CN112213459B - Biochemical oxygen demand micro-fluidic detection device and method based on bacterial microcapsules - Google Patents
Biochemical oxygen demand micro-fluidic detection device and method based on bacterial microcapsules Download PDFInfo
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- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
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Abstract
The invention discloses a bacterial microcapsule-based biochemical oxygen demand micro-fluidic detection device and method. The detection equipment comprises a multi-channel micro-fluidic chip, a porous optical fiber probe, a fluorescence detector and a light source; the multi-channel micro-fluidic chip comprises a sample introduction channel, a storage channel communicated with the sample introduction channel and a detection channel communicated with the storage channel through a connecting channel, wherein bacterial microcapsules are stored in the storage channel; one end of the porous optical fiber probe is inserted into the detection channel, and the other end of the porous optical fiber probe is connected with the fluorescence detector; the light source is positioned above the multi-channel micro-fluidic chip. The bacteria microcapsule is stored in the channel of the multi-channel micro-fluidic chip, and the device can directly inject a sample into the channel of the multi-channel micro-fluidic chip for direct detection, so that the rapid, sensitive, accurate and reliable detection of the biochemical oxygen demand is realized; the problems of short service life, harsh application conditions, poor repeatability and the like of the microbial film in the traditional sensor are solved; the method has the advantages of simplicity, portability, stable detection process and wide application range.
Description
Technical Field
The invention relates to the technical field of environmental water sample detection, in particular to a bacterial microcapsule-based biochemical oxygen demand micro-fluidic detection device and method.
Background
Biochemical oxygen demand (biochemical oxygen demand) is a comprehensive index representing the content of aerobic pollutants such as organic matters in water, and it indicates the total amount of dissolved oxygen in water consumed when organic matters in water are decomposed by oxidation due to biochemical action of microorganisms to make them become inorganic or gasified. The total time of oxidizing and decomposing various organic matters in the sewage is about 20 days, and in order to shorten the detection time, the general biochemical oxygen demand is represented by the oxygen consumption of an inspected water sample within 5 days at 20 ℃, and is called as the biochemical oxygen demand of 5 days, which is abbreviated as BOD5。BOD5Higher values represent more severe water pollution.
BOD5The classical test method is a dilution inoculation method, is widely applied and is suitable for measuring surface water domestic sewage and industrial wastewater, but has the defects of low measurement precision, complex operation and long measurement period, cannot reflect the water quality condition in time and is not beneficial to making scientific judgment on the pollution condition in time. Similar limitations exist in methods such as a temperature rise method, a pressure measurement method, a pressure detection coulometer method and the like which are improved on a dilution inoculation method. BOD5Another common assay method is the microbial sensor assay. The microbial sensor solves the problem of long measurement period of the classical determination method, is relatively simple to operate, has great advantages in application, but has problems in the actual use process, such as low stability, short microbial film service life, harsh application conditions, poor repeatability and the like; in addition, the inorganic salt with too high concentration and heavy metal ions can inhibit and poison the microbial membrane; furthermore, when a water sample contains a large amount of suspended matter contributing to the BOD value, the deviation of the measurement result is large, which limits the range of use and the practicability of the microbial sensor. How to realize accurate, simple and convenient biochemical oxygen demand measurement is a problem to be solved urgently in environmental monitoring.
Microfluidic chips, also known as micro total analysis systems or lab-on-a-chip, can integrate on a small-sized chip the various steps required for analysis, such as sample pre-treatment, reagent delivery, mixing, separation and detection. The method is widely applied to the fields of laboratory analysis, environmental monitoring, food detection, biological protection and the like. The micro-fluidic chip has the properties of light transmission, heat transfer, easy modification and the like, and can load detection elements such as optics, electrochemistry and the like. In addition, the microfluidic chip has the designability of coverage, and can meet different detection requirements. Therefore, the development of microfluidic chips provides new ideas and methods for many analytical problems. In recent years, the demand of people on environmental water sample monitoring is more and more urgent, portable, accurate and reliable BOD5The detection equipment provides powerful support for environmental protection and sustainable development. At present on the marketBOD of5The microbial sensor device still has shortcomings in practical use, and the problems of instability of a bacterial membrane in the sensor and the like are difficult to overcome.
