Transient loading of CD34+ hematopoietic progenitor cells with polystyrene nanoparticles

Abstract

CD34+ hematopoietic progenitor cells (HPCs) offer great opportunities to develop new treatments for numerous malignant and non-malignant diseases. Nanoparticle (NP)-based strategies can further enhance this potential, therefore a thorough understanding of the loading behavior of HPCs towards NPs is essential to a successful application. Present study focusses on the interaction kinetics of 40-nm sized carboxylated polystyrene (PS) NPs with HPCs. Interestingly, a transient association of the NPs with HPCs is observed, reaching a maximum within one hour and declining afterwards. This behavior is not seen in dendritic cells (CD34-DCs) differentiated from HPCs, which display a monotonic increase in NP load. We demonstrate that this transient interaction requires an energy-dependent cellular process, suggesting active loading and release of NPs by HPCs. This novel observation offers a unique approach to transiently equip HPCs. A simple theoretical approach modelling NP loading and release is presented, contributing to a framework to describe this phenomenon.