Magnetically assisted hemodialysis is a development of conventional hemodialysis and is based on the circulation of ferromagnetic nanoparticle-targeted binding substance conjugates (FN-TBS Cs) in the bloodstream of the patient and their eventual removal by means of a 'magnetic dialyzer'. Presented here is an in vitro investigation on the biocompatibility of bare Fe(3)O(4) FNs and Fe(3)O(4)-bovine serum albumin Cs with blood cells, namely red blood cells (RBCs), white blood cells (WBCs) and platelets (Plts). Atomic force microscopy (AFM) and optical microscopy (OM) enabled the examination of blood cells at the nanometer and micrometer level, respectively. The observations made on FN- and C-maturated blood samples are contrasted to those obtained on FN- and C-free reference blood samples subjected to exactly the same maturation procedure. Qualitatively, both AFM and OM revealed no changes in the overall shape of RBCs, WBCs and Plts. Incidents where bare FNs or Cs were bound onto the surface of RBCs or internalized by WBCs were very rare. Detailed examination by means of OM proved that impaired coagulation of Plts is not initiated/promoted either by FNs or Cs. Quantitatively, the statistical analysis of the obtained AFM images from RBC surfaces clearly revealed that the mean surface roughness of RBCs maturated with bare FNs or Cs was identical to the one of reference RBCs.

Background/Aims: Cell membranes facilitate the transport of water, ions, and necessary nutrients by hosting a great variety of transport channels that have either a ‘simple’ pore-like structure or more complex architecture that is based on the utilization of specific receptors. The present study reveals the impact of AgNO₃, a well-known inhibitor of water channel activity, on transport channels that emerge at the membrane of intact red blood cells (iRBCs). Methods: Atomic force microscopy is employed to survey the morphological modification of all transport channels by directly comparing the respective images obtained on the exact same iRBCs prior to and after spraying the AgNO₃ solution. Results: Small pores of mean size 50 nm that were assigned to water channels, and extended orifices of mean size 300 nm that exhibit a neck-like extracellular segment were observed at the iRBC membrane. Conclusion: Our results reveal that AgNO₃ exerts noticeable influence on all transport channels so that its selective water channel inhibitory action should be reconsidered. For low AgNO₃ concentrations extended recovery of the small pore network was observed upon waiting, giving strong evidence that iRBCs have a recovery potential upon simply removing the inhibition cause without the need for specific reducing agents.

Together with impaired production of erythropoietin and iron deficiency, the decreased lifespan of red blood cells (RBCs) is a main factor contributing to the chronic anaemia observed in haemodialysis (HD) patients. Atomic force microscopy is employed in this work to thoroughly survey the membrane of intact RBCs (iRBCs) of HD patients in comparison to those of healthy donors, aiming to obtain direct information on the structural status of RBCs that can be related to their decreased lifespan. We observed that the iRBC membrane of the HD patients is overpopulated with extended circular defects, termed 'orifices', that have typical dimension ranging between 0.2 and 1.0 μm. The 'orifice' index-that is, the mean population of 'orifices' per top membrane surface-exhibits a pronounced relative increase of order 54 ± 12% for the HD patients as compared to healthy donors. Interestingly, for the HD patients, the 'orifice' index, which relates to the structural status of the RBC membrane, correlates strongly with urea concentration, which is a basic index of the uraemic milieu. Thus, these results indicate that the uraemic milieu downgrades the structural status of the RBC membrane, possibly triggering biochemical processes that result in their premature elimination from the circulation. This process could decrease the lifespan of RBCs, as observed in HD patients.

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