Microparticle multi-channel time-sharing separation device and method based on arcuate interdigital transducer

Abstract

The invention discloses microparticle multi-channel time-sharing separation device and method based on an arcuate interdigital transducer. An arcuate interdigitated electrode is connected to an output channel of a signal generator. The arcuate interdigitated electrode and a polydimethylsiloxane (PDMS) microfluidic channel are placed on a lithium niobate chip. The arcuate interdigitated electrode is mainly formed by an interdigitated electrode being asymmetrically bent from a straight line into an arcuate curve. Two electrode ends of the arcuate interdigitated electrodes are asymmetrically arranged with one end big and another end small. The PDMS microfluidic channel includes a main flow channel, two inlet ends, and multiple outlet ends. The main flow channel is an approximately arcuate flow channel arranged around an outer side of the arcuate interdigitated electrode. Particles are patterned in a coverage section of surface acoustic waves to complete separation of microparticles.

Claims

1. A microparticle multi-channel time-sharing separation device based on an arcuate interdigital transducer, comprising: a lithium niobate chip, an arcuate interdigitated electrode, and a polydimethylsiloxane microfluidic channel, wherein the arcuate interdigitated electrode is arranged on the lithium niobate chip, the arcuate interdigitated electrode and the lithium niobate chip form a surface acoustic wave arcuate interdigital transducer, the arcuate interdigitated electrode is connected to an output channel of a signal generator, and the polydimethylsiloxane microfluidic channel is arranged on the lithium niobate chip on a side of the arcuate interdigitated electrode and is bonded to the lithium niobate chip through oxygen plasma bonding; the arcuate interdigitated electrode is mainly formed by an interdigitated electrode being asymmetrically bent from a straight line into an arcuate curve, two electrode ends of the arcuate interdigitated electrode are asymmetrically arranged with one of the two electrode ends which is big and another one of the two electrode ends which is small, spacing between strip-shaped interdigitated electrodes of the arcuate interdigitated electrode at a same radial angle is the same, and spacing between the strip-shaped interdigitated electrodes from the one of the two electrode ends to the another one of the two electrode ends gradually increases progressively or decreases progressively; the polydimethylsiloxane microfluidic channel comprises a main flow channel, two inlet ends, and a plurality of outlet ends, the two inlet ends are respectively a particle flow inlet and a sheath flow inlet which are connected to an end of the main flow channel together, the particle flow inlet and the sheath flow inlet respectively let in a hybrid particle flow and a sheath flow, the hybrid particle flow comprises microparticles of different sizes, the main flow channel is provided with 1 to 4 bifurcations between a middle part and another end, and each of the bifurcations is provided with 1 to 3 outlet ends of the outlet ends.

2. A microparticle multi-channel time-sharing separation device based on an arcuate interdigital transducer according to claim 1, wherein the signal generator applies electrical signals to the arcuate interdigitated electrode, the arcuate interdigitated electrode serves as a surface acoustic wave source to emit surface acoustic waves to the polydimethylsiloxane microfluidic channel, the microparticles in the PDMS microfluidic channel are dispersed and separated by the surface acoustic waves, thereby implementing time-sharing separation of the hybrid particle flow in the polydimethylsiloxane microfluidic channel.

3. A microparticle multi-channel time-sharing separation device based on an arcuate interdigital transducer according to claim 2, wherein the surface acoustic waves are excited radially outward at different radial angular positions of the arcuate interdigitated electrode through applying electrical signals of different frequencies at different times.

4. A microparticle multi-channel time-sharing separation device based on an arcuate interdigital transducer according to claim 1, wherein the main flow channel of the polydimethylsiloxane microfluidic channel is an arcuate flow channel arranged around an outer side of the arcuate interdigitated electrode.

5. A microparticle multi-channel time-sharing separation device based on an arcuate interdigital transducer according to claim 1, wherein a material of the arcuate interdigitated electrode is aluminum and the arcuate interdigitated electrode is formed on the lithium niobate chip through photolithography and physical vapor deposition.

