Combined use of optical tweezers and scanning electron microscopy to reveal influence of nanoparticles on red blood cells interactions

As a promising drug delivery system, itself or coupled with red blood cells (RBC), nanoparticles (NP) should be studied in frames of their interaction at the cellular level. Experiments were performed on RBC in autologous blood plasma incubated with different NP – TiO2, ZnO, nanodiamonds and polymeric nanocapsules. RBC aggregates formation in RBC suspension was observed with conventional microscopy, while quantitative interaction force measurements between individual RBC was assessed with optical tweezers. Scanning electron microscopy (SEM) imaging demonstrated NP localization and RBC membrane modifications upon binding with NP. Among tested NP, nanodiamonds caused increasing the size of aggregates in RBC suspensions, RBC interaction force increase and strong membrane surface modifications, comparing to other tested NP and control sample. Nanocapsules do not cause any adverse effects on RBC properties, confirming biocompatibility and applicability for drug delivery purposes. Optical tweezers combined with SEM imaging serves as fast informative assessment of NP effects on RBC.