Aptamer-based cell-free detection system to detect target protein

Junhong Chen; Xiaoyan Zhuang; Jiyang Zheng; Ruofan Yang; Fei Wu; Aihui Zhang; Baishan Fang

doi:10.1016/j.synbio.2021.07.004

Aptamer-based cell-free detection system to detect target protein

Synth Syst Biotechnol. 2021 Aug 13;6(3):209-215. doi: 10.1016/j.synbio.2021.07.004. eCollection 2021 Sep.

Authors

Junhong Chen^{1

2}, Xiaoyan Zhuang^{1

2}, Jiyang Zheng^{1

2}, Ruofan Yang^{1

2}, Fei Wu¹, Aihui Zhang^{1

2

3}, Baishan Fang^{1

2

3}

Affiliations

¹ XMU-China Team, Xiamen University, Xiamen, 361005, PR China.
² College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China.
³ The Key Laboratory for Chemical Biology of Fujian Province, Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China.

Abstract

Biomarkers of disease, especially protein, show great potential for diagnosis and prognosis. For detecting a certain protein, a binding assay implementing antibodies is commonly performed. However, antibodies are not thermally stable and may cause false-positive when the sample composition is complicated. In recent years, a functional nucleic acid named aptamer has been used in many biochemical analysis cases, which is commonly selected from random sequence libraries by using the systematic evolution of ligands by exponential enrichment (SELEX) techniques. Compared to antibodies, the aptamer is more thermal stable, easier to be modified, conjugated, and amplified. Herein, an Aptamer-Based Cell-free Detection (ABCD) system was proposed to detect target protein, using epithelial cell adhesion molecule (EpCAM) as an example. We combined the robustness of aptamer in binding specificity with the signal amplification ability of CRISPR-Cas12a's trans-cleavage activity in the ABCD system. We also demonstrated that the ABCD system could work well to detect target protein in a relatively low limit of detection (50-100 nM), which lay a foundation for the development of portable detection devices. This work highlights the superiority of the ABCD system in detecting target protein with low abundance and offers new enlightenment for future design and development.

Keywords: Aptamer; Biomarker; CRISPR-Cas; Protein detection.