A radon detection device, an ECL detection system and applications thereof

Abstract

The present application relates to a kind of radon detection device, ECL detection system and its application, ECL detection system includes radon detection device, radon detection device includes by working electrode, counter electrode and reference electrode constitute three electrode system, the electrolyte of three electrode system contains ruthenium bipyridine salt solution, and working electrode contains specific recognition radon gas aptamer and DNA molecule complementary with aptamer part;Wherein, aptamer is fixed on working electrode, and DNA molecule complementary with aptamer part is modified with amino group.The present application solves the defects of prior art in selectivity, sensitivity, detection time and the like, by electrochemiluminescence (ECL) detection and imaging technology, provide a kind of radon detection device and matching detection system with high selectivity, ultra-low detection limit, fast and the like advantages.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of substance detection, and particularly relates to a radon detection device, an ECL detection system and application thereof. BACKGROUND

[0002] Radon (Rn) is derived from the natural decay of some natural radioactive substances such as Ra, and is a colorless, odorless and inert radioactive gas widely existing in the environment. It is identified by the World Health Organization (WHO) as the second largest lung cancer pathogen after smoking. Rn and its decay products have been listed as carcinogens by the International Agency for Research on Cancer (IARC). Although the half-life of Rn is only 3.8 days, the progeny is still radioactive, such as 210 Pb with a half-life of 22.3 years can be mixed in dust and inhaled into the body to cause continuous damage. The final product of the decay of Rn is 206 Pb, which is still biotoxic. The WHO standard and the national standard (GB-T16146-2015) of China both stipulate that the Rn concentration of newly built houses should be lower than 100 Bq / m 3 . Since the density of Rn (9.73 kg / m 3 ) is much higher than that of air (1.217 kg / m 3 ), it is easy to accumulate in closed places such as basements, and its concentration can even reach 300 Bq / m 3 or more.

[0003] The current Rn detection methods include α particle or α energy spectrum detection of radon and its daughter and chemical probe detection method. The active carbon box method and track etching method stipulated in the national standard all belong to α particle or α energy spectrum detection, and their advantages lie in low detection limit, which can reach 5-6 Bq / m 3 . However, if there are other substances that can undergo α decay in the environment, they will have obvious interference. At the same time, the radon content in different environments differs greatly, and the radon content in some closed spaces can even reach 500 Bq / m 3 . However, the concentration in some well-ventilated indoor spaces is only 1-10 Bq / m 3 . Therefore, if real-time monitoring of radon in the environment is to be achieved, the detection limit is still not low enough. The chemical probe is mainly a fluorescence and colorimetric probe designed for the stable radon decay daughter 210 Pb, and the selectivity is relatively good compared with α particle or α energy spectrum detection, but the detection limit is a significant defect. At the same time, the detection time is also a common defect of the two types of detection methods, and the detection time is generally 1 day to 3 months, which cannot realize real-time and rapid detection of radon in the environment. SUMMARY

[0004] To solve the above technical problems, the present application considers the defects of the prior art in selectivity, sensitivity, detection time and the like, and provides a radon detection device and a matching detection system with high selectivity, ultra-low detection limit and fast detection speed by using electrochemiluminescence (ECL) detection and imaging technology.

[0005] The first object of the present application is to provide a radon detection device, which comprises a three-electrode system composed of a working electrode, a counter electrode and a reference electrode, and a salt solution of ruthenium bipyridine in an electrolyte of the three-electrode system, wherein the working electrode contains an aptamer specifically recognizing radon and a DNA molecule partially complementary to the aptamer; wherein the aptamer is fixed on the working electrode, and the DNA molecule partially complementary to the aptamer is modified with an amino group.

[0006] Further, the aptamer is fixed on the working electrode through an Au-S bond.

[0007] Further, the nucleotide sequence of the aptamer is as follows:

[0008] GGTTGGTGTGGTTGGTTGGTGTGGTTGGTTGGTGTGGTTGGTTGGTGT GGTTGG.

[0009] Further, the nucleotide sequence of the DNA molecule partially complementary to the aptamer is CAACC.

[0010] Further, the DNA molecule partially complementary to the aptamer is modified with an amino group at both ends.

[0011] Further, the target substance is adsorbed by activated carbon after acid washing, and after elution with acid, the supernatant is taken to treat the working electrode, and then detection is performed.

