Full on-chip nanoliter immuno-assay by geometrical magnetic trapping of nanoparticle chains

We propose an original concept to perform a complete on-chip sandwich immunoassay on magnetic nanoparticles that are self-assembled in chains in a uniform magnetic field. The magnetic chains are retained over periodically enlarged cross sections of a microfluidic channel. Thereby they strongly interact with the flow and rapidly capture the total of a low number of target molecules from nanoliter sample volumes. As an example, we demonstrate the detection of murine monoclonal antibodies in a noncompetitive sandwich immunoassay with a detection limit of 1 ng mL-1 in nanoliters of hybridoma cell culture medium.

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Martinus Gijs, Frédéric Lacharme, Caroline Vandevyver
2008
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https://infoscience.epfl.ch/record/115330?ln=fr

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Concepts associés (8)

Concepts associés

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Publications associées (2)

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Magnetic beads retention device for sandwich immunoassay: comparison of off-chip and on-chip antibody incubation

Martinus Gijs, Frédéric Lacharme, Caroline Vandevyver

We use magnetic microbeads, which are magnetically self-assembled in chains in a microfluidic chip, as reaction substrates to implement two different sandwich immunoassay protocols for the detection of mouse monoclonal target antibodies. The magnetic chains form when the chip is placed in a magnetic field, and are geometrically trapped and accurately positioned in a microchannel with periodically enlarged cross-sections. In the first immunoassay protocol, capture and target antibodies are incubated off-chip, while exposure to the detection antibody is performed on-chip. In the second protocol, the complete immunoassay is fully executed on-chip. In the ‘off-chip incubation–on-chip detection’ protocol, antibodies can be detected down to a concentration of 50 ng/mL in a total assay time of 120 min, while consuming 1.5 mL of target antibody solution. Using the full on-chip protocol, our system is able to detect target antibodies in the range of a few ng/mL in 30 min, using only a few tens of nanoliters of target antibody solution and reagents. The ‘off-chip incubation–on-chip detection’ protocol is also applied for dosing antibodies obtained from the supernatant of a cell culture medium.

Springer-Verlag2009

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Optofluidic nanoplasmonic biosensor for label-free live cell analysis in real time

Hatice Altug, Alexander Belushkin, Xiaokang Li, Maria Soler Aznar, Filiz Yesilköy

Cell signaling activities play a critical role in physiological and disease processes. The analysis of the tumor microenvironment or the immune system activation is nowadays providing valuable insights towards disease understanding and novel therapies development. Due to the various dynamic profiles, it is essential to implement a continuous monitoring methodology for accurate analysis. The current fluorescent and colorimetric approaches hinder such applications due to their multiple time-consuming steps, molecular labeling, and the ‘snapshot’ endpoint readouts. Photonics technology, and especially nanoplasmonic biosensors offer a unique opportunity to implement lab-on-a-chip systems that provide highly sensitive and label-free analysis of cell signaling events in real time. Here, we will present a microfluidics-integrated nanoplasmonic biosensor for long-term and real-time monitoring of cell secretion activity. The biosensor consists of a gold nanohole array supporting extraordinary optical transmission (EOT), which has been optimized to enable ultra-sensitive and high-throughput biomolecular detection. The nanobiosensor is integrated with a specifically designed microfluidic system that provides well-controlled cell culture conditions for long-term monitoring. We achieved an outstanding sensitivity for the detection of vascular endothelial growth factor (VEGF) directly secreted from microfluidic-cultured cancer cells. We demonstrated real-time monitoring for over 10 hours, preserving good cell viability. The multiplexing capability of our nanobiosensor could enable simultaneous analysis of different cell types and molecules-of-interest. Thus, our innovative approach of probing live cells can be a powerful tool to evaluate cellular activities for diagnostics and novel therapy development.

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Microfluidique

La microfluidique est la science et la technique des systèmes manipulant des fluides et dont au moins l'une des dimensions caractéristiques est de l'ordre du micromètre. Définition Georg

Auto-assemblage

L’auto-assemblage, parfois rapproché de l'auto-organisation, désigne les procédés par lesquels un système désorganisé de composants élémentaires s'assemble et s'organise de façon spontanée et autono

Detection

In general, detection is the action of accessing information without specific cooperation from with the sender. In the history of radio communications, the term "detector" was first used for a devi