Method for simultaneously realizing OCT (Optical Coherence Tomography) enhancement and identification by using quantum dot particles
By preparing particles with the quantum dot core and shell, using their forward scattering effect and fluorescent identification functions, the problems of limited imaging depth and insufficient identification of the OCT system are solved, and the imaging depth enhancement and position identification are achieved simultaneously.
Patent Information
- Application Number
- CN202510372952.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2025-07-08
AI Technical Summary
The imaging depth of existing OCT systems is limited, and the identification of imaging enhancement and enhancement locations cannot be achieved simultaneously, resulting in problems of biocompatibility and enhancement inhomogeneity.
Particles with the quantum dot core bound to the shell are prepared, and the imaging depth is enhanced by dispersing or covering the detection object or surface by scattering or covering the imaging body with the forward scattering effect of the quantum dot particles, and the enhancement site is identified by fluorescence.
It has achieved the improvement of OCT imaging depth and the fluorescent marking of enhanced parts, which has the advantages of good biocompatibility, simple operation and low cost.
Smart Images
Figure CN120275346A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of optoelectronic technology, and particularly relates to a method for simultaneously realizing the enhancement and identification of optical coherence tomography (OCT) using quantum dot particles. Background Art
[0002] Quantum dots (QDs) are quasi-zero-dimensional materials, which are semiconductor nanostructures that confine excitons in three spatial directions. Their particle composition consists of a small number of atoms, so their particle size is usually very small, usually 1 - 20 nm. Size confinement causes the semiconductor energy band structure to transform from a macroscopically continuous energy band into a discrete and discontinuous energy level structure. Quantum dots have unique optical properties: their excitation spectra are broad and continuously distributed, while their emission spectra are narrow and symmetric. Quantum dots have adjustable sizes, adjustable emission colors, high photochemical stability, high fluorescence efficiency, high chromatographic purity, a wide color gamut, a long fluorescence lifetime, and many other excellent properties. Therefore, they have great application prospects in fields such as solar cells, light-emitting diodes, and life sciences. Currently, representative and widely studied quantum dots include: perovskite quantum dots, II-VI group quantum dots (such as CdSe, CdS, etc.), III-V group quantum dots (such as InP, InAs, etc.), I-III-VI group quantum dots (such as CuInS, AgInS), etc.
[0003] Although quantum dots have excellent optical properties and wide application prospects in many fields, their stability problems still greatly limit their use. Taking perovskite quantum dots as an example, due to the large specific surface area of perovskite quantum dots, they are extremely sensitive to the surrounding environment. Factors such as water and oxygen in the air can cause their structures to be damaged, resulting in severe quenching of their luminescence. Therefore, preparing a core-shell structure or coating can effectively improve their stability and luminescence performance. At the same time, further controlling their sizes through this means is also an important means for light enhancement.
[0004] Optical Coherence Tomography (OCT) is a major optical imaging modality in biomedical optics and medicine. It uses near-infrared light and the principle of optical interference for imaging. The light emitted by the light source is split into two beams. One beam is emitted onto the object to be measured (human tissue), and this beam is called the signal arm. The other beam goes to a reference mirror and is called the reference arm. Then the two optical signals reflected from the tissue (signal arm) and from the mirror are superimposed. When the lengths of the signal arm and the reference arm are the same, interference occurs. The optical signal reflected from the tissue shows different intensities according to the shape of the tissue. When it is superimposed with the reference optical signal reflected from the mirror, the signal is enhanced (increased interference) when the optical wave fixed points are the same, and the signal is weakened (reduced interference) when the optical wave fixed points are in opposite directions. The condition for forming interference is that the frequencies are the same and the phase difference is constant. Using the interference principle, OCT compares the standard light source with the reflected signal to enhance the single reflection and weaken the emission of scattered light. Since interference only occurs when the lengths of the signal arm and the reference arm are the same, changing the position of the mirror changes the length of the reference arm, and thus signals of tissues at different depths can be obtained. These optical signals are processed by a computer to obtain a tissue tomographic image. The scan generates a two-dimensional data set that represents the optical backscattering through the cross-section of the tissue. The image is represented as a false-color image or a grayscale image to visualize the internal organizational structure of the pathology. The three-dimensional volume data set is generated by acquiring consecutive cross-sectional images and scanning the incident light beam in a raster or other two-dimensional pattern.
