CN116445162A - Preparation of near-infrared luminous Nd and Yb synchronous high-doped core-shell structure nanocrystalline and application thereof in immunochromatography detection - Google Patents

Preparation of near-infrared luminous Nd and Yb synchronous high-doped core-shell structure nanocrystalline and application thereof in immunochromatography detection Download PDF

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CN116445162A
CN116445162A CN202310374871.9A CN202310374871A CN116445162A CN 116445162 A CN116445162 A CN 116445162A CN 202310374871 A CN202310374871 A CN 202310374871A CN 116445162 A CN116445162 A CN 116445162A
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冀天星
魏嵬
丁卫东
宋庆炜
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Second Affiliated Hospital of Guangzhou Medical University
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Abstract

The invention belongs to the technical field of immunology detection, and particularly relates to preparation of near-infrared luminescence Nd and Yb synchronous high-doped core-shell structure nanocrystals and application thereof in immunochromatography detection. In order to further improve the absorption capacity of the nanocrystal to 808nm light and the utilization rate of excitation energy, the invention makes sensitized ions Nd by a method of accelerating phase transition 3+ And luminescent ion Yb 3+ At the same time, the high-concentration doping is realized,wherein Nd 3+ And Yb 3+ The doping ratio of (2) is 40% and 60%, respectively. The doping proportion not only ensures the high absorption capacity of the nano-crystal to 808nm, but also improves the luminescent center Yb 3+ For the full utilization rate of excitation energy, the quantum yield of the finally prepared nanocrystalline is up to 35.5%, and the high-brightness near-infrared light-emitting nanocrystalline is used as an immunofluorescence probe to prepare an immunochromatography test strip, so that the detection of various indexes in a complex sample without background interference and with high sensitivity is realized.

Description

Preparation of near-infrared luminous Nd and Yb synchronous high-doped core-shell structure nanocrystalline and application thereof in immunochromatography detection
Technical Field
The invention belongs to the technical field of immunology detection, and particularly relates to preparation of near-infrared luminescence Nd and Yb synchronous high-doped core-shell structure nanocrystals and application thereof in immunochromatography detection.
Background
Lateral Flow Analysis (LFA), which is the most common point-of-care testing method worldwide, has received great attention in the academic research and industrial manufacturing community due to its advantages of fast reading, low cost, and ease of use. Among them, LFA is the most common one. However, immunochromatographic test strips based on gold nanoparticles, latex beads and europium fluorescent microspheres still have the problems of low sensitivity and low signal to noise ratio, which are caused by high light absorption and autofluorescence interference of Nitrocellulose (NM) membranes of the test strips and blood and plasma sample matrixes. Therefore, development of an immunochromatographic test strip capable of eliminating light absorption and automatic fluorescence interference can realize sensitivity and accurate quantitative detection of biomarkers in complex biological matrixes (such as blood plasma, whole blood, urine and fecal samples).
The rare earth down-conversion nanocrystalline serving as a new generation luminescent material has the following advantages: (1) The stokes shift is large, the half-peak width of the emission spectrum is narrow, and multi-index and multi-detection can be realized; (2) The fluorescent quantum yield is high, the bleaching property is not realized, the light stability is good, and the repeated detection can be carried out for many times; (3) Excitation light and emission light are located in a near infrared region, light penetration capacity is high, background interference is avoided, and detection with high signal-to-noise ratio can be achieved. Wherein, rare earth ion Nd 3+ And Yb 3+ Excitation of co-doped nanocrystalsThe luminescence and the emission light are respectively near infrared light 800nm excitation and near infrared light 980nm excitation, and the fluorescent material is a potential fluorescent material for realizing detection of disease indexes in complex samples without background interference.
Has the research that the rare earth ion Nd 3+ And Yb 3+ There is a strong energy transfer efficiency between such that Nd 3+ And Yb 3+ The mass yield of the co-doped nanocrystalline reaches 20.7 percent. Nevertheless, how Nd is further improved 3+ And Yb 3+ The near infrared emission brightness of co-doped nanocrystals to meet the need for highly sensitive detection is still a worthy of exploration. Numerous studies suggest that the luminous efficiency of rare earth nanocrystals is affected by surface defects of the nanocrystals, doping concentrations of rare earth ions. Therefore, the method is an effective method for improving the luminous efficiency of the rare earth nanocrystalline by constructing an inert shell layer and optimizing the doping concentration of rare earth ions. For example, chinese patent invention CN111044493A and CN110514825A respectively provide a core-shell structure alpha-phase NaLnF 4 :Nd,Yb@CaF 2 /NaLnF 4 And alpha-phase NaYF 4 :Yb,Nd@NaYF 4 The highest quantitative yield of near infrared luminescence of the above-mentioned nanocrystal probe was only 20.7%. Meanwhile, the adopted alpha phase luminous efficiency is obviously lower than that of the beta phase, because the arrangement of doped rare earth ions in the alpha phase and the beta phase is obviously different. In addition, the main matrix component adopted by the nano-crystalline material contains other Ln elements including Y element, gd element or Lu element, and the doping of the elements can influence the content, arrangement, distance among ions and the like of the Nd element and the Yb element of the nano-crystalline material, so that the nano-crystalline material is unfavorable for the efficient absorption and utilization of the excitation energy of the nano-crystalline material, and finally the luminous intensity of the nano-crystalline material cannot be further improved. Therefore, it is necessary to improve the nanocrystal to further improve the absorption capacity of the nanocrystal to 808nm light and the utilization rate of excitation energy, so as to realize high-sensitivity detection of zero background signal interference in the immunochromatography detection method.