Liquid drop microcavity device capable of being used for generating micro bar code and food detection method

Abstract

The invention discloses a droplet microcavity device capable of generating a micro bar code and a food detection method, the device comprises a multicolor droplet arranged on a sample, the sample is located in an emission light path of a pulse laser, an optical lens is arranged at an emission end of the pulse laser, a lens is arranged on the other side of the sample, the lens receives emission light of the sample, and the emission light of the sample is emitted by the optical lens. An optical filter and a spectrograph are sequentially arranged on the output side of the lens; the method comprises the following steps: selecting one of multi-color liquid drops, carrying out specific marking treatment, and adding into a food sample; the pulse laser emits pulse laser which is focused by the optical lens to irradiate the food sample, and emitted light of the liquid drops enters the spectrograph through the lens and the optical filter; the emission spectrum of the typical echo wall mode laser of the liquid drop is obtained; monitoring the laser signal change condition of the liquid drop in the spectrum; and determining the bit code of the liquid drop. According to the invention, the change of spectral characteristics and corresponding codes is caused by liquid drops, food detection is realized, and the detection is convenient and sensitive.

Description

Technical Field

[0001] The present invention belongs to the technical field of food detection, and in particular relates to a droplet micro-cavity device and a food detection method that can be used to generate a micro-barcode. Background Art

[0002] There are various methods to assess food authenticity and quality, such as mass spectrometry, DNA barcoding, isotope and element fingerprinting, and gas chromatography [Trends in Food Science & Technology, 2019, 85: 163-176]. However, the implementation of the above technologies relies on precision instruments, which are not only time-consuming and expensive to operate, but also usually require sample collection for analysis, which cannot meet the needs of consumers in daily life.

[0003] At present, the most widely used technology for identifying product authenticity in the market is to label the product by printing barcodes on the packaging. However, due to limiting factors such as limited data capacity, fragility, poor confidentiality and lack of interoperability, the information of printed barcodes is relatively easy to copy and misappropriate and can only provide static information, which cannot meet people's needs for food or drug authenticity and real-time status inspection.

[0004] With the rapid development of modern optical technology, optical microbarcodes based on microcavity lasers have attracted much attention due to their great potential in tracking, labeling, biological detection, cell labeling, information security and anti-counterfeiting [ACS Photonics, 2023, 10(5): 1202-1224]. Microcavity lasers have extremely narrow emission spectra, which provides good distinguishability and significantly increases the amount of encoded information. At the same time, microcavity lasers can extremely accurately and sensitively detect any physical, chemical or biological process that changes the refractive index or physical size or other optical properties of the laser (such as scattering, absorption and fluorescence). These properties provide new ideas for the development of optical microbarcode technology and food detection methods based on multicolor droplet microcavity lasers. Summary of the invention

[0005] The present invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a droplet micro-cavity device and a food detection method that can be used to generate a micro-barcode.

[0006] The technical solution of the present invention is: a droplet microcavity device and a food detection method that can be used to generate a microbarcode, including a multicolor droplet placed on a sample, the sample is located in the emission light path of a pulse laser, the emission end of the pulse laser is provided with an optical lens, the other side of the sample is provided with a lens, the lens receives the emission light of the sample, and the output side of the lens is provided with a filter for filtering and a receiving spectrometer in sequence.

[0007] Furthermore, the multi-color droplets are formed by respectively mixing four fluorescent materials into oil.

[0008] Furthermore, the multi-color droplets on the sample are droplets of different sizes.

[0009] Furthermore, the pulse laser emits pulse lasers of different wavelengths which are focused by an optical lens and irradiated onto the droplets. The fluorescence generated by the dye in the droplets being excited is totally internally reflected and amplified at the interface between the droplet resonant cavity and the surrounding sample environment to be tested, ultimately generating whispering gallery mode laser emission.

[0010] Furthermore, the spectrometer reads the emission spectrum and identifies the type of dye contained in the droplets and the size of the droplets, obtains information about the droplets in the sample, and generates a barcode.

[0011] Furthermore, the emission bands of the four fluorescent materials in the multi-color droplets are different.

