CN105385447A - A low-cost method for mass-preparing NaREF4 type up-conversion luminescent porous microspheres - Google Patents

Abstract

The invention provides a low-cost method for mass-preparing NaREF ₄ type up-conversion luminescent porous microspheres, comprising: adding one or more of ammonium fluoride, ammonium bifluoride, sodium fluoride, and rare earth inorganic salt solids to polyacrylic acid A step of stirring in an aqueous sodium solution to obtain a uniform solution; and a step of heating the above solution in a hydrothermal reaction kettle or a microwave synthesis device to obtain an up-conversion material. The advantage of the method is that the water-soluble up-conversion luminescent porous microspheres can be prepared efficiently and in large quantities by one-step reaction. The material has the functions of upconversion luminescence and mesoporous drug adsorption, and has excellent application prospects in the field of bioimaging diagnosis and intelligent drug carrier, and is expected to provide a high-quality and low-cost solution for the design of an integrated platform for tumor diagnosis and treatment .

Description

A low-cost method for mass-preparing NaREF4 type up-conversion luminescent porous microspheres

technical field

The invention relates to a preparation method of a porous up-conversion luminescent material, in particular to a method for preparing a large amount of water-soluble porous NaREF ₄ type up-conversion luminescent micro-nanospheres at low cost.

Background technique

Up-conversion materials refer to materials that can emit fluorescence with a shorter wavelength than the excitation light when irradiated by excitation light, that is, absorb low-frequency light and emit high-frequency light, so it is called frequency up-conversion. Up-conversion luminescent materials are widely used in the research and application of biological fields because they can be excited by infrared light to emit visible light, have the advantages of low photodamage to biological tissues, and large light penetration depth. In recent years, the huge application potential of porous rare earth upconversion luminescent materials in multimodal diagnosis and synergistic therapy of tumors has attracted widespread attention.

Among the luminescent hosts of various types of up-conversion luminescent materials, the up-conversion materials based on NaREF ₄ are one of the up-conversion fluorescent materials with the highest luminous efficiency. The currently known preparation methods of NaREF ₄ upconversion porous microspheres mainly include hydrothermal synthesis of PEI/DEG system or sodium citrate/EG/H ₂ O system and high temperature oil phase thermal decomposition synthesis + mesoporous SiO ₂ coating Methods, etc. (Non-Patent Documents 1~3).

Non-Patent Document 1: L. Zhouetal. Nanoscale, 2014, 6(3): 1445-1452.

Non-Patent Document 2: X. Quetal. RSCAdvances, 2013, 3(14): 4763-4770.

Non-Patent Document 3: X. Kang etal. The Journal of Physical Chemistry C, 2011, 115(32): 15801-15811.

The known preparation methods of NaREF ₄ microspheres have the following problems to be solved urgently: cumbersome process, high input and low output, high toxicity of reaction raw materials and solvents, and high environmental hazards. Whether the input can be reduced and the output can be increased is the key to determining whether the material can move from the laboratory research stage to the commercial application stage.

Contents of the invention

The main purpose of the invention is to increase the output of porous up-conversion luminescent materials and provide a low-cost method for preparing NaREF ₄ type up-conversion luminescent porous microspheres in large quantities. It is characterized in that: add fluoride and rare earth inorganic salt into sodium polyacrylate aqueous solution (PAAS), and stir to obtain a mixed solution; seal the above mixed solution in a high-pressure reactor or a microwave reactor with a polytetrafluoroethylene liner for heating After reaction, NaREF ₄ porous microspheres were obtained after centrifugation, washing and drying.

The purpose of the present invention is achieved through the following technical solutions:

A low-cost method for mass-preparing NaREF ₄ type up-conversion luminescent porous microspheres: add rare earth inorganic salts and fluoride salts into the reaction vessel, and then add them at a mass concentration of 5% to 100% and a relative molecular mass of 2 to 90 million Sodium polyacrylate (PAAS) aqueous solution is used as a solvent, stirred at room temperature or heated for 0.5~2h to mix evenly, then moved into a hydrothermal reaction kettle or a microwave reactor, and reacted at a temperature of 80°C~400°C for 0.5~96h, that is Porous microspheres are available.