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims at Nd 3+ And Yb 3+ The preparation method of the co-doped core-shell structure nanocrystalline is improved by synthesizing beta-phase NaNdF 4 :Yb@NaLnF 4 Core-shell structure nanocrystallineThereby greatly improving the absorption capacity of 808nm excitation light and simultaneously improving the sensitized ion Nd in the nanocrystalline 3+ The utilization rate of excitation energy realizes the efficient emission of the nanocrystalline at 980nm (the mass yield is up to 35.5 percent), and overcomes the existing Nd 3+ And Yb 3+ The near infrared light emission intensity of the co-doped core-shell structure nanocrystal is insufficient. At the same time, using the obtained high-bright near-infrared light emission Nd 3+ And Yb 3+ Co-doped core-shell structure nanocrystalline NaNdF 4 :Yb@NaLuF 4 As fluorescent recognition probes, the immunochromatography detection method is established, compared with the existing near infrared immunochromatography method, the stability of the fluorescent marker is equivalent, the fluorescence emission is stronger, and the detection result has better sensitivity, so that various indexes in the fields of medicine, agriculture, food safety and the like realize background interference-free and high-sensitivity immunochromatography detection.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the first aspect of the invention provides a high-brightness near-infrared light-emitting beta-phase Nd 3+ And Yb 3+ The preparation method of the co-doped core-shell structure nanocrystalline comprises the following steps:
s1, preparation of core NaNdF 4 :Yb：
S11, weighing rare earth acetate Ln (CH) 3 COO) 3 Wherein neodymium acetate Nd (CH) 3 COO) 3 40% of ytterbium acetate Yb (CH) 3 COO) 3 60 percent of the rare earth precursor solution is heated to 150-180 ℃ in an inert gas atmosphere after oleic acid and 1-octadecene are added until the solid is completely dissolved, so as to obtain the rare earth precursor solution;
s12, adding a methanol solution containing sodium hydroxide and a methanol solution containing ammonium fluoride into the rare earth precursor solution, stirring and uniformly mixing under an inert gas atmosphere, and heating the solution to 120 ℃ to remove methanol in the solution; finally heating the solution to 290-310 ℃ and maintaining the reaction for 50-70min;
s13, after the reaction is finished, cooling the solution to room temperature, and then collecting the precipitate through centrifugation to obtain the nuclear NaNdF 4 60 percent of Yb; finally NaNdF is added 4 Yb60% nanocrystalline dispersed in cyclohexaneIs ready for use;
s2, preparing NaNdF 4 :Yb60％@NaLuF 4 Core-shell structure:
s21, lutetium oxide Lu 2 O 3 Adding into an aqueous solution containing trifluoroacetic acid; heating to 90-110 ℃ until the solid is completely dissolved, and then continuously heating until the solution is completely evaporated to dryness to obtain lutetium trifluoroacetate solid powder;
s22, adding sodium trifluoroacetate Na (CF) into the lutetium trifluoroacetate solid powder 3 COO) 3 Oleic acid, 1-octadecene, and NaNdF obtained in step S13 4 Yb60% cyclohexane solution; heating to 110-130 ℃ under inert gas atmosphere, and keeping for 20-40min to remove cyclohexane and water in the system; then heating to 290-310 ℃ for reaction for 50-70min for epitaxial growth of NaLuF 4 A shell layer;
s23, after the solution is cooled to room temperature, centrifugally collecting the precipitate to obtain the highlight near-infrared luminous beta-phase Nd 3+ And Yb 3+ Co-doped core-shell structure nanocrystals, i.e., naNdF 4 :Yb60％@NaLuF 4 Nanocrystalline with core-shell structure, namely beta-NaNdF for short 4 :Yb@NaLnF 4 。
The near infrared luminous beta-phase Nd prepared by the method of the invention 3+ And Yb 3+ The co-doped nanomaterial comprises a core, and the core is an inorganic matrix doped ion; the inorganic matrix core is NaLnF 4 ，Ln＝Yb 3+ And Nd 3+ Co-doping ions; the inorganic matrix core cannot contain other Ln elements (ln=y 3+ 、Gd 3+ 、Er 3+ 、Ho 3+ Or Ce (Ce) 3+ Any one or more of the following); the near infrared luminescent rare earth nanomaterial also comprises a shell layer, wherein the shell layer is one or more layers and is coated outside the inner core; the matrix of the shell layer comprises NaLnF 4 Where ln=yb 3+ 。
The invention adopts a method of accelerating phase transition to realize sensitization of ions Nd 3+ And luminescent ion Yb 3+ Simultaneous high concentration doping in which the sensitising ion Nd 3+ And luminescent ion Yb 3+ The doping ratio of (2) is 40% and 60%, respectively. This doping ratio not only ensures the nanoThe high absorption capacity of the rice crystal to 808nm, and the luminous center Yb is improved 3+ For the full utilization of excitation energy, the quantum yield of the finally prepared nanocrystalline is as high as 35.5%, which is obviously higher than 20.7% of the highest yield reported. Meanwhile, the high-brightness near-infrared luminescent nanocrystalline is used as an immunofluorescence probe to prepare an immunochromatography test strip, and an immunochromatography method for detecting disease indexes in complex samples such as feces, blood, urine and the like without background interference with high sensitivity is established.
Preferably, in the step S11, the dosage ratio of the rare earth acetate to oleic acid to 1-octadecene is 1-3mmol:7.5mL:15mL.
Preferably, in step S12, the molar concentration of the methanol solution containing sodium hydroxide is 0.2-0.5mmol/mL, and the molar concentration of the methanol solution containing ammonium fluoride is 0.3-0.5mmol/mL.
Preferably, in step S12, the volume ratio of the methanol solution containing sodium hydroxide to the methanol solution containing ammonium fluoride is 1:1.
Preferably, in step S21, the dosage ratio of lutetium oxide to trifluoroacetic acid aqueous solution is 0.5-2mmol/10-20mL, and the volume fraction of trifluoroacetic acid aqueous solution is 50%.
Preferably, in step S22, the sodium trifluoroacetate, oleic acid, 1-octadecene and NaNdF 4 The dosage ratio of Yb60% cyclohexane solution is 1-3mmol:10mL:10mL:10-20mL of the NaNdF 4 The molar concentration of Yb60% cyclohexane solution is 0.1-0.2mmol/mL.
The second aspect of the invention provides the high-brightness near-infrared luminous beta-phase Nd prepared by the preparation method of the first aspect 3+ And Yb 3+ Co-doping core-shell structure nanocrystals.
A third aspect of the present invention provides the highlighting near infrared luminescent beta-phase Nd of the second aspect 3+ And Yb 3+ The application of the co-doped core-shell structure nanocrystalline in immunochromatography detection.
