Development of Planetary Protection Technology: Bacterial Spore Detection using Lanthanide Luminescence

The core of bacterial spores contains 1 molar dipicolinic acid, DPA, which can be released into bulk solution by inducing germination with L-alanine or by autoclaving the sample. The released DPA binds terbium, Tb, as a tridentate ligand with high affinity, 10e9 M-1, which triggers bright green luminescence under UV excitation that can be correlated to a DPA concentration and subsequently to endospore concentration. Current detection limits of this method are at 10e4 spores per ml. We will present our current efforts to reach single spore per ml detection limits.