RE represents one or more of the 17 rare earth elements. The ratio of rare earth inorganic salt to fluorine element is 1:2.5~1:24, and the concentration of rare earth inorganic salt in the reaction system is 0.1~2mol/L.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. A large amount of water-soluble NaREF ₄ up-conversion luminescent micro-nanospheres can be produced in one reaction in a reactor with the same volume, which greatly simplifies the process steps of material preparation, and can better ensure Consistency of product morphology and structure. Using the known porous upconversion microsphere synthesis method, PEI/DEG system or sodium citrate/EG/H ₂ O system in 40mL hydrothermal kettle, high temperature pyrolysis synthesis in 100mL flask + mesoporous SiO ₂ coating method can only Obtain 1 mmol product, about 0.2 g (non-patent literature 1~3). And use this method, do a synthesis in 40mL reactor, can obtain 15mmol product, about 3.0g, is 15 times of known method;

2. The product has good mesoporous structure and water solubility, and is an ideal drug carrier;

3. It does not contain SiO ₂ and other components that only provide porous structure. The NaREF ₄ mesoporous material synthesized by this method has both up-conversion fluorescence imaging labeling function and drug adsorption function, and the active ingredient is close to 100%;

4. The price of raw materials is low, no organic solvent is used, and it is green and environmentally friendly. It is an ideal solution for mass industrial production.

Description of drawings

Fig. 1 is an X-ray diffraction pattern of NaYF ₄ :Yb, Er prepared in Example 1 of the present invention.

Fig. 2 is a field emission scanning electron microscope image of NaYF ₄ :Yb, Er prepared in Example 1 of the present invention.

Fig. 3 is a field emission scanning electron microscope image of the product prepared in Example 2 of the present invention.

Fig. 4 is a field emission scanning electron microscope image of the product prepared in Example 3 of the present invention.

FIG. 5 is the energy spectrum of the porous NaYF ₄ :Yb,Er prepared in Example 1.

Fig. 6 is the nitrogen adsorption-desorption curve (a) and the pore size distribution diagram (b) of the porous NaYF ₄ :Yb, Er prepared in Example 1.

FIG. 7 is an up-conversion emission spectrum of the porous NaYF ₄ :Yb,Er prepared in Example 1. FIG.

Fig. 8 is the infrared spectrogram of the porous NaYF ₄ :Yb, Er up-conversion microspheres (b) and the PAAS aqueous solution (a) prepared in Example 4.

Fig. 9 is a comparison chart of the total amount of products prepared in Example 1 and the total amount of products prepared at one time in a 40mL reactor according to the literature scheme 1. The light spot is the fluorescence generated by the material under 980nm laser irradiation.

FIG. 10 is a photograph of the dispersion of the product prepared in Example 1 in deionized water. The light spot is the fluorescence generated by the material under 980nm laser irradiation.

detailed description

In order to better understand the present invention, the present invention will be further described below in conjunction with the accompanying drawings and examples, but the protection scope of the present invention is not limited to the scope described in the examples.

Example 1

Add RE(NO ₃ ) ₃ (where RE is Y: 80%, Yb: 18%, Er: 2%) and NH ₄ F into an aqueous solution of 50% PAAS (relative molecular mass is 50 million to 70 million), RE The mass ratio of (NO ₃ ) ₃ to NH ₄ F is 1:4, and the concentration of RE(NO ₃ ) ₃ in the mixed solution is 0.6 mol/L. Stir at room temperature for 1 h, put it into a reaction kettle, seal it, and react at 220 ° C for 12 h. Cool to room temperature, centrifuge and wash, then dry in an oven at 70°C for 12 hours to obtain a white powder.

Combining the XRD data in Figure 1 and the EDS data in Figure 5, the product is pure hexagonal NaYF ₄ :Yb,Er.

It can be judged from Figure 2 and Figure 6 that the obtained product is a porous microsphere, the average size of the microsphere is 311 nm, and the average pore size is 3.4 nm.

Figure 7 is the upconversion luminescence spectrum of the product under the excitation of 980nm laser with a power of 1w, which shows that the product has emission peaks at green light (521nm, 541nm), red light (656nm) and near infrared (842nm).

Figure 8 is the infrared spectrogram of the product (b) and the PAAS aqueous solution (a) used, indicating that the surface of the product is covered with PAAS.

Fig. 9 is the actual contrast photo of the product obtained by this method and the method of reference 1 in two 40ml reactors respectively, it can be seen that the amount of the product synthesized by the method of the present invention is much higher than the synthetic method reported in document 1.

