Abstract: “Manganese doped zinc sulfide (ZnS:Mn2+) quantum dots (QDs) were surface derivatized for use as versatile fluorescent reporters is the study of microorganisms of relevance in environmental bioprocesses. When intracellularly introduced into permeabilized target bacterial cells, mercaptoacetic acid (MAA) or dithiothreitol (DTT) treated ZnS:Mn2+ QDs proved to be good visualization enhancers for morphological observations with epifluorescence microscopy. Alternatively, cell surface adhesion of chitosan capped ZnS:Mn2+ QDs also led to a similar effect, namely of QD enhanced contrast of target cells from intrinsic background fluorescence. When DTT surface derivatized ZnS:Mn2+ QDs were conjugated with oligonucleotide probes and used in fluorescent in situ hybridization (FISH) analysis, specific detection of bacterial strains representative of some proteobacterial classes was achieved.”

Keywords: quantum dots, surface functionalization, fluoresence in situ hybridization, fluoresence imaging, microbial characterization