Submicrometer fiber-optic biosensors have been developed and used to measur
e toxic chemicals within single cells. Optical fibers that have been pulled
to a distal-end diameter of less than 1 mu m are coated with antibodies to
selectively bind the species of interest. This paper describes the use of
these fibers to selectively measure the concentration of benzo[a]pyrene tet
rol (BPT), a metabolite of benzo[a]pyrene, within individual cells of two d
ifferent cell lines, human mammary carcinoma cells and rat liver epithelial
cells. The results from these measurements have been used to determine the
sensitivity, reproducibility, and usefulness of these nanosensors. The det
ection limit of these biosensors has been determined to be 0.64 +/- 0.17 x
10(-11) M for BPT. (C) 2000 Academic Press.