Background: Platelets play a crucial role in regulating coagulation. However, balancing the supply and clinical demands of platelet concentrates is a tough challenge. It is urgent to explore a novel platelet substitute with biosafety and efficacy in traumatic hemorrhage. Methods: The platelet-like PLGA-PSP nanoparticles were synthesized by covalently coupling the linear platelet-specific peptides including CBP, VBP and FMP to the active carboxyl functional group of PLGA-PEG nanoparticles. The biosafety of the platelet-like PLGA-PSP nanoparticles was assessed. Subsequently, in vitro experiments were conducted to verify the effects of PLGA-PSP nanoparticles on platelet adhesion, aggregation and activation. Furthermore, the hemostatic efficacy of PLGA-PSP nanoparticles was confirmed in the tail vein, liver and femoral artery hemorrhage of normal and thrombocytopenic mice. Results: We successfully designed and synthesized the non-toxic PLGA-PSP nanoparticles with specific hemostatic ability that significantly induced platelet adhesion and aggregation without triggering unexpected platelet activation. Moreover, the application of PLGA-PSP nanoparticles was demonstrated to effectively reduce the bleeding time and blood loss in the tail vein, liver and femoral artery of both normal and thrombocytopenic mice. Conclusion: The novel platelet-like PLGA-PSP nanoparticles present a promising therapeutic option for the rapid hemostasis of traumatic hemorrhage based on the biosafety and efficacy.

CD47 is an important immune checkpoint in haematopoietic and solid malignancies. However, panreactivity of anti-CD47 agents leads to interference during pretransfusion compatibility testing binding to red blood cells. To address this issue, we created immunomagnetic beads (IMBs) to adsorb anti-CD47 monoclonal antibodies (mAbs): IMB-OVCAR3, coated with lysed protein from the OVCAR3 cell line, which was screened using flow cytometry and immunofluorescence staining, and IMB-CD47, coated with a recombinant CD47 protein. Plasma adsorbed by IMBs was collected for gel column agglutination testing and flow cytometry to verify elimination of anti-CD47 mAb interference. The effects of IMBs on irregular antibody screening and adsorption ability of IMBs over preservation time were also analysed. Following successful preparation, IMBs were shown to adsorb anti-CD47 mAb in plasma and reduce anti-CD47 mAb interference of simulated and clinical samples in 30 ​s. Moreover, IMBs did not adsorb irregular antibodies. Both IMBs retained their anti-CD47 mAb adsorption capacity for 3 weeks in a preservation solution. IMB-OVCAR3 and IMB-CD47 can serve as novel tools for the efficient removal of CD47 interference during transfusion compatibility testing in transfusion laboratories.

Bacterial contamination remains a critical safety concern in platelet transfusion, and there is an urgent demand for decontamination technologies that eliminate contaminating bacteria without damaging platelet viability and physiological function. Herein, Fe₃O₄-QCS-PEI-Cu-apt microparticles with enlarged magnetic cores were rationally fabricated to improve aptamer immobilization, aiming at targeted bacterial elimination via near-infrared (NIR) irradiation while maintaining platelet function. Fluorescence assays confirmed their specific targeting capability toward Staphylococcus aureus (S. aureus) without binding to platelets. Magnetic separation experiments demonstrated that the aptamer-functionalized microparticles could efficiently capture and remove 91.35% of S. aureus from platelets. NIR irradiation of the Fe₃O₄-QCS-PEI-Cu core induced marked bactericidal activity against S. aureus in suspension, as determined by plate counting and LIVE/DEAD staining. This antibacterial ability originated from the intrinsic photo-responsive property of the composite rather than from aptamer-mediated recognition, and could be easily extended to bacteria captured by aptamer-functionalized particles. Comprehensive biocompatibility evaluations, including morphological observation, hematological parameter analysis, CD62P expression detection, and thromboelastography (TEG) were performed. And the results demonstrated that there were no significant changes in platelet morphology, count, activation state, or overall hemostatic function, apart from an increase in the α angle. This platform achieves efficient targeted NIR-triggered antibacterial efficacy while maintaining excellent platelet compatibility, offering a promising strategy to enhance the safety of platelet transfusion.