Based on the above problems, the applicant finds that the direct implantation of bacterial microspheres into a microfluidic chip for culture is an innovative technology and can be BOD5The detection brings about a great influence, so that the construction of the micro-fluidic chip detection technology for embedding the bacterial microspheres is very important.
Disclosure of Invention
In view of the above, the invention aims to provide a bacterial microcapsule-based biochemical oxygen demand micro-fluidic detection device, which embeds bacterial microcapsules in a multi-channel micro-fluidic chip, can directly inject a water sample into the multi-channel micro-fluidic chip for direct detection, and realizes rapid, sensitive, accurate and reliable detection of biochemical oxygen demand; the problems of short service life of the microbial film, harsh application conditions, poor repeatability and the like in the traditional sensor are solved.
The invention also aims to provide a micro-fluidic biochemical oxygen demand detection method based on the bacterial microcapsule.
The above purpose of the invention is realized by the following technical scheme:
according to one aspect of the invention, the invention provides a bacterial microcapsule-based biochemical oxygen demand microfluidic detection device, which comprises: multichannel micro-fluidic chip, porous fiber probe, fluorescence detector, and light source, wherein, multichannel micro-fluidic chip includes: the device comprises a sample feeding channel, a storage channel communicated with the sample feeding channel and a detection channel communicated with the storage channel through a plurality of connecting channels, wherein bacterial microcapsules are stored in the storage channel, and the size of each connecting channel is smaller than that of each bacterial microcapsule; one end of the porous optical fiber probe is inserted into the detection channel, and the other end of the porous optical fiber probe is connected with the fluorescence detector; the light source is positioned above the multi-channel micro-fluidic chip.
Preferably, the storage channel is a straight channel. Wherein, the storage channel can be one or more. Further, when there are a plurality of detection channels, they are preferably arranged side by side at intervals, and the detection channel is arranged between two adjacent storage channels. For example, the number of the storage channels may be two, the number of the detection channels is one, and the two storage channels are respectively located at two sides of the detection channel. The detection channel may also be a straight channel.
Preferably, the connecting channel is a plurality of connecting channels which are arranged at intervals between the storage channel and the detection channel. More preferably, the connection channel is perpendicular to the storage channel and the detection channel, respectively.
Preferably, the bacterial species in the bacterial microcapsule may be filamentous bacillus, pseudomonas, clostridium, etc. Preferably, the diameter of the bacterial microcapsule is 30-200 μm. Preferably, the bacterial microcapsule is prepared by a flow focusing method of a microfluidic chip. More preferably, the bacterial species in the bacterial microcapsule may be bacillus subtilis microcapsules. The preparation method of the bacillus subtilis microcapsule comprises the following steps: preparing a bacillus subtilis suspension; mixing the suspension with sodium alginate and polyvinyl alcohol solution, and adding Ca-EDTA as disperse phase; adopting fluorinated oil mixed surfactant and acetic acid as continuous phase; and carrying out flow focusing on the dispersed phase and the continuous phase in a multi-channel micro-fluidic chip at respective preset flow rates to obtain the bacillus subtilis microcapsule. Further, the preset flow rate of the dispersed phase is 10-200 muL/min, for example, 50 muL/min; the preset flow rate of the continuous phase is 300-800 mu L/min, for example 400 mu L/min.
Preferably, the storage channel and the detection channel are both in a cuboid structure.
Preferably, the width of the storage channel is 2-200 mm, for example, 25 mm; the length is 2-200 mm, for example, 50 mm; the height is 1 to 1500 micrometers, for example 800 micrometers.
