The effects of potassium citrate (K3cit) on sedimentation and aggregation of 50 nm calcium oxalate dihydrate (COD) crystals was studied in order to explore the mechanism of formation and inhibition of kidney stone. In four different systems, including pure water, urine of healthy person and CaOx stone former before and after taking medicine K3cit, the influences of K3cit on average size (), Zeta potential and optical density of nanoCOD suspensions were studied by nanoparticle size Zeta potential analyzer and ultraviolet spectrophotometer. It was showed that K3cit could specifically adsorb on nanoCOD crystals, and also competed with the inhibitor molecules in urine. Due to the decrease of inhibitors in urine of patients, K3cit can be better to fulfill its inhibitory effect, leading to the largest reduced values of the diameter of COD crystal and the optical density of urine suspension. In conclusion, the inhibitory effect of K3cit on aggregation and sedimentation of calcium oxalate crystals is better in urine of patients, whereas the inhibitory effect has been reduced in urine of control group and patients after taking k3cit.
