Multiplexed biosensing of proteins and virions with disposable plasmonic assays

Our growing ability to tailor healthcare to the needs of individuals has the potential to transform clinical treatment. However, the measurement of multiple biomarkers to inform clinical decisions requires rapid, effective, and affordable diagnostics. Chronic diseases and rapidly evolving pathogens in a larger population have also escalated the need for improved diagnostic capabilities. Current chemical diagnostics are often performed in centralized facilities and are still dependent on multiple steps, molecular labeling, and detailed analysis, causing the result turnaround time to be over hours and days. Rapid diagnostic kits based on lateral flow devices can return results quickly but are only capable of detecting a handful of pathogens or markers. Herein, we present the use of disposable plasmonics with chiroptical nanostructures as a platform for low-cost, label-free optical biosensing with multiplexing and without the need for flow systems often required in current optical biosensors. We showcase the detection of SARS-CoV-2 in complex media as well as an assay for the Norovirus and Zika virus as an early developmental milestone toward high-throughput, single-step diagnostic kits for differential diagnosis of multiple respiratory viruses and any other emerging diagnostic needs. Diagnostics based on this platform, which we term “disposable plasmonics assays,” would be suitable for low-cost screening of multiple pathogens or biomarkers in a near-point-of-care setting

Определение природных и техногенных радионуклидов в бальнеологических объектах

Quantitative detection of angiogenic biomarkers provides a powerful tool to diagnose cancers in early stages and to follow its progression during therapy. Conventional tests require trained personnel, dedicated laboratory equipment and are generally time-consuming. Herein, we propose our developed biosensing platform as a useful tool for a rapid determination of Angiopoietin-2 biomarker directly from patient plasma within 30 minutes, without any sample preparation or dilution. Bloch surface waves supported by one dimensional photonic crystal are exploited to enhance and redirect the fluorescence arising from a sandwich immunoassay that involves Angiopoietin-2. The sensing units consist of disposable and low-cost plastic biochips coated with the photonic crystal. The biosensing platform is demonstrated to detect Angiopoietin-2 in plasma samples at the clinically relevant concentration of 6 ng/mL, with an estimated limit of detection of approximately 1 ng/mL. This is the first Bloch surface wave based assay capable of detecting relevant concentrations of an angiogenic factor in plasma samples. The results obtained by the developed biosensing platform are in close agreement with enzyme-linked immunosorbent assays, demonstrating a good accuracy, and their repeatability showed acceptable relative variations

Développement d'un système optique d'imagerie en résonance de plasmons de surface pour l'analyse simultanée de multiples interactions biomoléculaires en temps réel

