Biodegradable quaternized silk fibroin sponge with highly uniform pore structure for traumatic hemostasis and anti-infection.

Developing a biodegradable sponge with rapid shape recovery and potent antibacterial and coagulation properties for traumatic hemostasis and anti-infection remains challenging. Herein, we fabricated quaternized silk fibroin (SF) sponges by freeze-drying under a constant cooling rate and modification with quaternary ammonium groups. We found the constant cooling rate enabled the sponges with a highly uniform pore structure, which provided excellent self-elasticity and shape recovery. Decoration with quaternary ammonium groups enhanced blood cells adhesion, aggregation, and activation, as well as resistance to infections from Staphylococcus aureus and Escherichia coli. The SF sponge had superior hemostatic capacity to gauze and commercial gelatin sponge in different hemorrhage models. The SF sponge exhibited favorable biodegradability and biocompatibility. Moreover, The SF sponge also promoted host cell infiltration, capillary formation, and tissue ingrowth, suggesting its potential for guiding tissue regeneration. The developed SF sponge holds great application prospects for traumatic hemostasis, anti-infection, and guiding tissue regeneration.

A macroporous composite sponge with high water absorbency and active coagulation mechanism for traumatic hemostasis and anti-infection.

The development of a composite sponge with high water absorbency and active coagulation mechanism for traumatic hemostasis and anti-infection remains a challenge. Herein, we developed a composite sponge using gelation, swelling, and freeze-drying methods based on quaternized chitosan, succinimidyl-modified F127, and bioactive glass. The sponge exhibited macroporous structure, high porosity, and water absorbency. When exposed to blood, it strongly interacted with blood cells, promoting their adhesion, aggregation, and activation. Moreover, it activated the intrinsic coagulation pathway. The sponge/powder demonstrated superior hemostatic capacity to commercial gauze, gelatin sponge, Yunnan Baiyao, and chitosan hemostatic powder in rat tail amputation, liver superficial injury, liver resection, and liver semi-perforation wound models. The sponge also presented robust anti-infection activity against methicillin-resistantStaphylococcus aureusandEscherichia coli. Additionally, the sponge showed low cytotoxicity, hemolysis activity, inflammation response, and systemic toxicity, demonstrating its favorable biocompatibility.

A self-elastic chitosan sponge integrating active and passive hemostatic mechanisms for effectively managing uncontrolled coagulopathic hemorrhage.

Developing a self-elastic sponge integrating active and passive hemostatic mechanisms for the effective management of uncontrolled coagulopathic hemorrhage remains a challenge. We here developed a chitosan-based sponge by integrating freeze-drying, chemical decoration of alkyl chains and phosphate groups, and physical loading of thrombin. The sponge exhibited high mechanical strength, self-elasticity, and rapid shape recovery. The sponge facilitated blood cell adhesion, aggregation, and activation through hydrophobic and electrostatic interactions, as well as accelerated blood clotting. The sponge exhibited higher efficacy than commercial gauze and gelatin sponge in managing uncontrolled hemorrhage from heparinized rat tail amputation, liver superficial injury, and liver perforating wound models. In addition, the sponge exhibited favorable biodegradability and biocompatibility. These findings revealed that the developed sponge holds great potential as a novel hemostat for effectively managing uncontrolled coagulopathic hemorrhage from superficial and perforating wounds.

Three-dimensional echo light field analysis for dual-band laser active detection of a cat-eye optical system.

Laser active detection technology utilizing the cat-eye effect provides rapid response, precise positioning, and long detection distances. However, current research mainly focuses on active detection within a single visible or near-infrared band, lacking quantitative analyses of the echo spot. In this paper, a four-interval theoretical model for dual band cat-eye target echo detection was constructed using matrix optics theory and Collins diffraction integration method. Dual-band echo detection experiments were conducted using 10.6 um far-infrared waves and 532 nm visible light waves, also the power, radius, and target-missing quantities of the echo spots were collected and quantitatively compared with the theoretical results. Results indicate that, due to the diffraction limit's effect on the distribution of the echo field, the echo power of far-infrared band detection is smaller than that of visible light band detection. The impact on the light spot caused by the positive and negative defocus values is asymmetric, with positive defocus having a lower impact on the echo spot than negative defocus at the same value. A weak positive defocus value that minimizes the radius of the echo spot and maximizes the echo power exists, with the value of weak positive defocus varying between detection bands. A linear relationship exists between the incident angle of the detection laser and the deviation of the echo spot. These findings provide a foundation for extracting working band details, predicting the motion trajectory of moving cat-eye targets, and achieving real-time tracking and detection recognition during laser active detection.

Microchannelled alkylated chitosan sponge to treat noncompressible hemorrhages and facilitate wound healing.

