A chemically synthesized capture agent enables the selective, sensitive, and robust electrochemical detection of anthrax protective antigen.
We report on a robust and sensitive approach for detecting protective antigen (PA) exotoxin from Bacillus anthracis in complex media. A peptide-based capture agent against PA was developed by improving a bacteria display-developed peptide into a highly selective biligand through in situ click screening against a large, chemically synthesized peptide library. This biligand was coupled with an electrochemical enzyme-linked immunosorbent assay utilizing nanostructured gold electrodes. The resultant assay yielded a limit of detection of PA of 170 pg/mL (2.1 pM) in buffer, with minimal sensitivity reduction in 1% serum. The powdered capture agent could be stably stored for several days at 65 °C, and the full electrochemical biosensor showed no loss of performance after extended storage at 40 °C. The engineered stability and specificity of this assay should be extendable to other cases in which biomolecular detection in demanding environments is required.
Department of Applied Physics and Materials Science, and ‡Division of Chemistry and Chemical Engineering, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States.
Blake
B
Farrow
Sung A
SA
Hong
Errika C
EC
Romero
Bert
B
Lai
Matthew B
MB
Coppock
Kaycie M
KM
Deyle
Amethist S
AS
Finch
Dimitra N
DN
Stratis-Cullum
Heather D
HD
Agnew
Sung
S
Yang
James R
JR
Heath
D000942:Antigens, Bacterial / Q000032:analysis*; D001427:Bacterial Toxins / Q000032:analysis*; D055664:Electrochemical Techniques / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay; D057230:Limit of Detection
D000942:Antigens, Bacterial; D001427:Bacterial Toxins; C030325:anthrax toxin