[0012] Furthermore, the multi-color droplets determine the type of dye by emitting a laser wavelength band, and each droplet with a specific dye and size corresponds to a position in the barcode bit string. When the droplet exists in the food sample, it is encoded as 1, and when it does not exist, it is encoded as 0; the encoding of the food sample is achieved by controlling whether the droplets are added to the food sample or not.

[0013] Furthermore, a microscope objective lens and a CCD camera are placed under the sample, and a halogen lamp is used as an illumination light source to monitor the condition of the droplets in the sample in real time.

[0014] A droplet micro-chamber device and a food detection method for generating a micro-barcode, comprising the following steps:

[0015] A. Select one of the multi-color droplets for specific labeling and add it to the food sample;

[0016] B. The pulse laser emits pulse laser which is focused by an optical lens to irradiate the food sample. The emitted light of the droplet enters the spectrometer through the lens and filter.

[0017] C. Obtain the emission spectrum of the typical whispering gallery mode laser of the droplet in the spectrometer;

[0018] D. Monitor the change of the laser signal of the droplet in the spectrum;

[0019] E. The laser signal disappears, and the bit position where the droplet is located is encoded as 0, otherwise it is encoded as 1.

[0020] The beneficial effects of the present invention are as follows:

[0021] The present invention proposes for the first time a new technology for whispering gallery mode spectral encoding of multi-color droplets, i.e., droplets containing several gain media with different absorption spectra. The droplet group, i.e., droplets of different sizes, is scanned by pump lasers of different wavelengths. The amount of information that can be encoded is huge, thus realizing the optical micro-barcode technology for verifying the authenticity of food.

[0022] The present invention selects natural / edible materials as emulsifiers for droplets, and specifically marks the droplet cavity occupying a specific coding bit position. Slight changes in food ingredients or their physical and chemical properties can cause changes in spectral characteristics and corresponding codes, thereby achieving highly sensitive detection of food quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of a bar code encoding device of the present invention;

[0024] Figure 2 It is a schematic diagram of the microfluidic technology of the present invention;

[0025] Figure 3 is an example diagram of the coded droplet of the present invention;

[0026] Figure 4 It is a schematic diagram of the measuring method in the present invention;

[0027] in:

[0028] 1 Pulse laser 2 Optical lens

[0029] 3 microscope objective 4 multicolor droplets

[0030] 5 samples 6 lenses

[0031] 7 filters 8 spectrometer

[0032] 9CCD camera 10External phase solution channel

[0033] 11 internal phase solution channel 12 droplets

[0034] 13 Specific labeling of droplets 14 First emission spectrum

[0035] 15 Second emission spectrum. DETAILED DESCRIPTION

[0036] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and embodiments:

[0037] like Figures 1 to 4As shown, a droplet microcavity device and a food detection method that can be used to generate a microbarcode include a multicolor droplet 4 placed on a sample 5, wherein the sample 5 is located in the emission light path of a pulse laser 1, an optical lens 2 is provided at the emission end of the pulse laser 1, a lens 6 is provided on the other side of the sample 5, the lens 6 receives the emission light of the sample 5, and a filter 7 for filtering and a spectrometer 8 for receiving are provided in sequence on the output side of the lens 6.

[0038] The multi-color droplets 4 are formed by mixing four fluorescent materials into oil respectively.

[0039] The multi-color droplets 4 on the sample 5 are droplets of different sizes.

[0040] The pulse laser 1 emits pulse lasers of different wavelengths which are focused by the optical lens 2 and irradiated onto the droplets. The fluorescence generated by the dye in the droplets being excited is totally internally reflected and amplified at the interface between the droplet resonant cavity and the surrounding sample environment to be tested, and finally generates whispering gallery mode laser emission.

[0041] The spectrometer 8 reads the emission spectrum and identifies the type of dye contained in the droplets and the size of the droplets, obtains the information of the droplets in the sample, and generates a barcode.

[0042] The four fluorescent materials in the multi-color droplet 4 have different emission wavelength bands.

[0043] The multicolor droplets 4 determine the type of dye by emitting a laser wavelength band. Each droplet with a specific dye and size corresponds to a position in the barcode bit string. When the droplet exists in the food sample, it is encoded as 1, and when it does not exist, it is encoded as 0. The coding of the food sample is achieved by controlling whether the droplet is added to the food sample or not.

