System and method for measuring viscosity of ultramicro liquid

Abstract

The invention provides a system and a method for measuring the viscosity of ultramicro liquid. The method comprises the following steps: accurately depositing a small amount of liquid sample on a glass slide by using a sample transfer tool; calculating the dehumidification speed of the liquid according to the spreading process of the liquid sample; calculating the liquid surface tension when the contact angle is 0; calculating a fluid contact angle according to interference fringes formed by the micro-droplets; calculating the liquid viscosity according to the liquid dehumidification speed, the liquid contact angle and the liquid surface tension; according to the invention, high-precision viscosity measurement under the condition of 1 microliter sample size is realized, the sample consumption is effectively reduced, meanwhile, the accuracy and efficiency of measurement are improved, and the method is simple and convenient to operate and suitable for high-throughput and rapid screening; through fine physical calculation and a high-precision image processing technology, the limitation of a traditional viscosity measurement technology is effectively overcome, and powerful technical support is provided for research and application in the fields of biotechnology, chemical engineering and the like.

Description

Technical Field

[0001] The invention relates to the technical field of liquid viscosity measurement, in particular to a system and method for measuring ultra-trace liquid viscosity. Background Art

[0002] With the rapid development of the field of biological preparation development, higher requirements are put forward for the measurement of viscosity of trace liquid samples. The existing viscosity measurement methods mainly include pressure measurement method, electroosmotic measurement method and fluorescence measurement method.

[0003] Among them, the pressure measurement method uses VROC viscosity rheology integrated technology. Although the measurement is accurate and stable, its complex structure and strict operation requirements limit its application in the early development of biological agents with extremely small sample volumes, complex components and preciousness.

[0004] Electroosmosis measurement method, electroosmosis is one of the electrokinetic phenomena, which refers to the phenomenon that the liquid moves relative to the fixed solid phase in contact with it under the action of an electric field. Generally, under the action of an electric field, the solution will move in a certain direction. For example, the liquid dynamic viscosity measurement platform based on the electroosmosis principle of patent CN108872016A uses the electroosmosis principle and combines infrared heating technology to measure the change characteristics of liquid viscosity with temperature.

[0005] The fluorescence measurement method, such as CN116973273A, a method for detecting microviscosity of the friction contact zone of a polymer coating, uses a molecular rotor-type fluorescent probe to dye the polymer coating before and after mixing different lubricants, and quantitatively tests the microviscosity of the contact zone. Based on this, the instantaneous interface response mechanism of lubricant mixing is revealed from the perspective of microviscosity, and the relationship between microviscosity and friction coefficient mutation is established.

[0006] However, the above viscosity measurement method requires at least 15 μl of sample volume during the measurement process, which makes it uneconomical in many cases and limits its application in the early development of biological preparations with extremely small sample volume, complex components and preciousness. Summary of the invention

[0007] In view of the deficiencies of the prior art, the present invention provides a system and method for measuring the viscosity of ultra-trace liquids, which can significantly reduce the sample volume required in the early stages of biological preparation development and improve the efficiency and accuracy of viscosity measurement.

[0008] The technical solution of the present invention is: a method for measuring the viscosity of an ultra-trace liquid, comprising the following steps:

[0009] S1) Use the sample transfer tool to accurately deposit a small amount of liquid sample on the slide;

[0010] S2), calculating the dewetting speed of the liquid according to the spreading process of the liquid sample;

[0011] S3), calculate the liquid surface tension γ when the contact angle θ is 0;

[0012] S4), calculating the fluid contact angle θ based on the interference fringes formed by the microdroplets;

[0013] S5) Calculate the liquid viscosity η according to the liquid dewetting speed, liquid contact angle, and liquid surface tension:

[0014]

[0015] In the formula, v d represents the liquid dewetting rate, θ is the liquid contact angle, γ represents the liquid surface tension; ∝ represents a proportional relationship.

[0016] Preferably, in step S1), a surface temperature controller is connected to the coverslip carrier, and the surface temperature of the coverslip carrier is controlled by the surface temperature controller to be stable at 25-30°C, and a small amount of liquid sample is accurately deposited on the slide using a sample transfer tool.

[0017] Preferably, in step S2), the spreading process of 1 μl of liquid sample on the glass slide is recorded by a high-speed camera; the change of the liquid radius R within a certain time t is extracted from the video; and the dewetting speed v of the liquid is calculated. d , the specific calculation formula is:

[0018]

[0019] Where R is the radius of the liquid.

[0020] Preferably, in step S3), the liquid surface tension γ is measured using Wilhelmy plate technology.

