Turn-on fluorescent assay based on purification system via magnetic separation for highly sensitive probing of adenosine

• Published in: Sensors and actuators. B, Chemical Chemical, 2018-04, Vol.259, p.855-861
• Main Authors: Zhu, Wanying, Shen, Xin, Zhu, Chunhong, Li, Bingzhi, Hong, Junli, Zhou, Xuemin
• Format: Article
• Language: English
• Subjects: Adenosine; Aptamer labeled-carbon dots (Apt-CDs); Assaying; Biological properties; Biomarkers; Fe3O4@polypyrrole (Fe3O4@PPY); Fluorescence; Fluorescent indicators; Food safety; Hydrophobicity; Iron oxides; Magnetic separation; Medical diagnosis; Polypyrroles; Purification system; Turn-on fluorescent assay; Water purification
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2017.12.147

[Display omitted] •A turn-on fluorescent assay for highly sensitive and selective detection of possible biomarkers was constructed.•Purification system via magnetic separation was designed and fabricated, improving the sensitivity dramatically.•Superparamagnetism Fe3O4@PPY was used not only for fluorescence quenching but also for analysis system purification.•The proposed assay showed immense universality for other clinical biomarkers by changing the specific aptamer sequence. In this work, based on purifying the analysis system by magnetic separation, we constructed a turn-on fluorescent assay for highly sensitive detection of possible biomarkers, employing adenosine as the model target analyte. Aptamer labeled-carbon dots (Apt-CDs) was applied as fluorescence probes as well as selective recognition elements, while Fe3O4@polypyrrole (Fe3O4@PPY) was used as fluorescence quenching and magnetic separating materials for system purification. In absence of adenosine, the Apt-CDs were attached to the surface of PPY through π-π stacking and hydrophobic interaction and its fluorescence was quenched by Fe3O4@PPY. In presence of adenosine, the aptamer could specifically bind with adenosine to form a three dimensional Apt-CDs-adenosine complex and detach from PPY, leading to the fluorescence recovery of Apt-CDs. More importantly, with analysis system purification via twice convenient magnetic separations of free CDs and Apt-CDs-adenosine complex respectively, the detection limit could be reduced from 8 nmol L−1 to 0.15 nmol L−1. This concept offers potential application for simple, rapid, cost-effective, and highly sensitive assay of biological samples.