[Progress in antibacterial coatings of titanium implants surfaces].

In recent years, bone implant materials such as titanium and titanium alloys have been widely used in the biomedical field due to their excellent mechanical properties and good biocompatibility. However, in clinical practice, bacterial adhesion to the material surface and postoperative infection issues may lead to implantation failure. Based on the antibacterial mechanism, this review elaborated on the antibacterial surface design of titanium implants from the aspects of anti-bacterial adhesion, contact sterilization and photocontrol sterilization. Surface modification of titanium or titanium-based alloy implants with different techniques can inhibit bacteria and promote osseointegration. Thus, the application range of multifunctional titanium-based implants in the field of orthopedics will be expanded.

[Progress in preparation and application of sodium alginate microspheres].

Sodium alginate (SA) is a kind of natural polymer material extracted from kelp, which has excellent biocompatibility, non-toxicity, biodegradability and abundant storage capacity. The formation condition of sodium alginate gel is mild, effectively avoiding the inactivation of active substances. After a variety of preparation methods, sodium alginate microspheres are widely used in the fields of biomaterials and tissue engineering. This paper reviewed the common methods of preparing alginate microspheres, including extrusion, emulsification, electrostatic spraying, spray drying and coaxial airflow, and discussed their applications in biomedical fields such as bone repair, hemostasis and drug delivery.

Research and application of hydrogel-encapsulated mesenchymal stem cells in the treatment of myocardial infarction.

Myocardial infarction (MI) stands out as a highly lethal disease that poses a significant threat to global health. Worldwide, heart failure resulting from MI remains a leading cause of human mortality. Mesenchymal stem cell (MSC) therapy has emerged as a promising therapeutic approach, leveraging its intrinsic healing properties. Nevertheless, pervasive issues, including a low cell retention rate, suboptimal survival rate, and incomplete differentiation of MSCs, present formidable challenges for further research. The introduction and advancement of biomaterials have offered a novel avenue for the exploration of MSC therapy in MI, marking considerable progress thus far. Notably, hydrogels, among the representative biomaterials, have garnered extensive attention within the biomedical field. This review delves into recent advancements, specifically focusing on the application of hydrogels to augment MSC therapy for cardiac tissue regeneration in MI.

Sodium alginate/carboxycellulose/polydopamine composite microspheres for rapid hemostasis of deep irregular wounds.

Hemostasis of deep irregular wounds is a severe problem in clinical practice. The development of rapid-acting hemostatic agents for deep and irregular wound is urgently needed. Here, sodium alginate/carboxycellulose/polydopamine (SA/CNF/PDA) microspheres was prepared by reverse emulsification and crosslinking with Ca2+, and SA/CNF/PDA composite hemostatic microspheres with porous structure were obtained by freeze-drying. SA/CNF/PDA composite hemostatic microspheres exhibited excellent porosity and water absorption which could rapidly absorb blood on the wound surface. Moreover, SA/CNF/PDA composite microspheres demonstrated remarkable hemostatic capabilities both in vitro and in vivo. It exhibited strong hemostatic performance in models of mouse tail-break and liver damage. Especially in liver injury model, it was completely hemostatic in 95 s, and blood loss (19.3 mg). The hemostatic efficacy of the SA/CNF/PDA composite microspheres was amplified through the stimulation of both exogenous and endogenous coagulation pathways. Therefore, SA/CNF/PDA composite hemostatic microspheres are suitable for rapid hemostasis of deep irregular wounds which are potential rapid hemostatic material for surgical application.

Improving osseointegration and antimicrobial properties of titanium implants with black phosphorus nanosheets-hydroxyapatite composite coatings for vascularized bone regeneration.

For decades, titanium implants have shown impressive advantages in bone repair. However, the preparation of implants with excellent antimicrobial properties as well as better osseointegration ability remains difficult for clinical application. In this study, black phosphorus nanosheets (BPNSs) were doped into hydroxyapatite (HA) coatings using electrophoretic deposition. The coatings' surface morphology, roughness, water contact angle, photothermal properties, and antibacterial properties were investigated. The BP/HA coating exhibited a surface roughness of 59.1 nm, providing an ideal substrate for cell attachment and growth. The water contact angle on the BP/HA coating was measured to be approximately 8.55°, indicating its hydrophilic nature. The BPNSs demonstrated efficient photothermal conversion, with a temperature increase of 42.2°C under laser irradiation. The BP/HA composite coating exhibited a significant reduction in bacterial growth, with inhibition rates of 95.6% and 96.1% against Staphylococcus aureus and Escherichia coli. In addition, the cytocompatibility of the composite coating was evaluated by cell adhesion, CCK8 and AM/PI staining; the effect of the composite coating in promoting angiogenesis was assessed by scratch assay, transwell assay, and protein blotting; and the osteoinductivity of the composite coating was evaluated by alkaline phosphatase assay, alizarin red staining, and Western blot. The results showed that the BP/HA composite coating exhibited superior performance in promoting biological functions such as cell proliferation and adhesion, antibacterial activity, osteogenic differentiation, and angiogenesis, and had potential applications in vascularized bone regeneration.

Calcium Phosphate Bone Cements Incorporated with Black Phosphorus Nanosheets Enhanced Osteogenesis.

For decades, calcium phosphate bone cements (CPCs) showed impressive advantages for their good biocompatibility, injectability, and osteoconductivity in the bone repair field. However, it is still difficult to prepare CPCs with outstanding antibacterial and self-curing properties, sufficient phosphorus release, and osteoinductivity for clinical application. Herein, we used partially crystallized calcium phosphate and dicalcium phosphate anhydrate particles incorporated with black phosphorous nanosheets to prepare calcium phosphate bone cements (CPCs). The curing time, compressive strength, photothermal properties, and degradation performance of BP/CPC were investigated. In addition, the cytocompatibility and osteoinductivity of BP/CPC were evaluated by cell adhesion, cytotoxicity, alkaline phosphatase detection, alizarin red staining, and western blot assay. The results indicated that BP/CPC showed adjustable curing time, good cytocompatibility, outstanding photothermal properties, and osteoinductivity, suggesting their potential application for bone regeneration.

Cellulose based composite sponges with oriented porous structure and superabsorptive capacity for quick hemostasis.

Excessive bleeding is the leading cause of death in accidents and operations. Ca2+ crosslinked carboxyl nanocellulose (CN)/montmorillonite (MMT) composite (CaCNMMT) sponges were prepared by uniform mixing and directional freeze-drying methods which was inspired by the coordination mechanism of blood clot formation and coagulation cascade activation in natural hemostasis process. Carboxyl nanocellulose (CaCN) sponge has instantaneous water absorption capacity, and CaCNMMT sponges could further activate clotting factors. Therefore, CaCNMMT sponges achieved quick hemostasis by efficient concentrating blood, inducing hemocyte aggregation and stimulating coagulation cascade activation based on the synergistic effects of CN and MMT. Blood clotting index of CaCNMMT (15.90 ± 0.52 %) was significantly lower than CaCN (59.3 ± 1.43 %), and APTT time (22 ± 2 s) was almost equivalent to MMT (20 ± 2 s). CaCNMMT sponge showed good quick hemostatic effect on massive hemorrhage in both tail-breaking and liver injury model which provided a new strategy for the application of MMT in hemostatic and trauma treatment fields.