Detection of bacteria based on quantum dots by using a laboratory-made system

This study investigated a method that simultaneously detects three bacteria, Salmonella typhimurium, Escherichia coli, and Staphylococcus aureus via an approach that use antibody-conjugated quantum dots (QDs) as fluorescence markers, by using a laboratory-made system. QDs with different emission wavelenghs were immobilized with antibody. Antibody conjugated QDs capture the bacteria selectively and specifically so that ”sandwich” complex were formed. The suspension of the labeled bacteria was trickled onto a microporous membrane. A 450nm semiconductor laser was used as a part of the laboratory-made system to excite the QDs. Three PMT detectors were utilized to detect the fluorescence intensity. This method, of which the detection procedures are completed within 1 h, can be applied to the cost-effective and rapid detecting of bacterial contamination.