Preferably, the width of the detection channel is 2-200 mm, for example, 50 mm; the length is 2 to 200mm, for example 50mm, and the height is 1 to 1500 micrometers, for example 800 micrometers.
Preferably, the connecting channel is of a rectangular parallelepiped structure or a tubular structure. The size of the connecting channel is smaller than the size of the bacterial microcapsule to avoid the bacterial microcapsule from diffusing into the detection channel. Not all dimensions are required here, and for example the height of the connecting channel may be such that it is lower than the height of the storage and detection channels, and also smaller than the dimensions of the bacterial microcapsules. Specifically, for example, the height of the connecting channel can be 1-100 micrometers, for example, 20 micrometers, which is smaller than the diameter of the bacterial microcapsule of the present application.
Preferably, the porous optical fiber probe inserted into the detection channel is modified with oxygen sensitive fluorescent indicator [ Ru (dpp)3 [ ]]Cl2. The fluorescence detector may be hand-held. The light source may be an LED light source.
According to another aspect of the invention, the invention provides a bacterial microcapsule-based biochemical oxygen demand microfluidic detection method, which comprises the following steps:
installing the bacterial microcapsule-based biochemical oxygen demand microfluidic device;
injecting a sample to be detected into a storage channel from a sample introduction channel of a multi-channel microfluidic chip, wherein the sample to be detected enters a detection channel after passing through the storage channel and is contacted with a porous optical fiber probe in the detection channel; and then directly outputting a detection result through the fluorescence detector. Preferably, the sample to be tested is drawn up with a syringe and injected into the storage channel. The detection principle is as follows: after each power supply is turned on, the porous optical fiber probe transmits the detected fluorescence signal to the fluorescence detector, and the fluorescence detector converts the fluorescence signal into an electric signal and outputs a detection result.
Preferably, the volume of the sample of ambient water may be 50-500 microliters, for example 100 microliters.
Further, in the detection method, the step of installing the biochemical oxygen demand microfluidic detection device based on the bacterial microcapsule comprises the following steps: preparing a multi-channel micro-fluidic chip; preparing bacterial microcapsules; injecting the bacterial microcapsules into a storage channel of the multi-channel micro-fluidic chip, and storing the multi-channel micro-fluidic chip at a low temperature, wherein the low temperature can be 1-10 ℃, for example, 4 ℃; the low-temperature preservation time can be generally 6 months; preparing a porous optical fiber probe; taking out the multi-channel micro-fluidic chip, activating for 8-24 h, inserting one end of the porous optical fiber probe into a detection channel of the multi-channel micro-fluidic chip, and connecting the other end of the porous optical fiber probe with a fluorescence detector; and arranging a light source above the multi-channel micro-fluidic chip, and finishing the installation. Preferably, the bacterial microcapsule is prepared by a flow focusing method of a microfluidic chip.
Further, the step of preparing the holey fiber probe comprises: 1-10 mg of [ Ru (dpp)3]Cl2Adding 10-100 mL of mixed solution to prepare sol, wherein the mixed solution comprises: 20-40% ethyl orthosilicate, specifically 20-40% Octyl-triEOS (n-octyltriethoxysilane), 30-50% ethanol, and 1-10% HCl; soaking the porous optical fiber in NaOH for 1-4 h, cleaning, pumping the sol under a negative pressure condition, and standing for 2-8 h at room temperature to obtain the modified porous optical fiber probe.
Compared with the prior art, the device is formed by storing the bacterial microcapsules in the channels of the multi-channel micro-fluidic chip, and is applied to the detection of the Biochemical Oxygen Demand (BOD) to realize the BOD of the water sample5) The method is rapid, sensitive, accurate and reliable in detection. Specifically, the method comprises the following steps:
(1) the bacterial microcapsule adopted by the invention can fix a large amount of bacteria, such as a large amount of bacillus subtilis, and has very stable performance; meanwhile, the microcapsule structure can avoid direct contact between bacteria and pollutants in a water sample, and the problems of short service life, harsh application conditions, poor repeatability and the like of a microbial film in a traditional sensor are solved.
