CN208155808U - A kind of device improving particle detections precision and flux using static focusing - Google Patents

Abstract

The utility model discloses a kind of devices that particle detections precision and flux are improved using static focusing, which includes the PDMS micro-fluidic chip, signal amplification circuit and Signal acquiring and processing unit with microchannel, and the microchannel includes：Multiple sample channels, each sample channel are divided into sample channel front end and sample channel rear end between passing through sense channel；And it is both symmetrically distributed in perpendicular to the straight line two sides at sense channel center；Platinum electrode in the liquid storage hole of rear end passes through a reference resistance respectively and connect with the cathode of each DC power supply, and the platinum electrode in the liquid storage hole of front end is connect with the anode of DC power supply；The both ends of reference resistance pass through conducting wire and connect with the input terminal of the signal amplification circuit, and the output end of each signal amplification circuit is connect with Signal acquiring and processing unit.The utility model can by the single sense channel of more times of line widths multidiameter delay detect, considerably increase detection flux and detection accuracy, and effectively prevent channel block phenomenon.

Description

A kind of device improving particle detections precision and flux using static focusing

Technical field

The utility model relates to particle monitoring technique fields, particularly relate to a kind of utilization static focusing raising particle inspection Survey the device of precision and flux.

Background technique

In fields such as environmental monitoring, machining, communications and transportation, biomedicines, for realizing that object is (such as gold in sample Metal particles object, bacterium, virus and marine microorganism etc.) the portable particle fast counting apparatus of accurate counting and grinding for method Study carefully, there is very much theoretical value and application prospect.

The method of current existing common grain count includes following several：

1) light blockage method：Also known as light obstruction method or light block method, are most widely used grain count methods, it utilizes particle The detection blocked intensity variation occurred and realize diameter of particle to light.The method principle is simple, but needs expensive and multiple Miscellaneous photo-translating system, detection accuracy be not also high.

2) inductance method：Inductance method is passed through caused inductance variation when detecting micropore using particle and realizes grain count.This side Method principle is simple, and suitable for detecting to various metallic particles, detection accuracy is limited.

3) capacitance method：Capacitance method is a kind of non-contact detection method, can cause micropore when particle micropore after testing The variation of capacitor may be implemented to count by monitoring the variation of micropore capacitor.The method is only applicable to low conducting solution (such as oil Liquid) in metallic particles count, but the detection of small capacitance depend on high-precision detecting instrument.

4) laser-Induced Fluorescence Detection method：Particle can carry fluorescence after laser irradiation, can be detected by photoelectric sensor, To realize grain count.The method is usually used in the fields such as blood analysis, immunology and microbiology, easy to detect, counts quasi- Really, it but needs to pre-process before detecting, optical element is at high cost and structure is complicated, can not detect atomic small particle.

5) resistance impulse method (RPS)：Resistance impulse method is based on when particle flows through micropore there are electric field, both ends at micropore Voltage change and generate detection signal, realize detection；The method is easy to operate, is the highest grain count method of current precision.

Wherein, micro flow control chip device is a kind of by biology, chemistry, the sample preparation of medical analysis process, reaction, separation The microdevice of analysis overall process is integrated on the chip of one piece of micro-meter scale and is automatically performed with basic operations such as detections.Its liquid The features such as flowing is controllable, consumption reagent and sample are few, analysis speed improves with obtaining into ten hundreds of times, makes it possible to rather It is analyzed while realizing up to hundreds of samples in the clock even shorter time, and completes the pretreatment of sample online and analyze complete Process.

Micro-fluidic chip Processing Technology Development is rapid in recent years, micro- there are many being realized on micro-fluidic chip using RPS Receive the micro/nano levels object such as particle, cell, bacterium and virus counting research report.Traditional micro-fluidic RPS counts core Piece is to process the sense channel that one section of size is slightly larger than candidate particles, channel in the straight microchannel middle section for being applied with DC electric field The variation that the variation of middle size can cause channel electric fields to be distributed, so that the local electric field strength at sense channel is much higher than straight channel The electric field of rest part；The disturbance of sense channel internal electric field can be shown when the insulated particle channel after testing to be measured in solution Work influences the variation of its both ends component voltage, can be acquired and be exported a voltage arteries and veins using suitable signal acquiring and processing system Signal is rushed, the number of pulse signal is the number of particle in detection process.Based on the above principles, to effectively utilize this voltage Variation realizes detection and counts that people have investigated different chip structures.

