CN207899469U - A kind of wideband belt surface acoustic wave sorting chip based on bionical substrate - Google Patents

Abstract

The model discloses a wide-band surface acoustic wave sorting chip based on a bionic substrate. The chip is composed of a piezoelectric substrate, a broadband interdigital transducer and a sorting channel system, wherein the interdigital transducer and the sorting channel system are arranged on the piezoelectric substrate at a certain angle, and the sorting channel system The bottom is made into a concave-convex structure similar to the moving surface of a dustpan. The sorting channel includes an inlet channel, a sorting channel and an outlet channel, wherein the inlet channel, the sorting channel and the outlet channel are connected in sequence to form a sorting channel system. By using the surface acoustic wave generated by the broadband interdigital transducer and the sorting flow channel with a concave-convex structure imitating the moving surface of the dustpan screen, the movement trajectories of particles of different sizes in the sorting flow channel are different, and then Realize multi-stage sorting of particles. The new type also has the advantages of simple structure, wide sorting range and high sorting efficiency.

Description

A Broadband Surface Acoustic Wave Sorting Chip Based on Bionic Substrate

Technical field:

The invention relates to a particle sorting chip, in particular to a novel broadband surface acoustic wave sorting chip with a bionic base.

Background technique:

Particle sorting chips based on surface acoustic waves have the advantages of simple structure, compactness, easy fabrication, suitable for mass production, integration, no damage to biological particles (such as cells), and high sorting accuracy. , inorganic particle sorting and therapeutic diagnostics and other fields have a wide range of applications.

In recent decades, microfluidic technology has developed rapidly in the fields of chemistry, biology and pharmaceuticals. In recent years, in the field of microfluidic research, people have carried out fruitful research on the use of surface acoustic waves to drive microfluidics, and great progress has been made in particle sorting technology. At present, many research teams have devoted themselves to the research of microfluidic particle sorting technology. The applied technologies include passive sorting technology using microstructure, fluid dynamics, etc., and external force fields such as sound, light, electricity, and magnetism. Active sorting technology. Passive sorting technology generally needs to rely on the microstructure of the flow channel, which not only requires strict control of the size and flow rate of the flow channel, but also the flow channel is easy to block and the sorting accuracy is low. In the active sorting technology, the structure of the optical sorting chip is complex and the equipment is relatively expensive, while sorting based on electric and magnetic fields requires particles to have special electrical and magnetic properties, which is not general.

Microfluidic particle sorting technology based on surface acoustic wave (SAW) is an emerging sorting technology in recent years. A surface acoustic wave is an elastic sound wave that propagates on a solid surface. A sinusoidal voltage is applied to the interdigital transducer on the surface of the piezoelectric substrate, and the surface of the substrate is deformed due to the piezoelectric inverse effect, thereby generating a surface acoustic wave on the surface, and the amplitude of the surface acoustic wave attenuates rapidly with the increase of the depth of the substrate, and the mechanical energy Concentrated within the depth range of one wavelength on the surface of the piezoelectric substrate. Therefore, the SAW system has a high energy density.

According to the principle of action, the application of SAW in particle sorting is mainly divided into two categories. One is traveling wave surface acoustic wave sorting. The sorting principle is that when the surface acoustic wave acts on the fluid in the microchannel in one direction, the particles with different properties (density, diameter, compressibility) receive different acoustic radiation forces. Therefore, the lateral migration distance is also different, and then the sorting is realized. The other is standing wave surface acoustic wave sorting. The sorting principle is that when standing waves act on the fluid in the microchannel, due to the acoustic flow effect, periodic distribution of pressure nodes and counterpressure nodes will be formed in the channel, and the particles will be separated by acoustic radiation. Under the action of force, it will migrate to the pressure node or counter pressure node, and then realize the sorting. Compared with traveling wave surface acoustic wave sorting, standing wave surface acoustic wave sorting requires two sets of interdigital transducers to be arranged symmetrically on both sides of the microchannel in terms of device design, and the alignment between the microchannel and the interdigital transducers Accuracy requirements are very high.

At present, most of the interdigital transducers used in the field of surface acoustic wave particle separation can only generate maximum energy at one frequency, and it is difficult to achieve a wide range of energy when using traveling wave surface acoustic wave particle separation. particle sorting.

Invention content:

The purpose of this new model is to solve the above problems, and provide a new type of broadband surface acoustic wave sorting chip based on the bionic substrate, which uses the surface acoustic wave generated by the broadband interdigital transducer and has a dustpan sieving motion The surface structure substrate works together in the sorting flow channel to realize the multi-stage sorting of particles in a large range.

The technical scheme that this novel adopts is:

A layer of photoresist with a double-trapezoidal interdigital transducer pattern is drawn on the surface of a clean piezoelectric substrate (1) by photolithography technology, and the interdigital transducer and the sorting flow channel are placed at a certain angle. A double-trapezoidal interdigital transducer (2) is fabricated on the surface of a piezoelectric substrate by the irradiation+lift-off process.