[0005] OCT is a powerful medical imaging technology because it can perform optical detection on living bodies, that is, it can visualize the microstructure and pathology of tissues in real time and in situ without removing and processing specimens. One of the main problems faced by current traditional OCT systems is the imaging depth problem. Currently, the imaging depth of traditional OCT systems is on the order of several millimeters, which is quite different from detection means such as CT and ultrasound. How to obtain a larger imaging depth is a hot research topic in the field of OCT technology. At the same time, most of the current methods for depth enhancement are through algorithms and cannot show the enhanced position.
[0006] Existing related patents have proposed a method for improving the imaging depth of optical coherence tomography based on the forward scattering characteristics of scattering particles in an optical thin film. However, it still cannot identify the position of the enhanced part while enhancing, and there are problems of biocompatibility and uneven enhancement. Therefore, based on the proposed patents, improvements and optimizations are made to the enhancement method to simultaneously achieve better enhancement performance and identification of the enhanced part.
[0007] Mie scattering is an optical phenomenon and a type of scattering. Also known as "coarse-grained scattering" and "large-particle scattering". When the particle size is close to or larger than the wavelength of the incident light, the intensity of the scattered light is asymmetric in all directions, and most of the incident light is scattered along the forward direction, that is, forward enhancement. Summary of the Invention
[0008] The present invention prepares particles in which a light-emitting quantum dot core is combined with a shell, injects the particles into a detected object or covers the surface of the detected object. When performing OCT imaging, the core can emit fluorescence, and the particles enhance the forward scattering of the electromagnetic wave of OCT, while achieving the functions of improving the imaging depth and fluorescence labeling. This technology has the advantages of being harmless or substantially harmless to biological tissues, easy to operate, low cost, easy to observe, etc. It can be widely applied to various OCT imaging systems.
[0009] The technical solution of the present invention is a method for simultaneously realizing OCT enhancement and labeling using quantum dot particles, characterized in that the realization method includes the following steps:
[0010] (1) Prepare a quantum dot core so that the quantum dot core can emit visible light with a wavelength shorter than the OCT band for fluorescence labeling;
[0011] (2) By using a method of coating or forming a core-shell structure on the outer layer of the quantum dot in the particle core, regulate the size of the quantum dot particles to obtain quantum dot particles with a size close to the wavelength of the OCT detection light, wherein the band gap width of the coating material or the shell material should be greater than the band gap width of the quantum dot core;
[0012] (3) When performing OCT detection, disperse the quantum dot particles in the detected object or cover its surface, and utilize the forward scattering effect of the quantum dot particles with a size close to the detection light wavelength to achieve the effect of increasing the imaging depth; at the same time, the quantum dots in the particle core emit visible light fluorescence under the excitation light, and this fluorescence provides information in the visible light band outside the OCT band for the detected part, while realizing the enhancement of the OCT detection signal and the fluorescence labeling effect of the detected part.
[0013] In step (1), the preparation method can be a hydrothermal method, a thermal injection method, a one-pot method, a supersaturated crystallization method, an electrochemical method, etc.
[0014] In step (1), the prepared quantum dots can be perovskite (ABX3) quantum dots synthesized in the laboratory, where A is generally a metal cation, B is a divalent metal, and X is a halogen element, and their size is generally 8nm - 20nm; II-VI group cadmium-based quantum dots (such as CdSe / ZnS, etc.), and their size is generally 4nm - 10nm; I-III-VI group quantum dots (such as CuInS, CuGaS, AgGaS, etc.), and their size is generally 4nm - 9nm.
[0015] In step (2), the coating material can be a metal oxide, a non-metal oxide, a polymer, etc.; the shell material can be a sulfide, a selenide, etc.