[0012] The detection principle of the radon detection device prepared by the present application is as follows: if the environment contains the target substance radon, it will specifically bind to the aptamer on the detection device, so that the DNA molecule complementary to the aptamer on the working electrode is freed, and the single-stranded DNA molecule modified with an amino group undergoes the following reactions in the electrode system:

[0013] NH2CH2-ssDNA– e - → ·+ NH2CH2-ssDNA (1)

[0014] ·+ NH2CH2-ssDNA– H + → ·+ NH2CH - -ssDNA (2)

[0015] Ru(bpy)3 2+ – e - → Ru(bpy)3 3+ (3)

[0016] Ru(bpy)3 3+ + ·+ NH2CH - –ssDNA→ Ru(bpy)3 2+* + + NH2=CH-ssDNA (4)

[0017] Ru(bpy)3 2+* → Ru(bpy)3 2+ + hv (5)

[0018] A second object of the present application is to provide an ECL detection system for radon, comprising the radon detection device as described above.

[0019] Further, the ECL detection system further comprises:

[0020] a photoelectric conversion amplification device, wherein a photomultiplier tube is arranged in the photoelectric conversion amplification device, the photomultiplier tube is located above the radon detection device, and an incident window is located on a side close to the radon detection device;

[0021] a darkroom, wherein the radon detection device and the photoelectric conversion amplification device are located in the darkroom.

[0022] Further, an opening is arranged on a side of the radon detection device close to the photomultiplier tube, and a light-transmitting component is arranged on a side of the photoelectric conversion amplification device close to the incident window.

[0023] Further, the working electrode is arranged in a liftable manner.

[0024] Further, the ECL detection system further comprises a data processing device, which receives and processes an output signal of the photomultiplier tube.

[0025] Further, the ECL detection system further comprises a control device, which controls the three-electrode system and the opening and closing of the photomultiplier tube.

[0026] A third object of the present application is to provide an application of the radon detection device or the ECL detection system as described above in the detection of radon, lead or elements decaying into lead.

[0027] Further, the elements decaying into lead include but are not limited to U238, Th232, Th230, Ra226, Ac228 and other actinides.

[0028] Further, the radon detection device can be applied to an imaging method, and the content of the detected substance is detected according to the brightness of the image.

[0029] Further, when the ECL detection system is applied, the ECL signal and the coordinate system of the detected target are established, and the detected substance is detected by data processing of the output electric signal.

[0030] By the above scheme, the present application has at least the following advantages:

[0031] (1) The present application realizes electrochemical luminescence through the competition of the partial complementary sequence of the aptamer and the target substance, the combination of the ruthenium solution and the electrode system, and the application of the ECL technology greatly improves the sensitivity and selectivity of the radon detection of the ECL detection device, and significantly shortens the radon detection time, and realizes real-time detection.

[0032] (2) The present application improves the traditional downward lighting detection system, designs an upward lighting method, solves the problems of limited detection electrode and difficulty in avoiding light in the traditional detection system, and at the same time, the ECL detection system and the device are matched, and the radon detection efficiency is maximized.

[0033] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, and the content of the specification can be implemented, the following is the preferred embodiment of the present application and the detailed description of the drawings as follows. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to make the content of the present application more easily understood, the following is a further detailed description of the present application according to the specific embodiments of the present application and in combination with the drawings.

[0035] Figure 1 The flowchart of the radon detection device is shown in the figure;

[0036] Figure 2 The lead detection result of the radon detection device is shown in the figure; wherein, (A) is the device physical map; (B) is the ECL signal of the device after being treated by lead ions; (C) is the lead detection linearity; (D) is the selectivity experiment, the interference ions (K + , Ca 2+ , Na + , Mg 2+ , Sr 2+ , Hg 2+ , Fe 3 + , Cd 2+ , Cs + , Ag + , Cu 2+ , each 1 mg / L, lead concentration 1 μg / L, PMT = 330 V, scan speed: 100 mV / s;

[0037] Figure 3 The radon detection results are shown in Figure 1, wherein (A) is the principle of radon decay; (B) is the ECL signal of the device corresponding to different radon concentrations; and (C) is the linearity of radon detection, PMT = 330 V, and the scanning speed is 100 mV / s.

[0038] Figure 4 The detection results of the actual samples by the detection device and the ECL detection system are shown in Figure 2, wherein (A) is the ECL imaging photo of radon; (B) is the ECL intensity of different actual samples; and (C) is the radon concentration measured from different samples.

