Influence of Silver Nanoparticles with Different Surface Coating on the Excised Frog Heart

ILIEVA, B., Y. IVANOVA, P. VASILEVA, H. GAGOV and I. SAZDOVA, 2014. Infl uence of silver nanoparticles with different surface coating on the excised frog heart. Bulg. J. Agric. Sci., Supplement 1: 3–8 The surface coating of silver nanoparticles is crucial to the nanoparticle properties as size and shape, stability, solubility and targeting, which are responsible to their biological effects. In order to study the infl uence of differently coated silver nanoparticles (AgNPs) on in vitro heart preparations of Rana ridibunda frog, we synthesized two types of AgNPs – nanoparticles coated with the polysaccharide starch (AgNPs/Starch, Dmean = 15 nm) and nanoparticles coated with the trisaccharide raffi nose (AgNPs/Raff, Dmean = 25 nm). The aqueous dispersions of both types of AgNPs were introduced in concentrations of 1, 3, 10, 30, 50 and 100 μg/ml by a cannula into the frog heart ventricle. The effects of AgNPs were estimated by using of as-synthesized nanoparticle dispersions and aqueous dispersions of nanoparticles purifi ed by ultracentrifugation. Separate measurements of heart contractions were performed with the addition of supernatants obtained by ultracentrifugation of as-synthesized AgNPs samples to estimate the biological effects of the stabilizing agents. The nanoparticles were administrated alone or together with prazosin or propranolol, the widely used blockers of α1-and β-adrenoreceptors, respectively. The data obtained showed that as-synthesized AgNPs/Raff signifi cantly increased the force of contraction of isolated frog hearts but was not affected by purifi ed AgNPs with the same coating. Both as-synthesized and purifi ed AgNPs/Starch did not infl uence the force of heart contraction. The positive inotropic effect of non-purifi ed raffi nose-coated AgNPs was partially abolished by 3 μmol/l prasozin and 30 μmol/l propranolol. It can be concluded that starch as a polysaccharide covers more tightly the metal core of silver nanoparticles and made AgNPs/Starch less reactive than the AgNPs/Raff. The results show that the purifi ed AgNPs/Raff was less potent to affect the cardiac activity because of their higher ability to aggregate in the medium studied.