6. A microparticle multi-channel time-sharing separation method based on an arcuate interdigital transducer applied to a device according to claim 1, the method comprising: constructing the surface acoustic wave arcuate interdigital transducer composed of the lithium niobate chip and the arcuate interdigitated electrode, and manufacturing the polydimethylsiloxane microfluidic channel of a specific shape; connecting the surface acoustic wave arcuate interdigital transducer to the output channel of the signal generator, activating the signal generator to apply the electrical signals to the arcuate interdigitated electrode, and generating surface acoustic waves on the lithium niobate chip to excite the polydimethylsiloxane microfluidic channel, so that an acoustic field of the travelling surface acoustic waves is generated at a location where the polydimethylsiloxane microfluidic channel is excited to form a coverage section of traveling surface acoustic wave; and respectively letting in the hybrid particle flow and the sheath flow from the polydimethylsiloxane microfluidic channel, wherein the microparticles are subjected to an acoustic radiation force of the surface acoustic waves when flowing through the coverage section of travelling surface acoustic wave, the acoustic radiation force increases with an increase of a diameter of the microparticles, causing the microparticles to move differently in a width direction of the polydimethylsiloxane microfluidic channel to be dispersed, and separation is completed at the bifurcations of the polydimethylsiloxane microfluidic channel; and exciting the surface acoustic waves outward at different circumferential angular positions of the arcuate interdigitated electrode at different times through changing a frequency of the electrical signals output by the signal generator, wherein the microparticles are dispersed and separated at the bifurcations of the polydimethylsiloxane microfluidic channel at the circumferential angular positions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic view of the device structure according to the invention.

(2) FIG. 2 is a top view of an arcuate interdigitated electrode according to the invention.

(3) FIG. 3 is a top view of a polydimethylsiloxane (PDMS) microfluidic channel according to the invention.

(4) FIG. 4 is a schematic view of activating the device under an electric signal of frequency f1 according to an embodiment.

(5) FIG. 5 is a schematic view of arranging and separating particles under an electrical signal of frequency f1 according to an embodiment.

(6) FIG. 6 is a schematic view of activating a device under an electric signal of frequency f2 according to an embodiment.

(7) FIG. 7 is a schematic view of arranging and separating particles under an electric signal of frequency f2 according to an embodiment.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

(8) The invention will be further described below with reference to the drawings and embodiments, but the embodiments of the invention are not limited thereto.

(9) As shown in FIG. 1, the time-sharing multi-channel separation device according to the embodiment includes a lithium niobate chip 1, an arcuate interdigitated electrode 2, and a polydimethylsiloxane (PDMS) microfluidic channel 3. The arcuate interdigitated electrode 2 is arranged on the lithium niobate chip 1. The arcuate interdigitated electrode 2 and the lithium niobate chip 1 form a surface acoustic wave arcuate interdigital transducer. The arcuate interdigitated electrode 2 is connected to an output channel of a signal generator. The PDMS microfluidic channel 3 is arranged on the lithium niobate chip 1 on a side of the arcuate interdigitated electrode 2 and is bonded to the lithium niobate chip 1 through oxygen plasma bonding.

(10) As shown in FIG. 2, the arcuate interdigitated electrode 2 is mainly formed by a normal conventional interdigitated electrode being asymmetrically bent from a straight line into an arcuate curve. Two electrode ends of the arcuate interdigitated electrode 2 are asymmetrically arranged with one end big and another end small. The spacing between interdigitated electrodes (strip-shaped) of the arcuate interdigitated electrode 2 at the same radial angle is the same. The spacing changes at different radial angles. The spacing between interdigitated electrodes (strip-shaped) from one end to another end increases progressively or decreases progressively.