(2) The sampling and detecting process of the invention is simple and rapid, for example, the injector can be used to rapidly complete the sampling of the water sample and the sample injection of the chip detection, and the stability of the dissolved oxygen in the water sample is maintained to the maximum extent in the process.
(3) The detection equipment disclosed by the invention is simple and portable, can be used for real-time detection, can be used in various complex environments, and has the advantage of wide application range.
Drawings
FIG. 1 is a schematic structural diagram of a micro-fluidic biochemical oxygen demand detection device based on bacterial microcapsules. In fig. 1, 1 storage channel, 2 detection channel, 3 connection channel, 4 multi-hole fiber probe, 5 sample introduction channel, 6 light source, 7 fluorescence detector, 8 injector, 9 bacteria microcapsule.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The experimental methods used in the following examples are all conventional methods unless otherwise specified; the materials, reagents and the like used are commercially available unless otherwise specified.
Fig. 1 schematically shows a structure of a micro-fluidic biochemical oxygen demand detection device based on bacterial microcapsules. As shown in fig. 1, the invention provides a micro-fluidic biochemical oxygen demand detection device based on bacterial microcapsules, comprising: the device comprises a multi-channel micro-fluidic chip, a porous optical fiber probe 4, a fluorescence detector 7 and a light source 6. Wherein, the multichannel micro-fluidic chip includes: sampling channel 5, with the storage passageway 1 of sampling channel 5 intercommunication and with store the passageway 1 through the detection channel 2 of a plurality of connecting channel 3 intercommunication, it has bacterium microcapsule 9 to store the interior embedding of passageway 1. One end of the porous optical fiber probe 4 is inserted into the detection channel 2, and the other end is connected with the fluorescence detector 7. The light source 6 is positioned above the multi-channel micro-fluidic chip. The fluorescence detector 8 may be a commercially available handheld fluorescence detector 7. The light source 6 may be an LED light source.
In the present application, the storage channel 1 is a straight channel. The storage passage 1 may be provided in one or more. When being a plurality of, the interval sets up side by side, sets up measuring channel 2 between two adjacent storage passageways 1, stores and communicates through the connecting channel 3 of a plurality of low height between passageway 1 and the measuring channel 2. As shown in fig. 1, two storage channels 1 may be provided, which are respectively located at two sides of the detection channel 2, and the storage channel 1 at each side is communicated with the detection channel 2 through a connecting channel 3. The connecting channels 3 are arranged between the storage channel 1 and the detection channel 2 at intervals, and the distance between the connecting channels 3 is the same, and more preferably, the connecting channels 3 are respectively arranged perpendicular to the storage channel 1 and the detection channel 2, so that the sectional area can be reduced, and the control effect of the tension valve formed at the interface between the connecting channel 3 and the storage channel 1 is better. The size of the connecting channel 3 is smaller than that of the bacterial microcapsule 9; it should be noted that the "size" herein is not all the size of the connecting channel 3/bacterial microcapsule 9, and any size smaller than the bacterial microcapsule 9 may be used as long as the bacterial microcapsule 9 cannot pass through. For example, the height of the connecting channel 3 is defined, and the height of the connecting channel 3 is lower than the storage channel 1 and the detection channel 2 and smaller than the size of the bacterial microcapsule 9, so that the bacterial microcapsule 9 can be effectively prevented from diffusing from the storage channel 1 to the detection channel 2. The storage channel 1 may be a rectangular parallelepiped structure (but not limited thereto), and may have a width of 2 to 200mm, a length of 2 to 200mm, and a height of 1 to 1500 μm. The detection channel 2 can be a cuboid structure (but not limited thereto), the width can be 2-200 mm, the length can be 2-200 mm, and the height can be 1-1500 microns. Connecting channel 3 can be cuboid structure or tubular structure, and when being the cuboid structure, the height can be 1 ~ 100 microns, is far less than this application bacterium microcapsule 9's diameter, of course connecting channel 3's width also can be defined as 1 ~ 100 microns, and length does not do specifically and limits. When the structure is a tubular structure, the inner diameter of the structure is smaller than the diameter of the bacterial microcapsule 9. The sample introduction channel 5 may be provided with a plurality of branches for connecting with a plurality of storage channels 1, and may be configured in a U-shape, a Y-shape, or the like, for example.