Developing an anti-infective shape-memory hemostatic sponge able to guide in situ tissue regeneration for noncompressible hemorrhages in civilian and battlefield settings remains a challenge. Here we engineer hemostatic chitosan sponges with highly interconnective microchannels by combining 3D printed microfiber leaching, freeze-drying, and superficial active modification. We demonstrate that the microchannelled alkylated chitosan sponge (MACS) exhibits the capacity for water and blood absorption, as well as rapid shape recovery. We show that compared to clinically used gauze, gelatin sponge, CELOX™, and CELOX™-gauze, the MACS provides higher pro-coagulant and hemostatic capacities in lethally normal and heparinized rat and pig liver perforation wound models. We demonstrate its anti-infective activity against S. aureus and E. coli and its promotion of liver parenchymal cell infiltration, vascularization, and tissue integration in a rat liver defect model. Overall, the MACS demonstrates promising clinical translational potential in treating lethal noncompressible hemorrhage and facilitating wound healing.

Influence of Cu on the Improvement of Magnetic Properties and Structure of L10 FePt Nanoparticles.

L10 ordered FePt and FePtCu nanoparticles (NPs) with a good dispersion were successfully fabricated by a simple, green, one-step solid-phase reduction method. Fe (acac)3, Pt (acac)2, and CuO as the precursors were dispersed in NaCl and annealed at different temperatures with an H2-containing atmosphere. As the annealing temperature increased, the chemical order parameter (S), average particle size (D), coercivity (Hc), and saturation magnetization (Ms) of FePt and FePtCu NPs increased and the size distribution range of the particles became wider. The ordered degree, D, Hc, and Ms of FePt NPs were greatly improved by adding 5% Cu. The highest S, D, Hc, and Ms were obtained when FePtCu NPs annealed at 750 °C, which were 0.91, 4.87 nm, 12,200 Oe, and 23.38 emu/g, respectively. The structure and magnetic properties of FePt and FePtCu NPs at different annealing temperatures were investigated and the formation mechanism of FePt and FePtCu NPs were discussed in detail.

Biomimetic Design of Mitochondria-Targeted Hybrid Nanozymes as Superoxide Scavengers.

Development of enzyme mimics for the scavenging of excessive mitochondrial superoxide (O2 •- ) can serve as an effective strategy in the treatment of many diseases. Here, protein reconstruction technology and nanotechnology is taken advantage of to biomimetically create an artificial hybrid nanozyme. These nanozymes consist of ferritin-heavy-chain-based protein as the enzyme scaffold and a metal nanoparticle core as the enzyme active center. This artificial cascade nanozyme possesses superoxide dismutase- and catalase-like activities and also targets mitochondria by overcoming multiple biological barriers. Using cardiac ischemia-reperfusion animal models, the protective advantages of the hybrid nanozymes are demonstrated in vivo during mitochondrial oxidative injury and in the recovery of heart functionality following infarction via systemic delivery and localized release from adhesive hydrogels (i.e., cardiac patch), respectively. This study illustrates a de novo design strategy in the development of enzyme mimics and provides a promising therapeutic option for alleviating oxidative damage in regenerative medicine.

Targeted Repair of Vascular Injury by Adipose-Derived Stem Cells Modified with P-Selectin Binding Peptide.

Percutaneous coronary intervention for coronary artery disease treatment often results in pathological vascular injury, characterized by P-selectin overexpression. Adipose-derived stem cells (ADSCs) therapeutic efficacy remains elusive due to poor ADSCs targeting and retention in injured vessels. Here, conjugated P-selectin binding peptide (PBP) to polyethylene glycol-conjugated phospholipid derivative (DMPE-PEG) linkers (DMPE-PEG-PBP; DPP) are used to facilitate the modification of PBP onto ADSCs cell surfaces via hydrophobic interactions between DMPE-PEG and the phospholipid bilayer. DPP modification neither has influence on ADSCs proliferation nor apoptosis/paracrine factor gene expression. A total of 5 × 10-6 m DPP-modified ADSCs (DPP-ADSCs) strongly binds to P-selectin-displaying activated platelets and endothelial cells (ECs) in vitro and to wire-injured rat femoral arteries when administered by intra-arterial injection. Targeted binding of ADSCs shields injury sites from platelet and leukocyte adhesion, thereby decreasing inflammation at injury sites. Furthermore, targeted binding of ADSCs recovers injured ECs functionality and reduces platelet-initiated vascular smooth muscle cells (VSMCs) chemotactic migration. Targeted binding of DPP-human ADSCs to balloon-injured human femoral arteries is also demonstrated in ex vivo experiments. Overall, DPP-ADSCs promote vascular repair, inhibit neointimal hyperplasia, increase endothelium functionality, and maintain normal VSMCs alignment, supporting preclinical noninvasive utilization of DPP-ADSCs for vascular injury.

