THERMOPHORESIS MEASUREMENTS IN NANOLITERDROPLETS

• US 20150316480A1
• Filed: 11/05/2014
• Published: 11/05/2015
• Est. Priority Date: 05/05/2014
• Status: Active Grant

• Current Assignee: NanoTemper Technologies GmbH
• Original Assignee: NanoTemper Technologies GmbH
• Inventors: Braun, Dieter, Duhr, Stefan, Baaske, Philipp, Seidel, Susanne
• Granted Patent: US 9,995,684 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01L 2200/0642 Filling fluids into wells by specific techniques
• CPC Class Codes: B01L 2200/0673 Handling of plugs of fluid surrounded by immiscible fluid
• CPC Class Codes: B01L 2300/0663 Whole sensors
• CPC Class Codes: B01L 2300/0819 Microarrays; Biochips
• CPC Class Codes: B01L 2300/0829 Multi-well plates; Microtitration plates
• CPC Class Codes: B01L 2300/0838 Capillaries
• CPC Class Codes: B01L 2300/1872 Infrared light
• CPC Class Codes: B01L 2400/0451 Thermophoresis; Thermodiffusion; Soret-effect
• CPC Class Codes: B01L 3/0268 using pulse dispensing or spraying, eg. inkjet type, piezo actuated ejection of droplets from capillaries
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: B01L 3/50851 specially adapted for heating or cooling samples laboratory heating apparatus B01L7/00; incubators C12M
• CPC Class Codes: G01N 15/0205 by optical means
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters
• CPC Class Codes: G01N 21/6456 Spatial resolved fluorescence measurements; Imaging
• CPC Class Codes: G01N 21/6486 Measuring fluorescence of biological material, e.g. DNA, RNA, cells G01N21/6428 takes precedence
• CPC Class Codes: G01N 2201/06113 Coherent sources; lasers

Abstract

The present invention relates generally to a system and a method for thermo-optical measurements in a droplet of aqueous solution comprising particles of interest, the method comprising the following steps: providing the droplet of aqueous solution with a volume of less than 200 nl, wherein the aqueous solution is a first liquid and at least a part of the particles of interest are fluorescent particles; embedding the droplet of aqueous solution at least partly in a second liquid; irradiating a laser light beam into the droplet to obtain a spatial temperature distribution in the droplet around the irradiated laser light beam; exciting fluorescently said fluorescent particles and detecting fluorescence at least at one position or at around one position in the droplet or detecting the fluorescence distribution of said fluorescently excited particles, wherein said detection of fluorescence is performed at least once at a predetermined time after the start of the laser irradiation; and determining a characteristic of the particles of interest from the detected fluorescence intensity or fluorescence intensity distribution.

Claims

1. A method for thermo-optical measurements in a first volume of aqueous solution comprising particles of interest, the method comprising the steps:

providing the first volume of aqueous solution with a volume of less than 200 nl, wherein the aqueous solution is a first liquid and at least a part of the particles of interest are fluorescent particles;

embedding the first volume of aqueous solution at least partly in a second liquid;

irradiating a laser light beam into the first volume to obtain a spatial temperature distribution in the first volume around the irradiated laser light beam;

exciting fluorescently said fluorescent particles and detecting the fluorescence at least at one position or around one position in the first volume or detecting the fluorescence distribution of said fluorescently excited particles, wherein said detection of fluorescence is performed at least once at a predetermined time after the start of the laser irradiation; and

determining a characteristic of the particles of interest from the detected fluorescence intensity or fluorescence intensity distribution.

2. The method according to claim 1, wherein

a. the second liquid only partly embeds the first volume, such that the first volume is covered with a layer of the second liquid;

or

b. the first volume is fully embedded within the second liquid, wherein the second liquid does preferably not absorb IR radiation; and

/or

c. the aqueous solution is preferably immiscible with the second liquid such that a boundary surface is formed between the aqueous solution and the second liquid.

3. The method according to claim 1, wherein the second liquid is non-aqueous, an oil, a surfactant, a surfactant-oil mix or a detergent-oil mix, which preferably ensures that the aqueous solution of the first volume forms a droplet, preferably a spherical, substantially spherical, egg shaped, oval, elongated, partly flat, partly convex or partly concave droplet, which comprises preferably a substantially constant diameter.