[0044] A microscope objective lens 3 and a CCD camera 9 are placed under the sample 5 , and a halogen lamp is used as an illumination light source to monitor the conditions of the droplets in the sample 5 in real time.

[0045] Specifically, the components in the multi-color droplet 4 are as follows:

[0046] Chlorophyll a excitation band is 430-450nm, and the emission band is 670-680nm;

[0047] Chlorophyll b excitation band 450-470nm, emission band 650-660nm;

[0048] Phycocyanin excitation band 620-630nm, emission band 640-650nm;

[0049] The excitation band of carminic acid is 500-550nm, and the emission band is 590-610nm;

[0050] The oil is cinnamon oil.

[0051] Specifically, multi-color droplets 4 of different sizes are all prepared by a droplet generator, with diameters of 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, and 80 μm, respectively. An emulsifier is added to the external phase solution to prevent the droplets from dissolving into each other, thereby forming stable droplets.

[0052] Specifically, four edible fluorescent dyes and six different sizes of droplets are used to encode a total of 24 bits of information. The sample is encoded by controlling the droplet corresponding to the code 1 to be added to the food sample.

[0053] Specifically, the emulsifier is polysorbate.

[0054] Specifically, the external phase solution is deionized water.

[0055] Specifically, the bandpass wavelength of the filter 7 is 550-700 nm, which includes the emission wavelengths of the four dyes.

[0056] Specifically, the pulse laser is a pumped OPO pulse laser with an emission wavelength ranging from 400 to 700 nm.

[0057] Specifically, the spectral resolution of the spectrometer 8 is 0.02 nm, and the wavelength measurement range is 550-700 nm.

[0058] Specifically, the sample 5 is a transparent solution.

[0059] As an implementation mode, the first 23 bits are selected as the date code of the food, and the corresponding date is encoded according to the binary encoding rules, the 1st to 14th bits are used as the bit string of the year, the 15th to 18th bits are used as the bit string of the month, and the 19th to 23rd bits are used as the bit string of the day, for example, 00011111101000110011111 (i.e., December 31, 2024) is selected. The 24th bit is used as the barcode bit string of the specific marker, and the specific marker droplet (12) as 1 is added to the sample.

[0060] Laser 1 emits pulsed lasers of different wavelengths, which are focused by optical lens 3 and sequentially illuminate multi-color droplets 4. The emission light of droplets 12 is focused by lens 6 and filter 7 and enters spectrometer 8. Information about droplets in the sample is obtained based on the emission spectrum to generate a barcode.

[0061] A droplet micro-chamber device and a food detection method for generating a micro-barcode, comprising the following steps:

[0062] A. Select one of the multi-color droplets 4 for specific labeling and add it to the food sample 5;

[0063] B. The pulse laser 1 emits pulse laser which is focused by the optical lens 2 to irradiate the food sample, and the emission light of the droplet enters the spectrometer 8 through the lens 6 and the filter 7;

[0064] C. Obtaining the emission spectrum of the typical whispering gallery mode laser of the droplet in the spectrometer 8;

[0065] D. Monitor the change of the laser signal of the droplet in the spectrum;

[0066] E. The laser signal disappears, and the bit position where the droplet is located is encoded as 0, otherwise it is encoded as 1.

[0067] Specifically, in step A, a specific labeling droplet 13 is selected for specific labeling treatment.

[0068] As an embodiment, pectin is selected as an emulsifier for droplets for specific labeling.

[0069] For the above 23-bit barcode, the detection principle is as follows:

[0070] First, determine the encoded information and convert it into a 23-bit binary number;

[0071] Then, the droplet corresponding to the bit value of 1 is added to the sample;

[0072] Then, the sample 5 is scanned by a pulsed laser 1 under the observation of a microscope objective 3, and the emitted light enters a spectrometer 8 through a lens 6 and a filter 7;

[0073] Then, the whispering gallery mode laser spectrum is obtained on the spectrometer 8;

[0074] Then, the size of the droplets and the type of dye in the sample are read through emission spectroscopy;

[0075] Finally, the corresponding bit of the read droplet is encoded as 1, and the remaining bits are encoded as 0.

