M. Zborowski et al., DARK-FIELD MICROSCOPY ANALYSIS OF THE MAGNETIC DEPOSITION OF BACTERIAON A GLASS-SURFACE, Colloids and surfaces. A, Physicochemical and engineering aspects, 77(3), 1993, pp. 209-218
Suspensions of bacteria, Escherichia coli, in 0.9% saline were treated
by addition of a paramagnetic lanthanide salt, erbium chloride (ErCl3
), and concentrated on a microscope slide using a magnetic field. The
final concentration of Er3+ in solution was kept constant at 5 mM, and
the concentration of bacteria, c, varied from 10(4) colony forming un
its (CFU) ml-1 to 10(8) CFU ml-1. The magnetic deposition of bacterial
cells on the microscopic slide was examined using dark-field microsco
py. The sections of the magnetic deposition were scanned using the sca
ttered light. The average intensity of the scattered light ASL was cor
related with the initial concentration of bacterial cells in suspensio
n, c. The data distribution was characterized by the regression line,
log ASL = 0.3157 log c - 0.6388, number of slides N = 14, correlation
coefficient R = 0.8881. The analysis of bacterial deposition from susp
ension using a paramagnetic reagent, magnetic field and scattered-ligh
t scanning may provide a quick means of testing for the presence of ba
cteria in biological fluids or in environmental waters.