We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress
Sign In
Advertise with Us
INTEGRA BIOSCIENCES AG

Download Mobile App




Nanostar Biosensors Use Raman Scattering for Direct Detection of Cancer-Related MicroRNAs

By LabMedica International staff writers
Posted on 03 Aug 2020
Print article
Image: Micrograph of gold nanostar biosensors used to detect cancer-related microRNAs (Photo courtesy of Duke University School of Engineering)
Image: Micrograph of gold nanostar biosensors used to detect cancer-related microRNAs (Photo courtesy of Duke University School of Engineering)
A novel non-invasive nanoparticle-based assay detects cancer-related microRNAs without use of labels or target amplification.

MicroRNAs (miRNAs) comprise a class of about 20 nucleotides-long RNA fragments that block gene expression by attaching to molecules of messenger RNA in a fashion that prevents them from transmitting the protein synthesizing instructions they had received from the DNA. With their capacity to fine-tune protein expression via sequence-specific interactions, miRNAs help regulate cell maintenance and differentiation. In addition to miRNAs playing an essential role in tumor development, dysregulation of certain miRNAs has been associated with many different diseases, such as dementia, and cardiovascular conditions. However, due to technical difficulties in detecting these small molecules, miRNAs have not been adopted into routine clinical practice for early diagnostics. Thus, it is important to develop alternative detection strategies that could offer more advantages over conventional methods.

In this regard, investigators at Duke University (Durham, NC, USA) developed nanophotonics technology termed "the inverse molecular sentinel (iMS) nanobiosensor, with surface-enhanced Raman scattering (SERS) detection".

The iMS-SERS technique is based on plasmonics, which refers to the enhanced electromagnetic properties of metallic nanostructures. The term plasmonics is derived from "plasmons", which are the quanta associated with longitudinal waves propagating in matter through the collective motion of large numbers of electrons. Incident light, usually from a laser, irradiating these surfaces excites conduction electrons in the metal, and induces excitation of surface plasmons leading to enormous electromagnetic enhancement of spectral signature, such as surface-enhanced Raman scattering (SERS) and surface-enhanced fluorescence (SEF) for ultrasensitive detection of chemical and biological species.

The SERS nanoprobe used in the current study relied on plasmonic-active nanostars as the sensing platform. An “OFF-to-ON” signal switch was based on a nonenzymatic strand-displacement process and the conformational change of stem-loop (hairpin) oligonucleotide probes upon target binding. This technique was used previously to detect a synthetic DNA sequence of interest. In this study, the design of the nanoprobe was modified to be used for the detection of short miRNA sequences.

In the current study, the investigators found that the iMS-SERS nanostar method detected miR-21, the microRNA biomarker linked to esophageal adenocarcinoma (EAC) and Barrett's esophagus (BE), the premalignant metaplasia associated with EAC. This approach enabled the direct detection of the esophageal cancer biomarker in RNA extracted from 17 endoscopic tissue biopsies. Thus, the potential of this label-free, homogeneous biosensor for cancer diagnosis without the need for target amplification was demonstrated by discriminating esophageal cancer and Barrett's esophagus from normal tissue with notable diagnostic accuracy.

"Gold nanostars have multiple spikes that can act as lighting rods for enhancing electromagnetic waves, which is a unique feature of the particle's shape," said senior author Dr. Tuan Vo-Dinh, professor of biomedical engineering at Duke University. "Our tiny nanosensors, called "inverse molecular sentinels", take advantage of this ability to create clear signals of the presence of multiple microRNAs. The Raman signals of label molecules exhibit sharp peaks with very specific colors like spectral fingerprints that make them easily distinguished from one another when detected. Thus we can actually design different sensors for different microRNAs on nanostars, each with label molecules exhibiting their own specific spectral fingerprints. And because the signal is so strong, we can detect each one of these fingerprints independently of each other."

"The general research focus in my lab has been on the early detection of diseases in people before they even know they are sick," said Dr.Vo-Dinh. "And to do that, you need to be able to go upstream, at the genomic level, to look at biomarkers like microRNA."

The gold nanostar paper was published in the May 4, 2020, online edition of the journal Analyst.

Related Links:
Duke University

Platinum Member
COVID-19 Rapid Test
OSOM COVID-19 Antigen Rapid Test
One Step HbA1c Measuring System
GREENCARE A1c
Anti-Cyclic Citrullinated Peptide Test
GPP-100 Anti-CCP Kit
Gold Member
Xylazine Immunoassay Test
Xylazine ELISA

Print article

Channels

Clinical Chemistry

view channel
Image: Reaching speeds up to 6,000 RPM, this centrifuge forms the basis for a new type of inexpensive, POC biomedical test (Photo courtesy of Duke University)

POC Biomedical Test Spins Water Droplet Using Sound Waves for Cancer Detection

Exosomes, tiny cellular bioparticles carrying a specific set of proteins, lipids, and genetic materials, play a crucial role in cell communication and hold promise for non-invasive diagnostics.... Read more

Hematology

view channel
Image: The Gazelle Hb Variant Test (Photo courtesy of Hemex Health)

First Affordable and Rapid Test for Beta Thalassemia Demonstrates 99% Diagnostic Accuracy

Hemoglobin disorders rank as some of the most prevalent monogenic diseases globally. Among various hemoglobin disorders, beta thalassemia, a hereditary blood disorder, affects about 1.5% of the world's... Read more

Microbiology

view channel
Image: The new platform is designed to perform blood-based diagnoses of nontuberculosis mycobacteria (Photo courtesy of 123RF)

New Blood Test Cuts Diagnosis Time for Nontuberculous Mycobacteria Infections from Months to Hours

Breathing in nontuberculous mycobacteria (NTM) is a common experience for many people. These bacteria are present in water systems, soil, and dust all over the world and usually don't cause any problems.... Read more

Industry

view channel
Image: These new assays are being developed for use on the recently introduced DxI 9000 Immunoassay Analyzer (Photo courtesy of Beckman Coulter)

Beckman Coulter and Fujirebio Expand Partnership on Neurodegenerative Disease Diagnostics

Beckman Coulter Diagnostics (Brea, CA, USA) and Fujirebio Diagnostics (Tokyo, Japan) have expanded their partnership focused on the development, manufacturing and clinical adoption of neurodegenerative... Read more
Copyright © 2000-2024 Globetech Media. All rights reserved.