[0076] Specifically, a typical whispering gallery mode laser spectrum related to the size of the droplet 12 is observed as follows Figure 4 As shown, the approximate size of the cavity can be determined according to the free spectral range values ​​of the first laser spectrum 14 and the second laser spectrum 15 in the spectrum.

[0077] Specifically, the preparation method of the droplet 12 is as follows:

[0078] g1. Add polysorbate to deionized water and stir at room temperature for 5 minutes to obtain a uniform mixed solution.

[0079] More specifically, the mass ratio of polysorbate to deionized water is 5 wt %.

[0080] g2. Four kinds of fluorescent dyes were added to the cinnamon oil solution respectively, and the mixed solution was ultrasonically treated for 1 hour using an ultrasonic cleaner to mix it evenly to obtain four internal phase solutions.

[0081] More specifically, the four fluorescent dyes are chlorophyll a, chlorophyll b, phycocyanin, and carminic acid, and their mass ratio to the cinnamon oil solution is 1 wt %.

[0082] g3. Using microfluidic devices, highly monodisperse fluorescent dye-doped droplets were generated, such as Figure 2 shown.

[0083] More specifically, the microfluidic device consists of four different single cross channels (flow focusing geometry), each channel comprising two inlets for the inner phase solution and the outer phase solution and an outlet for collecting droplets, and a pressure controller is used to precisely control the pressure of the two inlets.

[0084] More specifically, four single cross channels are used to prepare four types of droplets doped with different dyes.

[0085] More specifically, by setting the pressure of the inner phase solution channel 11 to 60 mbar and the pressure of the outer phase solution channel 10 to 25 mbar, using a single cross channel with a diameter of 95 μm and a nozzle size of 80 μm, droplets 12 with a diameter of 95 μm were produced. For any single cross channel, by changing the pressure of one or two inlets and using nozzles of different sizes, 23 monodisperse droplets with specific dyes and sizes were obtained as the first 23 bits.

[0086] More specifically, in step A, pectin is used as an emulsifier for the droplet 13 corresponding to the 24th bit position for specific labeling.

[0087] Specifically, in combination with pectin, a droplet 12 is selected for specific labeling and added to the food sample. The specific process is as follows:

[0088] First, pectin was added to deionized water and stirred at room temperature for 5 minutes to obtain a uniform mixed solution;

[0089] More specifically, the mass ratio of pectin to deionized water is 5 wt %;

[0090] Then, the carminic acid was added to the cinnamon oil solution, and the mixed solution was ultrasonically treated for 1 hour using an ultrasonic cleaner to mix it evenly to obtain an inner phase solution;

[0091] Finally, using a microfluidic device, highly monodisperse fluorescent dye-doped droplets 12 are produced, as shown in the attached Figure 3 shown.

[0092] More specifically, by setting the pressure of the inner phase solution channel 11 to 60 mbar and the pressure of the outer phase solution channel 10 to 25 mbar, using a single cross channel with a diameter of 95 μm and a nozzle size of 80 μm, a droplet 13 with a diameter of 80 μm corresponding to the 24th bit is generated.

[0093] Specifically, the obtained droplets 13 are placed into a food sample for testing the quality of the food.

[0094] The key principles of the detection method of the present invention are as follows:

[0095] When food spoils, molds will be produced, and these molds secrete pectinase that can specifically degrade pectin. As pectin gradually decomposes, the droplet emulsification system originally composed of it loses stability, that is, the droplets 13 undergo aggregation, forming an oil layer separated from the water phase, which does not meet the conditions for the generation of the echo gallery mode. When this change is monitored by the spectrometer 8, it is directly manifested as the disappearance of the laser signal corresponding to the droplet, which is a sensitive and accurate indicator of food spoilage.

[0096] As a more specific implementation

[0097] Whispering gallery mode lasers can be observed on the spectrometer 8, as shown in the attached Figure 4 shown.

