阅读说明：本技术 一种基于平面电极阵列的藻类检测系统 (Algae detection system based on planar electrode array ) 是由 王晓磊 王玉皞 于 2020-12-09 设计创作，主要内容包括：本发明提供一种基于平面电极阵列的藻类检测系统,包括以下：多电极传感器阵列和微管道；所述多电极传感器阵列包括多组电极,每组电极由宽度和间距均不相等的叉指电极组成；所述叉指电极以对称和非对称的排列形式,封装于所述水流道中,用于测量水体电容；所述微管道包括入水口、水流道和出水口；藻类水质经由所述入水口进入所述水流道,并由所述多电极传感器阵列检测藻类数目,最后经由出水口流出。本发明的有益效果是：不但可以提供实时的检测结果,还能实现传感器的小型化和低功耗,降低制造成本,有效补充现有检测手段。(The invention provides an algae detection system based on a planar electrode array, which comprises the following components: a multi-electrode sensor array and a micro-pipe; the multi-electrode sensor array comprises a plurality of groups of electrodes, and each group of electrodes consists of interdigital electrodes with unequal widths and intervals; the interdigital electrodes are packaged in the water flow channel in a symmetrical and asymmetrical arrangement mode and are used for measuring the capacitance of the water body; the micro pipeline comprises a water inlet, a water flow channel and a water outlet; the water quality of the algae enters the water flow channel through the water inlet, the number of the algae is detected by the multi-electrode sensor array, and finally the algae flows out through the water outlet. The invention has the beneficial effects that: the method can provide real-time detection results, realize the miniaturization and low power consumption of the sensor, reduce the manufacturing cost and effectively supplement the existing detection means.)

1. An algae detection system based on a planar electrode array is characterized in that: the method specifically comprises the following steps:

a multi-electrode sensor array and a micro-pipe;

the multi-electrode sensor array comprises a plurality of groups of electrodes, and each group of electrodes consists of interdigital electrodes with unequal widths and intervals; the interdigital electrodes are packaged in the water flow channel in a symmetrical and asymmetrical arrangement mode and are used for measuring the capacitance of the water body;

the micro pipeline comprises a water inlet, a water flow channel and a water outlet;

the water quality of the algae enters the water flow channel through the water inlet, the number of the algae is detected by the multi-electrode sensor array, and finally the algae flows out through the water outlet.

2. The planar electrode array based algae detection system of claim 1, wherein:

the specific process of detecting the algae number by the multi-electrode sensor array comprises the following steps:

s101: the interdigital electrodes form a uniform electric field and a non-uniform electric field in a symmetrical and asymmetrical arrangement mode;

s102: the uniform electric field and the non-uniform electric field enable the blue algae cells to generate a polarization reaction, so that the water body capacitance is increased;

s103: and the interdigital electrodes detect the increased water capacitance, and the number of blue-green algae is calculated according to the increased water capacitance.

3. The algae detection system of claim 2, wherein:

in step S102, the water capacitance is increased, and the principle thereof is as shown in formula (1):

in the formula (1), C is the integral water capacitance measured after the polarization reaction of the blue algae cells; c_waterThe water body capacitance before polarization reaction; c_cellThe water body capacitance is increased after the polarization reaction; epsilon_waterIs the dielectric constant of the water body; epsilon_cellThe equivalent water dielectric constant is increased after the polarization reaction; and k is the electrode constant of the interdigital electrode.

4. The algae detection system of claim 3, wherein: the calculation formula of the electrode constant kappa of the interdigital electrode is as shown in formula (2):

wherein the content of the first and second substances,s is the distance between the electrode pairs, w is the electrode width, and N is the total number of electrodes; l is the electrode length; k is a first class of complete elliptic integrals, and is calculated as formula (3):

in the formula (2), k is determined by the electrode shape,t is an integral term and dt is a infinitesimal term.

5. The algae detection system of claim 4, wherein: the multi-electrode sensor array is also used for measuring the water conductivity, and the calculation formula of the water conductivity is as follows (4):

in the formula (4), σ is the water conductivity, and R is the resistance between the interdigital electrodes.

6. The planar electrode array based algae detection system of claim 1, wherein: the sizes of the water inlet and the water outlet of the micro-pipeline are matched with the size of the blue algae.

7. The planar electrode array based algae detection system of claim 1, wherein: the material of the micro flow channel is polydimethylsiloxane.

8. The planar electrode array based algae detection system of claim 1, wherein: and the multi-sensor array lead-out pin is connected with an external measuring circuit.

Technical Field

The invention relates to the field of water quality algae detection, in particular to an algae detection system based on a planar electrode array.

