Polydopamine functionalized polyurethane shape memory sponge with controllable expansion performance triggered by near-infrared light for incompressible hemorrhage control.

Uncontrolled expansion of shape memory sponges face a significant challenge in the treatment of lethal incompressible hemorrhage, which can lead to blood overflow or damage to the surrounding tissue. Herein, we developed a polydopamine functionalized polyurethane shape memory sponge (PDA-TPI-PU) with a controllable degree of expansion by near-infrared (NIR) light-triggered stimulation for the treatment of incompressible hemorrhage. The sponge has excellent liquid absorption performance and robust mechanical strength as well as good photothermal conversion ability. Under NIR light of 0.32 W/cm2, the maximum recovery rate of the fixed-shape compression sponge was 91% within 25 s in air and 80% within 25 s in blood. In the SD rat liver penetrating injury model, compared with commercial medical gelatin sponge and PVA sponge, the PDA-TPI-PU sponge could effectively control the bleeding under the NIR light irradiation and did not cause excessive compression of the wound. The sponge with these characteristics shows potential application prospects as a hemostatic material.

Gelatin Methacryloyl-Based Sponge with Designed Conical Microchannels for Rapidly Controlling Hemorrhage and Theoretical Verification.

It remains a challenge to develop effective hemostatic products in battlefield rescue for noncompressible massive hemorrhage. Some previous research had concentrated on the modification of different materials to improve the hemostasis ability of sponges. Herein, to investigate the relationship between the taper of microchannels and hemostatic performance of porous sponges, gelatin methacryloyl-based sponges with designed conical microchannels and a disordered porous structure were prepared using the 3D printing method and freeze-drying technology. Experiments and theoretical model analysis demonstrated that the taper and distribution of microchannels in the sponge affected the water and blood absorption properties, as well as the expansion ability. In treatment of SD rat liver defect and SD rat liver perforation wound, GS-1 sponge with the taper (1/15) microchannels exhibited an excellent hemostatic effect with blood loss of 0.866 ± 0.093 g and a hemostasis time of 280 ± 10 s. Results showed that the hemostatic capacities of GelMA sponges were increased with the bottom diameter (taper) of conical microchannels. This is a potential strategy to develop designed taper sponges with designed taper microchannels for rapidly controlling hemorrhage.

Photo-controllable burst generation of peroxynitrite based on synergistic interactions of polymeric nitric oxide donors and IR780 for enhancing broad-spectrum antibacterial therapy.

The newly attractive peroxynitrite (ONOO-) therapy can prominently enhance antibacterial therapeutic efficacy. However, it is a great challenge but urgently needed to generate ONOO- with adjustable release rate and dosage in order to satisfy personalized treatments for different disease types and severities. Herein, PSNO@IR780 nanoparticles are fabricated via co-assembly of an amphiphilic PEG-b-PAASNO block copolymer grafted with abundant nitric oxide (NO) donor units and IR780 as a photothermal and photodynamic agent. Photo-controllable burst generation of ONOO- from PSNO@IR780 nanoparticles could be realized based on synergistic reactions of rapid NO release induced by increased local temperature and efficiently produced superoxide anion radical (O2•-) from IR780. The maximum ONOO- release dosage is up to 6.73 ± 0.07 µM and release rate is up to 98.1 ± 1.38 nM/s. Furthermore, the ONOO- release behavior can be precisely manipulated by varying sample concentrations, irradiated durations, output power densities, and laser switches, respectively. Ultra-efficiently generated ONOO- from biocompatible PSNO@IR780 nanoparticles significantly elevated broad spectrum antibacterial efficiency through damaging bacterial membranes. Thus, PSNO@IR780 nanoparticles may present a new insight into preparation of burst and controllable generating ONOO- materials, and provide new opportunities for antibacterial therapy. STATEMENT OF SIGNIFICANCE: 1. Polymeric NO donor (PEG-b-PAASNO) grafted with abundant NO donor units was synthesized. 2. PSNO@IR780 nanoparticles were prepared by co-assembly of IR780 and amphiphilic PEG-b-PAASNOpolymer. 3. The maximum ONOO- release dosage from PSNO@IR780 nanoparticles was 6.73 ± 0.08 µM. 4. The fastest ONOO- release rate from PSNO@IR780 nanoparticles was 98.1 ± 1.4 nM/s. 5. Ultra-efficiently generated ONOO- significantly elevated antibacterial efficiency via damaging bac-terial membranes.

Poly(trimethylene carbonate) flexible intestinal anastomosis scaffolds to reduce the probability of intestinal fistula and obstruction.