In a fourth aspect, the present invention provides a method for emitting beta-phase Nd based on highlight near-infrared light 3+ And Yb 3+ Serum marker luminescent detection side flow of co-doped core-shell structure nanocrystallineThe paper strip is characterized in that the lateral flow test paper strip adopts the high-brightness near-infrared light-emitting beta-phase Nd 3+ And Yb 3+ The co-doped core-shell structure nanocrystalline is an immune label, and the lateral flow test strip is prepared from high-brightness near-infrared luminous beta-phase Nd 3+ And Yb 3+ The co-doped core-shell structure nanocrystal, a polyvinyl chloride supporting backboard, a detection pad, a combination pad, a sample pad and a water absorption pad, wherein the combination pad is loaded with a high-brightness near-infrared light-emitting beta-phase Nd modified by a combination antibody or target protein 3+ And Yb 3+ Co-doped core-shell structure nanocrystalline probe and anti-quality control object antibody modified high-brightness near-infrared light-emitting beta-phase Nd 3+ And Yb 3+ Co-doped core-shell structure nanocrystalline probes.
Preferably, the anti-quality control antibody comprises a goat anti-chicken IgY antibody.
A fifth aspect of the present invention provides the highlighting near infrared light emission-based beta-phase Nd of the fourth aspect 3+ And Yb 3+ The preparation method of the serum marker luminescence detection side flow test strip co-doped with the core-shell structure nanocrystal comprises the following steps:
(1)β-NaNdF 4 :Yb@NaLnF 4 probe surface modification recognition marker
S1、β-NaNdF 4 :Yb@NaLnF 4 The functional modification of (a) is carboxyl modification, and the adopted method is a ligand exchange method:
s11, beta-NaNdF 4 :Yb@NaLnF 4 Sufficiently mixing and vibrating the core-shell structure nanocrystalline cyclohexane solution, ethanol and hydrochloric acid aqueous solution (0.1M), and performing ultrasonic treatment for 30min to remove oleic acid ligand on the surface of the nanocrystalline;
beta-NaNdF prepared from S12 and S11 4 :Yb@NaLnF 4 Centrifuging (10000 r/min,30 min) the core-shell structure nanocrystalline solution to collect ligand-free beta-NaNdF 4 :Yb@NaLnF 4 Re-dissolving the core-shell structure nanocrystalline in 10mL of deionized water;
s13, beta-NaNdF prepared by S12 4 :Yb@NaLnF 4 Dropwise adding the core-shell structure nanocrystalline heavy suspension into an aqueous solution containing polyacrylic acid, and stirring at room temperature for 60min to obtain polyacrylic acid modified beta-NaNdF 4 :Yb@NaLnF 4 Core-shell structure nanocrystals;
s14, centrifugally collecting the polyacrylic acid modified beta-NaNdF prepared in S12 4 :Yb@NaLnF 4 Core-shell structured nanocrystals are dispersed in 10-20mL of deionized water.
S2、β-NaNdF 4 :Yb@NaLnF 4 In a functionalized binding recognition detection target binding antibody or target protein
S21, taking the amino or carboxyl functional modified near infrared light-emitting beta-NaNdF obtained in the step S14 4 :Yb@NaLnF 4 Adding MES buffer solution into the nano material for centrifugation, and discarding the supernatant; beta-NaNdF 4 :Yb@NaLnF 4 The nanomaterial pellet was redispersed in MES buffer.
S22. Beta. -NaNdF obtained in S21 4 :Yb@NaLnF 4 EDC/SulFo-NHS is added into the nano material buffer solution, and the activation is carried out for 10-60min. Centrifuging to obtain precipitate, re-dispersing in buffer solution,
s23, activating beta-NaNdF obtained in S22 4 :Yb@NaLnF 4 Adding a binding antibody or target protein for identifying a detection target into the nano material buffer solution, reacting for 1-3h at room temperature, then adding a blocking agent for blocking, and reacting for 0.5-2h.
S23, centrifuging the combined antibody or target protein modified beta-NaNdF obtained by S23 4 :Yb@NaLnF 4 The nano material buffer solution is taken to be precipitated (namely beta-phase Nd marked by detection target recognition antibody marked by near infrared luminescent rare earth nano material 3+ And Yb 3 + Codoped nanomaterial) is dispersed in a buffer solution such as PBS and the like and stored at 4 ℃.
Meanwhile, the quality control object antibody modified highlight near infrared luminous beta-phase Nd is prepared by the same method 3+ And Yb 3+ Co-doped core-shell structure nanocrystalline probes.
(2) Assembly is based on beta-NaNdF 4 :Yb@NaLnF 4 Near infrared light chromatography detection card for nano material
S11, preparation of a detection pad: and sticking a nitrocellulose membrane on the middle part of a polyvinyl chloride supporting floor for standby, diluting the detection target recognition antibody and the quality control antibody to 0.5-5mg/mL by using a coating buffer solution (PB buffer solution, 10mM, pH=7.4), and then uniformly scribing the detection target recognition antibody and the quality control antibody on the positions of a detection line and a quality control line of the nitrocellulose membrane of the polyvinyl chloride supporting floor by using a metal spraying scribing instrument at a scribing speed of 10-80mm/s and a scribing amount of 1 mu L/cm respectively, and drying the scribed polyvinyl chloride supporting floor in a blast drying box at 37 ℃ for 24 hours for standby.
S12, pretreatment of a bonding pad: fully soaking the polyester fiber membrane for 2-4 h by using a PB buffer solution (10 mM, pH=7.4) of S9 surfactant, casein, PVP-K30 and Tween-20; cutting the glass fiber film dried at 37 ℃ into long strips with the width of 10mm and the length of 300mm by an automatic cutter;
s13, preparation of a bonding pad: adding 1% (v/v) of the binding antibody or target protein modified beta-NaNdF obtained in step (1) to a metal spraying diluent [ comprising 10% (w/v) sucrose, 0.3% (w/v) Bovine Serum Albumin (BSA), 0.5% (w/v) polyvinylpyrrolidone (PVP K-30), 5% (w/v) S9 surfactant, 0.03% (v/v) Proclin-3000) ] 4 :Yb@NaLnF 4 Nanomaterial dispersion and 2% (v/v) quality control antibody modified beta-NaNdF 4 :Yb@NaLnF 4 A nanomaterial dispersion; uniformly spraying the metal spraying film drawing instrument on the previously pretreated bonding pad at the spraying speed of 50mm/s and the spraying amount of 4uL/cm, and then placing the prepared bonding pad in a blast drying oven at 37 ℃ for drying for 24 hours for later use.
S14, preparation of a sample pad: fully soaking the glass fiber membrane for 2-4 h by using PB buffer solution (10 mM, pH=7.4) containing S9 surfactant, casein, PVP-K30 and Tween-20; cutting the glass fiber film dried at 37 ℃ into long strips with the width of 21mm and the length of 300mm by an automatic cutter; during sample addition, samples such as blood, urine and the like containing the target to be detected are directly added.
