Strontium-based quaternary ammonium salt chitosan particles for ultrafast hemostasis of open fracture

The management of open bone defects poses a formidable challenge in clinical practice, primarily due to issues such as profuse bleeding, inflammation, bacterial infections, and compromised bone fracture healing. To tackle these complexities, we have devised a novel hemostatic powder, namely the compound strontium-based chitosan quaternary ammonium salt hemostatic powder (QCS@SrT-TA). This innovative powder leverages the self-assembly of tripolyphosphate and strontium ions, facilitated by a positively charged core cross-linker. Furthermore, its surface has been strategically modified with polyphenol and positively charged macromolecules, imparting unique properties. The mesoporous architecture of QCS@SrT-TA facilitates rapid moisture absorption, enhancing its efficacy. In preclinical studies using rat tail artery amputation and liver bleeding models, QCS@SrT-TA exhibited remarkable performance, significantly reducing both bleeding time and volume (62.39 ± 2.89 mg, 35.33 ± 4.16 s in tail amputation, 63.7 ± 5.19 mg, 62.33 ± 9.61 s in liver bleeding). Notably, the positively charged strontium ions and quaternary ammonium salts within the powder were effective in removing bacteria, minimizing the risk of infection. Beyond hemostasis, QCS@SrT-TA demonstrates additional therapeutic benefits. It polarizes M2 macrophage phenotypes and promotes angiogenesis within bone defect sites, accelerating bone healing processes. Ultimately, a substantially enhanced and notable functional recovery is achieved. In summary, the rapid hemostatic, potent antibacterial, anti-inflammatory, and angiogenesis-promoting characteristics of QCS@SrT-TA hold immense promise as a groundbreaking clinical treatment strategy for open bone defects.