[0016] In step (1), taking cesium lead bromide perovskite quantum dots as an example, the preparation method of the perovskite quantum dots can be as follows: Using the thermal injection method, first dissolve cesium carbonate and oleylamine in octadecene, heat to about 130 °C and keep warm in a nitrogen environment to obtain a cesium oleate precursor. In another reaction vessel, dissolve lead bromide material, oleic acid, and oleylamine in octadecene, and heat to about 150 °C in a nitrogen environment. Then use a long syringe to extract the previously prepared cesium oleate precursor and quickly inject it under an inert gas and high-temperature conditions. After reacting for 3 - 5 s, quickly cool it in ice water. After centrifugal washing, cesium lead bromide quantum dots are obtained. Under the condition of 140 °C - 180 °C, the central wavelength of the quantum dot emission spectrum is 510 nm - 550 nm, and the full width at half maximum is 25 nm - 30 nm. Under ultraviolet or blue light excitation, it can be used for fluorescence labeling during OCT.
[0017] The coating layer used for perovskite quantum dots can be polymers, non-metal oxides, metal-organic frameworks, etc. Taking silica as an example, the method of coating with silica is to dissolve the quantum dots prepared by the thermal injection method in 50 ml of n-hexane, ultrasonically oscillate to disperse it, and then add a small amount (30 - 100 μL) of 3-aminopropyltriethoxysilane (APTES) as a silicon source, and stir with a magnetic stirrer for 30 min or longer to obtain perovskite quantum dot particles. After centrifugal washing the obtained product with cyclohexane and ethyl acetate, disperse the quantum dot particle dispersion in a freezing environment, freeze and solidify it, then take it out, seal the bottle mouth with plastic wrap and pierce several small holes, and then place it in a freeze dryer to dry for about 2 h. Stop when it is observed that the dispersion has volatilized and the powder has completely precipitated, and SiO2-coated perovskite quantum dot particle powder can be obtained, which can be used for subsequent processing.
[0018] In step (1), the methods for controlling the size of the perovskite quantum dot particles are as follows: ① Adjust the amount of APTES added during coating from 30 μL - 100 μL. After stirring for the same time, the size of the obtained quantum dots is 700 nm - 1400 nm. ② Use 50 μL of APTES to change the coating time from 30 min - 90 min, and the size of the obtained quantum dot particles is 700 nm - 1900 nm.
[0019] In step (1), the II-VI group quantum dots can be CdSe, CdS, etc. The preparation methods can be solvothermal method, thermal injection method, supersaturated crystallization method, etc. The heterojunction shell can be ZnSe, ZnS, CdS, etc. Taking the preparation of CdSe / ZnS quantum dot particles by the three-phase hydrothermal method as an example, when preparing CdSe / ZnS, oleic acid and ethanol added to the reaction system are the liquid phase (L), sodium oleate is the solid phase (S), and the aqueous solution containing metal and ethanol are the solution phase (S), forming an LSS three-phase system. Using cadmium acetate as the cadmium source and selenium powder as the selenium source, after the ratio is completed at room temperature, it is transferred to a hydrothermal synthesis reaction kettle and reacted at 150 °C for 8 hours to obtain quantum dots. After the obtained quantum dots are dissolved again, zinc acetate and sodium sulfide are weighed respectively as the Zn source and S source, and are successively added to the quantum dot dispersion after the reaction, and continuous stirring is carried out during this process. Then it is transferred to a hydrothermal synthesis reaction kettle and reacted at 180 °C for 10 hours to obtain the reaction product. The precipitate of the product is taken, added with cyclohexane for dispersion and ultrasonic treatment, and a certain amount of ethanol is added. After centrifugal separation for many times, CdSe / ZnS quantum dot particles are obtained. The sample is dispersed in cyclohexane, and the measured spectral center wavelength is 590 nm, and the full width at half maximum is about 48 nm. It presents red under ultraviolet light excitation and can be used for fluorescence labeling during OCT. When the temperature is set at 140 °C - 200 °C during nucleation, the center wavelengths of quantum dot particles of different sizes are 620 - 680 nm, all in the red light range, and can be used for visible light labeling.
