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Updated: Jan 2, 2026
Author Spotlight: Advancements in DNA Nanosensors – Addressing Sensitivity and Selectivity Challenges in Molecular Detection
Published on: February 9, 2024
A nanobiosensor based on graphene oxide and DNA binding dye for multi-microRNAs detection
Mahdi Rahaie1, Saman Khayat Noroozi1
1Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran 1439957131, Iran.
Abstract:
Multiplex assays for detection of biomarkers, provide advantageous analyses of different factors related to diagnoses of diseases. The Alzheimer's disease (AD) is one of the most common disease in old people in societies which is increasing, significantly. A group of microRNAs (miRNAs) play an important role in developing the disease which can be considered as early stage biomarkers. Since, selective, sensitive, simple and rapid method for detection of these miRNAs in a single test is critical for early diagnosis and efficient therapy of the disease, herein, we report a sensitive fluorescence assay based on enzyme-free and isothermal hybridization chain reaction with SYBR Green and graphene oxide (GOX) for early detection of miR-137 and miR-142, as two Alzheimer's biomarkers. Fluorescence spectrophotometry based on SYBR Green signal and GOX as the fluorescence quencher was used for detection and quantification of targets' miRNAs and change in fluorescence intensity due to absence and presence of the targets was measured. The limit of detection in the newly designed nanobiosensor was achieved as 82 pM with a sensitive detection of the miRNAs from 0.05 to 5 nM, that is critical for detecting the biomarkers. Given the real range of concentrations of miRNAs in blood (from nanomolar to femtomolar values), the method holds great promise in dual and multiple targets detection due to its sensitivity, rapidness, inexpensive and specificity which provides a convenient detection method of Alzheimer's in early stage.
Insights
This study presents a novel fluorescence assay for the early detection of Alzheimer's disease biomarkers, microRNAs (miRNAs). The sensitive, rapid, and inexpensive method enables simultaneous detection of miR-137 and miR-142 in blood samples.
Area of Science:
- Biomarker detection
- Nanotechnology
- Molecular diagnostics
Background:
- Alzheimer's disease (AD) is a progressive neurodegenerative disorder with increasing prevalence.
- MicroRNAs (miRNAs) are crucial in AD pathogenesis and serve as potential early diagnostic biomarkers.
- Sensitive, rapid, and multiplex detection of miRNAs is critical for early AD diagnosis and treatment.
Purpose of the Study:
- To develop a sensitive fluorescence assay for the simultaneous detection of Alzheimer's disease-related miRNAs (miR-137 and miR-142).
- To utilize enzyme-free isothermal hybridization chain reaction (HCR) with SYBR Green and graphene oxide (GOX) for enhanced miRNA detection.
Main Methods:
- A novel fluorescence assay employing enzyme-free isothermal HCR was developed.
- SYBR Green was used as the fluorescent reporter, and graphene oxide (GOX) acted as a fluorescence quencher.
- Fluorescence intensity changes were measured using spectrophotometry to quantify target miRNAs.
Main Results:
- The developed nanobiosensor achieved a sensitive detection limit of 82 pM for miRNAs.
- The assay demonstrated sensitive detection of miRNAs in the concentration range of 0.05 to 5 nM.
- The method showed high sensitivity, specificity, and rapidness, suitable for detecting clinically relevant miRNA concentrations in blood.
Conclusions:
- The developed fluorescence assay offers a promising, cost-effective, and convenient method for the early and multiplex detection of Alzheimer's disease biomarkers.
- This approach holds significant potential for improving early diagnosis and therapeutic strategies for Alzheimer's disease.