Figure 10 is a photo of the product dispersed in deionized water, it can be seen that the product can be uniformly dispersed in deionized water.

Example 2

Add RECl ₃ (where RE is Y: 80%, Yb: 18%, Er: 2%) and NH ₄ F to 30% PAAS (relative molecular mass is 50 million to 70 million) aqueous solution, RECl ₃ and NH ₄ The ratio of the amount of substance of F is 1:4, and the concentration of RECl ₃ in the mixed solution is 0.6mol/L. Stir at room temperature for 1 h, put it into a reaction kettle, seal it, and react at 220 ° C for 12 h. Cool to room temperature, centrifuge and wash, then dry in an oven at 70°C for 12 hours to obtain a white powder.

Fig. 3 is the SEM image of the product obtained in Example 2, the obtained product is uniform spherical, with an average size of 703nm. The XRD test results showed that the obtained product was pure hexagonal NaREF ₄ , and the product had emission peaks around 521nm, 541nm and 842nm under 980nm laser irradiation.

Example 3

Add RE(NO ₃ ) ₃ (where RE is Yb: 98%, Er: 2%) and NH ₄ F to 30% PAAS (relative molecular mass is 50 million to 70 million) aqueous solution, RE(NO ₃ ) ₃ The ratio of the amount of substance to NH ₄ F is 1:5, and the concentration of RE(NO ₃ ) ₃ in the mixed solution is 0.6mol/L. Stir at room temperature for 1.5h, put it into a reaction kettle, seal it, and react at 200°C for 12h. Cool to room temperature, centrifuge and wash, then dry in an oven at 70°C for 12 hours to obtain a white powder.

Fig. 4 is the SEM picture of the product obtained in Example 3, it can be seen from the figure that the obtained product is a uniform ellipsoid.

The XRD test results showed that the obtained product was pure hexagonal NaREF ₄ , and the product had emission peaks around 521nm, 541nm and 842nm under 980nm laser irradiation.

Example 4

Add RE(NO ₃ ) ₃ (where RE is Gd: 80%, Yb: 18%, Ho: 2%) and NH ₄ HF ₂ into 40% PAAS (relative molecular mass: 30 million to 50 million) aqueous solution, The ratio of RE(NO ₃ ) ₃ to NH ₄ HF ₂ is 1:2.5, and the concentration of RE(NO ₃ ) ₃ in the mixed solution is 1.2 mol/L. Place in a microwave reactor, heat and stir at 300°C for 0.5h. Cool to room temperature, centrifuge and wash, then dry in an oven at 70°C for 12 hours to obtain a white powder.

The XRD test results show that the product is pure hexagonal NaREF ₄ , and the product has emission peaks around 365nm and 405nm under 980nm laser excitation.

Example 5

Add RE(NO ₃ ) ₃ (where RE is La: 79%, Yb: 20%, Tm: 1%) and NaF to 30% PAAS (relative molecular mass: 20 million) aqueous solution, RE(NO ₃ ) ₃ The ratio of the amount of substance to NaF is 1:4, and the concentration in PAAS aqueous solution is 2mol/L. Stir at room temperature for 2 hours, put it into a reaction kettle, seal it, and react at 80°C for 96 hours. Cool to room temperature, centrifuge and wash, then dry in an oven at 70°C for 12 hours to obtain a white powder.

The XRD test results show that the product is pure hexagonal NaREF ₄ , and the product has emission peaks around 365nm and 405nm under 980nm laser irradiation.

Example 6

Add RE(NO ₃ ) ₃ (where RE is Lu: 80%, Yb: 18%, Er: 2%) and NaF to 5% PAAS aqueous solution (relative molecular mass is 200), RE(NO ₃ ) ₃ and The ratio of NaF to substance is 1:4, and the concentration of RE(NO ₃ ) ₃ in the mixed solution is 1.2mol/L. Stir at room temperature for 1 h, put it into a reaction kettle, seal it, and react at 180°C for 48 h. Cool to room temperature, wash and dry in an oven at 70°C for 12 hours to obtain a white powder.

XRD test results show that the product is pure hexagonal phase NaREF ₄ , and the product has emission peaks at 542nm and 656nm under 980nm laser excitation.