[0020] The obtained CdSe / ZnS quantum dot particle dispersion is placed in a freezing environment and frozen until solidified, then taken out, the bottle mouth is sealed with plastic wrap and several small holes are pricked, and then placed in a freeze dryer for drying for about 2 h. Stop when it is observed that the dispersion has volatilized and the powder has completely precipitated, and CdSe / ZnS quantum dot particle powder can be obtained, which can be used for subsequent processing.
[0021] In step (1), taking CdSe / ZnS quantum dot particles as an example, the size control methods are as follows: ① Adjust the reactant concentration when growing the heterojunction shell. After increasing the concentration, the size of the obtained quantum dot particles can reach 1000 nm - 1300 nm. ② Change the growth time of the heterojunction shell. When the growth time is increased to 15 h and above, the size of the obtained quantum dot particles can reach 900 nm - 1400 nm.
[0022] In step (1), the I-III-VI group quantum dots can be CuInS2, AgInS2, CuGaS2, CuGaSe2, and their synthesis methods can be thermal solvent method, thermal injection method, etc. Taking the preparation of AgGaS2 / ZnS quantum dot particles as an example, the preparation method is as follows: silver iodide is used as the Ag source, gallium acetylacetonate is used as the Ga source, and sulfur powder is used as the S source; dodecanethiol serves as the reaction solvent and provides the sulfur source at the same time. The precursor uses anhydrous zinc acetate as the Zn source, oleylamine is added to enhance the activity, and octadecene is used as the reaction environment. It is heated to about 140 °C and dissolved for standby. When preparing the quantum dots, first transfer silver iodide, gallium acetylacetonate, and sulfur powder to a 100 mL three-necked flask, measure dodecanethiol and oleylamine with a test tube and drop them into the flask, then perform multiple vacuum pumping and nitrogen filling operations, and then raise the temperature to 240 °C and keep it for 30 min to synthesize AgGaS2 quantum dots. Then all the precursor solution of Zn is injected, and the shell layer is continuously grown at 240 °C for 70 min to obtain AgGaS2 / ZnS quantum dot particles.
[0023] Take out the reaction solution, add 10 mL of n-hexane to the reaction solution to prevent the solidification of organic solvents such as octadecene. Take 4 mL of the mixed solution of the original reaction solution and n-hexane into a centrifuge tube and add 4 mL of ethanol. Then centrifuge at 10000 r / min for 10 min at high speed to completely separate the precipitate. Then dissolve the precipitate with n-hexane and ultrasonically vibrate for 15 min. Then use a pipette to drop an appropriate amount of ethanol into the centrifuge tube to make obvious precipitation appear, centrifuge at 8000 r / min for 5 min, collect the supernatant and continue to add ethanol, repeat 4-6 times, and disperse the separated solid in the n-hexane dispersion for fluorescence spectrophotometer testing. Under the experimental conditions described above, when the quantum dots are excited by 350 nm ultraviolet light, the central wavelength of their emission spectrum is about 550 nm, which is yellow light and can be used for fluorescence labeling. Place the quantum dot dispersion after washing and separation in a freezing environment until it freezes and then take it out. Seal the bottle mouth with plastic wrap and make several small holes, and then place it in a freeze dryer to dry for about 2 h. Stop when it is observed that the dispersion has volatilized and the powder has completely precipitated, and AgGaS2 / ZnS quantum dot particle powder can be obtained, which can be used for subsequent treatment.
[0024] In step (1), the methods for controlling the size of the AgGaS2 / ZnS quantum dot particles are as follows: ① Adjust the concentration of the reactants when growing the heterojunction shell layer. ② Change the time for growing the heterojunction shell layer.