S15, assembling an immunochromatography test paper board: taking out the polyvinyl chloride supporting base plate of the nitrocellulose membrane with the fixed antibody, pasting a prepared S13 bonding pad at one end close to a nitrocellulose membrane detection line, pasting a water absorption pad at one end close to a nitrocellulose membrane quality control line, and pasting a sample pad at the other end of the prepared bonding pad, wherein the sample pad is prepared at S14; 2mm overlap joint between every two components, namely finish the assembly of the test paper board;
s16, preparing an immunochromatography test paper card: cutting the assembled test paper board into a test paper strip with the width of 4.00mm by using an automatic strip cutting machine, and loading the test paper strip into a plastic card shell; to obtain beta-NaNdF 4 :Yb@NaLnF 4 Immunochromatography test paper card of nano material near infrared luminescence (based on high-brightness near infrared light emission beta-phase Nd) 3+ And Yb 3+ The serum marker luminescent detection side flow strip co-doped with the core-shell structure nanocrystal).
Compared with the prior art, the invention has the beneficial effects that:
the invention discloses a preparation method of near infrared luminescence Nd and Yb synchronous high-doped core-shell structure nanocrystalline, which synthesizes Nd without other Ln elements by utilizing a scheme of accelerating phase transition 3+ And Yb 3+ While highly doped nanocrystals. On the one hand solve Nd 3+ And Yb 3+ The lattice mismatch of the ceramic matrix is synthesized into Nd with regular morphology and uniform grain size 3+ And Yb 3+ Co-doped nanocrystals, on the other hand, realize Nd 3+ And Yb 3+ Is a high concentration doping at the same time, determines Nd 3+ And Yb 3+ The doping ratio of the nano-crystal is 40 percent and 60 percent respectively, under the doping ratio, the high absorption of the nano-crystal to 808nm is realized, and simultaneously the excitation energy of 808nm is fully utilized, so that the near infrared 980nm emission intensity of the nano-crystal with the core-shell structure is greatly improved (compared with the alpha-NaYF with the core-shell structure disclosed by Chinese invention and patent CN 110514825B) 4 :Nd60％,Yb7％@CaF 2 The ratio of the nano crystal phase is improved by 30 times), the fluorescence quantum yield is up to 35.5 percent, which is obviously higher than that of the literature (Cao C, xue M, zhu X, yang P, feng W, li F. Energy Transfer Highway in Nd) 3+ Sensitized Nanoparticles for Efficient near-Infinised bioimaging. ACS Appl Mater interfaces.2017Jun 7;9 (22): 18540-18548) report α -NaLnF 4 :Nd,Yb@CaF 2 /NaLnF 4 20.7%. Then, the fluorescent immune probe is constructed by utilizing the high-brightness near-infrared light-emitting nanocrystalline to construct an immunochromatography test strip, so that high-sensitivity detection of disease indexes in complex samples without background interference is realized.Specifically, the invention has the following advantages:
(1) The invention synthesizes the beta-phase NaNdF with regular morphology and uniform particle size by adopting the method of accelerating phase transformation 4 ：Yb@NaLuF 4 Core-shell structure nanocrystalline and high-concentration Nd 3+ Doping achieves high absorption of 808nm photons. At the same time, nd is utilized 3+ →Yb 3+ Efficient energy transfer and high Yb concentration 3+ The doping realizes the full utilization of the nanocrystal for absorbing 808nm photons, so that 980nm near infrared light is emitted in a highlighting way. By NaLnF 4 Coating of inert shell layer, inhibiting high concentration Yb 3+ Quenching of surface defects by doping. Finally prepares NaNdF emitted by 980nm of high-brightness near-infrared light 4 :Yb60％@NaLnF 4 The nanocrystalline, the high-brightness near-infrared light emitting nanocrystalline is used as an immunofluorescence mark to facilitate the high-sensitivity detection of immunochromatography. Compared with the existing near infrared immunochromatography method, naNdF 4 :Yb60％@NaLnF 4 The near infrared light emission of the nanocrystalline is stronger, and the sensitivity of the detection result is higher.
(2) NaNdF provided by the invention 4 :Yb60％@NaLuF 4 When the nanocrystalline immunochromatographic test strip is used for detecting an actual body fluid marker, a proper amount of body fluid sample is required to be dripped on a sample pad, and after a period of reaction, a handheld portable detection instrument (808 nm excitation and 980nm emission) is used for detecting the luminescence of the test strip. Due to NaNdF 4 :Yb60％@NaLuF 4 The excitation and emission spectrums of the nanocrystalline fluorescent probe are all in the near infrared region, so that the interference of various micromolecules and macromolecular substances in cellulose membranes and body fluid on detection fluorescent signals is eliminated, and the immunochromatography detection method realizes high-sensitivity real-time detection without background signal interference on various indexes in complex samples such as blood, urine, excrement and the like.
Drawings
FIG. 1 shows a core-shell NaNdF structure 4 :Yb60％@NaLuF 4 XRD diffraction pattern of the nanocrystals;
FIG. 2 shows a core-shell NaNdF structure 4 :Yb60％@NaLuF 4 A transmission electron microscope image of the nanocrystal (a bar graph shows the size of the nanocrystal of the core-shell structure);
FIG. 3 shows a core-shell NaNdF structure 4 :Yb60％@NaLuF 4 Nanocrystalline and conventional NaYF 4 :Nd20％，Yb10％@NaYF 4 Fluorescent spectrum contrast chart of the nanocrystalline;
FIG. 4 shows a core-shell NaNdF structure 4 :Yb60％@NaLuF 4 Nanocrystalline and core-shell structure NaYF disclosed in patent CN110514825B 4 :Nd60％,Yb7％@NaYF 4 Is a fluorescence spectrum contrast chart of (1);
FIG. 5 shows NaNdF in core-shell structure 4 :Yb60％@NaLuF 4 The nanocrystal is a schematic diagram of an immunochromatographic test strip of a fluorescent immunolabel [ 1 ] is a sample pad, (2) is a bonding pad, (3) is a detection line (T line), (4) is a quality control line (C line), and (5) is a water absorption pad ];
FIG. 6 shows NaNdF in core-shell structure 4 :Yb60％@NaLuF 4 The nanocrystalline is a physical image of an immunochromatography test strip marked by fluorescence immunity;
FIG. 7 shows NaNdF in core-shell structure 4 :Yb60％@NaLuF 4 The nanocrystalline is a relation curve of the concentration of the SARS-CoV-2 neutralizing antibody detected by the fluorescence immune marked immunochromatography test strip and the ratio of the fluorescence intensity of the detection line (T line) and the quality control line (C line).