An anti-infective hydrogel adhesive with non-swelling and robust mechanical properties for sutureless wound closure.

A non-swelling hydrogel adhesive is urgently needed in clinical application for wound closure; however, preparing a non-swelling hydrogel adhesive with superior mechanical and tissue adhesion properties remains a challenge. In this study, we developed a new family of non-swelling hydrogel adhesives composed of Pluronic F127 diacrylate, poly(ethylene glycol) diacrylate, modified sodium alginate, and tannic acid. Physical and biological properties of the hydrogels were systematically evaluated in vitro/vivo. The results indicated that the hydrogels exhibited non-swelling features, robust mechanical properties and good adhesion abilities toward various tissues. The hydrogels also exhibited good cytocompatibility and strong antibacterial activities against S. aureus and E. coli. Additionally, the hydrogel could be used for sutureless wound closure and displayed better advantages compared to sutures and commercial adhesive pads. The above results demonstrated that our non-swelling hydrogel adhesive with robust mechanical properties holds great promise for applications in clinical surgery.

Anti-Infective and Pro-Coagulant Chitosan-Based Hydrogel Tissue Adhesive for Sutureless Wound Closure.

Multifunctional tissue adhesives with excellent adhesion, antibleeding, anti-infection, and wound healing properties are desperately needed in clinical surgery. However, the successful development of multifunctional tissue adhesives that simultaneously possess all these properties remains a challenge. We have prepared a novel chitosan-based hydrogel adhesive by integration of hydrocaffeic acid-modified chitosan (CS-HA) with hydrophobically modified chitosan lactate (hmCS lactate) and characterized its gelation time, mechanical properties, and microstructure. Tissue adhesion properties were evaluated using both pigskin and intestine models. In situ antibleeding efficacy was demonstrated via the rat hemorrhaging liver and full-thickness wound closure models. Good antibacterial activity and anti-infection capability toward S. aureus and P. aeruginosa were confirmed using in vitro contact-killing assays and an infected pigskin model. The result of coculturing with 3T3 fibroblast cells indicated that the hydrogels have no significant cytotoxicity. Most importantly, the biocompatible and biodegradable CS-HA/hmCS lactate hydrogel was able to close the wound in a sutureless way and promote wound healing. Our results demonstrate that this hydrogel has great promise for sutureless closure of surgical incisions.

Injectable hydrogel composed of hydrophobically modified chitosan/oxidized-dextran for wound healing.

An injectable hydrogel dressing with multifunctional properties of superior hemostasis, antibacterial activity, tissue adhesive and cytocompatibility is desirable candidate in wound healing. In this study, we developed a novel hydrogel dressing composed of hydrophobically modified chitosan (hmCS) and oxidized dextran (OD). The gelation time, microstructure, injectability, self-healing and rheological properties were characterized. The in vitro ability of the precursor solution of the hydrogels to coagulate heparinized whole blood was confirmed. The in vivo hemostatic activity was demonstrated in a rat hemorrhaging liver model. The antibacterial activity against S. aureus and P. aeruginosa was evaluated in vitro through surface antibacterial test. The corresponding killing efficiencies were up to 95.0% and 96.4% at bacterial concentration of 108 CFU/mL. The cytotoxicity was examined by co-culturing with 3 T3 fibroblast cells. The wound healing functions were further verified with an infected wound model of rat skin. The aforementioned findings demonstrated that the hydrogel with multifunctional activities has potential for hemorrhagic and infected wound healing.

Multifunctional Hydrogel Patch with Toughness, Tissue Adhesiveness, and Antibacterial Activity for Sutureless Wound Closure.

A multifunctional hydrogel patch with a combination of high toughness, superior adhesion, and good antibacterial effect is a highly desired surgical material. In this study, we developed a novel hydrogel patch composed of poly(ethylene glycol) diacrylate/quaternized chitosan/tannic acid (PEGDA/QCS/TA) based on mussel-inspired chemistry. The physical and biological properties of the hydrogel patch were systematically evaluated in vitro and in vivo. The results indicated that this hydrogel patch possessed compact microstructure, low swelling ratio, tough mechanical properties, good antibacterial activities against S. aureus and E. coli, and excellent dry/wet adhesive ability to a wide range of substrates. The hydrogel patch could also be degraded and absorbed in vivo and used as a sutureless material for wound closure. All these findings demonstrate that the PEGDA/QCS/TA hydrogel patch with multifunctional properties has great potential for application in biomedical fields.