[0021] Preferably, in step S3), by suspending the glass cover slip on the force sensor, when the liquid contacts the Wilhelmy plate, the force sensor measures the tension F exerted on the Wilhelmy plate;

[0022] According to the tension F on the Wilhelmy plate, the wetting perimeter l, and the contact angle θ between the fluid droplet and the Wilhelmy plate = 0, the surface tension γ of the liquid is calculated; its calculation expression is:

[0023]

[0024] In the formula, when the contact angle θ=0, cosθ=1.

[0025] Preferably, in step S3), the wetted perimeter l=2w+2d; w and d are the width and thickness of the Wilhelmy plate respectively.

[0026] Preferably, in step S4), the contact angle θ is calculated as follows:

[0027] The sample was precisely deposited onto a microscope slide using a micro-liquid transfer device to form micro-droplets with an average radius of 5 μm. The micro-droplets were imaged in high definition using a pE-300ultra LED light source with a narrow-band filter and a high-magnification microscope. The contact angle θ of the droplet was calculated based on the incremental height difference of the interference fringes and the radial distance of the interference fringes by analyzing the interference fringes formed by the micro-droplets, i.e.:

[0028]

[0029] Wherein, Δh is the incremental height difference between the first two interference fringes; Δx is the radial distance between the first two interference fringes.

[0030] As a preferred embodiment, the present invention also provides a system for measuring the viscosity of ultra-trace liquids, comprising:

[0031] A cover glass carrier, used to fix the cover glass;

[0032] A surface temperature controller, which is connected to the cover glass carrier and is used to control the surface temperature of the cover glass carrier to be stable at 25-30°C;

[0033] A high-speed camera to capture video of the liquid sample spreading on the slide;

[0034] Force sensor, used to collect the tension when the liquid contacts the Wilhelmy plate;

[0035] High-power microscope for collecting high-definition images of microdroplets;

[0036] pE-300ultra LED light source with narrow-band filter for collecting high-definition images of microdroplets in conjunction with high-power microscopes;

[0037] A computer system, wherein the computer system is connected to a high-speed camera, a force sensor, and a high-power microscope respectively; the computer system is used to obtain a video of the liquid sample spreading on a glass slide collected by the high-speed camera to calculate the dewetting speed v of the liquid. d ;

[0038] The computer system also calculates the liquid surface tension γ by acquiring the tension data F collected by the pressure sensor;

[0039] The computer system also calculates the contact angle θ of the droplet by acquiring the image of the droplet collected by a high-power microscope and analyzing the interference fringes formed by the droplet;

[0040] Finally, according to the liquid dehumidification speed v d , liquid contact angle θ, and liquid surface tension γ are used to calculate the liquid viscosity η.

[0041] The beneficial effects of the present invention are:

[0042] 1. The present invention realizes high-precision viscosity measurement under the condition of 1μl sample volume, effectively reduces sample consumption, and improves the accuracy and efficiency of measurement. It is also easy to operate and suitable for high-throughput and rapid screening.

[0043] 2. The present invention effectively overcomes the limitations of traditional viscosity measurement technology through sophisticated physical calculations and high-precision image processing technology, and provides strong technical support for research and application in the fields of biotechnology, chemical engineering, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the process of the present invention;

[0045] Figure 2 It is a schematic diagram of the framework of the method of the present invention. DETAILED DESCRIPTION

[0046] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0047] Example 1

[0048] like Figure 1 and 2 As shown, this embodiment provides a method for measuring the viscosity of an ultra-trace liquid, comprising the following steps:

[0049] S1) Use the sample transfer tool to accurately deposit the sample on the slide;

[0050] In this embodiment, a surface temperature controller is connected to the cover glass carrier, and after the temperature is stabilized at 25-30° C., a sample transfer tool is used to accurately deposit 1 μl of liquid sample on the cover glass carrier.

[0051] And during the sample deposition process, avoid excessive exposure of the sample to air to prevent evaporation and viscosity measurement errors.

[0052] S2), calculating the dehumidification rate of the liquid;

[0053] After the liquid sample is deposited, the spreading process of 1 μl of liquid sample on the glass slide is recorded by a high-speed camera; the change of the liquid radius R within a certain time t is extracted from the video; and the dewetting speed v of the liquid is calculated. d , the specific calculation formula is:

[0054]

[0055] In this embodiment, when the high-speed camera records the spreading process of the liquid sample on the glass slide, the recording angle is perpendicular to the liquid spreading plane, while ensuring that the edge of the droplet is clear;

[0056] S3), calculate the liquid surface tension γ when the contact angle θ is 0;

[0057] In this embodiment, the liquid surface tension γ is measured using the Wilhelmy plate technique, specifically:

[0058] By suspending the glass cover slip on the force sensor, when the liquid contacts the Wilhelmy plate, the force sensor measures the tension F on the Wilhelmy plate; and according to the tension F on the Wilhelmy plate, the wetting perimeter l, and the contact angle θ between the fluid droplet and the Wilhelmy plate = 0, the surface tension γ of the liquid is calculated; its calculation expression is:

[0059]

[0060] In the formula, when the contact angle θ=0, cosθ=1.

[0061] In this embodiment, the wetted perimeter l=2w+2d; w and d are the width and thickness of the Wilhelmy plate respectively.

[0062] S4), calculate the fluid contact angle θ based on the interference fringes formed by the microdroplets; specifically:

[0063] The sample was precisely deposited onto a microscope slide using a micro-liquid transfer device to form micro-droplets with an average radius of 5 μm. The micro-droplets were imaged in high definition using a pE-300ultra LED light source with a narrow-band filter and a high-magnification microscope. The contact angle θ of the droplet was calculated based on the incremental height difference of the interference fringes and the radial distance of the interference fringes by analyzing the interference fringes formed by the micro-droplets, i.e.:

[0064]

[0065] Wherein, Δh is the incremental height difference between the first two interference fringes; Δx is the radial distance between the first two interference fringes.

[0066] S5) Calculate the liquid viscosity η according to the liquid dewetting speed, liquid contact angle, and liquid surface tension:

[0067]

[0068] In the formula, v drepresents the liquid dewetting rate, θ is the liquid contact angle, γ represents the liquid surface tension; ∝ represents a proportional relationship.

[0069] Example 2

[0070] This embodiment provides a system for measuring the viscosity of an ultra-trace liquid, comprising:

[0071] A cover glass carrier, used to fix the cover glass;

[0072] A surface temperature controller, which is connected to the cover glass carrier and is used to control the temperature of the cover glass carrier to be stable at 25-30°C;

[0073] A high-speed camera to capture video of the liquid sample spreading on the slide;

[0074] Force sensor, used to collect the tension when the liquid contacts the Wilhelmy plate;

[0075] High-power microscope for collecting high-definition images of microdroplets;

[0076] pE-300ultra LED light source with narrow-band filter for collecting high-definition images of microdroplets in conjunction with high-power microscopes;

[0077] A computer system, wherein the computer system is connected to a high-speed camera, a force sensor, and a high-power microscope respectively; the computer system is used to obtain a video of the liquid sample spreading on a glass slide collected by the high-speed camera to calculate the dewetting speed v of the liquid. d ;

[0078] The computer system also calculates the liquid surface tension γ by acquiring the tension data F collected by the pressure sensor;

[0079] The computer system also calculates the contact angle θ of the droplet by acquiring the image of the droplet collected by a high-power microscope and analyzing the interference fringes formed by the droplet;

[0080] Finally, the liquid viscosity η is calculated based on the liquid dewetting rate, liquid contact angle, and liquid surface tension.

[0081] As a preferred embodiment of the present invention, the computer system extracts the change of the liquid radius R within a certain time t from the video of the liquid sample spreading on the glass slide; and calculates the dewetting speed v of the liquid. d , the specific calculation formula is:

[0082]

[0083] As a preferred embodiment of the present invention, the computer system calculates the surface tension γ of the liquid according to the tension F on the Wilhelmy plate, the wetting perimeter l, and the contact angle θ between the fluid droplet and the Wilhelmy plate = 0; the calculation expression is:

[0084]

[0085] In the formula, when the contact angle θ=0, cosθ=1.

[0086] As a preferred embodiment of the present invention, the computer system calculates the contact angle θ of the droplet through the interference fringes formed by the micro-droplets, according to the incremental height difference of the interference fringes and the radial distance of the interference fringes, that is:

[0087]

[0088] Wherein, Δh is the incremental height difference between the first two interference fringes; Δx is the radial distance between the first two interference fringes.

[0089] As a preferred embodiment of the present invention, the calculation expression of the liquid viscosity η is:

[0090]

[0091] In the formula, v d represents the liquid dewetting rate, θ is the liquid contact angle, γ represents the liquid surface tension; ∝ represents a proportional relationship.

[0092] The above embodiments and descriptions are only for illustrating the principles and best embodiments of the present invention. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and improvements, all of which fall within the scope of the present invention to be protected.

Claims

1. A method for measuring the viscosity of an ultra-trace liquid, characterized in that: The following steps are involved: S1) Use the sample transfer tool to accurately deposit a small amount of liquid sample on the slide; S2), calculating the dewetting speed of the liquid according to the spreading process of the liquid sample; S3), calculate the liquid surface tension γ when the contact angle θ is 0; S4), calculating the fluid contact angle θ based on the interference fringes formed by the microdroplets; S5) Calculate the liquid viscosity η according to the liquid dewetting speed, liquid contact angle, and liquid surface tension: In the formula, v d represents the liquid dewetting rate, θ is the liquid contact angle, γ represents the liquid surface tension; ∝ represents a proportional relationship.

2. The method for measuring the viscosity of an ultra-trace liquid according to claim 1, characterized in that: In step S1), a surface temperature controller is connected to the coverslip carrier, and the surface temperature of the coverslip carrier is controlled by the surface temperature controller to be stable at 25-30° C., and then a sample transfer tool is used to accurately deposit the liquid sample on the slide.

3. The method for measuring the viscosity of an ultra-trace liquid according to claim 2, characterized in that: In step S2), after the liquid sample is deposited, the spreading process of 1 μl of the liquid sample on the glass slide is recorded by a high-speed camera; and the change of the liquid radius R within a certain time t is extracted from the video; in order to calculate the dewetting speed v of the liquid d , the specific calculation formula is: Where R is the radius of the liquid.

4. The method for measuring the viscosity of an ultra-trace liquid according to claim 1, characterized in that: In step S3), the liquid surface tension γ is measured using the Wilhelmy plate technique.

5. The method for measuring the viscosity of an ultra-trace liquid according to claim 4, characterized in that: In step S3), by suspending the glass cover slip on the force sensor, when the liquid contacts the Wilhelmy plate, the force sensor measures the tension F exerted on the Wilhelmy plate; According to the tension F on the Wilhelmy plate, the wetting perimeter l, and the contact angle θ between the fluid droplet and the Wilhelmy plate = 0, the surface tension γ of the liquid is calculated; its calculation expression is: In the formula, when the contact angle θ=0, cosθ=1.

6. The method for measuring the viscosity of an ultra-trace liquid according to claim 5, characterized in that: In step S3), the wetted perimeter l=2w+2d; w and d are the width and thickness of the Wilhelmy plate respectively.

7. The method for measuring the viscosity of an ultra-trace liquid according to claim 1, characterized in that: In step S4), the contact angle θ is calculated as follows: The liquid sample is accurately deposited onto a microscope slide using a micro-liquid transfer device to form micro-droplets with an average radius of 5 μm. The micro-droplets are imaged in high definition using a pE-300ultra LED light source with a narrow-band filter and a high-magnification microscope. The contact angle θ of the micro-droplets is calculated based on the interference fringes formed by the micro-droplets, i.e.: Wherein, Δh is the incremental height difference between the first two interference fringes; Δx is the radial distance between the first two interference fringes.

8. A system for measuring the viscosity of ultra-trace liquids, characterized in that: The system uses the method described in any one of claims 1 to 7 to measure the concentration of the liquid, and the system includes: A cover glass carrier, used to fix the cover glass; A surface temperature controller, which is connected to the cover glass carrier and is used to control the surface temperature of the cover glass carrier to be stable at 25-30°C; A high-speed camera to capture video of the liquid sample spreading on the slide; Force sensor, used to collect the tension when the liquid contacts the Wilhelmy plate; High-power microscope for collecting high-definition images of microdroplets; pE-300ultra LED light source with narrow-band filter for collecting high-definition images of microdroplets in conjunction with high-power microscopes; A computer system, wherein the computer system is connected to a high-speed camera, a force sensor, and a high-power microscope respectively; the computer system is used to obtain a video of the liquid sample spreading on a glass slide collected by the high-speed camera to calculate the dewetting speed v of the liquid. d ; The computer system also calculates the liquid surface tension γ by acquiring the tension data F collected by the pressure sensor; The computer system also calculates the contact angle θ of the droplet by acquiring the image of the droplet collected by a high-power microscope and analyzing the interference fringes formed by the droplet; Finally, according to the liquid dehumidification speed v d , liquid contact angle θ, and liquid surface tension γ are used to calculate the liquid viscosity η.

9. The system for measuring the viscosity of ultra-trace liquid according to claim 8, characterized in that: The computer system extracts the change of the liquid radius R within a certain time t from the video of the liquid sample spreading on the slide to calculate the dewetting speed v of the liquid. d , the specific calculation formula is: The computer system calculates the surface tension γ of the liquid according to the tension F on the Wilhelmy plate, the wetting perimeter l, and the contact angle θ between the fluid droplet and the Wilhelmy plate when θ=0; the calculation expression is: In the formula, when the contact angle θ = 0, cosθ = 1; The computer system calculates the contact angle θ of the droplet through the interference fringes formed by the micro-droplets, according to the incremental height difference of the interference fringes and the radial distance of the interference fringes, that is: Wherein, Δh is the incremental height difference between the first two interference fringes; Δx is the radial distance between the first two interference fringes.

10. The system for measuring the viscosity of ultra-trace liquid according to claim 9, characterized in that: The calculation expression of the liquid viscosity η is: In the formula, v d represents the liquid dewetting rate, θ is the liquid contact angle, γ represents the liquid surface tension; ∝ represents a proportional relationship.

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