Detailed Description
The following describes the invention in more detail. The description of these embodiments is provided to assist understanding of the present invention, but is not intended to limit the present invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
The experimental methods in the following examples, unless otherwise specified, are conventional, and the experimental materials used in the following examples, unless otherwise specified, are commercially available.
Example 1 preparation and luminescence property study of near-infrared luminescence Nd and Yb synchronous highly doped core-shell structure nanocrystalline (NaNdF 4: yb60% @ NaLuF4 core-shell structure nanocrystalline)
1. Preparation of core NaNdF 4 :Yb60％：
1) 0.4mmol of neodymium acetate (Nd (CH) 3 COO) 3 ) And 0.6mmol of ytterbium acetate (Yb (CH) 3 COO) 3 ) Adding the mixture into a three-neck flask containing 7.5mL of Oleic Acid (OA) and 15mL of 1-Octadecene (ODE), heating to 100 ℃ under the nitrogen atmosphere to react for 10min so as to remove moisture and oxygen in the mixture, heating to 160 ℃ to react for 60min until the solid is completely dissolved, and finally cooling to room temperature to obtain a rare earth precursor solution;
2) Firstly, 10mL of methanol solution containing 2.5mmol of sodium hydroxide (NaOH) is slowly added into the rare earth precursor solution of the three-neck flask, and the mixture is vigorously stirred for 20min, and then 10mL of solution containing 4mmol of ammonium fluoride (NH) is slowly added into the solution 4 F) Under the atmosphere of nitrogen, stirring vigorously for 60min, heating to 120 ℃ for reaction for 30min, removing methanol, oxygen and water in the system, and finally heating to 300 ℃ for reaction for 60min;
3) After the reaction is finished, transferring the solution to a 50mL centrifuge tube after naturally cooling the solution to room temperature, adding 5mL of absolute ethyl alcohol, shaking and uniformly mixing, centrifuging for 5min at 7500r/min, and repeatedly washing and centrifuging for 2-3 times by using the absolute ethyl alcohol to obtain precipitate, namely nuclear NaNdF 4 :Yb60％；
The obtained core NaNdF 4 Yb60% was redispersed in 10mL cyclohexane to give NaNdF 4 Yb60% dispersion (molar concentration: 0.1 mmol/mL) was used.
2. Preparation of core-shell NaNdF 4 :Yb60％@NaLuF 4 ：
1) 1mmol lutetium oxide (Lu) 2 O 3 ) Added to a solution containing 5mL deionized water (H) 2 O) and 5mL of trifluoroacetic acid (CF) 3 COOH) was heated to 98 ℃ to react until the solution was completely clear, allowing the solids to dissolve completely; heating and evaporating to remove all water to obtain lutetium trifluoroacetate solid powder, and cooling to room temperature for later use;
2) Into the three-necked flask containing lutetium trifluoroacetate solid powder, 2mmol of sodium trifluoroacetate (CF) 3 COONa), 15mL Oleic Acid (OA), 15mL 1-Octadecene (ODE) and 10mL of a 60% Yb dispersion (0.1 mmol/mL) of NaNdF4 in step 1, and heating to 120℃under nitrogen atmosphere to react 30min to remove cyclohexane and water in the system, and then heating to 300 ℃ to react for 60min for epitaxial growth of NaLuF 4 An inert shell layer;
3) After the solution is naturally cooled to room temperature, adding 10mL of absolute ethyl alcohol, vibrating and washing, centrifuging for 5min at 8000r/min, and repeatedly washing with absolute ethyl alcohol and centrifuging for 2-3 times to obtain precipitate which is NaNdF with a core-shell structure 4 :Yb60％@NaLuF 4 。
The prepared core-shell structure NaNdF 4 :Yb60％@NaLuF 4 The nanocrystals were redispersed in 10mL cyclohexane to give NaNdF 4 :Yb60％@NaLuF 4 Core-shell structure nanocrystalline dispersion (0.1 mmol/mL) for standby.
First, naNdF prepared in this example 4 :Yb60％@NaLuF 4 XRD diffraction analysis is carried out on the nanocrystalline with the core-shell structure. As can be seen from the XRD diffraction pattern of FIG. 1, naNdF 4 :Yb60％@NaLuF 4 Nanocrystalline is a hexagonal phase crystalline phase structure.
Next, naNdF obtained in this example 4 :Yb60％@NaLuF 4 And (5) carrying out transmission electron microscope observation on the nanocrystalline with the core-shell structure. As can be seen from FIG. 2, the core-shell structure NaNdF 4 :Yb60％@NaLuF 4 The nanocrystalline is monodisperse, round particles with regular morphology and uniform particle size, and the diameter is 17nm.
In addition, for NaNdF prepared in this example 4 :Yb60％@NaLuF 4 Core-shell structure nanocrystalline, core-shell structure alpha-NaYF disclosed in patent CN110514825B 4 :Nd60％,Yb7％@CaF 2 Nanocrystalline and core-shell structure beta-NaYF reported in literature (Feng Xu, et al Rare-earth Doped Nanoparticles with Narrow NIR-II Emission for Optical Imaging with Reduced Autofluoroscreen. Chem. Res. Chinese Universities,2021,37 (4), 943-950) 4 :Nd60％,Yb7％@NaYF 4 The nanocrystals were analyzed for emission spectra under 808nm excitation. As shown in FIG. 3, with the core-shell structure beta-NaYF 4 :Nd60％,Yb7％@NaYF 4 NaNdF compared with the emission spectrum of the nanocrystal under 808nm excitation 4 :Yb60％@NaLuF 4 Core-shell structure nanocrystalline 980nm nearThe infrared luminescence is enhanced by 3.0 times. FIG. 4 shows that with the core-shell structure alpha-NaYF 4 :Nd60％,Yb7％@CaF 2 NaNdF compared with emission spectrum under 808nm excitation of nanocrystalline 4 :Yb60％@NaLuF 4 The 980nm near infrared luminescence of the core-shell structure nanocrystal is enhanced by 30 times.
