2D Material Detector for Activity Monitoring of Single Living Micro-Organisms and Nano-Organisms

Abstract

A motion detector adapted to detect activity of extremely small scale organisms, such as micro-organisms, bacteria and fungi, and even of viruses and genetic material, such as DNA and RNA. The motion detector is capable of detecting nano-motion, that is, motion in the order of nanometers or less.

Claims

1. A sensor assembly for activity monitoring of a microorganism, or living cell constituent, or virus, or living nano-organism, the sensor assembly comprising: a 2D microscale motion detector adapted to act as a sample receiver, comprising an inert suspended layer, wherein the suspended layer is 1-5 atoms thick; at least one support for the suspended layer; and a read-out system adapted for measuring alteration of the suspended layer.

2. The sensor assembly according to claim 1, wherein: material of the suspended layer is a two-dimensional crystal providing interlayer van der Waals interactions in a direction perpendicular to the layer surface, and comprises graphene, hexagonal-BN, black phosphorus, or transition metal dichaclogenides; the metal comprises Mo, W, or Nb; the chalcogen comprises S, Se and Te, MoS.sub.2, NbSe.sub.2, or WSe.sub.2, and combinations thereof.

3. The sensor assembly according to claim 1, wherein the read-out system comprises a Fabry-Perot interferometer, a Michelson interferometer, an optical interferometer, a laser Doppler vibrometer, one or more capacitor electrodes, a piezoelectrical element, a piezoresistive element, an impedance analyser, or combinations thereof; and wherein alteration of the suspended layer changes the deflection, resonance frequency, reflection spectrum, transmission spectrum, optical adsorption, orientation of at least part of the suspended layer, optical interference, 2D crystal structure, electromagnetic properties, resistivity, conductivity, or any other physical characteristic or combinations thereof.

4. The sensor assembly according to claim 3, the read-out system further comprising: a laser for providing light; an optical system for directing light from the laser to the sample; an optical system for directing reflected light from the sample to a photo detector; and a recorder for representing motion.

5. The sensor assembly according to claim 1, wherein: the suspended layer is about 1-3 atoms thick; the suspended layer is about 0.1-50 μm wide; and the suspended layer is about 0.1-50 μm broad.

6. The sensor assembly according to claim 1, wherein: the suspended layer has a stiffness of about <10 N/m; the suspended layer has a Youngs modulus of about >100 GPa; the suspended layer has a weight of about <10.sup.−15 kg; and a cavity of about >100 nm height is disposed under the suspended layer and the cavity comprises a fluid; the at least one support comprises an electrically insulating material comprising an electrical conductivity σ (20° C.) of about <10.sup.−3 S/m; the at least one support has a height of about 20-1000 nm; the at least one support is provided on a substrate; and the suspended layer, the at least one support, and the substrate, are each individually non-toxic, and at least partly support organism activity.

7. The sensor assembly according to claim 1, further comprising a humidity chamber for receiving the suspended layer and a sample.

8. The sensor assembly according to claim 1, comprising an array of sample receivers.

9. A chip comprising at least one 2D microscale motion detector according to claim 1.

10. A sensor assembly comprising a chip according to claim 9.

11. An electronic device comprising a sensor assembly according to claim 1, and further comprising: at least two channels each individually in electrical connection with the read-out system; and at least one readout line.

12. A method for operating the sensor assembly according to claim 1, the method comprising: providing a volume of liquid, the volume being about <10 μl, the volume comprising a microorganism, living cell constituent, virus, or living nano-organism; and measuring motion of the microorganism, living cell constituent, or virus, over time.

13. The method according to claim 12, further comprising: adding a chemical, wherein the chemical comprises pharmaceuticals, potential pharmaceuticals, anti-biotics, kanamycin, or chloramphenicol; and measuring a response of the microorganism, living cell constituent, or virus, to the chemical over time.

14. The method according to claim 12, wherein the liquid comprises nutrition for the microorganism or for the living cell constituent or for the virus, a physiological acceptable liquid, or a metabolic support compound.

15. A disposable sample stage comprising: a 2D microscale motion detector adapted to act as a sample receiver, comprising an inert suspended layer, wherein the suspended layer is 1-5 atoms thick; and at least one support for the suspended layer.

