scholarly journals Surface plasmon resonance biosensor for exosome detection based on reformative tyramine signal amplification activated by molecular aptamer beacon

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Wenqin Chen ◽  
Zhiyang Li ◽  
Wenqian Cheng ◽  
Tao Wu ◽  
Jia Li ◽  
...  

AbstractHuman epidermal growth factor receptor 2 (HER2)-positive exosomes play an extremely important role in the diagnosis and treatment options of breast cancers. Herein, based on the reformative tyramine signal amplification (TSA) enabled by molecular aptamer beacon (MAB) conversion, a label-free surface plasmon resonance (SPR) biosensor was proposed for highly sensitive and specific detection of HER2-positive exosomes. The exosomes were captured by the HER2 aptamer region of MAB immobilized on the chip surface, which enabled the exposure of the G-quadruplex DNA (G4 DNA) that could form peroxidase-like G4-hemin. In turn, the formed G4-hemin catalyzed the deposition of plentiful tyramine-coated gold nanoparticles (AuNPs-Ty) on the exosome membrane with the help of H2O2, generating a significantly enhanced SPR signal. In the reformative TSA system, the horseradish peroxidase (HRP) as a major component was replaced with nonenzymic G4-hemin, bypassing the defects of natural enzymes. Moreover, the dual-recognition of the surface proteins and lipid membrane of the desired exosomes endowed the sensing strategy with high specificity without the interruption of free proteins. As a result, this developed SPR biosensor exhibited a wide linear range from 1.0 × 104 to 1.0 × 107 particles/mL. Importantly, this strategy was able to accurately distinguish HER2-positive breast cancer patients from healthy individuals, exhibiting great potential clinical application. Graphical Abstract

2018 ◽  
Author(s):  
Yong Cao ◽  
Mark T. McDermott

<div> <div> <div> <p>Quantitative measurement of small-molecule metabolites is now emerging as an effective way to link the metabolite profile to disease state. Surface plasmon resonance (SPR) is a sensing platform that has demonstrated applicability for a large range of biomolecules. However, direct detection of small molecules with SPR challenges the refractive index based detection mechanism. Herein, we utilized an indirect detection format and developed an inhibition immunoassay for the quantitative measurement of 17β-estradiol (E2) using SPR. One competitor, BSA-E2 conjugate, was immobilized to the SPR chip via the reaction between the primary amino group of the conjugate and the succinimide group (NHS) introduced by the formation of a thiol-NHS monolayer on gold surface. Free E2 molecules compete with BSA-E2 on chip surface for binding sites provided by a monoclonal anti-E2 antibody. It was found the binding affinity of the antibody to BSA-E2 conjugate increases with decreasing surface coverage of BSA-E2 conjugate. Under optimal conditions, a sigmoidal calibration curve with a negative slope and a dynamic range from 10 pM to 2 nM was generated. The detection limit of the immunoassay is estimated to be 0.3 pM. Moreover, the immunoassay exhibits high specificity for E2 detection using estrone (E1) as a potential interference.</p></div></div></div>


Optik ◽  
2018 ◽  
Vol 172 ◽  
pp. 697-707 ◽  
Author(s):  
Angad S. Kushwaha ◽  
Anil Kumar ◽  
Rajeev Kumar ◽  
Monika Srivastava ◽  
S.K. Srivastava

2017 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Wida Yanti ◽  
Asih Melati

<p><br />Halal foods and medicines are an absolute daily needs for the Muslim community in Indonesia. Therefore the authority institutions in indonesian goverment should ensure the availability of this. It is of course inseparable from the role of higher education through the development of its technology to develop halal detection of foods and drugs. This study is an effort to contribute to the Halal Research Center of UIN Sunan Kalijaga Yogyakarta through the biosensor development in halal detection foods and medicines based on biosensor SPR. This device using graphene materials to improve the detection sensitivity of pork gelatin material that is likely contained in foodstuffs and medicine. From analytical calculation and computation, enhancement of the SPR biosensor performance by involvement graphene it was shown through the ATR (Attenuated Total Reflectance) reflective curve. The result of this results was found the enhancement of the sensitivity 2,86 %.</p><p>Keyword: Surface Plasmon Resonance (SPR), Porcine Gelatin, Graphene, ATR</p>


2005 ◽  
Vol 68 (4) ◽  
pp. 728-735 ◽  
Author(s):  
PAUL LEONARD ◽  
STEPHEN HEARTY ◽  
GARY WYATT ◽  
JOHN QUINN ◽  
RICHARD O'KENNEDY

A polyclonal antibody was produced against Internalin B (InlB)–enriched extract and used to develop an inhibition assay to detect Listeria monocytogenes cells in solution using surface plasmon resonance. The gene sequence encoding for the InlB protein was cloned into a Qiagen pQE-60 vector, expressed in Escherichia coli, and purified by immobilized metal affinity chromatography. Protein G–purified anti-InlB–enriched extract polyclonal antibody was incubated with various concentrations of L. monocytogenes cells and subsequently injected over a purified-recombinant InlB (rInlB)–immobilized CM5 sensor chip surface. A decrease in antibody binding response was observed with increasing L. monocytogenes cell concentrations. Intraday and interday assay variability studies were carried out to evaluate precision and reproducibility. The assay had a limit of detection of less than 2 × 105 cells per ml and could be successfully reproduced with coefficients of variation of between 2.5 and 7.7%.


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