A visible and colorimetric aptasensor based on DNA-capped single-walled carbon nanotubes for detection of exosomes

Abstract

Recently, many studies have shown the potential use of circulating exosomes as novel biomarkers for monitoring and predicting a number of complex diseases, including cancer. However, reliable and cost-effective detection of exosomes in routine clinical settings, still remain a difficult task, mainly due to the lack of adequately easy and fast assay platforms. Therefore, we demonstrate here the development of a visible and simple method for the detection of exosomes by integrating single-walled carbon nanotubes that being excellent water solubility (s-SWCNTs) and aptamer. Aptamers, specific to exosomes transmembrane protein CD63, are absorbed onto the surface of s-SWCNTs and improve the minic peroxidase activity of s-SWCNTs, which can efficiently catalyze HO-mediated oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) and lead to a change from colorless to blue in solution. However, after adding exosomes, the aptamers are bound with CD63, leaving from the surface of s-SWCNTs through conformational changes, which results the color of solution from deep to moderate, and this can be observed by the naked eye and monitored by UV-vis spectrometry. Under optimal conditions, the linear range of exosomes is estimated to be 1.84×10 to 2.21×10 particles/μL with a detection of limit (LOD) of 5.2×10 particles/μL. Consequently, a visible and simple approach detecting exosomes is successfully constructed. Moreover, this proposed colorimetric aptasensor can be universally applicable for the detection of other targets by simple change the aptamer.

Exosomes for Non‐Invasive Cancer Monitoring

“…Effective signal generation methods are required for accurate identification of specific biomarkers that are highly expressed on the isolated exosomes. Until now, various signaling methods, including surface plasmon resonance, electrochemistry, colorimetry, and fluorometry, have been employed for this purpose . In the following section, key methods for the detection of specific exosome markers developed using these approaches are presented with emphasis given to their major components and techniques used.…”

A comprehensive overview of exosomes in ovarian cancer: emerging biomarkers and therapeutic strategies

“…Recently, Chinese scientists demonstrated a visible and simple method for the detection of exosomes by integrating DNA-capped single-walled carbon nanotubes [ 79 ]. This new method consists of two main elements: The first is s-SWCNTs, a tubular nanomaterial rich in carboxyl groups and water solubility.…”

Exosomes: Isolation, Analysis, and Applications in Cancer Detection and Therapy

“…Thirdly,t hese bioactive moleculesa re protected from externalp roteases and other enzymes by the exosomall ipid bilayer.B y combining antibodies, aptamers, and nanomaterials with different assay platforms, exosomes can be analyzed rapidly and exactly by use of fluorescence, electrochemical, and other new technologies(Ta ble 2). [54] Fluorescencea nalysis strategies have been used to detect exosomes because of that technique'se xtraordinary sensitivity and multiplex detection capability,a sw ell as its ease of automation. [55] Previous reports showed that some proteins are overexpressed in tumor-derived exosomes.…”