16. The sensor assembly of claim 4, wherein the photo detector is a photo diode.

17. The sensor assembly of claim 4, further comprising an amplifier for amplifying detected light response.

18. The sensor assembly of claim 4, wherein the recorder comprises an oscilloscope.

19. The sensor assembly according to claim 1, wherein the suspended layer is about 1-2 μm wide, and about 1-2 μm broad.

20. The sensor assembly according to claim 1, wherein: the suspended layer has a stiffness of about <1 N/m; the suspended layer has a Youngs modulus of about >500 GPa (ASTM E1111); the suspended layer has a weight of about <10.sup.−16 kg; the disposed under the suspended layer has a height about >250 nm; the fluid of the cavity is a gas or liquid; the electrically insulating material comprises silicon oxide, silicon nitride, or silicon carbide; and the at least one support has a height of about 100-300 nm.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0052] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one or more embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating one or more embodiments of the invention and are not to be construed as limiting the invention. In the drawings:

[0053] FIG. 1 is a schematic illustration of a sensor assembly according to an embodiment of the present invention;

[0054] FIG. 2 is a schematic illustration of a read-out system according to an embodiment of the present invention;

[0055] FIGS. 3a, 3b, 3c and 3d are a series of graphs or plots illustrating results of an embodiment of the present invention, FIG. 3a showing the motion of the 2d material in the presence of a droplet mixed with only nutrition, FIG. 3b showing the motion after adding bacteria, FIG. 3c showing the motion after addition of Chloramphenicol antibiotic and FIG. 3d showing the variance of the time traces given in FIGS. 3a, 3b and 3c;

[0056] FIGS. 4a, 4b, 4c, and 4d are a series of graphs or plots illustrating results of an embodiment of the present invention, FIG. 4a shows motion of the suspended layer with adhered bacteria, FIG. 4b showing the motion after addition of Kanamycin antibiotic, FIG. 4c showing the motion after addition of Chloramphenicol, and FIG. 4d showing the variance of the time traces given in FIGS. 4a, 4b, 4c and 4d;

[0057] FIGS. 5a and 5b are graphs or plots of the amplitude spectra of the time traces associated with FIGS. 4a and 4c; and

[0058] FIG. 6 is an optical microscope image of an array of silanized natural crystal exfoliated 10 nm few layer thick graphene as the suspended material in the presence of E. coli.

DETAILED DESCRIPTION OF THE INVENTION

[0059] The figures are detailed throughout the description, and specifically in the experimental section below.

[0060] In the figures the reference numbers represent the items mentioned thereafter: [0061] 100 sensor assembly [0062] 101 sample receiver [0063] 102 inert suspended layer [0064] 103 read-out [0065] 104 support [0066] 105 microorganism [0067] 106 channel [0068] 107 substrate [0069] 108 cavity [0070] 109 chip [0071] 110 electronic device [0072] 111 liquid [0073] 112 nutrition [0074] 113 chemical [0075] 115 optical components [0076] 116 humidity chamber [0077] 117 photo-diode [0078] 118 oscilloscope

[0079] FIG. 1 shows the sensor assembly 100 comprising a sample receiver 101 with inert 2D material layer 102 acting as the motion detector. The 2D material is suspended over a cavity 108 using at least one support 104. Such geometry can be obtained using semiconductor technology, such as by using a mask, and wet- or dry-etching.

[0080] Turning back to FIG. 1, it is shown that the sensor assembly also comprises a chip 109 that sits on a substrate 107. The substrate 107 may comprise an array of sample receivers 101 on top of an electrical device 110.

[0081] In the embodiment of FIG. 1 also a liquid droplet 111 is dispensed on top of the sample receiver 101. The droplet contains micro-organisms 105 and nutrition 112. Chemicals 113 can be added to the droplet to change the behaviour of the micro-organism. The micro-organism can be also adhered to the 2D material and its motion can be probed by a read-out system 103.