[0025] In step (3), the freeze-dried quantum dot particles are dispersed in a non-toxic medium such as water or ethanol, and then ultrasonically shaken to be uniform and dispersed in the object to be measured, such as being injected into the biological tissue to be observed; or being covered on the surface of the object to be measured, placed under the OCT probe, and irradiated with a purple light or blue light source at the same time, so that the core of the quantum dot particles emits light, and the fluorescence of the core can be used for fluorescence labeling to locate the enhanced part of OCT. At the same time, the visible light smaller than the OCT band provides information in the visible light band. Description of the Drawings
[0026] Figure 1 It is a schematic diagram of the implementation mode of a method for simultaneously realizing the enhancement and labeling of optical coherence tomography (OCT) using quantum dot particles according to the present invention. Detailed Embodiments
[0027] Example 1: Perovskite quantum dot CsPbBr3 particles with a size of 8 nm are prepared by the hot injection method, and the quantum dots are washed and dried. For an OCT system with a wavelength of 880 nm, 50 μL of APTES dissolved in cyclohexane is used to coat it with SiO2, so that the size of the quantum dots reaches between [0.8 μm, 1.0 μm], and it is dissolved in ethanol with a concentration between
[0028] [0.5, 0.6] (unit: mmol / L). When performing OCT, it is injected into the biological tissue to be measured or covered on the surface, and irradiated with a blue light or purple light flashlight nearby. Under the excitation of blue light or purple light, the quantum dots at the injection site emit green fluorescence. The quantum dot particles enhance the forward scattering of the light in the band used by OCT, and at the same time increase the detection depth.
[0029] Example 2: By changing the reaction time, perovskite quantum dot CsPbBr3 particles with a size of 10 nm are prepared by the hot injection method, and the quantum dots are washed and dried. For an OCT system with a wavelength of 1310 nm, 50 μL of APTES dissolved in cyclohexane is used to coat it with SiO2, so that the size of the quantum dots reaches between [1.3 μm, 1.5 μm], and it is dissolved in ethanol with a concentration between [0.5, 0.6] (unit: mmol / L). When performing OCT, it is injected into the biological tissue to be measured or covered on the surface or covered on the surface, and irradiated with a blue light or purple light flashlight nearby. Under the excitation of blue light or purple light, the quantum dots at the injection site emit yellow-green fluorescence. The quantum dot particles enhance the forward scattering of the light in the band used by OCT, and at the same time increase the detection depth.
[0030] Example 3: By changing the reaction time, perovskite quantum dot CsPbBr3 particles with a size of 8 nm were prepared by the hot injection method, and the quantum dots were washed and dried. For an OCT system with a wavelength of 1550 nm, 50 μL of APTES dissolved in cyclohexane was used to coat it with SiO2, so that the size of the quantum dots reached between [1.5 μm, 1.7 μm]. Then they were dissolved in ethanol with a concentration between [0.5, 0.6] (unit: mmol / L). When performing OCT, it was injected into the biological tissue to be measured or covered on the surface, and a blue or violet flashlight was irradiated nearby. Under the excitation of blue or violet light, the quantum dots at the injection site emitted green fluorescence. The quantum dot particles enhanced the forward scattering of the light in the wavelength band used by OCT and improved the detection depth at the same time.
[0031] Example 4: CdSe quantum dots with a size of 6 nm were prepared by the solvothermal method and washed and dried. For an OCT system with a wavelength of 880 nm, a ZnS shell was grown outside the quantum dots, so that the size of the quantum dot particles reached between [0.8 μm, 1.0 μm]. Then they were dissolved in ethanol with a concentration between [0.5, 0.6] (unit: mmol / L). When performing OCT, it was injected into the biological tissue to be measured or covered on the surface, and a blue or violet flashlight was irradiated nearby. Under the excitation of blue or violet light, the quantum dots at the injection site emitted orange fluorescence. The quantum dot particles enhanced the forward scattering of the light in the wavelength band used by OCT and improved the detection depth at the same time.
[0032] Example 5: CdSe quantum dots with a size of 8 nm were prepared by the solvothermal method and washed and dried. For an OCT system with a wavelength of 1310 nm, a ZnS shell was grown outside the quantum dots, so that the size of the quantum dot particles reached between [1.3 μm, 1.5 μm]. Then they were dissolved in ethanol with a concentration between [0.5, 0.6] (unit: mmol / L). When performing OCT, it was injected into the biological tissue to be measured or covered on the surface, and a blue or violet flashlight was irradiated nearby. Under the excitation of blue or violet light, the quantum dots at the injection site emitted red fluorescence. The quantum dot particles enhanced the forward scattering of the light in the wavelength band used by OCT and improved the detection depth at the same time.
