Detection of bacterial spores with lanthanide-macrocycle binary complexes
Abstract
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.
Additional Information
© 2009 American Chemical Society. Published In Issue: July 15, 2009; Article ASAP: June 19, 2009; Received: March 28, 2009. The authors thank Larry Henling and Mike Day for crystallographic analysis and Kyle Lancaster for assistance with mass spectrometry. The research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautic and Space Administration and was sponsored by NASA's Astrobiology and Planetary Protection Programs (A.P., J.P.K.), the Department of Homeland Security's Chemical and Biological Research & Development Program (A.P.), the National Defense Science and Engineering Graduate Fellowship Program (M.L.C.), the NASA Graduate Student Research Program (M.L.C.), the AmGen Scholars Program (D.J.L.), and the Caltech Summer Undergraduate Research Fellowship Program (D.J.L., M.J.M.). Work at the Beckman Institute was supported by the NIH, NSF, and the Arnold and Mabel Beckman Foundation (H.B.G.). Supporting Information Available: Crystallographic data (CIF) of the Ln(DO2A)(DPA)- complexes, where Ln ) Sm, Eu, Tb, or Dy; derivation of model for Ln(DPA) binding affinity; thermal ellipsoid plots of Dy(DO2A)(DPA)- ternary complex and Sm coordination geometry; normalized excitation and absorption spectra of Ln(DO2A)(DPA)- complexes; calculation of quantum yields and molar extinction coefficients for Ln(DO2A)(DPA)- complexes; Ka′ values of Tb(DO2A)(DPA)- complex over time; emission spectra of various terbium, europium, and samarium complexes; emission intensity variation in Tb(DO2A)(DPA)+ due to interference from common cations and anions; ion competition experiments with phosphate, sulfate, potassium, and carbonate; enthalpic and entropic components for Tb(DO2A)(DPA)- and Eu(DO2A)(DPA)-; time courses of DPA binding to Tb(DO2A)+ at various pH values; and calculation of signal-to-noise ratio for the bacterial spore detection study. This material is available free of charge via the Internet at http://pubs.acs.org.Attached Files
Accepted Version - nihms126100.pdf
Supplemental Material - ja902291v_si_001.cif
Supplemental Material - ja902291v_si_002.cif
Supplemental Material - ja902291v_si_003.cif
Supplemental Material - ja902291v_si_004.cif
Supplemental Material - ja902291v_si_005.pdf
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Additional details
- PMCID
- PMC2722938
- Eprint ID
- 14958
- DOI
- 10.1021/ja902291v
- Resolver ID
- CaltechAUTHORS:20090811-114903763
- NASA
- Department of Homeland Security
- Department of Defense
- AmGen Scholars Program
- Caltech Summer Undergraduate Research Fellowship Program
- NIH
- NSF
- Arnold and Mabel Beckman Foundation
- Created
-
2009-08-12Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field