Lyophilized Synthetic Platelets: In Vitro Characterization and In Vivo Evaluation in Mouse Thrombocytopenia Model

Area of Science:

• Biomaterials Science
• Nanotechnology
• Hematology

Background:

• Current platelet transfusions rely on donor platelets with short shelf-lives (5-7 days) due to bacterial contamination risks.
• Existing alternatives like cold-stored or freeze-dried platelets still face donor-dependency challenges.
• Liposome-based synthetic platelets (SP) were previously developed but exhibit storage instability in aqueous suspension.

Purpose of the Study:

• To develop a lyophilized, shelf-stable synthetic platelet (Lyo-SP) for improved availability and on-demand use.
• To evaluate the physico-chemical stability, hemostatic function, biosafety, and in vivo efficacy of Lyo-SP.

Main Methods:

• Synthetic platelets (SP) were lyophilized using lyoprotectants to create Lyo-SP.
• Lyo-SP stability was assessed through morphology, size, and charge analysis under various storage conditions.
• Platelet-mimetic functions were evaluated using multiparametric assays with human plasma and blood.
• Biosafety was determined by analyzing Lyo-SP's effects on endothelial cells, neutrophils, RBCs, and complement C3.
• In vivo efficacy was tested in a tail-clip bleeding model in thrombocytopenic mice.

Main Results:

• Lyo-SP maintained consistent morphology, size, and charge during long-term storage at various temperatures.
• Lyo-SP effectively conserved platelet-mimetic functions in human plasma and blood.
• Lyo-SP demonstrated biosafety, showing no adverse effects on key blood components and endothelial cells.
• Lyo-SP significantly reduced bleeding in a mouse model of thrombocytopenic bleeding.

Conclusions:

• Lyophilization successfully created a shelf-stable synthetic platelet (Lyo-SP).
• Lyo-SP retains essential characteristics and functions for hemostasis.
• Lyo-SP presents a promising, safe, and effective alternative to donor platelets for managing bleeding disorders.