Abstract 123: Hemostatic Fibrin Knob Triggered Microgel To Promote Clotting With Reduced Thrombotic Risks In Neonates

Introduction: Effective neonatal hemostatic therapies are vital for complex surgery-related life-threatening bleeding [1]. Neonatal hemostatic systems differ significantly from adults [2, 3]; however, current treatments for bleeding include adult blood products (ABP). Neonatal ABP use poses an elevated thrombotic risk [4, 5], necessitating alternative approaches. We propose hemostatic therapies leveraging age-dependent clotting differences. In adults, clot formation relies on fibrin(ogen) A:a knob-hole binding, while B:b binding dominates in neonates. Targeting B:b interactions with synthetic Bknob conjugated platelet-like particles (BK-PLP) could crosslink neonatal fibrinogen, catalyze clot formation, and enhance clot strength with lower thrombotic risk than ABP. To test this, we synthesized pNIPAm microgels and conjugated them to B-knob (AHRPYAAK), A-knob (GPRPFPAK), and non-binding control peptides (GPSPFPAK) to prepare BK-PLP, AK-PLP, and NB-PLP. Materials and Methods: We prepared BK-PLP, AK-PLP, and NB-PLP by conjugating microgels with mimetic peptides using EDC-Sulfo-NHS chemistry (Fig. 1A); Fibrin clot polymerization, stability, density, and stiffness, were analyzed via plate-based assays, confocal microscopy, and AFM. Results and Discussion: BK-PLPs significantly increased clot stability compared to AK-PLP, NB-PLP, or fibrin-only clots (Fig. 1B). Fiber density also increased with BK-PLPs, indicating a role in promoting denser fibrin clot structures (Fig. 1C). Clot mechanical properties assessment suggested that AKnob and NB-PLPs may disrupt clot networks, decreasing stiffness (Fig. 1D). Conclusion: Our study explored the effects of peptide conjugate particles on neonatal fibrin clots. BK-PLP incorporation increased clot stability, while AK-PLP and NB-PLP decreased clot stiffness, supporting further BK-PLP development for neonatal hemostasis.