مقالات پذیرفته شده در هشتمین کنگره بین المللی زیست پزشکی
A Fluorescence Biosensor for the Simultaneous Detection of miR-21-5p and miR-17-5p in Gastric Cancer
A Fluorescence Biosensor for the Simultaneous Detection of miR-21-5p and miR-17-5p in Gastric Cancer
Shamim Alizadeh Khorassani,1,*
1. Department of Biology, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Introduction: Gastric cancer (GC) remains a leading cause of cancer-related death worldwide. Less than half of GC cases are diagnosed at an advanced stage due to its lack of early symptoms. Early detection and effective monitoring of tumor progression are essential for reducing GC disease burden and mortality. The current widespread use of semi-invasive endoscopic methods and radiologic approaches has increased the number of treatable cancers: However, these approaches are invasive, costly, and time-consuming. Thus, novel molecular noninvasive tests that detect GC alterations seem more sensitive and specific than the current methods. The discovery of microRNAs (miRs) and their unique role in cancer and other diseases has prompted the development of highly sensitive molecular diagnostic tools using nanomaterials as sensitive and specific biosensors. Among these, fluorescent biosensors, which are based on a simple and inexpensive design, make them desirable in clinical applications as well as a mass-produced point-of-care devices. In this study, single- and dual-fluorophore DNA biosensors based on single-walled carbon nanotubes (SWCNT) were fabricated for the individual and simultaneous detection of the miR-21-5p and miR-17-5p in early diagnosis gastric cancer.
Methods: Our detection strategy was based on immobilizing dye-labeled single-stranded DNA (ROX, and FAM dye-labeled-ssDNA) to SWCNT that detect target miR-21-5p and miR-17-5p. For this purpose, in the first step, adsorption of ROX-, and FAM-labeled single-stranded DNA (ssDNA) on SWCNT leads to fluorescence quenching of ROX, and FAM. Next, by adding its complementary DNA (cDNA), a double-stranded DNA (dsDNA) was formed, resulting in recovering the fluorescence of ROX, and FAM by desorbing and releasing from SWCNT.
Results: Upon the addition of the complementary target DNA (ctDNA) to the hybridization reaction, the fluorescence emission of fluorophore-labeled probes was significantly recovered to 69.5 % for ROX-labeled probes (i.e. miR-21-specific probes), 71.5% for FAM-labeled probes (i.e. miR-17-specific probes), and 59.9% for dual-fluorophore biosensor compared to the quenching mode. The limit of detection (LOD) for ROX, and FAM was determined to be 3.6 nM, and 6.8 nM, respectively. For dual-color probes, LOD was found to be 4.9 (ROX) and 9.6 nM (FAM).
Conclusion: Finally, the clinical applicability of the proposed method was confirmed through the detection of both biomarkers in patient plasma samples, suggesting that the proposed nanosensing platform may be useful for the early detection of gastric cancer using miRNA.