[Show abstract][Hide abstract] ABSTRACT: The interactions between PAMAM G3.5 dendrimer, Cd2+, a complex of "PAMAM G3.5 dendrimer-Cd2+" and human serum albumin were studied by equilibrium dialysis, fluorescence quenching, fluorescence anisotropy and zeta-potential. It was found that in water one molecule of PAMAM 3.5 dendrimer can bind 38+/-9 cadmium ions with Kb=1.3+/-0.13 x 10(3). The calculated Stern-Volmer constants of albumin fluorescence quenching by Cd2+, G3.5 and the "PAMAM G3.5-Cd2+" complex were 2.2+/-0.2, 1.6+/-0.3 and 1.4+/-0.1(mmol/l)(-1), respectively. The data from the fluorescence and zeta-potential studies show that the "PAMAM G3.5-Cd2+" complex interacted much less strongly with human serum albumin than the pure dendrimer or Cd2+.
[Show abstract][Hide abstract] ABSTRACT: Binding of Cd(2+) by PAMAM 4.5 dendrimer was studied by equilibrium dialysis, isothermal titration calorimetry and zeta-potential measurement. The following binding parameters were obtained: n=23.8+/-9.5, K(b)=4.7+/-0.9x10(3) in water; and n=41.3+/-13.4, K(b)=2.1+/-0.8x10(3) in 0.15 mol/l phosphate-buffered saline. The location of the bound Cd(2+) is discussed. The interactions between bovine serum albumin, PAMAM 4.5 dendrimer and cadmium were analyzed using fluorescence and equilibrium dialysis. The competition between Cd(2+) binding to BSA and PAMAM 4.5 dendrimer was investigated. It is proposed that PAMAM 4.5 dendrimer could be successfully used for extracting Cd(2+) from aqueous solutions (environmental protection).