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Production and Targeting of Monovalent Quantum Dots
Published on: October 23, 2014
An approach toward miRNA detection via different thermo-responsive aggregation/disaggregation of CdTe quantum dots
Yasaman Sadat Borghei1, Morteza Hosseini1
1Department of Life Science Engineering, Faculty of New Sciences & Technologies, University of Tehran Tehran Iran smhosseini@khayam.ut.ac.ir.
Abstract:
MicroRNA-155 regulates the expression of 147 target genes that are involved in cancer pathways, and its expression level has been shown to be up-regulated in breast cancer. Thus, it is necessary to investigate the value of microRNA-155 for early diagnosis and prognosis of breast cancer. Here we present a novel and "light shift" spectral method for the detection of miRNA based on different thermo-responsive aggregation/disaggregation of CdTe quantum dots (CdTe QDs) by using single stranded DNA or a DNA/RNA heteroduplex as a template after heat treatment. In this method upon addition of the DNA/RNA heteroduplex, the CdTe QDs aggregate strongly due to their strong interaction with the double stranded nucleic acid, which results in fluorescence quenching. By applying the melting temperature (T m), the DNA/RNA heteroduplex denatures and two strands are dissociated, which disaggregates the QDs, effectively switching to fluorescence emission of QDs. These processes were investigated with Atomic Force Microscopy (AFM) and fluorescence spectroscopy. The proposed method has been used also for the determination of miR-155 in total RNAs extracted from the human breast carcinoma SK-BR-3 cells and normal human embryonic kidney cell line (HEK 293).
Insights
A new spectral method detects microRNA-155, a biomarker for breast cancer, using temperature-responsive quantum dots. This technique offers potential for early cancer diagnosis and prognosis.
Area of Science:
- Biochemistry
- Molecular Biology
- Nanotechnology
Background:
- MicroRNA-155 (miR-155) is implicated in cancer pathways and upregulated in breast cancer.
- Accurate detection of miR-155 is crucial for early diagnosis and prognosis of breast cancer.
Purpose of the Study:
- To develop a novel spectral method for detecting microRNA-155.
- To investigate the potential of this method for breast cancer diagnostics.
Main Methods:
- A "light shift" spectral method utilizing thermo-responsive aggregation/disaggregation of Cadmium Telluride quantum dots (CdTe QDs).
- Detection is based on the interaction of CdTe QDs with DNA/RNA heteroduplexes and their response to heat treatment (melting temperature, Tm).
- Atomic Force Microscopy (AFM) and fluorescence spectroscopy were used for investigation.
Main Results:
- The method demonstrated fluorescence quenching upon CdTe QD aggregation with DNA/RNA heteroduplexes.
- Disaggregation and fluorescence recovery were observed upon denaturation of the heteroduplex at Tm.
- Successful determination of miR-155 in breast carcinoma cells (SK-BR-3) and control cells (HEK 293) was achieved.
Conclusions:
- The proposed spectral method offers a sensitive approach for microRNA detection.
- This technique shows promise for the early diagnosis and prognosis of breast cancer by quantifying miR-155 levels.