4. The method according to claim 1, wherein the first volume is formed by the following steps:

providing a destination plate with the second liquid;

providing a liquid sample of the aqueous solution containing said fluorescent particles and generating at least one transfer droplet from said liquid sample; and

transferring at least one of said transfer droplets to the second liquid such that the first volume is formed by one or a plurality of said transfer droplets on the destination plate, wherein said first volume is at least partly embedded in said second liquid.

5. The method according to claim 4, wherein

a. the destination plate is a multiwell plate and the second liquid is provided in at least one of the wells of the multiwell plate;

and/or

b. the liquid sample is provided in a multiwell source plate.

6. The method according to claim 5, wherein the destination multiwell plate comprises conical wells and the first volume preferably touches a bottom of the conical well, wherein the multiwell plate is preferably a 6, 12, 24, 48, 96, 384 or a 1536 multiwell plate.

7. The method according to claim 4, wherein the transfer droplets are generated by a droplet generator which preferably comprises a transducer located preferably below the multiwell source plate, wherein the transducer preferably emits pulses, preferably acoustic pulses, to generate and transfer the transfer droplet from the multiwell source plate to the destination plate.

8. The method according to claim 1, wherein the second liquid is admixed with the aqueous solution such that the first volumes of the aqueous solution are formed within the second liquid;

preferably an emulsion with droplet of the aqueous solution in oil is formed, wherein

said second liquid with said droplets is guided into a channel of capillary, such that the droplet is embedded within said channel or capillary, wherein said channel is preferably a channel of a microfluidic device.

9. The method according to claim 1, wherein the first volume is a droplet which is generated by means of a piezo based droplet generator.

10. The method according to claim 1, wherein

the volume of the first volume is smaller than 100 nl, preferably smaller than 50 nl, preferably smaller than 10 nl, preferably smaller than 5 nl, preferably smaller than 2 nl, preferably smaller than 1 nl, preferably smaller than 500 pl, preferably smaller than 200 pl, preferably smaller than 100 pl;

and/or

the volume of the first volume is larger than 10 pl, preferably larger than 50 pl, preferably larger than 100 pl; and

/or

the diameter of the bordered volumes is smaller than 200 μ

m, preferably smaller than 115 μ

m; and

/or

preferably with a diameter larger than 500 nm.

11. The method according to claim 1, wherein the thickness of the second liquid is below 500 μ

m, preferably below 250 μ

m and preferably so formed that and the oil film is preferably centrifuged to create the oil film without bubbles, preferably centrifuged in a range between 1 to 1000 g.

12. The method according to claim 1, wherein the fluorescence is detected at least at any two positions or at around two positions in the first volume.

13. The method according to claim 1, wherein additionally the detection of fluorescence is performed at least once before the start of the laser irradiation.

14. The method according to claim 1, wherein laser is a IR laser and/or fluorescence is excited with a light emitting diode, LED (31), wherein the laser is preferably a low power laser within the range of from 5 mW to 60 mW.

15. A device for thermo-optical measurements in a first volume of aqueous solution preferably in accordance with claim 1, the device comprising:

a means for providing a first volume of the first liquid which is an aqueous solution, said first volume having a volume of less than 200 nl, wherein said first volume of aqueous solution is at least partly embedded in a second liquid;

a laser for irradiating a laser light beam into the first volume to obtain a spatial temperature distribution in the first volume around the irradiated laser light beam;

means for fluorescently exciting fluorescent particles in the first volume; and

means for detecting fluorescence and/or fluorescence distribution of the fluorescently excited particles.

16. A system with a device for creating a droplet of an aqueous solution with a volume of less than 200 nl and a device for thermo-optical measurements in said first volume according to claim 15, wherein the device for creating the first volume comprises:

means for providing a liquid sample of aqueous solution; and

a transducer for transferring at least a transfer droplet from the liquid sample to the means for providing the first volume such that the first volume is at least partly embedded within the second liquid.

17. They system of claim 16, wherein the means for providing the first volume is a destination plate, preferably a multiwell plate or a microfluidic device with at least a channel or capillary for obtaining said first volume at least partly embedded within the second liquid.