[0033] Example 6: CdSe quantum dots with a size of 6 nm were prepared by the solvothermal method and washed and dried. For an OCT system with a wavelength of 1550 nm, a ZnS shell was grown outside the quantum dots, so that the size of the quantum dot particles reached between [1.5 μm, 1.7 μm]. Then they were dissolved in ethanol with a concentration between [0.5, 0.6] (unit: mmol / L). When performing OCT, it was injected into the biological tissue to be measured or covered on the surface, and a blue or violet flashlight was irradiated nearby. Under the excitation of blue or violet light, the quantum dots at the injection site emitted orange fluorescence. The quantum dot particles enhanced the forward scattering of the light in the wavelength band used by OCT and improved the detection depth at the same time.
[0034] Example 7: AgGaS2 quantum dots with a size of 3 nm were prepared by the hot injection method, washed and dried. For an OCT system with a wavelength of 880 nm, a ZnS shell was grown outside the quantum dots to make the quantum dot particle size reach between [0.8 μm, 1.0 μm]. It was dissolved in ethanol with a concentration between [0.5, 0.6] (unit: mmol / L). During OCT, it was injected into the biological tissue to be measured or covered on the surface, and a blue or violet flashlight was irradiated nearby. Under the excitation of blue or violet light, the quantum dots at the injection site emitted yellow fluorescence. The quantum dot particles enhanced the forward scattering of the light in the OCT wavelength band and simultaneously increased the detection depth.
[0035] Example 8: AgGaS2 quantum dots with a size of 4 nm were prepared by the hot injection method, washed and dried. For an OCT system with a wavelength of 1310 nm, a ZnS shell was grown outside the quantum dots to make the quantum dot particle size reach between [1.3 μm, 1.5 μm]. It was dissolved in ethanol with a concentration between [0.5, 0.6] (unit: mmol / L). During OCT, it was injected into the biological tissue to be measured or covered on the surface, and a blue or violet flashlight was irradiated nearby. Under the excitation of blue or violet light, the quantum dots at the injection site emitted orange-red fluorescence. The quantum dot particles enhanced the forward scattering of the light in the OCT wavelength band and simultaneously increased the detection depth.
[0036] Example 9: AgGaS2 quantum dots with a size of 3 nm were prepared by the hot injection method, washed and dried. For an OCT system with a wavelength of 1550 nm, a ZnS shell was grown outside the quantum dots to make the quantum dot particle size reach between [1.5 μm, 1.7 μm]. It was dissolved in ethanol with a concentration between [0.5, 0.6] (unit: mmol / L). During OCT, it was injected into the biological tissue to be measured or covered on the surface, and a blue or violet flashlight was irradiated nearby. Under the excitation of blue or violet light, the quantum dots at the injection site emitted yellow fluorescence. The quantum dot particles enhanced the forward scattering of the light in the OCT wavelength band and simultaneously increased the detection depth.
[0037] Example 10: CuGaSe2 quantum dots with a size of 5 nm were prepared by the one-pot method, washed and dried. For an OCT system with a wavelength of 1550 nm, a ZnS shell was grown outside the quantum dots to make the quantum dot particle size reach between [1.5 μm, 1.7 μm]. It was dissolved in ethanol with a concentration between [0.5, 0.6] (unit: mmol / L). During OCT, it was injected into the biological tissue to be measured or covered on the surface, and a blue or violet flashlight was irradiated nearby. Under the excitation of blue or violet light, the quantum dots at the injection site emitted yellow-green fluorescence. The quantum dot particles enhanced the forward scattering of the light in the OCT wavelength band and simultaneously increased the detection depth.
[0038] Example 11: CuGaS2 quantum dots with a size of 6 nm were prepared by a one-pot method, washed and dried. For an OCT system with a wavelength of 1310 nm, a ZnS shell was grown outside the quantum dots to make the quantum dot particle size reach between [1.3 μm, 1.5 μm], and it was dissolved in ethanol with a concentration between [0.5, 0.6] (unit: mmol / L). During OCT, it was injected into the biological tissue to be measured or covered on the surface, and a blue or violet flashlight was irradiated nearby. Under blue or violet light excitation, the quantum dots at the injection site emitted orange-yellow fluorescence, and the quantum dot particles enhanced the forward scattering of the light in the OCT wavelength band, while increasing the detection depth.