Finally, naNdF prepared in this example 4 :Yb60％@NaLuF 4 The core-shell structure nanocrystals were subjected to relative fluorescence quantum yield calculations. Determination of NaNdF Using ultraviolet absorption Spectrometry 4 :Yb60％@NaLuF 4 The absorbance of DMSO solution (0.1 mg/mL, DCNPs solution) and ICG solution (0.1 mg/mL, ICG solution) at 808nm of excitation light source, respectively designated A DCNPs And A ICG . After that, naNdF was measured by using a near infrared fluorescence spectrometer 4 :Yb60％@NaLuF 4 Emission spectra of DMSO solution (0.1 mg/mL) and ICG DMSO solution (0.1 mg/mL) at 808nm excitation, naNdF was calculated 4 :Yb60％@NaLuF 4 The emission peak areas of the core-shell nanocrystal and the near infrared fluorescent dye ICG are respectively marked as F DCNPs And F ICG . QY from relative fluorescence quantum yield calculation formula DCNPs =35.5%. The calculation formula is as follows:
and->
Wherein QY ICG The fluorescence quantum yield of the organic fluorescent dye ICG in DMSO solution is shown, and the value is 13% by reference of the literature; n is n DCNPs And n ICG The refractive indices of the DCNPs solution and the ICG solution are shown, respectively.
Example 2 preparation of high-near-infrared-light-emitting immunochromatographic test strip
The immunochromatographic test strip of the embodiment is advantageousWith NaNdF from example 1 4 :Yb60％@NaLuF 4 The core-shell structure nanocrystalline is prepared from an immune marker, and the test strip consists of a sample pad, a combination pad, a water absorption pad, a detection pad and a polyvinyl chloride supporting bottom plate;
wherein, detect the pad and constitute by the nitrocellulose membrane that contains detection line and matter control line: the detection line is a line which is drawn on the nitrocellulose membrane in parallel by a certain amount (3.5-4.2L) of serum index antibody solution, the quality control line is a line which is drawn on the nitrocellulose membrane in parallel by a certain amount (3.5-4.5L) of sheep anti-chicken IgY antibody solution, the line widths of the detection line and the quality control line are 1-1.2 mm, and the dripping volume amounts are 1-1.2 mL/cm;
the binding pad is NaNdF modified by loading binding antibody or target protein 4 :Yb60％@NaLuF 4 Core-shell structure nanocrystalline probe and chicken IgY antibody modified NaNdF 4 :Yb60％@NaLuF 4 The core-shell structure nanocrystalline probe consists of a polyester cellulose membrane.
The detection pad is stuck to the middle part of the polyvinyl chloride supporting base plate, and a bonding pad is stuck to one end of the detection pad, which is close to the detection line; sticking a sample pad at the other end of the bonding pad; one end of the quality control line of the detection pad is stuck with a water absorption pad, and the structure of the water absorption pad is shown in fig. 5 and 6.
The preparation method of the immunochromatographic test strip comprises the following steps of:
1. preparation of binding antibodies or target protein modified NaNdF 4 :Yb60％@NaLuF 4 Core-shell structure nanocrystalline probe and chicken IgY antibody modified NaNdF 4 :Yb60％@NaLuF 4 Core-shell structure nanocrystalline probe (namely, preparing rare earth down-conversion near infrared two-region luminescent probe)
1) To NaNdF prepared in example 1 4 :Yb60％@NaLuF 4 Adding 10mLHCI solution (0.1M) and 10mL absolute ethyl alcohol into core-shell structure nanocrystalline dispersion liquid (10 mL,0.1 mmol/mL), vibrating and mixing uniformly at room temperature, and removing oleic acid ligand by ultrasonic treatment for 30 min; then centrifuging (10000 r/min,30 min) to collect ligand-free NaNdF 4 :Yb60％@NaLuF 4 A nanocrystalline; centrifugal washing (10000 r/min,20 min) with deionized water, and repeating the operation for 2-3 times; will be ligand-freeNaNdF 4 :Yb60％@NaLuF 4 The nanocrystals were redispersed in 10mL deionized water, then added dropwise to 10mL deionized water containing 50mg polyacrylic acid (PAA), vigorously stirred at room temperature for 60min, and after completion of the reaction, polyacrylic acid-modified NaNdF was collected by centrifugation (10000 r/min,30 min) 4 :Yb60％@NaLuF 4 Nanocrystalline (i.e. PAA-NaNdF 4 :Yb60％@NaLuF 4 Nanocrystalline), and centrifugally washing with deionized water (10000 r/min,20 min), repeating the operation for 2-3 times, and then re-dispersing in 10mL of deionized water to obtain PAA-NaNdF 4 :Yb60％@NaLuF 4 Nanocrystalline dispersion (0.1 mmol/mL);
2) Taking 100uLPAA-NaNdF 4 :Yb60％@NaLuF 4 Nanocrystalline dispersion (0.1 mmol/mL) was added to a 1.5mL EP tube, followed by washing with 1mL MES buffer (ph=6.0), removal of supernatant by centrifugation (15000 r/min,15 min), followed by redispersion of PAA-nandf4:yb60% @ nanrof 4 nanocrystals in 1mL MES buffer (ph=6.0); 400uL of MES buffer containing 40ug EDC (pH=6.0) and 400uL of MES buffer containing 70ug Sulfo-NHS (pH=6.0) were sequentially added to the above solution, followed by reaction on a mixer for 30min, removal of supernatant by centrifugation (15000 r/min,15 min) after completion of the reaction, and then the Sulfo-NHS-activated PAA-NaNdF was prepared 4 Yb60% @ NaLuF4 nanocrystals were resuspended in 1mLMES buffer (pH=6.0);
adding 60mg RBD protein (novel coronavirus antigen) or chicken IgY antibody into the obtained nanocrystalline suspension, placing on a mixing instrument to react for 90min, then continuously adding 1mL Tris buffer (pH=8.0, 10 mM) of a sealing buffer (containing 1% (w/v) Bovine Serum Albumin (BSA)) to react for 60min on the mixing instrument to seal other unreacted activated sites, centrifuging (15000 r/min,15 min) and removing supernatant, and collecting NaNdF coupled with RBD protein or chicken IgY antibody 4 :Yb60％@NaLuF 4 A nanocrystalline;
washing of RBD protein or chicken IgY antibody conjugated NaNdF with final wash buffer [ Tris buffer (pH=8.0, 10 mM) containing 1% (w/v) Bovine Serum Albumin (BSA), 0.1% (v/v) Tween-20,0.03% (v/v) Proclin-300 ] 4 :Yb60％@NaLuF 4 Nanocrystalline crystalThen re-dispersing it in 100uL final wash buffer to obtain RBD protein or chicken IgY antibody coupled NaNdF 4 :Yb60％@NaLuF 4 Nanocrystal dispersion (0.1 mmol/mL) was used.