(11) As shown in FIG. 3, the PDMS microfluidic channel 3 includes a main flow channel, two inlet ends, and a plurality of outlet ends. The main flow channel is approximately arcuate and is arranged around the outer side of the arcuate interdigitated electrode 2. The two inlet ends are respectively a particle flow inlet 4 and a sheath flow inlet 5, which are connected to an end of the main flow channel together. The particle flow inlet 4 and the sheath flow inlet 5 respectively let in a hybrid particle flow 9 and a sheath flow 10. The hybrid particle flow 9 contains microparticles of different sizes. The main flow channel is provided with 1 to 4 bifurcations between a middle part and another end, and each bifurcation is provided with 1 to 3 outlet ends.

(12) The specific implementation is as shown in FIG. 1 and FIG. 3. The main flow channel is provided with 1 bifurcation in the middle part and the bifurcation is provided with 1 outlet end, which is the no. 1 outlet 6. At another end, 1 bifurcation is provided and the bifurcation is provided with 2 outlet ends, which are the no. 2 outlet 7 and the no. 3 outlet 8.

(13) The material of the arcuate interdigitated electrode 2 is aluminum with a thickness of 200 nm. The arcuate interdigitated electrode 2 is formed on the lithium niobate chip 1 through photolithography and physical vapor deposition. The PDMS microfluidic channel is a polydimethylsiloxane microfluidic channel.

(14) The embodiments of the invention and the specific implementation process are as follows.

(15) (1) The arcuate interdigitated electrode 2 and the PDMS microfluidic channel 1 are first prepared. A layer of positive photoresist is spin-coated on the lithium niobate (LiNO.sub.3) chip 1. Mask exposure is performed using a pre-made mask plate. Subsequently, the exposed photoresist is washed away to obtain a non-resistive region on the chip with the same shape as the metal electrode. A layer of aluminum metal with a thickness of 200 nm is deposited on the lithium niobate chip using physical vapor deposition after photolithography. Then, the remaining photoresist and excess metal film is dissolved using acetone to obtain the arcuate interdigitated electrode 2 as shown in FIG. 2.

(16) The PDMS microfluidic channel 3 is obtained using soft lithography method to make SU-8 mold and heating to cure after pouring PDMS. The shape thereof is shown in FIG. 3. The PDMS microfluidic channel 3 is bonded to a location opposite to the arcuate interdigitated electrode 2 on the lithium niobate chip 1 through oxygen plasma bonding.

(17) (2) The separation device is placed on a horizontal working stand. The arcuate interdigital transducer is connected to the output channel of the signal generator. The signal generator is activated and the electrical signal of frequency f1 is output. As shown in FIG. 4, the arcuate interdigital transducer generates a surface acoustic wave (f1) 11 on a piezoelectric chip and generates a traveling wave field of surface acoustic waves at a specific location of the PDMS microfluidic channel 3.

(18) (3) The hybrid particle flow 9 and the sheath flow 10 are respectively let in from the particle flow inlet 4 and the sheath flow inlet 5 of the PDMS microfluidic channel 3, and the flow rates thereof are respectively 25 L/h and 75 L/h. As shown in FIG. 5, when flowing through the coverage section of surface acoustic wave (f1) 13, particles of different diameters are subjected to different magnitudes of acoustic radiation forces, so as to move at different distances in the width direction of the flow channel to complete the arrangement. The particles with a diameter of 3 m at the subsequent bifurcation flow to the no. 3 outlet 8 and the particles with a diameter of 10 m flow to the no. 1 outlet 6 to complete the separation.

(19) (4) The frequency of the output signal of the signal generator is changed to f2. As shown in FIG. 6, the arcuate interdigital transducer excites a surface acoustic wave (f2) 12 at another angle. As shown in FIG. 7, the particles in the hybrid particle flow is arranged in the coverage section of surface acoustic wave (f2) 14. The particles with a diameter of 3 m at the subsequent bifurcation flow to the no. 3 outlet 8 and the particles with a diameter of 10 m flow to the no. 2 outlet 7 to complete the separation.

(20) It can be seen from the embodiments that the invention implements the multi-channel time-sharing separation of microparticles, which is easy to operate, has low energy consumption, and has a wide application range.