Les besoins actuels grandissants pour l'analyse des interactions biomoléculaires nécessitent le développement de systèmes automatisés à forte capacité et haut débit comme la microscopie de fluorescence qui reste une méthode de prédilection. Bien que les méthodes directes (sans marquage des molécules à analyser) présentent une sensibilité plus faible que celles utilisant des marqueurs, leurs nombreux avantages (suivi en temps réel, préparation simplifiée des échantillons) sont des atouts d'importance pour l'analyse quantitative des interactions biomoléculaires. En outre, l'imagerie en résonance des plasmons de surface permet de mesurer simultanément de nombreuses interactions comme les méthodes avec marqueurs. Pour élaborer un tel dispositif, nous avons d'abord identifié les différents paramètres critiques, susceptibles d'être améliorés, comme la nature de la couche métallique. L'utilisation du capteur ainsi développé repose en grande partie sur la chimie de surface: nous avons choisi la synthèse électrochimique de films de polypyrrole qui permet, de manière contrôlée et structurée, une fonctionnalisation simple et robuste de plots contenant diverses molécules. Parallèlement, nous avons développé un programme d'acquisition d'images dont le traitement permet de suivre en temps réel les réactions biomoléculaires sur chaque plot et d'en extraire constantes d'association, de dissociation et d'affinité entre molécules. Enfin, nous avons démontré les possibilités d'application de ce système à l'étude de maladies héréditaires ou du cancer à travers des interactions ADN/ADN (K-ras), ADN/protéines (p53), protéines/protéines (hCG) et oligosaccharides/protéines (HP6/SDF-1).The current growing requirements, in the field of biomolecular interactions analysis, require the development of automated high throughput systems like fluorescence microscopy that remains the method of choice. Although direct methods (without labeling of the molecules to be analyzed) have a lower sensitivity than those using labels, their many advantages (real time monitoring, simplification of the sample preparation) are of importance for biomolecular interactions quantitiative analysis. Moreover, the surface plasmon resonance imaging allows simultaneous measurements of many interactions like the methods with labels. To implement such a device, we identified its various critical parameters, likely to be improved, like the nature of the metal layer. The use of the thus developed sensor relies largely on surface chemistry: we have chosen the electrochemical synthesis of polypyrrole films that allows, in a controlled and structured manner, a simple and robust functionalization of spots containing various molecules. In parallel, an adequate home-developed software, including acquisition of images whose processing allows the real time monitoring of the biomolecular reactions occurring on each spot and the extraction of their association rate, dissociation rate and affinity constant between molecules. Lastly, we demonstrated the application possibilities of this system to the stufy of hereditary diseases or cancer through DNA/DNA (K-ras), DNA/protein (p53), protein/protein (hCG) and oligosaccharide/protein interactions (HP6/SDF-1).ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Generalization Of The Rouard Method To An Absorbing Thin-Film Stack And Application To Surface Plasmon Resonance

In the context of surface plasmon resonance (SPR) kinetic biochips, it is important to model the SPR phenomenon (i.e., extinction of reflectivity) toward biochip design and optimization. The Rouard approach that models reflectivity off a thin-film stack is shown to be extendable to any number of absorbing layers with no added complexity. Using the generalized Rouard method, the effect of SPR is simulated as a function of the wavelength for various metal thicknesses. Given an optimal metal thickness, the dependence of SPR on the angle of incidence and wavelength is also demonstrated. Such a model constitutes a potential basis for the efficient design and optimization of multidimensional sensors. © 2006 Optical Society of America

Improving performances of surface plasmon resonance imaging biosensors: real-time multi-spectral interrogation (Orale)

International audienc

Improving performances of surface plasmon resonance imaging biosensors: real-time multi-spectral interrogation (Orale)

International audienc

Réduction de la dispersion des mesures en imagerie par résonance des plasmons de surface (SPRi) par interrogation spectrale (Orale)

poster présenté par Alexandra Sered

Multiresonant plasmonic nanostructure for ultrasensitive fluorescence biosensing

A novel metallic nanostructure for efficient plasmon-enhanced fluorescence readout of biomolecular binding events on the surface of a solid sensor chip is reported. It is based on gold multiperiod plasmonic grating (MPG) that supports spectrally narrow plasmonic resonances centered at multiple distinct wavelengths. They originate from diffraction coupling to propagating surface plasmons (SPs) forming a delocalized plasmonic hotspot associated with enhanced electromagnetic field intensity and local density of optical states at its surface. The supported SP resonances are tailored to couple with the excitation and emission transitions of fluorophores that are conjugated with the biomolecules and serve as labels. By the simultaneous coupling at both excitation and emission wavelengths, detected fluorescence intensity is enhanced by the factor of 300 at the MPG surface, which when applied for the readout of fluorescence immunoassays translates to a limit of detection of 6 fM within detection time of 20 min. The proposed approach is attractive for parallel monitoring of kinetics of surface reactions in microarray format arranged on a macroscopic footprint. The readout by epi-fluorescence geometry (that inherently relies on low numerical aperture optics for the imaging of the arrays) can particularly take advantage of the reported MPG. In addition, the proposed MPG nanostructure can be prepared in scaled up means by UV-nanoimprint lithography for future practical applications

Wallarray: a project to design glycan microarrays of cell wall polysaccharides for functional genomics

National audienc

Wallarray: a project to design glycan microarrays of cell wall polysaccharides for functional genomics

National audienc