2. The steps of assembling the near infrared two-region luminous immunochromatography test strip are as follows:
1) Preparation of sample pad: fully soaking the glass fiber membrane for 2-4 h by using PB buffer solution (10 mM, pH=7.4) containing 1% (v/v) tween-20; then placing the mixture into a blast drying oven at 37 ℃ for drying for 24 hours; cutting the dried glass fiber film into long strips with the width of 21mm and the length of 300mm by an automatic cutter, and placing the prepared sample pad in a drying oven for standby;
2) Pretreatment of the bonding pad: fully soaking the polyester fiber membrane for 2-4 h by using PB buffer solution (10 mM, pH=7.4) containing 1% (v/v) tween-20; then placing the mixture into a blast drying oven at 37 ℃ for drying for 24 hours; cutting the dried glass fiber film into long strips with the width of 10mm and the length of 300mm by an automatic cutter, and placing the pretreated bonding pad in a drying oven for standby;
3) Preparation of the detection pad: firstly, sticking a nitrocellulose membrane on the middle part of a polyvinyl chloride supporting floor for standby, then diluting angiotensin converting enzyme 2 (ACE 2) and goat anti-chicken IgY antibody to 1mg/mL by using a coating buffer solution (PB buffer solution (10 mM, pH=7.4)), then uniformly scratching 1mg/mL of angiotensin converting enzyme 2 solution and goat anti-chicken IgY antibody solution on the positions of a detection line and a quality control line of the nitrocellulose membrane of the polyvinyl chloride supporting floor by using a metal spraying scratching instrument at a scratching speed of 50 mm/cm and a scratching amount of 1uL/cm, and placing the scratched polyvinyl chloride supporting floor in a blast drying box at 37 ℃ for drying for 24 hours for standby.
4) Preparation of the bond pad: to a gold spraying dilution (containing 10% (w/v) sucrose, 0.3% (w/v) Bovine Serum Albumin (BSA), 0.5% (w/v) polyvinylpyrrolidone (PVP K-30), 5% (w/v) S9 surfactant, 0.03% (v/v) Proclin-3000 Tris buffer (20 mM, pH=7.4)), 1% (v/v) RBD protein coupled NaNdF was added 4 :Yb60％@NaLuF 4 Nanocrystalline dispersion and 2% (v/v) chicken IgY antibody-conjugated NaNdF 4 :Yb60％@NaLuF 4 A nanocrystal dispersion; spraying at a speed of 50mm/s by a metal spraying film drawing instrumentThe speed and the spraying amount of 4uL/cm are evenly sprayed on the bonding pad which is pretreated before, and then the prepared bonding pad is placed in a blast drying oven at 37 ℃ for drying for 24 hours for standby.
5) Assembling an immunochromatography test strip: taking out the polyvinyl chloride supporting base plate of the nitrocellulose membrane with the fixed antibody, pasting a prepared bonding pad at one end close to a nitrocellulose membrane detection line, pasting a water absorption pad at one end close to a nitrocellulose membrane quality control line, and pasting a prepared sample pad at the other end of the prepared bonding pad; the lap joint distance between each component is 2mm, and the assembly of the test paper board is completed; cutting the assembled test paper board into a test paper strip with the width of 4.00mm by an automatic strip cutting machine, and loading the test paper strip into a plastic card shell to obtain a high-brightness near-infrared luminous immunochromatography test paper strip, which is also called a high-brightness near-infrared luminous Nd and Yb co-doped core-shell structure nanocrystalline SARS-CoV-2 neutralizing antibody measuring test paper strip.
3. NaNdF prepared in this example and emitting light in the near infrared region 4 :Yb60％@NaLuF 4 The using method of the immunochromatography test strip with the core-shell structure nanocrystalline as the immunofluorescence labeling probe comprises the following steps: mixing 50uL of blood sample and 80uL of sample buffer solution [ containing 0.85% (w/v) sodium chloride (NaCl), 0.5% (v/v) triton 100 (TX-100), 0.1% (v/v) Tween-20 (T-20) and 0.1% (w/v) Tris buffer solution (100 mM, pH=8.0) of S9 surfactant ] in a vibration mode, adding the mixture into a sample pad, standing for 15min, and then detecting fluorescent signals of a detection line and a quality control line in a test strip at 980nm by using a handheld detection instrument; and a standard curve is established according to the measured fluorescence intensity and the concentration of the standard sample SARS-CoV-2 neutralizing antibody; and comparing the fluorescence intensity of the detection sample with a standard curve to obtain the concentration of the SARS-CoV-2 neutralizing antibody in the sample.
Example 3 detection Limit of high-light near-infrared luminescent immunochromatographic test strip
The detection limit of the SARS-CoV-2 neutralizing antibody is determined by exploring the high-light near infrared luminescent immunochromatography test strip prepared in example 2, and the specific method is as follows:
1) The standard of SARS-CoV-2 neutralizing antibody was added to sample buffer [ Tris buffer (100 mM, pH=8.0) containing 0.85% (w/v) sodium chloride (NaCl), 0.5% (v/v) triton 100 (TX-100), 0.1% (v/v) Tween-20 (T-20), 0.1% (w/v) S9 surfactant ], and the concentration of the prepared SARS-CoV-2 neutralizing antibody was 0ug/mL,0.6ug/mL,0.13ug/mL,0.25ug/mL,0.5ug/mL,1ug/mL,2ug/mL,4ug/mL,8ug/mL,16/mL, respectively;
2) 100uL of sample solution with each concentration is added into a sample adding hole of a reagent card (the immunochromatographic test strip prepared in the embodiment 2), standing and chromatography reaction is carried out for 15min at room temperature, a handheld detection instrument is used for collecting 980nm emission light signal intensity at a detection line and a quality control line of a near infrared two-region luminous immunochromatographic test strip, the test result and a corresponding standard curve of a sample with the concentration of each SARS-CoV-2 neutralizing antibody are shown as figure 7, and the detection limit of the immunochromatographic test strip is 0.11ug/mL and has good repeatability as can be seen from figure 7.
The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, and yet fall within the scope of the invention.