Background

The water bloom phenomenon generated by the excessive propagation of various algae represented by blue algae is one of the most main threats to the water ecological safety in China. Common blue algae detection methods at the present stage comprise a laboratory analysis method, a remote sensing detection method and a living body fluorescence analysis method, but from the aspect of water bloom prevention and control effect, the existing methods still have the problems of long detection period, insufficient measurement precision, high cost and the like.

Disclosure of Invention

In view of this, the present invention provides an algae monitoring sensor based on a planar electrode array, which is directed to the actual demand in the water bloom prevention and control, and the concentration difference of algae in different water bloom stages, and realizes the concentration measurement of algae represented by blue algae by the optimized design of the electrode array and the micro-pipe.

The invention provides an algae detection system based on a planar electrode array, which specifically comprises the following components:

a multi-electrode sensor array and a micro-pipe;

the multi-electrode sensor array comprises a plurality of groups of electrodes, and each group of electrodes consists of interdigital electrodes with unequal widths and intervals; the interdigital electrodes are packaged in the water flow channel in a symmetrical and asymmetrical arrangement mode and are used for measuring the capacitance of the water body;

the micro pipeline comprises a water inlet, a water flow channel and a water outlet;

the water quality of the algae enters the water flow channel through the water inlet, the number of the algae is detected by the multi-electrode sensor array, and finally the algae flows out through the water outlet.

Further, the specific process of detecting the algae number by the multi-electrode sensor array comprises the following steps: s101: the interdigital electrodes form a uniform electric field and a non-uniform electric field in a symmetrical and asymmetrical arrangement mode; s102: the uniform electric field and the non-uniform electric field enable the blue algae cells to generate a polarization reaction, so that the water body capacitance is increased; s103: and the interdigital electrodes detect the increased water capacitance, and the number of blue-green algae is calculated according to the increased water capacitance.

Further, in step S102, the capacitance of the water body is increased, and the principle is as shown in formula (1):

in the formula (1), C is the integral water capacitance measured after the polarization reaction of the blue algae cells; c_waterThe water body capacitance before polarization reaction; c_cellThe water body capacitance is increased after the polarization reaction; epsilon_waterIs the dielectric constant of the water body; epsilon_cellThe equivalent water dielectric constant is increased after the polarization reaction; k is the electrode constant of the interdigital electrode。

Further, the calculation formula of the electrode constant k of the interdigital electrode is as follows (2):

wherein the content of the first and second substances,s is the distance between the electrode pairs, w is the electrode width, and N is the total number of electrodes; l is the electrode length; k is a first class of complete elliptic integrals, and is calculated as formula (3):

in the formula (2), k is determined by the electrode shape,t is an integral term and dt is a infinitesimal term.

Further, the multi-electrode sensor array is also used for measuring the water conductivity, and the calculation formula of the water conductivity is as follows (4):

in the formula (4), σ is the water conductivity, and R is the resistance between the interdigital electrodes.

Furthermore, the sizes of the water inlet and the water outlet of the micro-pipeline are matched with the size of the blue algae.

Further, the material of the micro flow channel is polydimethylsiloxane.

And the multi-sensor array lead-out pin is connected with an external measuring circuit.

The beneficial effects provided by the invention are as follows: the method can provide real-time detection results, realize the miniaturization and low power consumption of the sensor, reduce the manufacturing cost and effectively supplement the existing detection means.

Drawings

FIG. 1 is a block diagram of an algae detection system based on a planar electrode array according to the present invention;

FIG. 2 is a schematic diagram showing the polarization reaction effect of cyanobacterial cells under non-uniform electric field and uniform electric field;

FIG. 3 is a schematic diagram of an asymmetric electrode design according to the present invention;

FIG. 4 is a sample of a multi-electrode sensor array according to the present invention;

FIG. 5 is a micro-pipe structure adapted to a sample of a multi-electrode sensor array according to the present invention;

FIG. 6 is a schematic diagram of a multi-electrode sensor array sample after encapsulation with micro-tubes;

FIG. 7 is a schematic plan view of a micro flow channel structure;

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be further described with reference to the accompanying drawings.

Referring to fig. 1, an algae detection system based on a planar electrode array includes the following components:

a multi-electrode sensor array and a micro-pipe;

the multi-electrode sensor array comprises a plurality of groups of electrodes, and each group of electrodes consists of interdigital electrodes with unequal widths and intervals; the interdigital electrodes are packaged in the water flow channel in a symmetrical and asymmetrical arrangement mode and are used for measuring the capacitance of the water body;

the micro pipeline comprises a water inlet, a water flow channel and a water outlet;

the water quality of the algae enters the water flow channel through the water inlet, the number of the algae is detected by the multi-electrode sensor array, and finally the algae flows out through the water outlet.