[0039] Example 12: CdS quantum dots with a size of 5 nm were prepared by a solvothermal method, washed and dried. For an OCT system with a wavelength of 1310 nm, a ZnS shell was grown outside the quantum dots to make the quantum dot particle size reach between [1.3 μm, 1.5 μm], and it was dissolved in ethanol with a concentration between [0.5, 0.6] (unit: mmol / L). During OCT, it was injected into the biological tissue to be measured or covered on the surface, and a blue or violet flashlight was irradiated nearby. Under blue or violet light excitation, the quantum dots at the injection site emitted yellow fluorescence, and the quantum dot particles enhanced the forward scattering of the light in the OCT wavelength band, while increasing the detection depth.
Claims
1. A method for simultaneously achieving enhancement and identification of optical coherence tomography (OCT) using quantum dot particles, characterized in that, The implementation method includes the following steps: (1) Prepare a quantum dot core that can emit visible light with a wavelength shorter than the OCT band for fluorescence labeling; (2) By wrapping or forming a core-shell structure on the outer layer of the core quantum dots of the particles, regulate the size of the quantum dot particles to obtain quantum dot particles with a size close to the wavelength of the OCT detection light. The bandgap of the wrapping material or the shell material should be greater than that of the quantum dot core; (3) When performing OCT detection, disperse the quantum dot particles in the detected object or cover its surface. Utilize the forward scattering effect of the quantum dot particles with a size close to the detection light wavelength to improve the imaging depth; at the same time, the quantum dots in the particle core emit visible light fluorescence under the excitation light, which provides information in the visible light band outside the OCT band for the detected part, and simultaneously realizes the enhancement of the OCT detection signal and the effect of fluorescence labeling of the detected part.
2. A method for simultaneously achieving OCT enhancement and identification using quantum particles according to step (1) of claim 1, characterized in that, The quantum dot core of the prepared quantum dot particles is a perovskite quantum dot synthesized in the laboratory, such as CsPbCl3, CsPbBr3, CsPbI3, or a II-VI group quantum dot, such as CdSe, CdS, CdTe, or a I-III-VI group quantum dot, such as CuInS2, AgInS2, CuGaS2, AgGaS2, CuGaSe2, CuInSe2, or a III-V group quantum dot, such as InP.
3. Regarding the preparation of the quantum dot particles described in step (2) of claim 1, the materials used for wrapping are oxides and polymers, such as the non-metal oxide silica; the methods for regulating the size of the quantum dot particles are: ① Adjust the amount of raw materials used for wrapping. The more the feeding amount, the larger the size of the quantum dot particles obtained after the same reaction time; ② Change the wrapping time. After the reaction time increases, the size of the quantum dot particles obtained is larger.
4. Regarding the preparation of the quantum dot particles described in step (2) of claim 1, the shell materials are sulfides, selenides, and metal oxides, such as zinc sulfide, zinc selenide, cadmium sulfide, gallium sulfide, titanium dioxide; the methods for regulating the size of the quantum dot particles are: ① Adjust the amount of source materials during the growth of the shell. The more the feeding amount, the larger the size of the quantum dot particles obtained after the same reaction time; ② Change the growth time of the shell. After the reaction time increases, the size of the quantum dot particles obtained is larger.
5. The quantum dot particles according to claim 1, characterized in that, In step (1), the quantum dot core is cesium lead bromide perovskite quantum dots. In step (2), the material of the encapsulation layer is silicon dioxide, and the source materials used are organosilicate and silane. The preparation method is as follows: inject the cesium oleate precursor solution into the organic solution of lead bromide at 180 °C, and after the reaction, quickly cool it in ice water to obtain the quantum dot core. Control the reaction time after injection within [5 s, 30 s], and its emission wavelength range is within [540 nm, 880 nm]. For the scheme of encapsulating silicon dioxide outside the quantum dot core using 3-aminopropyltriethoxysilane, dissolve the silane and the quantum dot core in 10 ml of n-hexane, stir at room temperature to decompose the silane into silicon dioxide, and encapsulate it on the quantum dot core. By adjusting the amount of silane within [30 μL, 100 μL] and stirring for 30 min, the obtained quantum dot particle size is within [700 nm, 1400 nm]. Using 50 μL of silane, by changing the encapsulation time within [30 min, 90 min], the obtained quantum dot particle size is within [700 nm, 1900 nm].
