Blood and the linings of blood vessels may be regarded as a fifth tissue type. Nowadays red blood cells are extensively used to study various metabolic functions. Nanoparticles NP are being widely accepted for drug delivery system. This review summarizes the red blood cells, NPs and their characteristics on the basis of the RBC components along with drug delivery systems through RBCs.
The Promotion of Erythropoiesis via the Regulation of Reactive Oxygen Species by Lactic Acid
TPC - Red blood cells
Red blood cells RBCs , also referred to as red cells ,  red blood corpuscles in humans or other animals not having nucleus in red blood cells , haematids , erythroid cells or erythrocytes from Greek erythros for "red" and kytos for "hollow vessel", with -cyte translated as "cell" in modern usage , are the most common type of blood cell and the vertebrate 's principal means of delivering oxygen O 2 to the body tissues —via blood flow through the circulatory system. The cytoplasm of erythrocytes is rich in hemoglobin , an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells and the blood. The cell membrane is composed of proteins and lipids , and this structure provides properties essential for physiological cell function such as deformability and stability while traversing the circulatory system and specifically the capillary network. In humans, mature red blood cells are flexible and oval biconcave disks. They lack a cell nucleus and most organelles , to accommodate maximum space for hemoglobin; they can be viewed as sacks of hemoglobin, with a plasma membrane as the sack. Approximately 2. Each circulation takes about 60 seconds one minute.
Erythrocytes in PET studies
Mature erythrocytes, when removed from the circulation, exhibit severe disturbances of glycolytic flow, with accumulation not only of lactate, the ultimate product of glycolysis, but also of several upstream metabolic intermediates, primarily fructose-1,6-diphosphate, glyceraldehydephosphate, and dihydroxyacetone phosphate. This accumulation may be prevented and also reverted by allowing the diffusible end products lactate and pyruvate to leave the cell by equilibrating with a much larger extracellular compartment. The disturbance of erythrocyte glycolysis does not result from direct inhibition by lactate itself but from the interplay between the lactate dehydrogenase and glyceraldehydephosphate dehydrogenase 3-PGAD reactions. The accumulation of intermediates reflects the increased lactate-to-pyruvate ratio; this leads to a secondary imbalance of the nicotinamide adenine dinucleotide-to-reduced nicotinamide adenine dinucleotide NAD-to-NADH ratio, which in turn slows down glycolysis at the 3-PGAD step, whose upstream metabolites then pile up. No accumulation, however, takes place if the lactate-to-pyruvate ratio is maintained constant in the extracellular compartment, regardless of concentrations.