Detection of bacterial spores with lanthanide-macrocycle binary complexes.
The detection of bacterial spores via dipicolinate-triggered lanthanide luminescence has been improved in terms of detection limit, stability, and susceptibility to interferents by use of lanthanide-macrocycle binary complexes. Specifically, we compared the effectiveness of Sm, Eu, Tb, and Dy complexes with the macrocycle 1,4,7,10-tetraazacyclododecane-1,7-diacetate (DO2A) to the corresponding lanthanide aquo ions. The Ln(DO2A)(+) binary complexes bind dipicolinic acid (DPA), a major constituent of bacterial spores, with greater affinity and demonstrate significant improvement in bacterial spore detection. Of the four luminescent lanthanides studied, the terbium complex exhibits the greatest dipicolinate binding affinity (100-fold greater than Tb(3+) alone, and 10-fold greater than other Ln(DO2A)(+) complexes) and highest quantum yield. Moreover, the inclusion of DO2A extends the pH range over which Tb-DPA coordination is stable, reduces the interference of calcium ions nearly 5-fold, and mitigates phosphate interference 1000-fold compared to free terbium alone. In addition, detection of Bacillus atrophaeus bacterial spores was improved by the use of Tb(DO2A)(+), yielding a 3-fold increase in the signal-to-noise ratio over Tb(3+). Out of the eight cases investigated, the Tb(DO2A)(+) binary complex is best for the detection of bacterial spores.
Cable
Morgan L
ML
Planetary Science Section, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, California 91109, USA.
Kirby
James P
JP
Levine
Dana J
DJ
Manary
Micah J
MJ
Gray
Harry B
HB
Ponce
Adrian
A
D018360:Crystallography, X-Ray; D006863:Hydrogen-Ion Concentration; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D049408:Luminescent Agents / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000737:chemistry*; D013171:Spores, Bacterial / Q000737:chemistry*; D013696:Temperature
D028581:Lanthanoid Series Elements; D049408:Luminescent Agents; D047028:Macrocyclic Compounds