Citrate-Coated Iron Oxide Nanoparticles Facilitate Endothelialization of Left Ventricular Assist Device Impeller for Improved Antithrombogenicity

Although left ventricular assist devices (LVADs) are an alternative to heart transplantation, their artificial surfaces often lead to serious thrombotic complications requiring high-risk device replacement. Coating blood-contacting surfaces with antithrombogenic endothelial cells is considered an effective strategy for preventing thrombus formation. However, this concept has not yet been successfully implemented in LVADs, as severe cell loss is to be expected, especially on the impeller surface with high prothrombogenic supraphysiological shear stress. This study presents a strategy that exploits the magnetic attraction of the impeller on ECs loaded with iron oxide nanoparticles (IONPs) to minimize shear stress-induced cell detachment from the rotating magnetic impeller while ensuring antithrombogenic EC adhesion, especially as a bridge until they formed their adhesion-promoting matrix. In contrast to polyvinylpyrrolidone (PVP)-coated IONPs, more efficient and safer cell loading is achieved with sodium citrate (Cit)-stabilized IONPs, where incubation with 6.6 µg iron mL-1 Cit-IONPs for 24 h resulting in an average internalization of 23 pg iron per cell. Internalization of Cit-IONP significantly improved cell attraction to the highly magnetic impeller surface without affecting cell viability or antithrombogenic function. This protocol is key for the development of a biohybrid LVAD impeller that can prevent life-threatening thrombosis and hemorrhage in a future clinical application.