Dual Nanoparticle Amplified Surface Plasmon Resonance Detection of Thrombin at Subattomolar Concentrations

Abstract

This version is available at https://strathprints.strath.ac.uk/50087/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the AbstractA novel dual nanoparticle amplification approach is introduced for the enhanced surface plasmon resonance (SPR) detection of a target protein at subattomolar concentrations.Thrombin was used as a model target protein as part of a sandwich assay involving an antithrombin (anti-Th) modified SPR chip surface and a thrombin specific DNA aptamer (Thaptamer) whose sequence also includes a polyadenine (A30) tail. Dual nanoparticle (NP) enhancement was achieved with the controlled hybridization adsorption of first polythymine-NP conjugates (T20-NPs) followed by polyadenine-NP's (A30-NPs). Two different nanoparticle shapes (nanorod and quasi-spherical) were explored resulting in four different NP pair combinations being directly compared. It was found that both the order and NP shape were important in optimizing the assay performance. The use of real-time SPR measurements to detect target concentrations as low as 0.1 aM is a ten-fold improvement compared to single NP-enhanced SPR detection methods.

Nanotechnology-Based Surface Plasmon Resonance Affinity Biosensors forIn VitroDiagnostics

“…The following step was the matching with the complementary polythymine aptamer (pT) previously modified with qsNPs, followed by a dual interaction with another polyadenine aptamer, modified with NRs for a double SPR signal enhancement. The sensor chip allowed detecting thrombin concentrations as low as 0.1 aM, with a 10-fold sensitivity enhancement compared with a simple NPs modification [45]. …”

Direct Detection of α-1 Antitrypsin in Serum Samples using Surface Plasmon Resonance with a New Aptamer–Antibody Sandwich Assay

“…SPR sensing of target proteins in crude serum via specific via direct affinity interactions has been demonstrated, [16][17][18][19][20] as well as achieving greater signal enhancement and 4 selectivity via the use of a secondary probe conjugated to particles. 16,[21][22][23][24][25][26] In addition, localized SPR measurements has also been explored for the sensing of antibiotin 27 and human epididymis secretory protein 28 in serum samples. Thus, after characterising the interactions between AAT with antiAAT and the AAT-sepcific aptamer in buffer, we also demonstrate a methodology for the analysis of AAT in serum samples at concentrations as low as 10 fM with a tuneable dynamic range depending on the antiAAT concentration.…”

Functionalized nanoparticle probes for protein detection

“…A similar, but much more improved concept for thrombin detection using aptamers forming sandwich structures was subsequently reported by the same research group, where the flat gold thin film was coated with antibodies, and the AuNP probes were functionalized with aptamers. [60] Importantly, the antibodyfunctionalized AuNPs were further able to hybridize with the other complementary AuNPs for additional signal amplification, which improved the sensitivity of the previous work by an order of magnitude (LOD = 0.1 aM). In spite of the difficulties to control non-specific adsorption of the AuNP probes and the dynamic range of the sensing system, the remarkably high sensitivity of the SPR-based protein detection schemes, using AuNP probes and aptamers, indicates great promise of using these components for other protein targets.…”