The characterization of phyco-based synthesis of TiO2 NPs from Spirulina platensis (GSSp.TiO2 NPs) and the efect of
such biosynthesized nanoparticles on morphology, growth, ultrastructure and enzymatic of the same alga have been studied.
These nanoparticles have a good solubility, are stable in water and the average size was 17.3 nm. GSSp.TiO2 NPs aggregated
and adsorbed on S. platensis membrane. Penetration and entrance of the nanoparticles into the Spirulina cells were also
recorded which stimulated cell wall deformity, plasmolysis, and damage to both cell wall and plasma membrane, combined
with the appearance of notch-like structure. A positive signifcant correlation was recorded between all applied concentrations of the biosynthesized nanoparticles and the antioxidant activities (CAT and APX) and LOX. More than 160 mg/l of
GSSp.TiO2 NPs have a harmful impact on S. platensis, so nanoparticles have to be managed before disposal to protect our
health and ecosystem.