title: Rapid onsite detection of bacterial spores of biothreat importance by paper-based colorimetric method using erbium-pyrocatechol violet complex.
abstract: Dipicolinic acid (DPA) is an important chemical marker for the detection of bacterial spores. In this study, complexes of lanthanide series elements such as erbium, europium, neodymium, and terbium were prepared with pyrocatechol violet and effectively immobilized the pyrocatechol violet (PV)-metal complex on a filter paper using polyvinyl alcohol. These filter paper strips were employed for the onsite detection of bacterial spores. The test filter papers were evaluated quantitatively with different concentrations of DPA and spores of various bacteria. Among the four lanthanide ions, erbium displayed better sensitivity than the other ions. The limit of detection of this test for DPA was 60 μM and 5 × 10(6) spores. The effect of other non-spore-forming bacteria and interfering chemicals on the test strips was also evaluated. The non-spore-forming bacteria did not have considerable effect on the test strip whereas chemicals such as EDTA had significant effects on the test results. The present test is rapid and robust, capable of providing timely results for better judgement to save resources on unnecessary decontamination procedures during false alarms.
authors.affiliation: Center of Excellence, Department of Biotechnology, Vignan's University, Vadlamudi, Guntur Dist., Andhra Pradesh, 522 213, India.
authors.forename: M S
authors.initials: MS
authors.lastname: Shivakiran
authors.affiliation: DRDO-BU Center for Life Sciences, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India.
authors.forename: M
authors.initials: M
authors.lastname: Venkataramana
authors.affiliation: DRDO-BU Center for Life Sciences, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India. pvlrao@rediffmail.com.
authors.forename: P V
authors.initials: PV
authors.lastname: Lakshmana Rao
mesh_terms: D001412:Bacillus subtilis / Q000302:isolation & purification*; D001557:Benzenesulfonates; D054045:Biological Warfare Agents; D003124:Colorimetry / Q000379:methods*; D003666:Decontamination / Q000379:methods; D004871:Erbium; D057230:Limit of Detection; D010209:Paper; D010848:Picolinic Acids; D012680:Sensitivity and Specificity; D013171:Spores, Bacterial / Q000302:isolation & purification*
chemical_list: D001557:Benzenesulfonates; D054045:Biological Warfare Agents; D010848:Picolinic Acids; C009134:pyrocatechol violet; D004871:Erbium; C004860:dipicolinic acid
keywords: Bacterial spores; Dipicolinic acid; Dye displacement; Paper-based colorimetric detection; Point-of-care detection; Pyrocatechol violet