Use photolithography technology to draw a layer of photoresist with a concave-convex structure similar to the moving surface of a dustpan screen on the clean piezoelectric substrate (1) where the flow channel is formed, and use sputtering + lift-off technology to sort the flow on the piezoelectric substrate A bionic base (10) for imitating the dustpan screening surface is made at the bottom of the road.

A micro-channel system mold is engraved by a fine engraving machine, and a material (such as PDMS) is selected from the mold to manufacture the micro-channel system (5), and the inlet and outlet interfaces are processed.

The cleaned micro-channel system (5) is bonded on the surface of the piezoelectric substrate (1).

The advantage of the new type is that according to the different acoustic radiation forces received by particles of different sizes at different frequencies, by adjusting the input frequency of the interdigital transducer, the multi-stage sorting of particles can be realized in a wide range and high efficiency. . And under the joint action of the surface acoustic wave generated by the broadband interdigital transducer and the structure base of the dustpan sieving surface at the bottom of the flow channel, high-purity multi-stage separation of particles can be realized. In addition, the present invention also has the characteristics of simple structure, easy manufacture, and low cost.

Description of drawings:

Fig. 1 is the isometric side view of the novel microfluidic chip

Fig. 2 is the front view of the sorting channel of the novel microfluidic chip

Fig. 3 is a schematic diagram of the principle of particle sorting by the microfluidic chip of the present invention.

Detailed ways:

Referring to Fig. 1, Fig. 2 and Fig. 3, the structural features and working principle of the present invention are described in detail.

The invention proposes a novel broadband surface acoustic wave sorting chip based on a bionic substrate. The chip is mainly composed of a piezoelectric substrate (1), a broadband interdigital transducer (2) and a microchannel system (5), wherein the microchannel system (5) includes a deionized water inflow interface (13) and (16), particle inflow interface (14), deionized water inflow channel (12) and (17), particle inflow channel (15), sorting channel (11), large particle outflow channel (9), medium Particle outflow channel (6), small particle outflow channel (3), large particle outflow outlet (8), medium particle outflow outlet (7), small particle outflow outlet (4).

When sorting particles, it is necessary to place the whole chip at a certain angle with the horizontal plane, and the angle needs to be adjusted according to the size and other characteristics of the sorted particles.

Connect the +/- poles of the output signal of the signal generator to the two poles of the interdigital transducer respectively, and then output a continuous sinusoidal signal.

The liquid mixed with particles of different sizes is injected into the sorting channel system through the inflow port (14) at a certain flow rate. The deionized water is injected into the sorting channel system through the inlet ports (13) and (16) at a certain flow rate, wherein the flow rate of the port (13) is greater than the flow rate of the port (16). Referring to Fig. 2, particles of different sizes flow into the sorting channel (11) and are affected by the uneven structure (10) at the bottom of the channel similar to the moving surface of the dustpan, and the large particles move faster than the small particles.

Referring to Fig. 3, after particles of different sizes enter the sorting flow channel (11), due to the different flow rates of deionized water injected into the inflow ports (13) and (16), it is ensured that the mixed particles are concentrated in the set area of the sorting flow channel . Under the joint action of fluid, dustpan imitation structure and acoustic radiation force, the trajectory of particles is parabolic, and the movement of large particles is relatively fast and the deflection angle is relatively large, so that large particles can move from the The outflow channel (9) flows out, while the medium particles flow out from the outflow channel (6), and the small particles flow out from the outflow channel (3).

The wide-band IDT used in this new model is different from the traditional IDT that can only generate the maximum energy at one frequency. The wide-band IDT can generate a lot of energy within a certain frequency range. big energy. Therefore, by adjusting the input frequency of the interdigital transducer according to the different acoustic radiation forces experienced by particles of different sizes at different frequencies, multi-stage sorting of particles can be realized in a wide range and high efficiency.

Claims (4)

1. a kind of wideband belt surface acoustic wave based on bionical substrate sorts chip, which is characterized in that including piezoelectric substrate (1), A wideband belt interdigital transducer (2) in piezoelectric substrate (1) and sorting flow passage system (5) composition based on PDMS, utilize The surface acoustic wave and collective effect is real in sorting runner with imitative dustpan structure substrate that wideband belt interdigital transducer (2) generates The multipass sort of existing particle.

2. the wideband belt surface acoustic wave according to claim 1 based on bionical substrate sorts chip, which is characterized in that micro- The uneven structure (10) that face is sieved similar to dustpan is made in runner bottom section piezoelectric substrate.

3. the wideband belt surface acoustic wave according to claim 1 based on bionical substrate sorts chip, which is characterized in that When sorting particles, chip is integrally at an angle to the horizontal surface placement, and adjusts core according to the difference of institute's sorting particles size The whole corner dimension with horizontal plane of piece.

4. the wideband belt surface acoustic wave according to claim 1 based on bionical substrate sorts chip, which is characterized in that institute It is double trapezoid wideband belt interdigital transducer to state interdigital transducer, can adjust wideband belt fork according to the size of institute's sorting particles The working frequency of finger transducer.