Claims (10)

1. High-brightness near-infrared light-emitting beta-phase Nd 3+ And Yb 3+ The preparation method of the co-doped core-shell structure nanocrystal is characterized by comprising the following steps of:
s1, preparation of core NaNdF 4 :Yb：
S11, weighing rare earth acetate, wherein neodymium acetate accounts for 40% and ytterbium acetate accounts for 60%, adding oleic acid and 1-octadecene, and heating to 150-180 ℃ in an inert gas atmosphere until all solids are dissolved to obtain a rare earth precursor solution;
s12, adding a methanol solution containing sodium hydroxide and a methanol solution containing ammonium fluoride into the rare earth precursor solution, stirring and uniformly mixing under an inert gas atmosphere, and heating the solution to 120 ℃ to remove methanol in the solution; finally heating the solution to 290-310 ℃ and maintaining the reaction for 50-70min;
s13, finishing the reactionAfter completion, the solution was cooled to room temperature, and then the precipitate was collected by centrifugation to obtain nuclear NaNdF 4 60 percent of Yb; finally NaNdF is added 4 Dispersing 60% Yb nanocrystalline in cyclohexane for standby;
s2, preparing NaNdF 4 :Yb60％@NaLuF 4 Core-shell structure:
s21, adding lutetium oxide into an aqueous solution containing trifluoroacetic acid; heating to 90-110 ℃ until the solid is completely dissolved, and then continuously heating until the solution is completely evaporated to dryness to obtain lutetium trifluoroacetate solid powder;
s22, adding sodium trifluoroacetate, oleic acid and 1-octadecene into the lutetium trifluoroacetate solid powder, and obtaining NaNdF in the step S13 4 Yb60% cyclohexane solution; heating to 110-130 ℃ under inert gas atmosphere, and keeping for 20-40min to remove cyclohexane and water in the system; then heating to 290-310 ℃ for reaction for 50-70min for epitaxial growth of NaLuF 4 A shell layer;
s23, after the solution is cooled to room temperature, centrifugally collecting the precipitate to obtain the highlight near-infrared luminous beta-phase Nd 3+ And Yb 3+ Co-doping core-shell structure nanocrystals.
2. A highlighting near infrared luminescent beta-phase Nd according to claim 1 3+ And Yb 3+ The preparation method of the co-doped core-shell structure nanocrystalline is characterized in that in the step S11, the dosage ratio of the rare earth acetate to oleic acid to 1-octadecene is 1-3mmol:7.5mL:15mL.
3. A highlighting near infrared luminescent beta-phase Nd according to claim 1 3+ And Yb 3+ The preparation method of the co-doped core-shell structure nanocrystal is characterized in that in the step S12, the molar concentration of the methanol solution containing sodium hydroxide is 0.2-0.5mmol/mL, and the molar concentration of the methanol solution containing ammonium fluoride is 0.3-0.5mmol/mL.
4. A highlighting near infrared luminescent beta-phase Nd according to claim 1 3+ And Yb 3+ The preparation method of the co-doped core-shell structure nanocrystalline is characterized in thatIn step S12, the volume ratio of the methanol solution containing sodium hydroxide to the methanol solution containing ammonium fluoride is 1:1.
5. A highlighting near infrared luminescent beta-phase Nd according to claim 1 3+ And Yb 3+ The preparation method of the co-doped core-shell structure nanocrystal is characterized in that in the step S21, the dosage ratio of lutetium oxide to trifluoroacetic acid aqueous solution is 0.5-2mmol/10-20mL, and the volume fraction of the trifluoroacetic acid aqueous solution is 50%.
6. A highlighting near infrared luminescent beta-phase Nd according to claim 1 3+ And Yb 3+ The preparation method of the co-doped core-shell structure nanocrystalline is characterized in that in the step S22, sodium trifluoroacetate, oleic acid, 1-octadecene and NaNdF are adopted 4 The dosage ratio of Yb60% cyclohexane solution is 1-3mmol:10mL:10mL:10-20mL of the NaNdF 4 The molar concentration of Yb60% cyclohexane solution is 0.1-0.2mmol/mL.
7. The high-brightness near-infrared light-emitting beta-phase Nd prepared by the preparation method of any one of claims 1-6 3+ And Yb 3+ Co-doping core-shell structure nanocrystals.
8. The highlighted near-infrared-emitting beta-phase Nd of claim 7 3+ And Yb 3+ The application of the co-doped core-shell structure nanocrystalline in immunochromatography detection.
9. Beta-phase Nd based on highlight near-infrared light emission 3+ And Yb 3+ A serum marker luminescent detection side flow test strip co-doped with core-shell structure nanocrystalline is characterized in that the side flow test strip is a high-brightness near-infrared luminescent beta-phase Nd according to claim 7 3+ And Yb 3+ The co-doped core-shell structure nanocrystalline is an immune label, and the lateral flow test strip is prepared from high-brightness near-infrared luminous beta-phase Nd 3+ And Yb 3+ Co-doped core-shell structure nanocrystalline, polyvinyl chloride supporting backboard, detection pad, bonding pad and sampleThe pad and the water absorption pad are formed, the binding pad is loaded with a high-brightness near-infrared luminous beta-phase Nd modified by a binding antibody or a target protein 3+ And Yb 3+ Co-doped core-shell structure nanocrystalline probe and anti-quality control object antibody modified high-brightness near-infrared light-emitting beta-phase Nd 3+ And Yb 3+ Co-doped core-shell structure nanocrystalline probes.
10. A highlighting-based near infrared light emitting beta phase Nd according to claim 9 3+ And Yb 3+ The serum marker luminescent detection side flow test strip co-doped with the core-shell structure nanocrystalline is characterized in that the anti-quality control antibody comprises a goat anti-chicken IgY antibody.
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CN113980682A (en) * 2021-11-16 2022-01-28 广州医科大学附属第二医院 Preparation of near-infrared luminescent Yb and Tm co-doped core-shell structure nanocrystal and application of nanocrystal in immunochromatography detection

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Publication number Priority date Publication date Assignee Title
CN112111275A (en) * 2020-08-26 2020-12-22 复旦大学 Temperature measurement method based on rare earth luminescent life temperature probe
CN113980682A (en) * 2021-11-16 2022-01-28 广州医科大学附属第二医院 Preparation of near-infrared luminescent Yb and Tm co-doped core-shell structure nanocrystal and application of nanocrystal in immunochromatography detection

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