Such as, the initial structure of traditional RPS detection chip only by the wide main channel of a hundreds of microns and is set to main logical One section of line width in the middle part of road sense channel composition more slightly larger than candidate particles, then will be inserted in the platinum electrode series connection at main channel both ends It is connected after resistance with DC power supply both ends, and acquires amplified resistance both end voltage signal intensity and realize grain count, still The method system signal noise ratio is low, and detection accuracy is not high；Improved detection chip respectively sets up an inspection before and after sense channel Test arm channel, directly utilizes electrode measurement channel both end voltage signal, then by exporting after differential amplification, make detection signal-to-noise ratio with Detection accuracy is improved；In recent years a kind of high-throughput counting chip occurred has used public inlet opening multichannel annular spread Structure, every channel all include main channel, sense channel and liquid storage hole etc., and inlet opening connects positive pole, each liquid storage hole string Power cathode is connected after connection resistance, mutually as reference, current counting chip can preferably eliminate system noise in each channel, It is successively worked by controlling each channel, realizes high-throughput count.

It should be understood that existing counting chip higher detection signal-to-noise ratio in order to obtain, generally requires guarantee Sense channel and particle are dimensionally close, to improve the cost of passageway machining.In addition, due to detection mouth size and Grain be closer to, be also easy to the phenomenon that particle occlusion detection channel occur so that grain diameter testing result occur error or Detection is interrupted, and the precision and stable operation of system are affected；Finally, due to which the realization of particle detections requires particle size and detection It is mouthful close, it also can the droplet measurement range of limiting channel and detection flux significantly.

Summary of the invention

In view of defects in the prior art, the purpose of this utility model is to provide for a kind of utilization static focusing raising The device of grain detection accuracy and flux, which in the detection process can be by more in the single sense channel of more times of line widths Road parallel detection considerably increases detection flux and detection accuracy, and effectively prevents channel block phenomenon.

To achieve the goals above, the technical solution of the utility model：

A kind of device improving particle detections precision and flux using static focusing, which includes the micro-fluidic core of PDMS Piece, signal amplification circuit and Signal acquiring and processing unit, the PDMS micro-fluidic chip are to be carved in PDMS substrate fovea superior The side of microchannel is packaged as a whole with glass slide, special to form the micro-fluidic chip for the microchannel circulated for sample to be tested Sign is that the microchannel includes：

Multiple sample channels, each sample channel pass through be divided between same sense channel sample channel front end and Sample channel rear end, sample channel front end one end have the front end liquid storage hole as sample holes, and the other end and detection are logical Road is connected, and sample channel rear end one end has the rear end liquid storage hole as waste liquid hole, the other end and sense channel phase Connection；And the sample channel front end of each sample channel and sample channel rear end are at perpendicular to sense channel center Straight line is symmetry axis, is symmetrically distributed in the symmetry axis two sides；

While platinum electrode is inserted in each front end liquid storage hole, rear end liquid storage hole；And make in the rear end liquid storage hole Platinum electrode pass through a reference resistance respectively and connect with the cathode for the DC power supply being each independently of the others, in the front end liquid storage hole Platinum electrode with above-mentioned DC power supply anode connect；The both ends of the reference resistance pass through conducting wire and the signal amplifies The input terminal of circuit connects, and the output end of each signal amplification circuit is connect with the Signal acquiring and processing unit.

Further,

The quantity of the sample channel is preferably 3, the line when line width of the sense channel is common single channel detection Wide 3 times.

Compared with prior art, the beneficial effects of the utility model：

1) the utility model when being detected, since its sample to be tested particle dimensionally differs greatly with sense channel (size of sense channel and sample particle can differ 10 times in such as example, and general detection chip sense channel and sample The size ratio of particle is 2-3), channel blockage phenomenon can be effectively avoided, detection stability is high；

2) ratio that the utility model passes through increase main channel (whole channels i.e. except sense channel) and detection mouth width Value or the signal-to-noise ratio that detection signal is continuously improved by reducing channel height, and then improve detection accuracy.

3) multiple groups particle multidiameter delay independent detection in same sense channel may be implemented in the utility model, detects flux It is high.

Detailed description of the invention

Fig. 1 is the microfluidic chip structure schematic diagram of counting device described in the utility model；

Fig. 2 is the structure example figure of device described in the utility model.

In figure：M, PDMS substrate, N, glass slide, the front end liquid storage hole of A, first sample channel, B, first sample are logical The rear end liquid storage hole in road, the front end liquid storage hole of C, second sample channel, the rear end liquid storage hole of D, second sample channel, E, The front end liquid storage hole of three sample channels, the rear end liquid storage hole of F, third sample channel, 1, first sample channel front end, 2, First sample channel rear end, 3, second sample channel front ends, 4, second sample channel rear ends, 5, third sample channel Front end, 6, third sample channel rear end, 7, sense channel.

Specific embodiment

To make the object, technical solutions and advantages of the present invention clearer, below in conjunction in the utility model embodiment Attached drawing, the technical solution of the utility model is clearly and completely described, it is clear that described embodiment is that this is practical Novel a part of the embodiment, instead of all the embodiments.Based on the embodiments of the present invention, ordinary skill people Member's every other embodiment obtained without making creative work, belongs to the model of the utility model protection It encloses.

