Ratiometric Fluorescent Biosensor Based on Forster Resonance Energy Transfer between Carbon Dots and Acridine Orange for miRNA Analysis

Zhiwei Sun; Yao Tong; Xiaoyu Zhou; Juan Li; Li Zhao; Hui Li; Chuanxin Wang; Lutao Du; Yanyan Jiang

doi:10.1021/acsomega.1c05901

Ratiometric Fluorescent Biosensor Based on Forster Resonance Energy Transfer between Carbon Dots and Acridine Orange for miRNA Analysis

ACS Omega. 2021 Nov 30;6(49):34150-34159. doi: 10.1021/acsomega.1c05901. eCollection 2021 Dec 14.

Authors

Zhiwei Sun^{1

2}, Yao Tong³, Xiaoyu Zhou¹, Juan Li³, Li Zhao¹, Hui Li¹, Chuanxin Wang^{3

4

5}, Lutao Du³, Yanyan Jiang^{1

2

6}

Affiliations

¹ Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China.
² Shenzhen Research Institute of Shandong University, Shenzhen 518057, China.
³ Department of Clinical Laboratory, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250033, China.
⁴ Shandong Engineering & Technology Research Center for Tumor Marker Detection, Jinan 250033, China.
⁵ Shandong Provincial Clinical Medicine Research Center for Clinical Laboratory, Jinan 250033, China.
⁶ Suzhou Institute of Shandong University, Suzhou 215123, China.

Abstract

The expression level of miRNA is highly correlated with the pathological process of malignant tumors. Therefore, the abnormal expression of miRNA in serum is considered as reliable evidence for the existence of tumor cells. Here, a ratiometric fluorescent biosensor based on the Forster resonance energy transfer between fluorophores is proposed for detecting colorectal cancer-specific miRNA (miR-92a-3p). The miRNA in serum was first isolated by carboxyl-modified SiO₂ microspheres. Then, the addition of miRNA to the detection system resulted in the distance change between the donor acridine orange (AO) and the acceptor fluorescent carbon dots (CDs), which made the fluorescence signal change. The physicochemical properties, especially the fluorescence characteristics of CDs and AO, which enabled the ratiometric fluorescence detection, were comprehensively studied. The ratiometric fluorescent biosensor could detect miRNA in the concentration range of 1-9 nM and showed a detection limit of 0.14 nM. Moreover, the ratiometric fluorescent biosensor exhibited high selectivity for the target miRNA. The validity of the ratiometric fluorescent biosensor was also verified using the serum sample, demonstrating its potential for enzyme-free miRNA analysis.