Device for detecting a bond between two biological species

Abstract

The invention relates to a device for characterizing the affinity of a bond between a biological species of interest, for example an antibody, and a capture biological species, for example an antigen. The bond is detected by a variation of fluorescence light, using a detection device comprising nanowires, each nanowire acting as a transducer of fluorescence light into an electrical signal. Figure 1E.

Claims

Claims

1. Device (1) for characterizing a binding affinity between a biological species of interest (28) and a capture biological species (26), the biological species of interest and the capture biological species being configured so as to induce, under the effect of the binding and of exposure to an excitation light, a variation of a fluorescence light, in a fluorescence spectral band, the device comprising: - a substrate (10), comprising at least one first electrode (lie); - a multilayer structure (20), comprising at least one second electrode (21c); - nanowires (30), extending between the first electrode (11c) and the second electrode (21c), parallel to a transverse axis (Z); - an encapsulation layer (15) extending around the nanowires, between the substrate and the multilayer structure (20), the encapsulation layer being formed from an insulating material; - the multi-layer structure comprising: • a conductive layer (22), comprising the second electrode; • an electrically insulating interface layer (23) covering each second electrode (21c), the second electrode being interposed between the interface layer and a nanowire, the interface layer being configured to be arranged between a sample, comprising the biological species of interest, and the second electrode, the interface layer being delimited by a functionalization surface (25), functionalized by the capture biological species, such that the functionalization surface forms an interface between the device and the sample; • the multilayer structure being such that the second electrode and the interface layer are transparent in the fluorescence spectral band; the device being such that: - each nanowire (30) comprises a junction (33) of homojunction type, or a heterojunction, or a Schottky junction between the first electrode and the second electrode; - the first electrode and the second electrode are configured to be connected to a detection circuit (40); - such that each nanowire forms a nanophotodetector in the fluorescence spectral band, the fluorescence light detected by each nanowire inducing an electrical detection signal in the detection circuit; the device comprising a processing unit, programmed to: • acquire the detection signal; • determine a variation, over time, of a fluorescence light • as a function of the variation, determination of a characteristic representative of an affinity between the biological species of interest and the biological capture species.

2. Device according to claim 1, comprising a fluidic chamber (4), in contact with the functionalization surface.

3. Device according to any one of the preceding claims, wherein the functionalization surface (25) is segmented into different capture sites, each capture site comprising the biological capture species, each capture site being configured to form a bond with the biological species of interest.

4. A dispenser according to any one of claims 2 and 3, wherein the fluidic chamber comprises channels, each channel extending opposite several capture sites.

5. Device according to any one of the preceding claims, in which each nanowire comprises: - a pn-type homojunction; - or a heterojunction; - or a p-metal or n-metal Schottky junction.

6. A device according to any preceding claim in which: - the interface layer comprises two sub-layers (23b 232), stacked on top of each other, forming a lower sub-layer and an upper sub-layer, the lower sub-layer being interposed between the conductive layer (22) and the upper sub-layer; - the upper sub-layer comprises wells, opening into the lower sub-layer, each well being arranged facing a nanowire, each well forming a part of the functionalization surface; - the functionalization surface is segmented at the level of each well, so that each well forms a capture site.

7. Device according to any one of the preceding claims, comprising several nanowires, extending between the same first electrode and the same second electrode, the nanowires forming a cluster of nanowires.

8. Device according to claim 7, comprising several clusters of nanowires (35), spaced apart from each other, such that a nanowire of a cluster is closer to another nanowire of said cluster than to another nanowire of another cluster, the nanowires of the same cluster extending between the same first electrode and the same second electrode.

9. A device according to any one of the preceding claims, comprising several nanowires, the device being such that: - several first electrodes are formed on the substrate, and several second electrodes are formed on the multilayer structure, each nanowire extending between a first electrode and a second electrode; - each first electrode is connected to a first addressing unit (40x), configured to select at least one first electrode; - each second electrode is connected to a second addressing unit (40Y), configured to select at least one second electrode; - such that the detection circuit (40) detects a current detection induced by each nanowire extending between the selected first electrode and second electrode.

10. A method of characterizing an affinity between a biological species of interest (28) and a capture biological species (26) using a device according to any one of the preceding claims, the method comprising: a. provision of a liquid sample, comprising the biological species of interest, in contact with the functionalization surface; b. establishment of a bond between the biological species of interest and the biological capture species, carried by the functionalization surface, on a capture site located directly above at least one nanowire; c. excitation of the capture site by an excitation light, so as to cause a variation of a fluorescence light emitted at the capture site; d. formation of a detection signal, by the detection circuit, the detection signal being representative of the variation in fluorescence; e. depending on the detection signal, determination of a characteristic of the affinity between the biological species of interest and the biological species of capture.

11. The method of claim 10, wherein - steps c) and d) are repeated; - during step e), the characteristic of the affinity between the biological species of interest and the biological capture species is determined based on the detection signal formed during several iterations of step d).

12. The method of claim 11, wherein - the binding between a biological species of interest and the capture biological species results in an increase or decrease in fluorescence light; - under the effect of the increase or decrease of the fluorescence light, the detection signal varies between a first level and a second level; - step e) comprises determining a duration during which the detection signal corresponds to the second level, assuming that at the capture site, the increase or decrease in fluorescence light is due to binding of a single biological species of interest to the capture biological species.

13. Method according to claim 11, wherein: - the bonds between a plurality of identical biological species of interest and capture biological species result in an increase or a decrease in the fluorescence light; - following first iterations of steps c) to d), steps c) and d) are repeated during second iterations; - prior to the second iterations of steps c) and d), a liquid sample, considered to be without the biological species of interest, is placed in contact with the functionalization surface; - during step e), the characteristic of the affinity between the biological species of interest and the capture biological species is determined as a function of detection signals formed during the first and second iterations of steps c) and d).

14. Method according to any one of claims 10 to 14 in which: - the biological species of interest is linked to a fluorescent marker; - the linking with the capture biological species results in an increase in the fluorescence light.

15. Method according to any one of claims 10 to 14, in which - the biological capture species is linked to a fluorescent marker; - the biological species of interest is linked to a fluorescence light quencher; - binding with the biological capture species results in a decrease in fluorescence light.

16. A method according to any one of claims 10 to 15, wherein the biological species of interest is an antibody and the capture biological species is an antigen.

Images