Example 7

Add RECl ₃ (where RE is La: 79%, Yb: 20%, Tm; 1%) and NH ₄ F to 10% PAAS aqueous solution (relative molecular mass is 3000), RE(NO ₃ ) ₃ and NH ₄ The ratio of the substance amount of F is 1:2.5, and the concentration of RE(NO ₃ ) ₃ in the mixed solution is 0.1mol/L. Stir at room temperature for 1 h, put it into a reaction kettle, seal it, and react at 150 ° C for 12 h. Cool to room temperature, wash and dry in an oven at 70°C for 12 hours to obtain a white powder.

The XRD test results showed that the obtained product was NaREF ₄ , and the product had emission peaks at 542nm and 656nm under 980nm laser excitation.

Example 8

Add RE(CH ₃ COO) ₃ (where RE is Gd: 80%, Yb: 18%, Er: 2%) and NH ₄ HF ₂ to 100% PAAS (relative molecular mass: 90 million), RE(NO ₃ ) ₃ and NH ₄ HF ₂ are 1:24, and the concentration of RE(NO ₃ ) ₃ in the mixed solution is 1.2 mol/L. Placed in a microwave reactor at 400 ° C for 1 h. Cool to room temperature, centrifuge and wash, then dry in an oven at 70°C for 12 hours to obtain a white powder.

XRD test results show that the product is pure hexagonal phase NaREF ₄ , and the product has emission peaks at 542nm and 656nm under 980nm laser excitation.

Example 9

Add RE(NO ₃ ) ₃ (where RE is Y: 80%, Nd: 18%, Er: 2%) and NH ₄ F to the aqueous solution of 70% PAAS (relative molecular mass is 80 million), RE(NO ₃ The ratio of ) ₃ to NH ₄ F is 1:12, and the concentration of RE(NO ₃ ) ₃ in the mixed solution is 1.2 mol/L. Stir under heating at 80°C for 0.5h, put it into a reaction kettle, seal it, and react at 200°C for 24h. After washing and drying, a white powder is obtained.

The XRD test results showed that the obtained product was pure hexagonal NaREF ₄ , and the product had emission peaks at 542nm and 656nm under 800nm laser excitation.

Claims (11)

1. a low cost prepares NaREF in a large number ₄the method of type up-conversion luminescence porous microsphere, is characterized in that: fluorochemical and inorganic salt of rare earth are added in aqueous sodium polyacrylate (PAAS), stirs and obtains mixing solutions; Above-mentioned mixing solutions is encapsulated in reacting by heating in teflon-lined autoclave or microwave reactor, after centrifugal, washing, drying, obtains NaREF ₄porous microsphere.

2. the preparation method of porous microsphere according to claim 1, is characterized in that, described fluorochemical is at least one in Neutral ammonium fluoride, ammonium bifluoride, Sodium Fluoride.

3. the preparation method of porous microsphere according to claim 1, is characterized in that, the mass concentration of described aqueous sodium polyacrylate (PAAS) is 5% ~ 100%, and relative molecular mass is 200 ~ 9,000 ten thousand.

4. the preparation method of porous microsphere according to claim 1, is characterized in that, described inorganic salt of rare earth is at least one in rare earth chloride, rare earth nitrate and lanthanon acetate.

5. the preparation method of porous microsphere according to claim 1, is characterized in that, described rare earth is at least one in lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, yttrium.

6. the preparation method of porous microsphere according to claim 1, is characterized in that, the volumetric molar concentration of described inorganic salt of rare earth in mixing solutions is 0.1 ~ 2mol/L.

7. the preparation method of porous microsphere according to claim 1, is characterized in that, described inorganic salt of rare earth is 1:2.5 ~ 1:24 with the ratio of the amount of substance of described fluorochemical.

8. the preparation method of porous microsphere according to claim 1, is characterized in that, described reacting by heating is carried out in teflon-lined autoclave or microwave reactor.

9. the preparation method of porous microsphere according to claim 1, is characterized in that, the temperature of reaction of described reacting by heating is 80 DEG C ~ 400 DEG C, and the reaction times is 0.5 ~ 96h.

10. the preparation method of porous microsphere according to claim 1, is characterized in that, described porous microsphere size is between 100nm ~ 5um.

The preparation method of 11. porous microspheres according to claim 1, is characterized in that, the pore dimension of described porous microsphere is between 1nm ~ 200nm.