title: Kinetics of bacterial fluorescence staining with 3,3'-diethylthiacyanine.
abstract: For more than a century, colorimetric and fluorescence staining have been the foundation of a broad range of key bioanalytical techniques. The dynamics of such staining processes, however, still remains largely unexplored. We investigated the kinetics of fluorescence staining of two gram-negative and two gram-positive species with 3,3'-diethylthiacyanine (THIA) iodide. An increase in the THIA fluorescence quantum yield, induced by the bacterial dye uptake, was the principal reason for the observed emission enhancement. The fluorescence quantum yield of THIA depended on the media viscosity and not on the media polarity, which suggested that the microenvironment of the dye molecules taken up by the cells was restrictive. The kinetics of fluorescence staining did not manifest a statistically significant dependence neither on the dye concentration, nor on the cell count. In the presence of surfactant additives, however, the fluorescence-enhancement kinetic patterns manifested species specificity with statistically significant discernibility.
authors.affiliation: Department of Bioengineering, University of California, Riverside, California 92521, USA.
authors.forename: Marlon S
authors.initials: MS
authors.lastname: Thomas
authors.forename: Vicente
authors.initials: V
authors.lastname: Nuñez
authors.forename: Srigokul
authors.initials: S
authors.lastname: Upadhyayula
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Zielins
authors.forename: Duoduo
authors.initials: D
authors.lastname: Bao
authors.forename: Jacob M
authors.initials: JM
authors.lastname: Vasquez
authors.forename: Baharak
authors.initials: B
authors.lastname: Bahmani
authors.forename: Valentine I
authors.initials: VI
authors.lastname: Vullev
mesh_terms: D002232:Carbocyanines / Q000737:chemistry* / Q000493:pharmacokinetics; D005453:Fluorescence; D006090:Gram-Negative Bacteria / Q000378:metabolism*; D006094:Gram-Positive Bacteria / Q000378:metabolism*; D007700:Kinetics; D013045:Species Specificity; D013194:Staining and Labeling
chemical_list: C521847:3,3'-diethyl-2,2'-thiacyanine; D002232:Carbocyanines