[0082] FIG. 2 shows a read-out system that can be used for monitoring the metabolic activity of micro-organisms. In the embodiment of FIG. 2 a red helium-neon laser 114 is directed through optical components 115 on the 2D material layer 102 which is placed in a controlled humidity chamber 116. The intensity of the reflected light from the chip 109 is altered by the motion of the micro-organism 105 in the liquid droplet 111 that in turn moves the suspended 2D material 102. This intensity is then measured by a photodiode 117 connected to an oscilloscope 118.

[0083] In one example a liquid droplet 111 containing micro-organism E. coli bacteria 105 and nutrition Lysogeny broth solution 112 has been dispensed on the sample receiver 101 comprising an array of single layer chemical vapour deposited graphene as the inert suspended layer 102. The motion is read out using the measurement system described in FIG. 2. The motion of the suspended layer is traced in a timeframe of a few seconds in the presence and absence of chemicals 113 and micro-organisms 105.

[0084] FIG. 3a shows the motion of the 2D material in the presence of the droplet 111 mixed with only the nutrition 112. This trace shows almost no fluctuations, indicating the absence of bacteria.

[0085] FIG. 3b shows the motion after adding bacteria 105. This trace shows large fluctuations associated with the metabolic activity of the bacteria.

[0086] FIG. 3c shows the motion after addition of Chloramphenicol antibiotic 113 that kills the bacteria. No fluctuations are observed as a result of no bacterial metabolic activity.

[0087] FIG. 3d Shows the variance of the time traces given in FIGS. 3a, 3b and 3c. It can be observed that the variance drops about three times after adding antibiotic to the droplet.

[0088] In another example a liquid droplet 111 containing micro-organism E. coli bacteria 105 and nutrition Lysogeny broth solution 112 has been dispensed on the sample receiver 101 comprising an array of silanized natural crystal exfoliated 10 nm few layer thick graphene as the suspended material 102. FIGS. 4a, 4b and 4c show the time traces of the suspended layer in a timeframe of twelve minutes.

[0089] FIG. 4a shows the motion of the suspended layer with adhered bacteria 105. This time trace shows large fluctuations associated with the metabolic activity of the bacteria

[0090] FIG. 4b shows the motion after addition of Kanamycin antibiotic 113 to which the micro-organism is resistant. No change in the fluctuations is observed as a result antibiotic resistance.

[0091] FIG. 4c shows the motion after addition of Chloramphenicol (CM) antibiotic 113 that kills the bacteria. No fluctuations are observed as a result of no metabolic activity of the bacteria

[0092] FIG. 4d Shows the variance of the time traces given in FIGS. 4a, 4b and 4c. It can be observed that the variance drops about hundred times after adding Chloramphenicol to the droplet. However, almost no change in the variance is observed after adding Kanamycin (Ka).

[0093] FIGS. 5a-b show the amplitude spectra of the time traces associated with FIG. 4a and FIG. 4c. A tenfold decrease is observed in the average amplitude of the spectrum after adding Chloramphenicol antibiotic to the droplet containing E. coli bacteria.

[0094] FIG. 6 shows an optical microscope image of an array of silanized natural crystal exfoliated 10 nm few layer thick graphene as the suspended material in the presence of E. coli. Only few bacteria can be observed per drum.

[0095] Although the invention has been discussed in the foregoing with reference to exemplary embodiments of the sensor assembly and method of the invention, the invention is not restricted to these particular embodiments which can be varied in many ways without departing from the invention. The discussed exemplary embodiments shall therefore not be used to construe the appended claims strictly in accordance therewith. On the contrary the embodiments are merely intended to explain the wording of the appended claims without intent to limit the claims to these exemplary embodiments. The scope of protection of the invention shall therefore be construed in accordance with the appended claims only, wherein a possible ambiguity in the wording of the claims shall be resolved using these exemplary embodiments.

[0096] Note that in the specification and claims, “about” or “approximately” means within twenty percent (20%) of the numerical amount cited.

[0097] Embodiments of the present invention can include every combination of features that are disclosed herein independently from each other. Although the invention has been described in detail with particular reference to the disclosed embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above are hereby incorporated by reference. Unless specifically stated as being “essential” above, none of the various components or the interrelationship thereof are essential to the operation of the invention. Rather, desirable results can be achieved by substituting various components and/or reconfiguration of their relationships with one another.