Biogenic synthesis of selenium nanoparticles by Shewanella sp. HN-41 using a modified bioelectrochemical system

BACKGROUND Synthesis of selenium nanoparticles from selenite by Shewanella sp. HN-41 demonstrated that particle size depended on the reaction time and biomass of cells. The slow reaction and low biomass tended to form small particles. In this study, Shewanella sp. HN-41 was introduced into the anode of a nonexternal circuit bioelectrochemical system (nec_BES) to convert chemical energy from lactate to low electron current to the cathode, where selenite was reduced. RESULTS Our experiment with two systems, one bioelectrochemical system with a cathode flushed with nitrogen and the other with a no-nitrogen-flushing cathode, showed that the former could not produce Se nanoparticles after 21 d, but the latter formed them with an average size of 37.7 nm. The SEM and TEM images demonstrated that the particle size of 10 nm occupied over 10% and most of the particles were in the range of 30­60 nm. The XRD result and SAED image demonstrated no clear peaks of crystal and proved that the Se nanoparticles are amorphous. CONCLUSIONS : The clean Se nanoparticles were synthesized and completely separated from bacterial cells in the bioelectrochemical system. This study opened a new approach for the biological synthesis of metal nanoparticles. Finally, the Se products in the range of 30­60 nm can be tested for antimicrobial activities in medical applications

Scintigraphic application for myocardial blood irrigation in Cho Ray hospital

During 5/2000 - 5/2001, the nuclear medicine depar. of Cho Ray hospital implemented the scintigraphic application of myocardial blood irrigation for 144 cases (93 with 99 mTc-MIBI, 33 with 201 TI and 14 with 99m Tc MIBI combined with 201 TI). The results from angiography have shown that the sensitivity and specificity of scintigraphy in the diagnosis of the coronary arterial pathology was 92% and 71.4%, respectively. The scintigraphy for myocardial blood irrigation was a sensitive, noninvasive and valuable method of diagnosis of the coronary arterial pathology