The invention provides a micro-fluidic detection method of biochemical oxygen demand based on bacterial microcapsules, namely the application of the micro-fluidic detection equipment of biochemical oxygen demand based on bacterial microcapsules in the detection of the biochemical oxygen demand of an environmental water sample, which comprises the following steps: installing the bacterial microcapsule-based biochemical oxygen demand microfluidic device; a sample to be detected is absorbed by an injector and is injected into a storage channel from a sample injection channel of the multi-channel microfluidic chip, and the sample to be detected enters a detection channel after passing through the storage channel and is in contact with a porous optical fiber probe in the detection channel; and (3) turning on a power supply, transmitting the detected fluorescent signal to a fluorescent detector by the porous optical fiber probe, and converting the fluorescent signal into an electric signal by the fluorescent detector to output a detection result.
In the present invention, the bacterial species in the bacterial microcapsule may be filamentous bacillus, pseudomonas, clostridium, etc. More preferably, the bacterial species in the bacterial microcapsules are bacillus subtilis microcapsules. Taking the bacillus subtilis microcapsule as an example (the preparation method and the detection method of other strains are basically the same as the bacillus subtilis microcapsule, and the components of the culture medium, the culture conditions, the activation time and the like can be adjusted slightly according to different strains), the detailed description of the specific process of the biochemical oxygen demand microfluidic detection method based on the bacterial microcapsule is provided, and the detailed description comprises the following steps: the method comprises the following steps of preparation of bacterial microcapsules, design of a multi-channel micro-fluidic chip, design of a porous optical fiber probe 4, installation of detection equipment and detection of an environmental water sample.
Example 1 preparation of Bacillus subtilis microcapsules
The bacillus subtilis microcapsule is prepared by a flow focusing method of a microfluidic chip. The method specifically comprises the following steps: firstly, culturing Bacillus subtilis at 30 ℃ and 170r/min for 24h, then centrifuging at 4 ℃ and 3000r/min for 15 min to collect thalli, and washing with phosphate buffer solution for 2 times to prepare 20mg/mL bacterial suspension. And then mixing a sodium alginate (with the concentration of 4-8 percent, specifically 4 percent) solution and a polyvinyl alcohol (with the concentration of 8-15 percent, specifically 10 percent) solution in a ratio of 9: 1, mixing the obtained mixed solution with an isometric bacterial suspension, obtaining a bacterial-containing mixed solution again, mixing the bacterial-containing mixed solution with 100mM Ca-EDTA isometric solution to obtain a dispersion phase, wherein the sodium alginate and the polyvinyl alcohol are used as wall materials, so that the mechanical strength is higher, and the stability of the bacterial microspheres is better facilitated. PFPE-PEG surfactant (0.5% by mass concentration) and acetic acid were then mixed as a continuous phase using fluorinated oil FC-40. Finally, performing flow focusing on the two solutions respectively at the flow rates of 50 mu L/min of a dispersed phase and 400 mu L/min of a continuous phase in a micro-fluidic chip to obtain a bacillus subtilis microgel capsule oil phase suspension; and collecting the suspension of the oil phase of the capsule, standing, collecting the precipitation of the bacillus subtilis hydrogel capsule, cleaning twice by using a phosphate buffer solution, and suspending in the phosphate buffer solution to obtain the suspension of the bacillus subtilis microgel capsule phosphate. Wherein the diameter of the bacillus subtilis microcapsule obtained in the step is 150-200 mu m.
