 intravitreal injections over a period of one week. In the HA needle group, HA remained at the injection site and blocked the hole after intravitreal injection. Dye regurgitation occurred significantly less frequently in the HA needle group (16.7%) than the control group (55.6%) after intravitreal ICG dye injection. Meanwhile, vitreous anti-VEGF levels were markedly higher in the HA needle group than the control group one and three days after intravitreal bevacizumab injections. After 12 intravitreal injections, expression levels of aqueous and vitreous IL-8 significantly increased in the control group compared to the HA needle and normal groups. Conversely, there were no significant differences in the expression of the other seven cytokines among the three groups. Intravitreal injections using HA-coated self-sealing 30-gauge needles can block the outflow of vitreous humor and drugs through the needle passage.

Endoscopic application of mussel-inspired phenolic chitosan as a hemostatic agent for gastrointestinal bleeding: A preclinical study in a heparinized pig model.

Marine mussels secrete adhesive proteins to attach to solid surfaces. These proteins contain phenolic and basic amino acids exhibiting wet adhesion properties. This study used a mussel-inspired hemostatic polymer, chitosan-catechol, to treat gastrointestinal bleeding caused by endoscopic mucosal resection in a heparinized porcine model. We aimed to evaluate the hemostatic efficacy and short-term safety of this wet adhesive chitosan-catechol. We used 15 heparinized pigs. Four iatrogenic bleeding ulcers classified as Forrest Ib were created in each pig using an endoscopic mucosal resection method. One ulcer in each pig was untreated as a negative control (no-treatment group). The other three ulcers were treated with gauze (gauze group), argon plasma coagulation (APC group), and chitosan-catechol hemostatic agent (CHI-C group) each. The pigs were sacrificed on Days 1, 5, and 10, and histological examination was performed (n = 5 per day). Rapid hemostasis observed at 2 min after bleeding was 93.3% (14/15) in the CHI-C group, 6.7% (1/15) in the no-treatment group, 13.3% (2/15) in the gauze group, and 86.7% (13/15) in the APC group. No re-bleeding was observed in the CHI-C group during the entire study period. However, a few re-bleeding cases were observed on Day 1 in the no-treatment, gauze, and APC groups and on Day 5 in the gauze and APC groups. On histological analysis, the CHI-C group showed the best tissue healing among the four test groups. Considering the results, chitosan-catechol is an effective hemostatic material with reduced re-bleeding and improved healing.

Coagulopathy-independent, bioinspired hemostatic materials: A full research story from preclinical models to a human clinical trial.

Since the first report of underwater adhesive proteins of marine mussels in 1981, numerous studies have reported mussel-inspired synthetic adhesive polymers. However, none of them have developed up to human-level translational studies. Here, we report a sticky polysaccharide that effectively promotes hemostasis from animal bleeding models to first-in-human hepatectomy. We found that the hemostatic material instantly generates a barrier layer that seals hemorrhaging sites. The barrier is created within a few seconds by in situ interactions with abundant plasma proteins. Therefore, as long as patient blood contains proper levels of plasma proteins, hemostasis should always occur even in coagulopathic conditions. To date, insufficient tools have been developed to arrest coagulopathic bleedings originated from genetic disorders, chronic diseases, or surgical settings such as organ transplantations. Mussel-inspired adhesion chemistry described here provides a useful alternative to the use of fibrin glues up to a human-level biomedical application.

Chitosan-catechol: a writable bioink under serum culture media.

Mussel-inspired adhesive coatings on biomedical devices have attracted significant interest due to their unique properties such as substrate independency and high efficiency. The key molecules for mussel-inspired adhesive coatings are catechol and amine groups. Along with the understanding of catechol chemistry, chitosan-catechol has also been developed as a representative mussel-inpired adhesive polymer that contains catechol and amine groups for adhesiveness. Herein, we demonstrated the direct writability of chitosan-catechol as a bioink for 3D printing, one of the additive techniques. The use of chitosan-catechol bioink results in the formation of 3D constructs in normal culture media via rapid complexation of this bioink with serum proteins; in addition, the metal/catechol combination containing tiny amounts of vanadyl ions, in which the ratio of metal to catechol is 0.0005, dramatically enhances the mechanical strength and printability of the cell-encapsulated inks, showing a cell viability of approximately 90%. These findings for mussel-inspired bioinks will be a promising way to design a biocompatible 3D bioink cross-linked without any external stimuli.

Modification of polyglutamic acid with silanol groups and calcium salts to induce calcification in a simulated body fluid.

The formation of hydroxyapatite is important for artificial materials to show high biological affinities for bone tissue. The present study focused on the synthesis of hydrogels capable of showing apatite formation, through modification of polyglutamic acid (PGA) with 3-aminopropyltriethoxysilane (APTES), followed by treatment with calcium chloride solution. A transparent bulk hydrogel was obtained at a molar ratio of PGA/APTES of 0.5. Prior soaking of the PGA hydrogel in calcium chloride solution accelerated the formation of bone-like apatite in a simulated body fluid. The modified PGA hydrogel is a candidate material for a biodegradable scaffold for bone regeneration.

In vitro apatite formation on organic-inorganic hybrids in the CaO-SiO(2)-PO (5/2)-poly(tetramethylene oxide) system.

The osteoconduction potential of artificial materials is usually evaluated in vitro by apatite formation in a simulated body fluid (SBF) proposed by Kokubo and his colleagues. This paper reports the compositional dependence of apatite formation on organic-inorganic hybrids in the CaO-SiO(2)-PO(5/2)-poly(tetramethylene oxide) system, initiated from tetraethoxysilane (TEOS), triethyl phosphate (OP(OEt)(3)), calcium chloride (CaCl(2)) and poly(tetramethylene oxide)(PTMO) modified with alkoxysilane. Formation of an apatite layer was observed on the surface of the organic-inorganic hybrids with molar ratios of TEOS/OP(OEt)(3) ranging from 100/0 to 20/80. The rate of apatite formation remarkably decreased when the hybrids were synthesized with TEOS/OP(OEt)(3) ratios of 40/60 or less. Hybrids without TEOS showed no apatite formation in SBF for up to 14 days. Addition of small amounts of OP(OEt)(3) to TEOS in the hybrids led to the high dissolution of calcium and silicate, while addition of large amounts of OP(OEt)(3) decreased the dissolution of calcium and silicate ions and resulted in reduced apatite formation regardless of the dissolution of phosphate ions from the hybrids.