Biological Synthesis of Size-Controlled Cadmium Sulfide Nanoparticles Using ImmobilizedRhodobacter sphaeroides

Abstract
Size-controlled cadmium sulfide nanoparticles were successfully synthesized by immobilizedRhodobacter sphaeroides in the study. The dynamic process that Cd2+was transported from solution into cell by livingR. sphaeroides was characterized by transmission electron microscopy (TEM). Culture time, as an important physiological parameter forR. sphaeroides growth, could significantly control the size of cadmium sulfide nanoparticles. TEM demonstrated that the average sizes of spherical cadmium sulfide nanoparticles were 2.3 ± 0.15, 6.8 ± 0.22, and 36.8 ± 0.25 nm at culture times of 36, 42, and 48 h, respectively. Also, the UV–vis and photoluminescence spectral analysis of cadmium sulfide nanoparticles were performed.