Example 2 design of multichannel microfluidic chip for bacillus subtilis microcapsules
Firstly, designing a specific structure of a multi-channel microfluidic chip; the chip bottom plate is made of glass materials, and each channel is made of polydimethoxysiloxane, polyacrylic acid and the like. The specific structural design is as follows: the multi-channel microfluidic chip is arranged into three main channels, including: a left storage channel 1, a middle detection channel 2 and a right storage channel 1, wherein the two storage channels 1 are 40mm long and 25mm wide; the length of the detection channel 3 is 40mm, the width of the detection channel is 50mm, and the specific sizes of the detection channel 2 and the storage channel 1 are ensured to be capable of accommodating enough liquid and optical fiber probes; the height of the reservoir channel 1 and the detection channel 2 is 800. mu.m. The storage channel 1 is communicated with the detection channel 2 through a thin connecting channel 3, the height of the connecting channel 3 is lower than that of the storage channel 1 and the detection channel 2, and the height can be 50 μm, so that bacterial microcapsules 9 (with the diameter of 150-200 μm) can be effectively prevented from diffusing from the storage channels 1 on the left side and the right side to the detection channel 2 in the middle. In addition, the multi-channel micro-fluidic chip also comprises a sample feeding channel 5, and an environmental water sample enters the detection channel 2 from the sample feeding channel 5 through the storage channel 1 for detection.
Then, the bacillus subtilis microgel capsule phosphate suspension prepared in the embodiment 1 is injected into the storage channel 1 and stored at low temperature of 4 ℃ to obtain the multi-channel microfluidic chip containing the bacillus subtilis capsule.
EXAMPLE 3 design of holey fiber Probe 6 and mounting of detection device
Firstly, cleaning and soaking a commercially available porous optical fiber by using 0.1Mol NaOH for 2 hours, then sucking modification sol under the condition of 0.08MPa, standing for 2 hours at room temperature, finishing modification, cleaning by using clear water, and drying for later use. The preparation method of the modified sol comprises the following steps: 1mg of [ Ru (dpp)3]Cl2To 7.5mL of a mixed solution (22.7% ethyl orthosilicate, 22.7% Octyl-triEOS, 50% ethanol, 8% HCl).
And then, taking out the multi-channel microfluidic chip, activating for 16h, inserting one end of the modified porous optical fiber probe 4 into the detection channel 2, and connecting the unmodified end with the fluorescence detector 7 to read and store a numerical value. Wherein, the tail end of the detection channel, namely the insertion end of the porous optical fiber probe, is in a film closed state before insertion. The porous optical fiber probe 4 can be repeatedly inserted into the middle detection channel 2 of the bacillus subtilis microcapsule chip for detection.
Finally, the LED light sources 6 required for detection are arranged vertically above the multi-channel microfluidic chip.
Example 4 detection of environmental Water samples
First, 100. mu.L of an ambient water sample is aspirated using the syringe 8, and the storage channel 1 and the detection channel 2 are filled. Then, the LED light source 6 and the fluorescence detector 7 are turned on to start recording the values. The specific principle is as follows: the dissolved oxygen in water passes through the bacillus subtilis microcapsule and [ Ru (dpp) on the porous fiber probe 43]Cl2Reacting, quenching fluorescence, converting a dissolved oxygen signal in the solution into a fluorescence signal through a coating of the porous optical fiber probe 4, and transmitting the fluorescence signal into a fluorescence detector 7 through a porous optical fiber; and (3) gradually consuming the dissolved oxygen by the bacillus subtilis in the microcapsule, gradually recovering the fluorescence, improving the fluorescence intensity, transmitting the fluorescence data to the fluorescence detector 7 through the porous optical fiber probe 4, outputting a signal by the fluorescence detector 7, and recording the change of the concentration of the dissolved oxygen to finish the detection.
