title: Detection of Bacillus anthracis spores by super-paramagnetic lateral-flow immunoassays based on "Road Closure".
abstract: Detection of Bacillus anthracis in the field, whether as a natural infection or as a biothreat remains challenging. Here we have developed a new lateral-flow immunochromatographic assay (LFIA) for B. anthracis spore detection based on the fact that conjugates of B. anthracis spores and super-paramagnetic particles labeled with antibodies will block the pores of chromatographic strips and form retention lines on the strips, instead of the conventionally reported test lines and control lines in classic LFIA. As a result, this new LFIA can simultaneously realize optical, magnetic and naked-eye detection by analyzing signals from the retention lines. As few as 500-700 pure B. anthracis spores can be recognized with CV values less than 8.31% within 5 min of chromatography and a total time of 20 min. For powdery sample tests, this LFIA can endure interference from 25% (w/v) milk, 10% (w/v) baking soda and 10% (w/v) starch without any sample pre-treatment, and has a corresponding detection limit of 6×10(4) spores/g milk powder, 2×10(5) spores/g starch and 5×10(5) spores/g baking soda. Compared with existing methods, this new approach is very competitive in terms of sensitivity, specificity, cost and ease of operation. This proof-of-concept study can also be extended for detection of many other large-sized analytes.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Dian-Bing
authors.initials: DB
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China; University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: Zhi-Ping
authors.initials: ZP
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: Xu-Ying
authors.initials: XY
authors.lastname: Wang
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Joy
authors.initials: J
authors.lastname: Fleming
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Bi
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Rui-Fu
authors.initials: RF
authors.lastname: Yang
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China. Electronic address: zhangxe@sun5.ibp.ac.cn.
authors.forename: Xian-En
authors.initials: XE
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001408:Bacillus anthracis / Q000302:isolation & purification* / Q000472:pathogenicity; D015374:Biosensing Techniques; D006801:Humans; D007118:Immunoassay; D008892:Milk / Q000382:microbiology; D017693:Sodium Bicarbonate / Q000737:chemistry; D013171:Spores, Bacterial / Q000302:isolation & purification* / Q000472:pathogenicity; D013213:Starch / Q000737:chemistry
chemical_list: D017693:Sodium Bicarbonate; D013213:Starch
keywords: Bacillus anthracis spores; Lateral-flow immunochromatographic assay; Super-paramagnetic particles