6. The quantum dot particles according to claim 1, characterized in that, In step (1), the quantum dot core is II-VI cadmium selenide quantum dots. In step (2), the material of the encapsulation layer is zinc sulfide. The preparation method is solvothermal method: oleic acid and ethanol added to the reaction system are the liquid phase (L), sodium oleate is the solid phase (S), and the aqueous metal-containing solution and ethanol are the solution phase (S), forming an LSS three-phase system. Using cadmium acetate as the cadmium source and selenium powder as the selenium source, after mixing at room temperature, transfer it to a hydrothermal synthesis reaction kettle, and after reacting at a certain temperature, obtain CdSe quantum dots. After dissolving the obtained quantum dots again, weigh zinc acetate and sodium sulfide respectively, and add them to the reacted quantum dot solution in sequence, and continuously stir during this process. Then transfer it to a hydrothermal synthesis reaction kettle, and after reacting at a certain temperature, obtain quantum dot particles. By changing the core reaction temperature to [140 °C, 200 °C], its emission wavelength range is within [550 nm, 690 nm]. By increasing the Zn source and S source concentrations to 5-15 times the original, after the same shell growth time, the obtained quantum dot particle size is within [750 nm, 1250 nm].
7. The quantum dot particles according to claim 1, characterized in that, In step (1), the quantum dot core is an I-III-VI group AgGaS2 quantum dot. The material of the encapsulation layer in step (2) is zinc sulfide. The preparation method is a one-pot method: silver iodide is used as the Ag source, gallium acetylacetonate is used as the Ga source, and sulfur powder is used as the S source; dodecanethiol is used as the reaction solvent; anhydrous zinc acetate is used as the Zn source for the precursor, oleylamine is added to enhance the activity, and octadecene is used as the reaction environment. It is heated to about 140 °C and dissolved for standby; when preparing the quantum dots, first transfer silver iodide, gallium acetylacetonate, and sulfur powder to a 100 mL three-necked flask, measure dodecanethiol and oleylamine with a test tube and drop them into the flask, then perform multiple repeated vacuum pumping and nitrogen filling operations, and then raise the temperature to 240 °C and keep it for 30 min to synthesize AgGaS2 quantum dots; then inject all the Zn precursor solution, and continue to grow the shell layer at 240 °C for 70 min; by changing the core reaction temperature [220 °C, 260 °C], its emission wavelength range is [500 nm, 560 nm]; by increasing the Zn source and S source concentrations to 6-10 times the original, after the same shell layer growth time, the obtained quantum dot particle size is in [700 nm, 1300 nm].
8. The quantum dot particles according to claim 1, characterized in that, In step (1), the quantum dot core is an I-III-VI group CuGaSe2 quantum dot. The material of the encapsulation layer in step (2) is zinc selenide. The preparation method is a one-pot method: copper iodide is used as the Cu source, gallium acetylacetonate is used as the Ga source, and selenium powder is used as the Se source; octadecene and dodecanethiol are used as the reaction solvents; zinc iodide is used as the Zn source, oleylamine is added to enhance the activity, and octadecene is used as the reaction environment. It is heated to about 90 °C and dissolved for standby; when preparing the quantum dots, first transfer the reactants to a 100 mL three-necked flask, and then perform multiple repeated vacuum pumping and nitrogen filling operations at 120 °C, and then raise the temperature to 240 °C and keep it for 5 min to synthesize CuGaSe2 quantum dots; then inject the Zn precursor solution in two portions with an interval of 30 min; by changing the Cu / Ga ratio to [1 / 13, 1 / 2], its emission wavelength range is [500 nm, 590 nm]; by increasing the Zn source and Se source concentrations to 4-8 times the original, after the same shell layer growth time, the obtained quantum dot particle size is in [800 nm, 1400 nm].