The specific process of detecting the algae number by the multi-electrode sensor array comprises the following steps:

s101: the interdigital electrodes form a uniform electric field and a non-uniform electric field in a symmetrical and asymmetrical arrangement mode;

referring to FIG. 2, FIG. 2 is a schematic diagram showing the polarization effect of cyanobacterial cells under non-uniform electric field and uniform electric field; the left half of fig. 2 is a non-uniform electric field. The right half of fig. 2 is a uniform electric field; under the uniform electric field, the cell polarization only shows the capacitance effect, and under the non-uniform electric field, besides the capacitance effect, the cell moves due to the different electric field forces at all parts, thereby forming the resistance effect.

Referring to FIG. 3, FIG. 3 is a schematic diagram of an asymmetric electrode according to the present invention, based on the polarization reaction of cyanobacterial cells; the upper part of the figure 3 is a cross section of an asymmetric interdigital electrode; the lower part of fig. 3 is a plan view of an asymmetric interdigital electrode;

s102: the uniform electric field and the non-uniform electric field enable the blue algae cells to generate a polarization reaction, so that the water body capacitance is increased;

s103: and the interdigital electrodes detect the increased water capacitance, and the number of blue-green algae is calculated according to the increased water capacitance.

When an external electric field acts on the cell, free ions in the cell are influenced by the electric field, move along the direction of the electric field or in the direction opposite to the electric field according to the self-charge property, and are finally limited by a cell membrane and accumulated at the inner edge of the cell. Although these ions cannot leave the cell, due to coulomb's law, they attract the opposite charges in the extracellular water to accumulate on the outer side of the cell membrane, forming a structure similar to capacitance, thereby increasing the total capacitance of the water, which is also called polarization of the cell.

Assuming that the electrodes used are parallel electrodes with a relative area A and a thickness of the water between the electrodes d, the capacitance can be expressed as

Wherein epsilon is the dielectric constant of the water body, usually a fixed value, and is equivalent to increasing the dielectric constant of the water body when the cell polarization effect occurs, so as to increase the whole capacitance.

Because the increased capacitance has a positive correlation with the concentration of the blue algae, the number of the blue algae can be evaluated by measuring the capacitance.

Concretely, the content of blue algae in a standard water sample is assumed to be N_preThe measured capacitance value is C_preThe measured capacitance value in the purified water is C_pureIn actual operation, the capacitance value of the water sample to be evaluated is measured to be C_sampleThen its content of blue algae is N_sampleIs calculated according to the following formula

Namely, it is

Wherein C is_sampleIs a measured value, N_pre，C_preAnd C_pureAll the fixed reference values are obtained in a calibration link after the sensor is manufactured, and are not influenced by later experiments.

Correspondingly, the interdigital electrode is adopted, and the electrode constant of the interdigital electrode can be correspondingly matched according to the size of the blue algae;

in step S102, the capacitance of the water body is increased, and the principle is as follows:

in the formula, C is the integral water body capacitance measured after the polarization reaction of the blue algae cells; c_waterThe water body capacitance before polarization reaction; c_cellThe water body capacitance is increased after the polarization reaction; epsilon_waterIs the dielectric constant of the water body; epsilon_cellThe equivalent water dielectric constant is increased after the polarization reaction; kappa is the forkThe electrode constant of the finger electrode is equal to that of the parallel electrode

The calculation formula of the electrode constant k of the interdigital electrode is as follows:

wherein the content of the first and second substances,s is the distance between the electrode pairs, w is the electrode width, and N is the total number of electrodes; l is the electrode length; k is a first type of complete elliptic integral calculated as:

where k is determined by the electrode shape,t is an integral term and dt is a infinitesimal term.

Therefore, the electrode constant k of the interdigital electrode is controllable as a parallel plate electrode, and after the electrode is designed according to the size of the blue algae, the specific value can be determined and further applied to the measurement of electrical parameters such as conductivity, capacitance and the like.

In the present application, the dimensions of the interdigital electrodes are shown in table 1.

TABLE 1 electrode array size parameter and cyanobacteria cell size matching reference

Marshalling	Finger width W	Spacing S	Length of finger L	Index N
					1	0.1mm	0.1mm	30mm	40
2	0.2mm	0.2mm	30mm	20
					3	0.5mm	0.5mm	30mm	10
4	0.5mm	2mm	30mm	4

In this embodiment, four sets of sensor electrodes can be used to obtain four concentrations of blue-green algae correspondingly, and the final result is obtained by averaging the two highest concentrations. The calculation method is characterized in that the higher the measured concentration is, the better the sensor electrode is coupled with the blue algae in the water body, and the potential error caused by measurement of a single group of electrodes can be reduced through the average value.

