A universal amplified strategy for aptasensors: enhancing sensitivity through allostery-triggered enzymatic recycling amplification.
A universal amplified sensing strategy based on endonuclease was developed for designing fluorescence aptasensors. By employing hairpin-structured design for both recognition and reporter probes to decrease background signal, and a nicking endonuclease to perform target-triggered enzymatic recycling amplification, the proposed biosensor showed high sensitivity to target protein. To demonstrate the feasibility of the design, immunoglobulin E (IgE) was studied as a model target. Upon the addition of target protein, the specific formation of IgE/aptamer complex induced the releasing of the 37-mer fragment which partially hybridized with the molecular beacon (MB) probe. In the presence of endonuclease Nt.BbvCI, the MB was cleaved into two parts. Then, the released 37-mer fragment hybridized with another MB, and triggered the second cycle of cleavage, leading to an accumulation of fluorescence signals. Under the optimal conditions, a detection limit of 5 pM was obtained. The proposed sensing system was used for detection of IgE in complex biological samples with satisfactory results.
Shandong Provincial Key Laboratory of Life-organic Analysis, College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu Shandong 273165, China.
Kejun
K
Feng
Rongmei
R
Kong
Hua
H
Wang
Shufang
S
Zhang
Fengli
F
Qu
D000494:Allosteric Regulation; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D004720:Endonucleases / Q000378:metabolism; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis / Q000097:blood*; D015335:Molecular Probes / Q000737:chemistry / Q000378:metabolism; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods
D052157:Aptamers, Nucleotide; D015335:Molecular Probes; D007073:Immunoglobulin E; D004720:Endonucleases