Technical background：When particle flows through the micropore there are electric field, apparent disturbance can be generated to electric field, while corresponding Micropore at both end voltage change and generate voltage pulse signal.Based on the principle, then can borrow makes sense channel In there are multiple superposition of electric field, multiple amplitudes size can be collected on multiple amplifying circuits simultaneously when particle flows through sense channel The pulse signal not waited --- since the signal that channel where particle generates is maximum, it can be used and filter out amplitude less than whole pulses Effective particle pulse signal that the pulse singaling of maximum amplitude is needed in signal, statistics useful signal quantity can obtain To the number of test sample particle.

Based on above-mentioned design background, the utility model devises a kind of using static focusing raising particle detections precision and logical The device of amount, the device (being illustrated by taking 3 sample channels as an example) are as shown in Figure 1 comprising PDMS micro-fluidic chip, signal Amplifying circuit and Signal acquiring and processing unit, the PDMS micro-fluidic chip are to be carved with microchannel in PDMS substrate fovea superior Side is packaged as a whole with glass slide, to form the micro-fluidic chip for the microchannel circulated for sample to be tested, which is characterized in that institute Stating microchannel includes：

3 sample channels, each sample channel pass through be divided between same sense channel sample channel front end and Sample channel rear end, sample channel front end one end have the front end liquid storage hole as sample holes, and the other end and detection are logical Road is connected, and sample channel rear end one end has the rear end liquid storage hole as waste liquid hole, the other end and sense channel phase Connection；And the sample channel front end of each sample channel and sample channel rear end are at perpendicular to sense channel center Straight line is symmetry axis, is symmetrically distributed in the symmetry axis two sides；

While platinum electrode is inserted in each front end liquid storage hole, rear end liquid storage hole；And make in the rear end liquid storage hole Platinum electrode pass through a reference resistance respectively and connect with the cathode for 3 DC power supplies being each independently of the others, the front end liquid storage Platinum electrode in hole is connect with the anode of above-mentioned DC power supply；The both ends of the reference resistance pass through conducting wire and 3 signals The input terminal of amplifying circuit connects, and the output end of 3 signal amplification circuits is connect with the Signal acquiring and processing unit. Sample to be tested in above structure in detection process in N number of difference sample channel can be in N number of different zones of same sense channel Interior realization detection.

Further, 3 times of line width when the line width of the sense channel is common single channel detection, three different samples are logical Sample to be tested in road can realize detection in three different zones of same sense channel.

Another object of the present invention is to provide for a kind of based on the utilization static focusing raising particle detections precision The method for carrying out grain count with the device of flux, which is characterized in that include the following steps：

S1, sample are added dropwise：PBS buffer solution is added dropwise in each front end liquid storage hole, rear end liquid storage hole, then drips sample to be tested It is added in each front end liquid storage hole；

S2, sample transport：Connect each independent DC power supply, and adjust liquid level in each liquid storage hole, make it is described into Sample to be tested in sample hole is acted on from sample channel front end in pressure through sense channel stream sample channel rear end, until flowing to rear end In liquid storage hole；

S3, signal amplify collection analysis：The voltage pulse signal at reference resistance both ends when acquisition particle flows through detection mouth, and After collected pulse signal is amplified by respective signal amplification circuit, remembered by the Signal acquiring and processing unit It records and shows the corresponding detection data i.e. number of test sample particle to realize in detection process in N number of difference sample channel Sample to be tested realizes detection in N number of different zones of same sense channel.

Further,

The detection method can be identified to be counted belonging to sample and be led to by the processing to collected pulse signal The sample count in road, i.e., three channels is not interfere with each other.Preferably, the Signal acquiring and processing unit includes NI capture card and meter Calculation machine.

It is detected by taking polystyrene sample particle as an example below, as shown in Figure 2：

The device parameter of the implementation case：50*30 μm of the size of chip sense channel used in the implementation case (wide × It is long), the distance of each liquid storage hole to chip sense channel is 5mm, and the size of rest channels is 200*20 μm (wide × high)；It is to be detected Sample is 5 μm of granules of polystyrene solution；Buffer is PBS (1 ×) solution；The electric field strength for being applied to channel positive and negative anodes is 40V/cm；

The microchannel of the device include first sample channel on the micro-fluidic chip front end liquid storage hole A, The rear end of the rear end liquid storage hole B of first sample channel, the front end liquid storage hole C of second sample channel, second sample channel Liquid storage hole D, the front end liquid storage hole E of third sample channel, the rear end liquid storage hole F and first sample of third sample channel The sample channel rear end 2, second of Channel front end 1, the first sample channel rear end 4 of sample channel front end 3, second, third Sample channel front end 5, third sample channel rear end 6 and sense channel 7；Platinum electrode is inserted into all liquid storage holes, after each End liquid storage hole in platinum electrode by a reference resistance with connect respectively with the cathode of a DC power supply, in remaining each liquid storage hole Platinum electrode is connected with the anode of above-mentioned corresponding DC power supply；Differential amplification is corresponded to by two conductor in parallel at the both ends each resistance R Two input terminals of device；The output end of difference amplifier is connected to the input terminal of NI data collecting card；NI output signal can be straight It connects in the Computer display connected and is analyzed.

