Colorimetric and ratiometric aggregation assay for streptomycin using gold nanoparticles and a new and highly specific aptamer

Aptamers specific for the antibiotic streptomycin were identified by a modified SELEX procedure that employs magnetic beads. After eight rounds of selection, twenty-six aptamers were identified and clustered into seven groups according to similarities in their sequences. The binding constant of thre...

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Bibliographic Details
Published in:Mikrochimica acta (1966) 2016-05, Vol.183 (5), p.1687-1697
Main Authors: Soheili, Vahid, Taghdisi, Seyed Mohammad, Hassanzadeh Khayyat, Mohammad, Fazly Bazzaz, BiBi Sedigheh, Ramezani, Mohammad, Abnous, Khalil
Format: Article
Language:English
Subjects:
Analysis
Analytical Chemistry
Antibacterial agents
Antibiotics
Assaying
Beads
Characterization and Evaluation of Materials
Chemistry
Chemistry and Materials Science
Colorimetry
Ethylenediaminetetraacetic acid
Gold
Microengineering
Milk
Nanochemistry
Nanoparticles
Nanotechnology
Original Paper
Selectivity
Spectrophotometry
Streptomycin
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Summary:Aptamers specific for the antibiotic streptomycin were identified by a modified SELEX procedure that employs magnetic beads. After eight rounds of selection, twenty-six aptamers were identified and clustered into seven groups according to similarities in their sequences. The binding constant of three sequences from different groups were determined by colorimetric assays using unmodified gold nanoparticles (AuNPs). These most suitable aptamers were then truncated, and finally a 23-base sequence was identified that has the highest affinity (K d  = 132.3 nM) and selectivity. The assay was employed to analyze streptomycin residue in raw milk samples by ratiometric spectrophotometry at 520 and 660 nm, respectively. The analytical range extends from 180 to 1000 nM, and the LOD is 47.2 nM which is better than that of HPLC (4 μM). The interaction between aptamer and streptomycin was studied by molecular modeling. In our perception, this colorimetric assay provides a viable method for fast analysis of streptomycin in raw milk. Graphical Sbtract We describe a 23-base aptamer for streptomycin that has high affinity (K d  = 132.3 nM) and selectivity. A gold nanoparticle (AuNP) based colorimetric assay was employed to analyze streptomycin residue in raw milk samples. The analytical range extends from 180 to 1000 nM, and the LOD is 47.2 nM.
ISSN:0026-3672
1436-5073
DOI:10.1007/s00604-016-1798-3