The embodiment of the invention can quickly finish the detection of the biochemical oxygen demand in the environmental water sample, the sampling is quick, the result can be obtained within 7 minutes, and the detection period of the existing sensor is mostly 15-30 min. The invention has stable and reliable detection result, simple and quick operation process and avoids the error of excessive manual operation. The detection equipment is simple, portable, capable of implementing detection and capable of being widely applied to various complex environments.
The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to practitioners skilled in this art. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
Claims (9)
1. A micro-fluidic biochemical oxygen demand detection device based on bacterial microcapsules is characterized by comprising: a multi-channel micro-fluidic chip, a porous optical fiber probe, a fluorescence detector, and a light source, wherein,
the multi-channel microfluidic chip comprises: the device comprises a sample feeding channel, at least two storage channels and a detection channel; the sample introduction channel is provided with a plurality of branches, and one branch is communicated with one storage channel; the detection channel is communicated with each storage channel through a plurality of connecting channels; the heights of the storage channel and the detection channel are both higher than that of the connecting channel to form a liquid tension valve, and bacterial microcapsules are stored in the storage channel; the size of the connecting channel is smaller than that of the bacterial microcapsule; the bacterial microcapsule is prepared by a flow focusing method of a micro-fluidic chip;
one end of the porous optical fiber probe is inserted into the detection channel, and the other end of the porous optical fiber probe is connected with the fluorescence detector; wherein, the porous optical fiber probe inserted into the detection channel is modified with oxygen sensitive fluorescent indicator [ Ru (dpp)3]Cl2；
The light source is positioned above the multi-channel micro-fluidic chip.
2. The microfluidic biochemical oxygen demand detection device according to claim 1, wherein the storage channel and the detection channel are both straight channels; the storage channels are arranged side by side at intervals.
3. The micro-fluidic bod detection device of claim 2, wherein there are two storage channels, one detection channel, and two storage channels are respectively located at two sides of the detection channel; the connecting channel is respectively perpendicular to the storage channel and the detection channel.
4. The micro-fluidic biochemical oxygen demand detection device according to any one of claims 1 to 3, wherein the width of the storage channel is 2 to 200mm, the length is 2 to 200mm, and the height is 1 to 1500 μm; the width of the detection channel is 2-200 mm, the length is 2-200 mm, and the height is 1-1500 mu m; the height of the connecting channel is 1-100 mu m.
5. The micro-fluidic biochemical oxygen demand detection device according to claim 1, wherein the bacterial species in the bacterial microcapsule is one of a group consisting of a filamentous bacillus, a pseudomonas and a clostridium.
6. The micro-fluidic biochemical oxygen demand detection device according to claim 1, wherein the diameter of the bacterial microcapsule is 30-200 μm.
7. A micro-fluidic biochemical oxygen demand detection method based on bacterial microcapsules is characterized by comprising the following steps:
installing a bod microfluidic device according to any one of claims 1-6;
and injecting a sample to be detected into a sample introduction channel of the multi-channel micro-fluidic chip, enabling the sample to be detected to enter the detection channel through the storage channel and to be in contact with the porous optical fiber probe in the detection channel, and outputting a detection result through the fluorescence detector.
8. The microfluidic biochemical oxygen demand detection method according to claim 7, wherein the step of installing the microfluidic biochemical oxygen demand device comprises:
preparing a multi-channel micro-fluidic chip;
preparing bacterial microcapsules;
injecting the bacterial microcapsules into a storage channel of the multi-channel micro-fluidic chip, and storing the multi-channel micro-fluidic chip at a low temperature of 1-10 ℃;
preparing a porous optical fiber probe;
taking out the multi-channel micro-fluidic chip, activating for 8-24 h, inserting one end of the porous optical fiber probe into a detection channel of the multi-channel micro-fluidic chip, and connecting the other end of the porous optical fiber probe with a fluorescence detector;
and arranging a light source above the multi-channel micro-fluidic chip.
9. The microfluidic biochemical oxygen demand detection method according to claim 8, wherein the bacterial microcapsule is prepared by a flow focusing method of a microfluidic chip.
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