A Biodegradable Flexible Micro/Nano-Structured Porous Hemostatic Dental Sponge

Influence of the ozone treatment on the environmental degradation of poly-3-hydroxybutyrate

The effect of oxidation on the structure and properties of polyesters remains an urgent issue due to the prospects for regulating the stability of the polymer and modifying its surface. The available data on the effect of ozone on the structure and properties of poly-3-hydroxybutyrate (PHB), in particular on the rate of its destruction, are contradictory. So, the purpose of the work was to study the effect of ozone oxidation on structure and properties of PHB to find the impact of the ozone treatment on controlling the rate of the biodegradation in environmental conditions. The surface of PHB films was modified using ozone treatment to accelerate its biodegradation rate in soil. The essence of ozonation is in the accumulation of various oxygen-containing functional groups, which leads to increased intermolecular interaction of PHB chains, which leads to the hardening of the surface. It was shown that the ozone treatment of the surface slowed down the diffusion of destructors to the volume of the PHB and prevented the fragmentation of the film. In addition, the strength of the films after 5 h of ozonation increased from 25 to 42 MPa, but the wetting angle did not change and no significant change in the surface crystallinity were detected before the soil exposure of the films. The soil burial test showed an approximately 1.5-fold decrease in the biodegradation rate for the ozone-treated sample. This study demonstrated that the surface morphology created by ozone treatment formed a unique outer layer of a new morphology. Ozonated PHB films were more resistant to fragmentation and remained stable in the soil for 300 days, while the control sample of PHB completely decomposed in 240 days. The paper discusses the causes and consequences of these observations and the role of ozone treatment for the modification of PHB surface. The results obtained can be used to control the rate of degradation and to predict the behavior of sterilized products in the field of packaging, medical products, and products with a limited service life due to the understanding of mechanism of surface modification.

A highly compressible and expandable cellulose sponge with arch-like lamellar structures for non-compressible hemorrhage

The development of highly expandable sponges for non-compressible hemorrhage remains a challenge in both civilian and war scenarios. Herein, a cellulose-based highly expandable sponge with arch-like lamellar structure was prepared by introducing interlayer calcium ion cross-linking in the sponges obtained by bi-directional freezing. The cellulose sponge, which has an arched layered structure that can withstand large stress strain, is compressed into small sizes to enter narrow and deep bleeding points, and then expand about 11 times after liquid absorption to apply sufficient and constant pressure on the bleeding points. The sponge can quickly absorb a large amount of blood, causing blood cells to aggregate, and activate the coagulation pathway through carboxyl groups and calcium ions, and exhibit effective hemostatic performance in rat liver defect and femoral artery hemostasis models (blood loss was reduced to about 6.3 % compared with the untreated group). In conclusion, this highly compressible and expandable cellulose sponge with an arch-like lamellar structure is expected to be used for hemostasis of non-compressible hemorrhages.

In Vitro Hemostatic Activity of Novel Fish Gelatin-Alginate Sponge (FGAS) Prototype

A hemostatic sponge prototype was successfully synthesized from fish gelatin as an alternative to mammalian gelatin; it was mixed with alginate in certain combinations, double cross-linked with calcium ions, and gamma irradiated at a dose of 20 kGy to improve the characteristics and effectiveness of its function as a local hemostatic agent. There were improvements in the physicochemical and mechanical properties, porosity index, absorption capacity, biodegradation properties, biocompatibility, and hemocompatibility of the fish gelatin-alginate sponge (FGAS) prototypes compared with the pure fish gelatin sponge. Hemostatic activity tests showed that the means for clotting time, prothrombin time, and activated partial thromboplastin time were shorter in the FGAS prototype than in the negative control, and there was no significant difference compared with the commercial gelatin sponge. The hemostatic mechanism of the FGAS prototype combined a passive mechanism as a concentrator factor and an active mechanism through the release of calcium ions as a coagulation factor in the coagulation cascade process.

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.

An All-In-One Transient Theranostic Platform for Intelligent Management of Hemorrhage

Developing theranostic devices to detect bleeding and effectively control hemorrhage in the prehospital setting is an unmet medical need. Herein, an all-in-one theranostic platform is presented, which is constructed by sandwiching silk fibroin (SF) between two silver nanowire (AgNW) based conductive electrodes to non-enzymatically diagnose local bleeding and stop the hemorrhage at the wound site. Taking advantage of the hemostatic property of natural SF, the device is composed of a shape-memory SF sponge, facilitating blood clotting, with ≈82% reduction in hemostatic time in vitro as compared with untreated blood. Furthermore, this sandwiched platform serves as a capacitive sensor that can detect bleeding and differentiate between blood and other body fluids (i.e., serum and water) via capacitance change. In addition, the AgNW electrode endows anti-infection efficiency against Escherichia coli and Staphylococcus aureus. Also, the device shows excellent biocompatibility and gradually biodegrades in vivo with no major local or systemic inflammatory responses. More importantly, the theranostic platform presents considerable hemostatic efficacy comparable with a commercial hemostat, Dengen, in rat liver bleeding models. The theranostic platform provides an unexplored strategy for the intelligent management of hemorrhage, with the potential to significantly improve patients' well-being through the integration of diagnostic and therapeutic capabilities.

Efficacy of a New Hemostatic Dental Sponge in Controlling Bleeding, Pain, and Dry Socket Following Mandibular Posterior Teeth Extraction-A Split-Mouth Randomized Double-Blind Clinical Trial

AIMS

This study aimed to clinically evaluate of a novel gelatin-based biodegradable sponge after mandibular posterior teeth extraction to assess its abilities in controlling bleeding, pain, and dry socket compared a commercial sponge.

TRIAL DESIGN

In this study, 26 patients who needed the extraction of two mandibular molar teeth were selected and, in each patient, after tooth extraction, the prepared gelatin sponge was used in the test group and the commercial sponge was used in the control group in the form of a randomized, double-blind, split-mouth clinical trial. The sterile gauzes were used on top of each sponge to absorb the extra blood (unabsorbed blood of sponges) to assess the blood absorption amount. Also, the amount of bleeding was recorded for 1 and 4 h after extraction for two groups. The amount of pain was measured for 12, 24, and 48 h after tooth extraction by Visual Analogue Scale (VAS). All patients also returned for examination four days after extraction to assess the occurrence of dry socket.

RESULTS

The results showed that the average weight of absorbed blood by sterile gauze in the control group (6.32 ± 1.06 g) was higher than in test group (3.97 ± 1.1 g), e.g., the bleeding control was better for the test group (p < 0.05). Bleeding was observed to be significantly reduced in the test group within 1 h (p = 0.003), within 1-4 h (p = 0.002), and after 4 h (p = 0.042) post-operatively in comparison to the control group. The average pain decreased significantly over time in both groups and the reduction of the pain was significantly higher for the test group (p < 0.05). Just one dry socket case occurred in the control group.

CONCLUSION

The prepared sponge is recommended for use in dental surgeries because of its abilities in bleeding, pain, and dry socket control.