Based on the method that above-mentioned grain count device carries out grain count, include the following steps：

S1) sample is added dropwise：The PBS buffer solution of 10 μ L is added dropwise in each liquid storage hole first, it is then each in the liquid storage hole of front end The sample to be tested of 10 μ L PBS buffer solution and 2.5 μ L is added dropwise；

S2) sample transport：DC power supply is connected, liquid level in each liquid storage hole is adjusted, the sample in each channel is enable to exist Pressure effect flows into each sample channel back segment through sense channel from the leading portion in respective channel, and it is corresponding to then pass to back segment channel Rear end liquid storage hole；

S3) signal amplifies collection analysis：The voltage pulse at each reference resistance both ends when flowing through detection mouth by acquiring particle Signal is remembered after being handled by signal acquiring and processing system after collected signal is amplified by respective difference amplifier Record and show corresponding detection data, the i.e. number of test sample particle.

Wherein, due to having application separate electric fields in the first, second, third sample channel, the electric-field strength in sense channel 7 Degree is very big (i.e. power line is very intensive)；When particle channel after testing, it can be easy to disturbance electric field line, make sense channel point electricity Pressure changes, and further results in the voltage change at the both ends resistance R, generates detection signal, and detection signal passes through such as AD620 difference It is input to NI capture card after amplifier differential signal amplification, NI capture card output signal can be directly on the computer connected It shows and is analyzed.

Specific testing result：Real-time detection and count results can be directly obtained by computer, of particle in sample Number is equal to the numbers of effective impulse signal, each Air conduct measurement and count results can show on different counting panels respectively or It is distinguished on same counting panel by the lines of different colours.

In conclusion the utility model its in the detection process, using multiple sample channels, this example is three channels connections Electric field line in the method focus detection channel of independent current source；Since the size of sense channel differs larger with sample to be tested, have Effect avoids channel block phenomenon and improves detection accuracy；In addition, three sample channels are logical in detection simultaneously in detection process Multidiameter delay detects in road, substantially increases the flux of detection and counting；And due in sense channel there are three superposition of electric field, The pulse signal that three amplitudes differ in size can be collected when particle flows through sense channel on three amplifying circuits simultaneously --- The signal that channel where particle generates is maximum, increases a section using filtering module such as LabVIEW program and compares filtering subprogram Two lesser signals of amplitude are filtered out, effective particle pulse signal of needs can be obtained, count useful signal quantity Obtain the number of test sample particle.

The preferable specific embodiment of the above, only the utility model, but the protection scope of the utility model is not It is confined to this, anyone skilled in the art is within the technical scope disclosed by the utility model, practical according to this Novel technical solution and its inventive concept is subject to equivalent substitution or change, should all cover the protection scope of the utility model it It is interior.

Claims (2)

1. it is a kind of using static focusing improve particle detections precision and flux device, the device include PDMS micro-fluidic chip, Signal amplification circuit and Signal acquiring and processing unit, the PDMS micro-fluidic chip are to be carved with micro- lead in PDMS substrate fovea superior The side in road is packaged as a whole with glass slide, and to form the micro-fluidic chip for the microchannel circulated for sample to be tested, feature exists In the microchannel includes：

Multiple sample channels, each sample channel are divided into sample channel front end and sample between passing through same sense channel Channel rear end, sample channel front end one end have the front end liquid storage hole as sample holes, the other end and sense channel phase Connection, sample channel rear end one end have the rear end liquid storage hole as waste liquid hole, and the other end is connected with sense channel； And the sample channel front end of each sample channel and sample channel rear end are perpendicular to the straight line at sense channel center For symmetry axis, it is symmetrically distributed in the symmetry axis two sides；

While platinum electrode is inserted in each front end liquid storage hole, rear end liquid storage hole；And make platinum in the rear end liquid storage hole Electrode passes through a reference resistance respectively and connect with the cathode for the DC power supply being each independently of the others, the platinum in the front end liquid storage hole Electrode is connect with the anode of above-mentioned DC power supply；The both ends of the reference resistance pass through conducting wire and the signal amplification circuit Input terminal connection, the output end of each signal amplification circuit connect with the Signal acquiring and processing unit.

2. the device according to claim 1 for improving particle detections precision and flux using static focusing, it is characterised in that：

The quantity of the sample channel is 3.