[0098] When lasers of different wavelengths are used to irradiate droplets in the food sample, the corresponding emission spectrum of each dye-doped droplet is obtained by the spectrometer 8. By reading the first emission spectrum 14 and the second emission spectrum 15, the wavelength band of the excitation light generated by the excited droplet can be determined, and the type of the corresponding droplet doped dye can be deduced. Secondly, the size of the droplet can be determined according to the free spectrum range corresponding to each dye-doped droplet.

[0099] The free spectrum range corresponding to the whispering gallery optical resonance mode in droplet 4 satisfies the formula:

[0100]

[0101] Where FSR is the free spectral range, n eff is the effective refractive index of the resonance mode, that is, the refractive index of cinnamon oil, R is the radius of the microcavity, m is the angular quantum number, λ m is the resonance wavelength.

[0102] From the above formula, we can see that the free spectral range (FSR) depends on the radius of the droplet. Substituting the obtained FSR value into the formula, the size of the droplet can be obtained through the formula.

[0103] According to the above principle, the emission spectrum can be used to deduce individual droplets with specific dyes and sizes, and then the coded information of the food sample can be identified. In other words, multi-color droplets can be used to encode food information and detect food quality.

[0104] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A droplet micro-chamber device and a food detection method for generating a micro-barcode, characterized in that: The invention comprises a multicolor droplet (4) placed on a sample (5), wherein the sample (5) is located in the emission light path of a pulse laser (1), an optical lens (2) is arranged at the emission end of the pulse laser (1), a lens (6) is arranged on the other side of the sample (5), the lens (6) receives the emission light of the sample (5), and a filter (7) for filtering and a spectrometer (8) for receiving are arranged in sequence on the output side of the lens (6).

2. The droplet micro-chamber device and food detection method for generating micro-barcodes according to claim 1, characterized in that: The multi-color droplets (4) are formed by respectively mixing four fluorescent materials into oil.

3. The droplet micro-chamber device and food detection method for generating micro-barcodes according to claim 2, characterized in that: The multi-color droplets (4) on the sample (5) are droplets of different sizes.

4. The droplet micro-chamber device and food detection method for generating micro-barcodes according to claim 3, characterized in that: The pulse laser (1) emits pulse lasers of different wavelengths which are focused by an optical lens (2) and irradiated onto the droplets. The fluorescence generated by the dye in the droplets being excited is totally internally reflected and amplified at the interface between the droplet resonant cavity and the surrounding sample environment to be tested, and finally generates whispering gallery mode laser emission.

5. The droplet micro-chamber device and food detection method for generating micro-barcodes according to claim 4, characterized in that: The spectrometer (8) reads the emission spectrum and identifies the type of dye contained in the droplets and the size of the droplets, obtains information about the droplets in the sample, and generates a barcode.

6. The droplet micro-chamber device and food detection method for generating micro-barcodes according to claim 2, characterized in that: The four fluorescent materials in the multi-color droplet (4) have different emission wavelength bands.

7. The droplet micro-chamber device and food detection method for generating micro-barcodes according to claim 6, characterized in that: The multicolor droplets (4) determine the type of dye by emitting a wavelength band of laser light. Each droplet having a specific dye and size corresponds to a position in a barcode bit string. When the droplet exists in the food sample, it is coded as 1, and when it does not exist, it is coded as 0. The coding of the food sample is achieved by controlling whether the droplet is added to the food sample or not.

8. The droplet micro-chamber device and food detection method for generating micro-barcodes according to claim 1, characterized in that: A microscope objective lens (3) and a CCD camera (9) are placed under the sample (5), and a halogen lamp is used as an illumination light source to monitor the condition of the droplets in the sample (5) in real time.

9. A droplet micro-chamber device and a food detection method for generating a micro-barcode, characterized in that: The following steps are involved: A. selecting one of the multi-color droplets (4) for specific labeling and adding it to the food sample (5); B. The pulse laser (1) emits pulse laser light which is focused by the optical lens (2) to illuminate the food sample, and the emission light of the droplet enters the spectrometer (8) through the lens (6) and the filter (7); C. Obtaining the emission spectrum of the typical whispering gallery mode laser of the droplet in the spectrometer (8); D. Monitor the change of the laser signal of the droplet in the spectrum; E. The laser signal disappears, and the bit position where the droplet is located is encoded as 0, otherwise it is encoded as 1.

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