Cell viability measurement using 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester and a cantilever sensor.
Detection of viable pathogenic bacteria has widespread application in food safety and human health. Antibody-based methods require a growth step which limits time-to-results performance. In this study, we use a mass-change sensitive cantilever biosensor and a probe, 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM), that accumulates only in live cells inducing a mass-change response to determine the cell viability in a short time. A poly-L-lysine coated sensor immobilized with live Escherichia coli JM101 (a surrogate for a pathogenic target) at various concentrations was exposed to BCECF-AM in a flow arrangement. A larger resonant frequency decrease in response to 100 μL of 60 μM BCECF-AM was observed when the sensor surface cell concentration was increased from 1 090 ± 580 to 3 960 ± 370 cells/mm(2) (n = 5). A log-linear relationship between the sensor surface cell concentration and frequency response was obtained in the range of 1 000-4 000 cells/mm(2) and as low as ∼2 000 viable E. coli cells were rapidly detected (<1 h).
Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA.
Sen
S
Xu
Raj
R
Mutharasan
D015374:Biosensing Techniques / Q000379:methods*; D002470:Cell Survival; D018914:Cells, Immobilized / Q000166:cytology; D004926:Escherichia coli / Q000166:cytology*; D005240:Feasibility Studies; D005452:Fluoresceins / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
D005452:Fluoresceins; D005456:Fluorescent Dyes; C057433:2',7'-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl ester