Label-Free Nanoplasmonic-Based Short Noncoding RNA Sensing at Attomolar Concentrations Allows for Quantitative and Highly Specific Assay of MicroRNA-10b in Biological Fluids and Circulating Exosomes

Abstract

MicroRNAs are short noncoding RNAs consisting of 18–25 nucleotides that target specific mRNA moieties for translational repression or degradation, thereby modulating numerous biological processes. Although microRNAs have the ability to behave like oncogenes or tumor suppressors in a cell-autonomous manner, their exact roles following release into the circulation are only now being unraveled and it is important to establish sensitive assays to measure their levels in different compartments in the circulation. Here, an ultrasensitive localized surface plasmon resonance (LSPR)-based microRNA sensor with single nucleotide specificity was developed using chemically synthesized gold nanoprisms attached onto a solid substrate with unprecedented long-term stability and reversibility. The sensor was used to specifically detect microRNA-10b at the attomolar (10–18 M) concentration in pancreatic cancer cell lines, derived tissue culture media, human plasma, and media and plasma exosomes. In addition, for the first time, our label-free and nondestructive sensing technique was used to quantify microRNA-10b in highly purified exosomes isolated from patients with pancreatic cancer or chronic pancreatitis, and from normal controls. We show that microRNA-10b levels were significantly higher in plasma-derived exosomes from pancreatic ductal adenocarcinoma patients when compared with patients with chronic pancreatitis or normal controls. Our findings suggest that this unique technique can be used to design novel diagnostic strategies for pancreatic and other cancers based on the direct quantitative measurement of plasma and exosome microRNAs, and can be readily extended to other diseases with identifiable microRNA signatures.

New Technologies for Analysis of Extracellular Vesicles

“…Interestingly, miR-10b level was found to be significantly higher in PDAC patients than in CP patients. 192 Importantly, a very high level of the miRNA was associated with pancreatic cancer exosomes.…”

Achieving biosensing at attomolar concentrations of cardiac troponin T in human biofluids by developing a label-free nanoplasmonic analytical assay

“…14 In this context, ultrasensitive and novel biosensors can be developed by characterizing the LSPR response (extinction or absorption peak position and intensity) of nanoparticles as a function of the changes in their local dielectric environment. 6,[15][16][17] In this article, we report the first quantification of cardiac Troponin-T (cTnT) in diverse human biofluids (plasma, serum, and urine) utilizing a LSPR biosensor. Our chip-based LSPR cTnT biosensor provides a limit of detection (LOD) as low as 507 fg/L, which is 10 4 fold more sensitive than the commercial Elecys troponin T electrolumi-nescense immunoassay (ECLIA, 4 th generation, Roche Diagnostic) 18 and at least 50 fold lower than other label-free analytical techniques.…”

Recent advances in nanoplasmonic biosensors: applications and lab-on-a-chip integration

“…Serum samples were directly diluted to 40% and measured with the biosensor, and results were correlated with quantitative reverse transcription-polymerase chain reaction (qRT-PCR), a technique commonly used for miRNA detection. By optimizing nanoprism structure, even better LOD can be reached (~91 aM in 1/25 diluted plasma) [65], which may represent one of the lowest LODs reported for LSPRbased biosensors. Even miRNA levels in exosomes (i.e.…”