Issue 11, 2015

Electroanalysis of pM-levels of urokinase plasminogen activator in serum by phosphorothioated RNA aptamer

Abstract

Protein biomarkers of cancer allow a dramatic improvement in cancer diagnostics as compared to the traditional histological characterisation of tumours by enabling a non-invasive analysis of cancer development and treatment. Here, an electrochemical label-free assay for urokinase plasminogen activator (uPA), a universal biomarker of several cancers, has been developed based on the recently selected uPA-specific fluorinated RNA aptamer, tethered to a gold electrode via a phosphorothioated dA tag, and soluble redox indicators. The binding properties of the uPA–aptamer couple and interference from the non-specific adsorption of bovine serum albumin (BSA) were modulated by the electrode surface charge. A nM uPA electroanalysis at positively charged surfaces, complicated by the competitive adsorption of BSA, was tuned to the pM uPA analysis at negative surface charges of the electrode, being improved in the presence of negatively charged BSA. The aptamer affinity for uPA displayed via the binding/dissociation constant relationship correspondingly increased, ca. three orders of magnitude, from 0.441 to 367. Under optimal conditions, the aptasensor allowed 10−12–10−9 M uPA analysis, also in serum, being practically useful for clinical applications. The proposed strategy for optimization of the electrochemical protein sensing is of particular importance for the assessment and optimization of in vivo protein ligand binding by surface-tethered aptamers.

Graphical abstract: Electroanalysis of pM-levels of urokinase plasminogen activator in serum by phosphorothioated RNA aptamer

Supplementary files

Article information

Article type
Paper
Submitted
21 Жел. 2014
Accepted
10 Қаң. 2015
First published
12 Қаң. 2015

Analyst, 2015,140, 3794-3802

Author version available

Electroanalysis of pM-levels of urokinase plasminogen activator in serum by phosphorothioated RNA aptamer

M. Jarczewska, L. Kékedy-Nagy, J. S. Nielsen, R. Campos, J. Kjems, E. Malinowska and E. E. Ferapontova, Analyst, 2015, 140, 3794 DOI: 10.1039/C4AN02354D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements