An optical-ultrasonic micro-mixer based on gold ion implantation into a quartz plate

Abstract

The application relates to the field of microfluidic technology, and particularly relates to a photo-induced ultrasonic micro-mixer based on gold ion injection into a quartz sheet; the technical key points are as follows: a microfluidic chip is arranged inside a microfluidic cavity and a photoacoustic driving part; the photoacoustic driving part is formed by adopting an ion injection process to inject gold target material into a quartz substrate, directly contacts liquid in the microfluidic cavity, is used for generating ultrasonic waves under pulse laser irradiation, disturbs fluid in the microfluidic cavity and accelerates the mixing speed of the fluid; the microfluidic cavity comprises a first microchannel, a second microchannel, an output channel and a microcavity; the first microchannel and the second microchannel are connected through the microcavity, and the output channel is connected with the microcavity; the first microchannel is provided with a Y-shaped structure formed by two branch channels at one end far from the microcavity; the microcavity is arranged at the edge of the microfluidic chip; and the effect of improving the mixing speed of fluid in the microfluidic channel is achieved.

Description

Technical Field

[0001] This invention relates to the field of microfluidics, specifically to a photo-induced ultrasonic micromixer based on a gold ion implanted quartz sheet. Background Technology

[0002] Microfluidics is a science and technology that precisely controls and manipulates fluids at the microscopic scale. It offers advantages such as low sample consumption, rapid reaction and analysis, and high-throughput processing, and has wide applications in medical diagnostics, drug development, and environmental monitoring. In traditional microfluidics, liquid aspiration and mixing are among the most fundamental and critical functions. However, the fluids within the microchannels of microfluidic chips are typically in a low Reynolds number laminar flow state, with different liquids moving in parallel laminar flow patterns, exhibiting slow lateral diffusion, and mixing is achieved solely through molecular diffusion.

[0003] Existing micromixers can be broadly classified into two categories: passive and active. Passive micromixers rely on fixed microstructures (such as serpentine or spiral channels) to enhance interfacial mixing. Although they do not require external energy, they are difficult to manufacture, prone to clogging, and cannot adjust the mixing state in real time according to needs. Active micromixers use external fields such as sound, electricity, and magnetism to disturb the liquid, resulting in fast mixing speeds and relatively controllable performance. However, traditional active devices contain internal microelectrodes and transducers, leading to complex internal structures, difficulties in integration and packaging, high costs, and low reliability.

[0004] Therefore, there is an urgent need in this field to develop a novel micro-mixing and microfluidic manipulation technology that is structurally simple, easy to integrate at high density, and capable of achieving ultra-fast response and efficient mixing. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a photo-induced ultrasonic micromixer based on a gold ion implanted quartz sheet, which can effectively solve the problems of the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a photo-induced ultrasonic micromixer based on a gold ion implanted quartz sheet, including a microfluidic chip, wherein the microfluidic chip has a microfluidic cavity and a photoacoustic driving part inside;

[0008] The microfluidic cavity is used to contain fluid;

[0009] The photoacoustic drive unit is used to generate ultrasonic waves under pulsed laser irradiation, which disturbs the fluid in the microfluidic cavity and accelerates the mixing speed of the fluid.

[0010] The photoacoustic drive unit is in direct contact with the liquid inside the microfluidic cavity.

[0011] Furthermore, the microfluidic cavity includes a first microchannel, a second microchannel, an output channel, and a microchamber;

[0012] The first microchannel and the second microchannel are connected through the microchamber, and the output channel is connected to the microchamber.

[0013] Furthermore, the end of the first microchannel away from the microchamber is a Y-shaped structure composed of two branch channels;

[0014] The photoacoustic driving unit is disposed on the surface of the microfluidic chip and spans the intersection of the Y-shaped channels of the first microchannel. The photoacoustic driving unit is in direct contact with the liquid in the first microchannel.

[0015] Furthermore, the microcavity is located at the edge of the microfluidic chip, and a window is provided on the side of the microcavity;

[0016] The photoacoustic drive unit is located at the window so that it can directly contact the liquid inside the microcavity.

[0017] Furthermore, the photoacoustic driving unit is formed by implanting a gold target into a quartz substrate using an ion implantation process.

[0018] Furthermore, the channel from the intersection of the Y-shaped channels to the micro-chamber is a non-linear configuration, with rounded corners or smooth arcs at the turning points, which facilitates liquid flow and effectively suppresses the generation of bubbles.

[0019] Furthermore, the photoacoustic drive unit is formed by implanting a gold target into a quartz substrate using an ion implantation process.

[0020] Furthermore, the injection voltage is 40-60 kV, and the injection dose is 2×10⁻⁶ kV. 17 / cm 2 .

[0021] Furthermore, the quartz substrate has dimensions of (0.7~1.1)×(0.7~1.1)cm and a thickness of 0.4~0.7mm.

[0022] Furthermore, the microfluidic chip is made of resin.

[0023] The technical solution provided by this invention has the following advantages compared with the known prior art:

[0024] 1. This invention combines a photoacoustic driving part formed by photoacoustic driving material with a microfluidic chip. Under pulsed laser irradiation, it has an ultra-fast response rate and high mixing efficiency. It can quickly break laminar flow and completely disrupt the parallel laminar flow at the Y-shaped intersection within 3 seconds, so that the fluid can be rapidly transformed into turbulent flow and achieve uniform mixing. The two solutions can be completely and uniformly mixed within 10 seconds in a microcavity. The coefficient of variation (CV) of the solution is less than 10%, while natural mixing without laser irradiation requires 35 minutes to achieve uniform mixing. The mixing efficiency is improved by hundreds of times.

[0025] 2. The present invention can be assembled by injecting the prepared gold ions into a quartz plate (i.e., the photoacoustic driving part) and fixing or pasting it onto the microfluidic chip or the window opened on the side of the microcavity. It does not require a complex mechanical pump structure, has a simple structure, and is very easy to integrate and package. High-precision remote control of fluid flow rate can be achieved by simply adjusting the repetition frequency of the external pulse laser.

[0026] 3. The photoacoustic drive unit of this invention drives and mixes fluids entirely by relying on the photo-induced ultrasonic effect generated by the external laser excitation material. It is a non-contact external field disturbance. Since the sound source (photoacoustic drive unit) is directly attached to the microchannel and does not involve any moving parts, it avoids the problems of wear of traditional active mechanical parts, electrode contamination or magnetic field interference, greatly reduces the risk of channel blockage caused by bubble generation, and significantly improves the long-term operational stability and service life of the entire microfluidic system.

[0027] 4. The microfluidic chip body of the present invention does not require pre-embedded complex circuits and can be directly processed by conventional methods such as 3D printing. Combined with the preparation of gold ion implanted quartz sheet (i.e. photoacoustic drive part), the processing and manufacturing threshold and manufacturing cost are greatly reduced. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0029] Figure 1 This is a schematic diagram of the photoinduced ultrasonic micromixer structure of the present invention;

[0030] Figure 2 The image shows a gold ion-implanted quartz sheet sample and its ultraviolet absorption rate, as provided in the embodiments of the present invention.

[0031] Figure 3 This is a schematic diagram of the microfluidic chip structure provided in an embodiment of the present invention;

[0032] Figure 4 An experimental schematic diagram of a micromixer in the microchannel of a microfluidic chip is provided for embodiments of the present invention;

[0033] Figure 5 This is an illustration of the effect of laminar flow mixing into turbulent flow after laser activation, provided in an embodiment of the present invention.

[0034] Figure 6 A graph showing the coefficient of variation of laminar flow being disrupted into turbulent flow after laser activation, provided in an embodiment of the present invention;

[0035] Figure 7 This invention provides an experimental schematic diagram of a micromixer in a microfluidic chip microchamber for embodiments of the invention.

[0036] Figure 8 This invention provides a diagram illustrating the microcavity mixing effect after laser activation, as shown in the embodiments of the invention.

[0037] Figure 9 This invention provides a diagram illustrating the microcavity mixing effect under natural conditions for embodiments of the invention.

[0038] Figure 10 This invention provides an embodiment of the microfluidic pump driving fluid in a flexible microchannel;

[0039] Figure 11 This is a physical image of the photo-induced ultrasonic micromixer of the present invention.

[0040] Reference numerals: 1-First microchannel, 2-Second microchannel, 3-Microchamber, 4-Output channel, 5-Photoacoustic drive unit, 6-Window, 7-Microfluidic chip. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0042] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail. The terms “comprising,” “including,” “having,” “containing,” etc., as used herein are open-ended terms, meaning that they include but are not limited to. Unless the context clearly indicates otherwise, the expressions “a” and “an” as used herein include plural references. It should be noted that “first,” “second,” etc., are used merely for convenience of description and distinction and should not be construed as indicating or implying relative importance. The term “about” as used herein indicates a range of ±20% of the following numerical value. In some embodiments, the term “about” indicates a range of ±10% of the following numerical value. In some embodiments, the term “about” indicates a range of ±5% of the following numerical value. The invention is further described below with reference to embodiments.

[0043] Example

[0044] Gold ion-implanted quartz sheet materials exhibit strong light absorption and thermal conversion capabilities at specific laser wavelengths. The photothermal effect induces rapid expansion and contraction of the particles and the surrounding medium, or induces the formation of gas films / bubbles at the solution-substrate interface. The vibration of these gas films or the rupture of the bubbles can further radiate acoustic signals, i.e., photosononic effects. These ultrasonic signals are characterized by strong directionality and high energy density, making them easier to use in various fluid applications. Therefore, this invention provides a novel micromixer and microfluidic pump technology that is simple in structure, highly efficient in mixing, easy to integrate, and flexible in drive control.

[0045] This invention provides a photo-induced ultrasonic micromixer based on a gold ion-implanted quartz sheet, such as... Figure 1 As shown, it includes a first microchannel 1, a second microchannel 2, a microchamber 3, an output channel 4, a photoacoustic drive unit 5, a window 6, and a microfluidic chip 7. The first microchannel 1 and the second microchannel 2 are connected through the microchamber 3, and the output channel 4 is connected to the microchamber 3. The end of the first microchannel 1 away from the microchamber 3 is a Y-shaped structure composed of two branch channels. The photoacoustic drive unit 5 is located at the intersection of the Y-shaped channels. The microchamber 3 is located at the side edge of the microfluidic chip 7 so that the ultrasonic driving flow field generated by the gold ion implantation into the quartz plate (photoacoustic drive unit 5) can be facilitated without obstruction. A window 6 is also opened on the side of the microchamber 3, and the photoacoustic drive unit 5 is also located at the side window 6 of the microchamber 3.

[0046] In some embodiments, the photoacoustic drive unit 5 can be fixed to the desired position by adhesive, and the liquid in the microcavity comes into contact with the photoacoustic drive unit 5.

[0047] In some embodiments, during use, liquid a and liquid b enter from the two branch channels of the first microchannel 1 respectively. After the photoacoustic driving part 5 at the window 6 position of the intersection of the Y-shaped channels is irradiated by the pulsed laser, the laminar liquid in the first microchannel 1 is disturbed and forms turbulence. Then it enters the microcavity 3 and flows out through the output channel 4.

[0048] In some embodiments, during use, liquid a enters the microchamber 3 from the first microchannel 1 and liquid b enters the microchamber 3 from the second microchannel 2, so that the two solutions form a laminar static state in the microchamber 3. Driven by the acoustic waves of the photoacoustic drive unit 5 on the side of the microchamber 3, the two liquids mix in the microchamber 3.

[0049] The microfluidic chip 7 is made of resin and can be formed using a 3D printer. In some embodiments, such as... Figure 3 As shown, the microfluidic chip 7 has dimensions of 2 cm long × 1 cm wide × 0.3 cm high. The width of the first microchannel 1 and the second microchannel 2 is 0.4 mm, and the thickness of all channels and microchambers 3 is 0.5 mm.

[0050] In some embodiments, the photoacoustic driving unit 5 can be directly disposed at one port of the microchannel to form a microfluidic pump. Under pulsed laser irradiation, it generates ultrasonic waves to drive the liquid. Under pulsed laser excitation, it can disrupt the laminar flow formed by the two liquids in the microchannel within 3 seconds, or accelerate the mixing of the liquids in the microcavity within 10 seconds, so that the coefficient of variation of the two solutions is <10%. Under pulsed laser excitation, the photoacoustic driving unit 5 can drive the liquid in the flexible microchannel, and the driving speed can reach 2.98 cm / s under the condition of single pulse energy of 29 µJ.

[0051] In this invention, the material constituting the photoacoustic driving part is prepared by gold ion implantation into a quartz sheet, as detailed below:

[0052] Au target material was implanted into a 1×1 cm quartz substrate with a substrate thickness of 0.5 mm under vacuum conditions. The implantation voltage was 40-60 kV, and the implantation dose was 2×10⁻⁶. 17 / cm 2 Samples such as Figure 2 As shown, the left image is a photograph of a gold ion-implanted quartz sheet. The side marked with a marker is the reverse side, while the front side is in direct contact with the liquid. The laser irradiates from the reverse side, generating an ultrasonically driven fluid on the front side. The right image is an absorptivity diagram measured by UV-vis, showing that the absorptivity of the quartz sheet is 30% at a wavelength of 532 nm.

[0053] Experimental test:

[0054] 1.1 Application and testing of micromixers in microchannels of microfluidic chips:

[0055] A microfluidic chip measuring 2 cm long × 1 cm wide × 0.3 cm high was fabricated using a 3D printer with resin as the raw material. The chip includes a Y-shaped channel for laminar-turbulent flow disturbance and a microchamber 3 for mixing two liquids. A schematic diagram of the micromixer within the microchannel of the microfluidic chip is shown below. Figure 4 As shown, the Lens is a focusing lens that can focus the laser, and the CCD is a camera used to capture the fluid mixing process in the microfluidic chip.

[0056] 1. Prepare 10 mL of red ink and blue ink respectively, dilute with a certain amount of pure water, and fix the photoacoustic driver 5 above the intersection of the Y-shaped channels of the chip.

[0057] 2. Place the ink into a 1 mL syringe and control the displacement stage to push the syringe at a speed of 6 µL / s, so that the diluted dye flows into the Y-shaped channel and forms a clear laminar flow.

[0058] 3. Irradiate region 5 of the photoacoustic drive unit using a pulsed laser (e.g., wavelength 532 nm, pulse width 35 ns, repetition frequency 2500 Hz). Figure 5 As shown in the image, the laminar flow disturbance in the microchannel of the microfluidic chip is transformed into turbulent flow. It can be observed that 3 seconds after the laser is turned on, the clear laminar flow is completely broken, and the two colors are mixed into a uniform brown, showing extremely high mixing efficiency.

[0059] The coefficient of variation of laminar flow being disrupted into turbulent flow after laser activation is shown in the figure. Figure 6 As shown, by importing the laminar flow image into ImageJ software, and then using image grayscale analysis methods, the standard deviation and average intensity of the pixels are calculated. Finally, the coefficient of variation is calculated according to the formula: coefficient of variation = (standard deviation / average intensity) × 100%. When the coefficient of variation is less than 10%, it is considered to be uniformly mixed. As shown in the figure, the coefficient of variation at 2.5s is 7.14%.

[0060] A schematic diagram of the optical path during microcavity mixing is shown below. Figure 7 As shown.

[0061] 1.2 Application and Testing of Micromixers in Microcavities of Microfluidic Chips

[0062] 1. For example Figure 7 As shown, a certain amount of red ink and pure water are prepared respectively, and the photoacoustic driver 5 is integrated into the side window 6 of the chip.

[0063] 2. Place the ink into a 1 mL syringe and control the displacement stage to push the syringe at a speed of 6 µL / s so that the dye and pure water flow into the microchamber 3 at a 1:1 ratio. Stop the injection of liquid after a clear laminar flow is formed.

[0064] 3. Using the same pulsed laser as in 1.1, the photoacoustic drive section 5 on the side of the microcavity 3 in the chip is irradiated. It can be observed that 10 seconds after the laser is turned on, the mixing speed of the two solutions accelerates, and they mix into a uniform light red color. Figure 8 As shown, the microcavity mixing image under laser conditions was imported into ImageJ software. Image grayscale analysis was used to calculate the standard deviation and average intensity of the pixels, and the coefficient of variation was obtained. When the coefficient of variation is less than 10%, it can be considered uniformly mixed. As shown in the figure, the coefficient of variation at 5s is 5.25%.

[0065] 4. Under the same conditions, create a control group where the mixture is naturally mixed within the cavity without laser irradiation to provide a comparison. For example... Figure 9 As shown, the microcavity mixing image under natural conditions was imported into ImageJ software. Image grayscale analysis was used to calculate the standard deviation and average intensity of the pixels, and the coefficient of variation was obtained. When the coefficient of variation is less than 10%, it can be considered uniformly mixed. As shown in the figure, the coefficient of variation at 35 minutes is 6.76%.

[0066] 1.3 Application Testing of Microfluidic Pumps

[0067] At one end of a microchannel with an inner diameter of 500 µm, a gold ion-implanted quartz plate is attached using UV adhesive. Pure water is then injected into the tube. A pulsed laser is applied to the junction of the quartz plate and the microchannel, utilizing photo-sonication to drive the fluid within the channel. The fluid driving speed can be adjusted by regulating the repetition rate. Specifically, at a laser repetition rate of 2500 Hz and a single pulse energy of 29 µJ, the maximum liquid driving speed can reach 2.98 cm / s. Figure 10 The image shows the effect of a microfluidic pump driving fluid in a flexible microchannel. The flow field diagram was obtained when the laser repetition rate was 2500 Hz and the single pulse energy was 29 microjoules. The maximum driving speed can be seen to be 2.98 cm / s.

[0068] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A photoinduced ultrasonic micromixer based on a gold ion-implanted quartz sheet, characterized in that, Includes a microfluidic chip, wherein the microfluidic chip has a microfluidic cavity and a photoacoustic driving unit inside; The microfluidic cavity is used to contain fluid; The photoacoustic drive unit is used to generate ultrasonic waves under pulsed laser irradiation, which disturbs the fluid in the microfluidic cavity and accelerates the mixing speed of the fluid.

2. The photo-induced ultrasonic micromixer based on a gold ion-implanted quartz sheet according to claim 1, characterized in that, The microfluidic cavity includes a first microchannel, a second microchannel, an output channel, and a microchamber; The first microchannel and the second microchannel are connected through the microchamber, and the output channel is connected to the microchamber.

3. The photo-induced ultrasonic micromixer based on a gold ion-implanted quartz sheet according to claim 2, characterized in that, The end of the first microchannel away from the microchamber is a Y-shaped structure composed of two branch channels; The photoacoustic driving unit is disposed on the surface of the microfluidic chip and spans the intersection of the Y-shaped channels of the first microchannel.

4. The photo-induced ultrasonic micromixer based on a gold ion-implanted quartz sheet according to claim 2, characterized in that, The microcavity is located at the edge of the microfluidic chip, and a window is provided on the side of the microcavity; The photoacoustic drive unit is located at the window.

5. The photo-induced ultrasonic micromixer based on a gold ion-implanted quartz sheet according to claim 1, characterized in that, The photoacoustic drive unit is formed by implanting a gold target into a quartz substrate using an ion implantation process.

6. The photo-induced ultrasonic micromixer based on a gold ion-implanted quartz sheet according to claim 5, characterized in that, The injection voltage is 40-60 kV, and the injection dose is 2×10⁻⁶ kV. 17 / cm 2 .

7. A photoinduced ultrasonic micromixer based on a gold ion-implanted quartz sheet according to claim 5 or 6, characterized in that, The quartz substrate has dimensions of (0.7~1.1)×(0.7~1.1)cm and a thickness of 0.4~0.7mm.

8. The photo-induced ultrasonic micromixer based on a gold ion-implanted quartz sheet according to claim 1, characterized in that, The microfluidic chip is made of resin.

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