[0039] Figure 5 The physical diagram of the ECL detection system is shown in Figure 3, wherein (A) is a customized sample cell; (B) is the upper light darkroom and controller; and (C) is the actual application photo; a. counter electrode; b. reference electrode, c. working electrode, d. sample cell, e. photomultiplier tube, f. control device, g. lock; h. darkroom.

[0040] Figure 6 The structure and principle diagram of the ECL detection system are shown in Figure 4, wherein (A) is the principle diagram of the controller; and (B) is the structure diagram of the upper light darkroom. DETAILED DESCRIPTION

[0041] The present application will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it, but the embodiments are not intended to limit the present application.

[0042] Embodiment 1

[0043] (1) Preparation of radon detection device

[0044] Into a 10 mL centrifuge tube, 10 μL of gold nanoparticle citric acid solution (5 μg / mL), 20 μL of tris (2-carboxyethyl) phosphine (TCEP) solution (0.01 M), and 70 μL of TBE buffer were added, and then 100 μL of prepared 12.5 μM HS-ssDNA was added after uniform mixing. Subsequently, 1.8 mL of n-butanol was added, and after slight shaking and centrifugation, the water phase was diluted to 200 μL, and then modified on the ITO conductive glass electrode with array (2.5 μL / well). After drying, 100 μL of NH2-ssDNA solution (25 μM) was continuously modified on the ITO electrode (2.5 μL / well). The schematic diagram of the preparation of the detection device is shown in Figure 5. Figure 1 .

[0045] The DNA sequence is as follows:

[0046] NH2-ssDNA (5'-3'): CAACC, modification group: 5'-NH2C6H 12- 3'-NH2C6H 12 -

[0047] HS-ssDNA (5'-3'):

[0048] GGTTGGTGTGGTTGGTTGGTGTGGTTGGTTGGTGTGGTTGGTTGG TGTGGTTGG, modifying group: 5'-HSC6H 12 -

[0049] (2) Adsorption and elution of radon

[0050] The coconut shell carbon was sonicated for 10 minutes, 1M nitric acid was added, stirred for 30 minutes, and then frozen dried and placed in an adsorption box. Different concentrations of radon samples were taken by adjusting the radon concentration in the radon chamber using the adsorption box. After 4 hours of cumulative adsorption, the coconut shell carbon was taken out, eluted with 1M nitric acid for 40 minutes, filtered, and the supernatant was taken.

[0051] (3) Radon detection and imaging

[0052] The eluted liquid was diluted 20 times and modified in the array of the device (2.5 μL / well), and after 10 minutes, it was washed with deionized water. 1 mL of 10 mM tris (bipyridyl) ruthenium chloride solution was diluted to 10 mL with 0.1M pH 7.4 PBS and placed in an electrolytic cell for ECL detection or imaging. The platinum wire electrode was the counter electrode, and the Ag / AgCl was the reference electrode.

[0053] Example 2

[0054] The matching ECL detection system is shown in Figures 5-6 . As shown in Figure 5 A, the system uses a custom sample cell. Figure 5 The upper light darkroom and controller newly designed for the radon detection device are shown in Figure 5 C, which can realize ECL detection after being connected to an electrochemical workstation. Figure 6 The structure of the darkroom and controller is shown in

[0055] The physical diagram of the ECL detection system is shown in Figure 5 . The system mainly includes a sample cell (d), a photomultiplier tube (e), and a darkroom (h). The sample cell is provided with a detection device, which is composed of a counter electrode (a), a reference electrode (b), and a working electrode (c). In order to avoid the influence of environmental light sources on the hv generated by the detection device, the sample cell and the photomultiplier tube are jointly arranged in the darkroom, and a lock (g) is provided.

[0056] The control device (f) is used to control the opening and closing of the ECL system. Specifically, it includes a high-voltage module and a low-voltage module. The high-voltage module is used to control the opening and closing of the photomultiplier tube, and the low-voltage module is used to control the opening and closing of the detection device.

[0057] Data processing device ( Figure 5 C), which is connected to a photomultiplier tube, receives the electrical signal output from the photomultiplier tube and displays the signal as a curve.

[0058] The working principle of this ECL system is as follows: Figure 6 Primarily, this includes electrochemiluminescence systems and photoelectric conversion systems (…). Figure 6 (B) In the electrochemiluminescence system, light emission is detected by a three-electrode system. The light signal passes through the light-transmitting component (glass in this invention) at the entrance window of the photomultiplier tube, reaches the photomultiplier tube, and is received by it. The photomultiplier tube can convert weak light signals into easily measurable electrical signals. In this invention, the photomultiplier tube includes a signal amplification module, a light source filtering module, and a photoelectric conversion module. The light emitted by the detection device is amplified by the signal amplification module, reaches the light source filtering module for wavelength selection, and obtains a light source with a wavelength of 620nm. This light then enters the photoelectric conversion module, and finally outputs an electrical signal.

