Geometry-Dependent Pitch Variation Controls Platelet Adhesion on FluidFM-Fabricated Residual-Layer-Free Micro/Nanostructures.

Platelet storage remains a critical challenge in transfusion medicine, with current WHO and FDA guidelines limiting storage to just 72 h due to the risk of platelet dysfunction and bacterial contamination. This study examines how platelet adhesion is influenced by the interstructured distance of various microstructured geometries printed by mask-free nanoimprinting fluid force microscopy (FluidFM) technology. Microstructures of multiple geometries (circles, Pacman, lines, grids, and triangles) were printed on glass surfaces using the commercial Loctite AA3491, composed of multiple acrylate monomers, at three different peak-to-peak distances: 10 μm, 5 μm, and 2 μm. Atomic force microscopy (AFM) was employed to characterize the topography and printing precision of these structures. All structures exhibited nanoscale heights and demonstrated high fidelity to the designed patterns. Adhered platelets on the structured surfaces were quantified using confocal laser scanning microscopy. Results demonstrated that platelet attachment is significantly affected by both structural geometry and peak-to-peak distance. Circular and Pacman-like structures consistently showed reduced platelet adhesion, particularly at the largest peak-to-peak distance of 10 μm. Platelet attachment generally increased with decreasing peak-to-peak distance between the microstructures, yet all structured surfaces showed reduced adhesion compared to unstructured glass and nonpatterned Loctite, indicating that microtopographical modifications can effectively inhibit platelet attachment. Our results provide insights into designing antifouling surfaces for medical applications, demonstrating the potential of FluidFM technology in fabricating precision microstructures to mitigate platelet attachment as a mechanistic model to study geometry-dependent platelet-surface interactions.