A ratiometric FRET sensor using Ti₃C₂T_x MXene for intracellular microRNA-21 quantitative measurement

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Molecular Diagnostics

Background:

• MicroRNA-21 (miRNA-21) is a biomarker implicated in various cancers.
• Accurate and sensitive detection of intracellular miRNA-21 is crucial for early cancer diagnosis.
• Existing detection methods often face challenges with sensitivity, specificity, or background noise.

Purpose of the Study:

• To develop a ratiometric fluorescence resonance energy transfer (R-FRET) sensor for sensitive and specific intracellular miRNA-21 detection.
• To utilize two-dimensional Ti3C2Tx MXene nanosheets as a fluorescence quencher and platform.
• To establish a potential tool for early cancer diagnosis through miRNA quantification.

Main Methods:

• Fabrication of an R-FRET sensor using MXene nanosheets, FAM-labeled hairpin probe (H1), and TAMRA-labeled hairpin probe (H2).
• Exploitation of MXene's quenching property to reduce background fluorescence.
• Initiation of a catalyzed hairpin assembly (CHA) reaction upon binding with target miRNA-21, bringing FAM and TAMRA into proximity for FRET.
• Quantitative analysis via the fluorescence intensity ratio (F_TAMRA/F_FAM).

Main Results:

• The sensor exhibited a linear response range from 100 pM to 20 nM for miRNA-21.
• A low limit of detection (LOD) of 40 pM was achieved.
• Successful quantification of intracellular miRNA-21 levels in HeLa cells was demonstrated.

Conclusions:

• The developed MXene-based R-FRET sensor provides a sensitive and specific method for intracellular miRNA-21 detection.
• The sensor's ability to quantify miRNA-21 in cells highlights its potential for early cancer diagnosis.
• This platform offers a promising approach for advancing molecular diagnostics and cancer screening.