Biodegradable anastomat play an important role in the reconstruction process of the digestive tract. However, the biocompatibility and organizational compliance of anastomotic tubes still need to be improved. Electrospun tissue engineering scaffolds have excellent biomimetic extracellular matrix properties, biocompatibility and biodegradability. In the present study, electrospun poly(trimethylene carbonate) (PTMC) intestinal anastomosis scaffolds loaded with triclosan (TCS) were reported to reduce the probability of intestinal fistula and obstruction. When the viscosity average molecular weight of PTMC was 157 × 103, the elastic modulus and tensile strength of the anastomosis scaffolds could reach 20.11 MPa and 16.08 MPa, respectively, which indicated that the anastomosis scaffolds exhibited excellent tensile flexibility. The degradation of PTMC was accelerated with the increase of Mw. After 28 days, the weight and length of the anastomosis scaffolds reduced 40% and 50%, respectively. Furthermore, the application of PTMC anastomosis scaffolds could promote intestinal healing and reduce the probability of intestinal fistula and obstruction.

Fabricating poly(vinyl alcohol)/gelatin composite sponges with high absorbency and water-triggered expansion for noncompressible hemorrhage and wound healing.

It is challenging for traditional hemostatic sponges to control massive and noncompressible hemorrhages in the military field and accidental trauma. In this work, a series of highly fluid-absorbent composite sponges with rapid expansion ability based on norbornene anhydride-modified poly(vinyl alcohol) and gelatin (PVA@Gel-Sps) were developed by a foaming technique, chemical and physical crosslinking reactions and lyophilization. The prepared PVA@Gel-Sp2 exhibited a 3500% maximum water absorption ratio with a fast water absorption speed, which was suitable for blood component concentration. Owing to its interconnected macroporous structure, robust mechanical strength and high resilience, the compressed sponge could rapidly re-expand to more than 10 times its volume in response to water and blood. Moreover, due to the synergistic effect of the PVA-based sponge and gelatin, PVA@Gel-Sp2 could obviously shorten the hemostasis time and reduce blood loss in SD rat liver defect noncompressible hemorrhage models, and exhibited better wound healing effects in a full-thickness skin defect model than commercial sponges. These results suggest that PVA@Gel-Sp2 is a potential candidate for controlling noncompressible hemorrhage and promoting wound healing.

Alginate-based composite microspheres coated by berberine simultaneously improve hemostatic and antibacterial efficacy.

It is important to develop effective, biocompatible, easily stored and affordable hemostats for controlling bleeding and preventing infection in prehospital trauma. In this study, we synthesized a series of alginate-based composite microspheres coated by different amounts of berberine (SCC-1B, SCC-5B and SCC-10B), which were further characterized using scanning electron microscopy (SEM), viscometer, particle analyzer and Fourier transform infrared (FT-IR) spectroscopy. The in vitro and vivo results demonstrated that compared to control group (SCC, Composite polysaccharide microspheres without berberine, and CMPHP, Commercial hemostatic agent), SCC-10B with proper content berberine (7%), not only exhibited inherent excellent antibacterial activity, but also enhanced hemostatic effect by increasing adhesion and aggregation of blood cells, which could be considered as synergistic effects. More importantly, through inserting berberine into the cross-linked network, biodegradability and biocompatibility of SCC-10B were also improved. Taken together, SCC-10B could be a candidate for emergency hemostatic and antibacterial treatment in prehospital trauma.

Microspheres of Carboxymethyl Chitosan, Sodium Alginate, and Collagen as a Hemostatic Agent in Vivo.

In the search for biocompatible composite microspheres to be used as a hemostatic agent, in a previous study, we designed a novel biomaterial, consisting of composite microspheres containing three natural biological ingredients, carboxymethyl chitosan, sodium alginate and collagen (CSCM). Furthermore, the chemical and physical properties, hemostatic ability, biocompatibility and cytotoxicity were investigated in vitro. In this work, the in vivo hemostatic performance, wound healing, hemocompatibility, histocompatibility, and biodegradability were evaluated by a series of experiments. The results showed that CSCM could both stop bleeding and enhance healing efficiency by accelerating the clotting and the wound closure rate, suggesting that CSCM acts as a hemostat, and enhances wound healing. In addition, the CSCM material had negligible intracutaneous stimulation reactions and no obvious hemolytic reactions. More importantly, CSCM can be degraded in vivo without significant impacts on physiology, biochemistry, and organization. Thus, CSCM may be a useful tool to stop bleeding in emergency conditions in both military and civilian settings.