[0059] Example 3

[0060] (1) Characterization of radon detection devices: finished products and lead testing

[0061] Modified detection devices such as Figure 2 As shown in A, Figure 2 B represents the device's detection limit for lead ions, which is 86 fM. Figure 2 C). Figure 2 D shows some of the ions that are predominantly present in the environment (K). + Ca 2+ Na + Mg 2+ 、Sr 2+ ) and some heavy metal ions (Hg 2+ Fe 3+ Cd 2+ Cs + Ag + Cu 2+ None of them significantly interfered with the device, demonstrating its good selectivity.

[0062] (2) Radon detection characterization of detection devices and ECL system

[0063] like Figure 3 A. The principle of radon detection is to detect its decay products. 210Pb. After 4h adsorption of radon on coconut shell activated carbon, the device can be treated by washing with 1M HNO3 for 40min. The ECL signal of the device is quenched with the increase of radon concentration Figure 3 B) with a detection limit of 0.87Bq / m 3 ( Figure 3 C), which is more than one order of magnitude lower than the prior art and the detection time is less than 5h, much faster than the detection method reported in the literature and the national standard, which can be used for real-time monitoring of trace radon in the environment.

[0064] (3) Radon imaging monitoring and actual sample detection

[0065] For example Figure 4 A, samples with different radon concentrations can make the ECL imaging show a quenching trend. Sample 1 was collected from a well-ventilated basement of Suzhou University, Suzhou Medical College, which had a significant quenching relative to the blank. When the radon concentration exceeds the national standard or WHO standard, it can be compared and judged by the naked eye. Figure 4 B and C show that the radon concentration of sample 1 is 6.5Bq / m 3 , Figure 4 The brightness of sample 1 in A is similar to 5Bq / m 3 , which proves the feasibility of imaging monitoring. Sample 2 was collected from a common classroom in the Dushu Lake campus of Suzhou University, with a radon concentration of 56.2Bq / m 3 , which is within the normal range of indoor radon concentration in Suzhou City (40-60Bq / m 3 ), which proves the practicability of the device.

[0066] Obviously, the above examples are only examples for clarity and do not limit the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, it is not necessary and impossible to exhaust all embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A radon detection device, characterized by: The radon detection device comprises a three-electrode system composed of a working electrode, a counter electrode and a reference electrode, and a solution of a salt of ruthenium bipyridine is contained in an electrolyte of the three-electrode system; the active carbon after acid washing is used to adsorb the target substance, and after the end of the adsorption, the active carbon is eluted with acid, and the supernatant is taken; after the working electrode is treated, the radon detection can be performed. The working electrode contains an aptamer specifically recognizing radon and a DNA molecule partially complementary to the aptamer; wherein the aptamer is fixed on the working electrode through an Au-S bond, and the DNA molecule partially complementary to the aptamer is modified with an amino group at both ends; The nucleotide sequence of the aptamer is: GGTTGGTGTGGTTGGTTGGTGTGGTTGGTTGGTGTGGTTGGTTGGTGTGGTTGG; The nucleotide sequence of the DNA molecule partially complementary to the aptamer is: CAACC.

2. An ECL detection system for radon, characterized by: The ECL detection system comprises the radon detection device of claim 1.

3. The ECL detection system of claim 2, wherein, The ECL detection system further comprises: A photoelectric conversion amplification device, wherein a photomultiplier tube is arranged in the photoelectric conversion amplification device, the photomultiplier tube is located above the radon detection device, and an incident window is located on a side close to the radon detection device; A darkroom, wherein the radon detection device and the photoelectric conversion amplification device are located in the darkroom.

4. The ECL detection system of claim 3, wherein: An opening is arranged on a side of the radon detection device close to the photomultiplier tube, and a light-transmitting component is arranged on a side of the photoelectric conversion amplification device close to the incident window.

5. The ECL detection system of claim 2, wherein: The radon detection device is arranged in a lifting manner.

6. Application of the radon detection device of claim 1 or the ECL detection system of any one of claims 2-5 in detection of radon, lead or an element decaying into lead.

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