Interaction between PAMAM 4.5 dendrimer, cadmium and bovine serum albumin: A study using equilibrium dialysis, isothermal titration calorimetry, zeta-potential and fluorescence

Binding of Cd2+ 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, Kb = 4.7 ± 0.9 × 103 in water; and n = 41.3 ± 13.4, Kb = 2.1 ± 0.8 × 103 in 0.15 mol/l phosphate-buffered saline. The location of the bound Cd2+ is discussed. The interactions between bovine serum albumin, PAMAM 4.5 dendrimer and cadmium were analyzed using fluorescence and equilibrium dialysis. The competition between Cd2+ binding to BSA and PAMAM 4.5 dendrimer was investigated. It is proposed that PAMAM 4.5 dendrimer could be successfully used for extracting Cd2+ from aqueous solutions (environmental protection).