title: Ultrasensitive electroanalysis of low-level free microRNAs in blood by maximum signal amplification of catalytic silver deposition using alkaline phosphatase-incorporated gold nanoclusters.
abstract: An ultrasensitive sandwich-type analysis method has been initially developed for probing low-level free microRNAs (miRNAs) in blood by a maximal signal amplification protocol of catalytic silver deposition. Gold nanoclusters (AuNCs) were first synthesized and in-site incorporated into alkaline phosphatase (ALP) to form the ALP-AuNCs. Unexpectedly, the so incorporated AuNCs could dramatically enhance the catalysis activities of ALP-AuNCs versus native ALP. A sandwiched hybridization protocol was then proposed using ALP-AuNCs as the catalytic labels of the DNA detection probes for targeting miRNAs that were magnetically caught from blood samples by DNA capture probes, followed by the catalytic ligation of two DNA probes complementary to the targets. Herein, the ALP-AuNC labels could act as the bicatalysts separately in the ALP-catalyzed substrate dephosphorylation reaction and the AuNCs-accelerated silver deposition reaction. The signal amplification of ALP-AuNCs-catalyzed silver deposition was thereby maximized to be measured by the electrochemical outputs. The developed electroanalysis strategy could allow for the ultrasensitive detection of free miRNAs in blood with the detection limit as low as 21.5 aM, including the accurate identification of single-base mutant levels in miRNAs. Such a sandwich-type analysis method may circumvent the bottlenecks of the current detection techniques in probing short-chain miRNAs. It would be tailored as an ultrasensitive detection candidate for low-level free miRNAs in blood toward the diagnosis of cancer and the warning or monitoring of cancer metastasis in the clinical laboratory.
authors.affiliation: Shandong Province Key Laboratory of Life-Organic Analysis, College of Chemistry and Chemical Engineering, Qufu Normal University , Qufu City, Shandong Province 273165, P. R. China.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Si
authors.forename: Zongzhao
authors.initials: Z
authors.lastname: Sun
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Qi
authors.forename: Shuying
authors.initials: S
authors.lastname: Li
authors.forename: Lijun
authors.initials: L
authors.lastname: Chen
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism*; D001774:Blood Chemical Analysis / Q000379:methods*; D002384:Catalysis; D055664:Electrochemical Techniques; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D035683:MicroRNAs / Q000097:blood*; D018030:Silver Compounds / Q000737:chemistry*
chemical_list: D035683:MicroRNAs; D018030:Silver Compounds; D006046:Gold; D000469:Alkaline Phosphatase