Those skilled in the art can design other different parameters according to other practical requirements, which are only illustrative and not limiting;

the micro-pipeline can preliminarily encapsulate the sensor electrode, and a channel and a place which are in contact with the electrode are constructed for the measured water body, so that the water body can be preliminarily filtered and then transmitted to the electrode to remove partial interference, and the measured water sample of the sensor can be increased and quantified by matching with external equipment such as a water pipe, a water pump and the like.

Referring to fig. 4-6, fig. 4-6 are diagrams illustrating the connection relationship between the electrodes and the microchannels;

FIG. 4 is a sample of a multi-electrode sensor array according to the present invention; it consists of an electrode part and a transparent substrate part, wherein the electrode can be divided into a measuring electrode part and an extraction pad part according to the function of the electrode. In fig. 4, the middle part is an electrode part, and the upper and lower sides are corresponding pad parts for lead-out;

FIG. 5 is a micro-pipe structure adapted to a sample of a multi-electrode sensor array according to the present invention; in the figure 4, the left and right independent convex parts are respectively a water inlet and a water outlet, the water inlet and the water outlet are connected with the hollow part below the water inlet and the water outlet to form a water flow channel together, and the sizes of the water inlet and the water outlet are designed according to the volume of algae and interfering substances.

FIG. 6 is a schematic diagram of a multi-electrode sensor array sample after being packaged with a micro-pipe, wherein the electrodes are packaged through a micro-pipe structure, and the leading-out electrode part can be changed into various interfaces such as SMA (shape memory alloy) according to a measuring circuit.

After the sensor electrode parameters and the micro-channel structure are basically determined, the structural performance can be improved by improving the micro-channel material.

Polydimethylsiloxane PDMS is commonly called silicon rubber, is the most common microfluidic material in microfluidic chips, and is low in cost, easy to mold and not easy to damage.

Referring to FIG. 7, FIG. 7 is a schematic plan view of a micro flow channel structure;

the micro-channel based on PDMS can be manufactured by micro-fluidic processing techniques such as illumination, etching, development and the like. The PDMS substrate is oxidized in oxygen plasma, sealed to the electrode substrate, coated with epoxy and perforated on the inside to provide a fluid path.

The sensor is present in the form of an electrode array for better detection of blue algae, and a micro-channel structure can be established for the electrode array as well.

Arranging a plurality of sensors in the micro-pipeline, and leading out electrode pins of the sensors for an external test circuit. The auxiliary electrode may also be integrated into the microchannel structure in view of its ability to improve sensor performance under certain conditions. Through linking to each other water injection mouth and egress opening with the water pump, can accelerate the speed that measured water body flowed through the electrode to increase the water yield that surveys, promote and detect the accuracy. Due to the addition of the micro-channel structure, the detection structure of the electrode and the measured water composition may be affected, and therefore, the electrode array needs to be recalibrated after the micro-channel is packaged.

The calibration needs to measure the water conductivity, the multi-electrode sensor array is further used for measuring the water conductivity, and a calculation formula of the water conductivity is as follows:

in the formula, sigma is the water conductivity, and R is the resistance between the interdigital electrodes.

Finally, the invention is summarized as follows:

the invention takes algae as a measuring object and blue algae as a core target, and carries out electrode design based on a classical interdigital electrode structure.

Designing a group of interdigital electrodes with different widths and intervals for measuring the blue algae in different states according to the monomer form of the blue algae cells and the space distribution state of the blue algae cells in different concentration intervals;

designing symmetrical and asymmetrical electrode combinations according to the movement mode and the equivalent electric effect of the blue algae in the uniform electric field and the non-uniform electric field;

in view of the ubiquitous presence of inorganic ions, measuring electrodes for conductivity were designed;

finally, a sensor array formed by measuring a series of electrodes is formed, and the blue algae under different concentrations is comprehensively measured.

On the basis of the electrode array, the fluid control concept in the micro-fluidic chip is used for reference, and the micro-pipeline is designed to guarantee the measuring effect of the sensor.

And (3) designing a pipeline structure and a filtering structure suitable for the blue algae by referring to the characteristics of the blue algae and main interference substances such as geometric dimensions, biological forms and the like, and separating the blue algae and the main interference substances.

The micro-pipeline adapts to the electrode array in geometric size and shape, so that on one hand, the full coupling of the blue algae and the electrode is ensured, and the detection performance of the sensor is ensured; on the other hand, interference substances with large volume and other pollutants are eliminated to be in direct contact with the electrodes, and the stability of the sensor is guaranteed.

The invention can cover different algae forms and volumes by designing the electrode parameters of the sensor and adjusting the detection range of the sensor.

The beneficial effects provided by the invention are as follows: the method can provide real-time detection results, realize the miniaturization and low power consumption of the sensor, reduce the manufacturing cost and effectively supplement the existing detection means.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.