Table 1.

Interactions of nanoparticles (NPs) and RBCs at cellular levels

Nanoparticles	Interaction with membrane	Effect on hemoglobin	References
Zinc oxide nanoparticles with 0-307 nm	The hemolytic activity shown by only < 50 nm-sized NPs, showed structural and membrane damage which decreased with size increase	UV imaging showed significant changes in hemoglobin by < 50 nm-sized NPs, fluorescence intensity of hemoglobin decreased with increasing size and concentration of NPs, circular dichroism showed changes in the secondary structure of the protein with increasing size of NPs	(Preedia et al., 2017)
Amino-acid based gold nanoparticles ~ 20-25 nm	Less hemolytic than traditional AuNPs	No significant change in hemoglobin structure and function even at higher concentration	(Kumar et al, 2020)
Superparamagnetic iron oxide nanoparticles (SPIONs) with chitosan, hyaluronic acid, and polyacrylic acid in the size range of 5-6 nm	Polyacrylic acid-modified NPs showed the highest hemolysis in same-sized NPs and the rate increased with increasing concentration of NPs. Polyacrylic acid-modified NPs caused the greatest crenation of RBCs and led to morphological alterations with increasing size	During hemolysis, RBCs released hemoglobin which affected both structure and function of hemoglobin	(Liu et al, 2020a, b)
Gold and silver NPs ~ 50 nm	Both induced oxidative stress in RBCs but the thiol concentration was much lower in silver NPs treated cells. This resulted in a higher change in membrane permeability and membrane alterations in silver NPs treated cells than gold NPs treated cells	The interaction of NPs deoxygenated the hemoglobin studied by Raman spectra and resulted in the loss of functionality. It was established that silver NPs are more harmful than gold nanoparticles	(Barkur et al, 2020)
Bovine serum albumin (BSA)-conjugated gold NPs ~ 540 nm	BSA conjugated gold NPs demonstrated negligible hemolysis and morphological changes when compared with traditional gold NPs	Negligible hemolysis signifies no change in the structure and function of hemoglobin protein	(Hameed et al, 2018)