Method for preparing a ratiometric fluorescent sensor for phycoerythrin based on a magnetic molecularly imprinted core-shell polymer

Patent metadata

Field	Value
Publication number	US-2020408689-A1
Application number	US-201916620690-A
Country	US
Kind code	A1
Filing date	Mar 14, 2019
Priority date	Nov 8, 2018
Publication date	Dec 31, 2020
Grant date	—

Abstract

A method for preparing a ratiometric fluorescent sensor for phycoerythrin based on a magnetic molecularly imprinted core-shell polymer is provided. With Fe3O4 magnetic nanoparticles as the core, blue fluorescence-emitting carbon quantum dots (B-CDs) are coupled on the surfaces of Fe3O4 magnetic nanoparticles, and SiO2 shells carrying template molecules (phycoerythrin) are grown on the surfaces of Fe3O4/B-CDs. Then, the molecularly imprinted polymer SiO2-MIPs are obtained by eluting the template molecules, that is, Fe3O4/B-CDs/SiO2-MIPs are obtained. Fluorescence emission spectra of the dispersion of Fe3O4/B-CDs/SiO2-MIPs in the presence of different concentrations of phycoerythrin are measured. By fitting the linear relationship between the ratios Iphycoerythrin/IB-CDs of fluorescence emission peak intensities of phycoerythrin and B-CDs and the molar concentrations of phycoerythrin, the ratiometric fluorescent sensor for phycoerythrin is constructed.

First claim

What is claimed is:

1 . A method for preparing a ratiometric fluorescent sensor for phycoerythrin based on a magnetic molecularly imprinted core-shell polymer, comprising the following steps:
(1) preparation of aminated B-CDs: taking 0.3 mL of 1,4-dioxane and 25 mL of catechol solution to mix well by ultrasound to obtain a first solution, transferring the first solution to a 50 mL high-pressure reactor with a polytetrafluoroethylene liner, heating the first solution for a first reaction at 180° C. for 12 hours to obtain a dark brown mixture; wherein the dark brown mixture is diluted with 20 mL of double-distilled water and centrifuged at 12,000 rpm to remove larger particles to obtain a supernatant; the supernatant is filtered through a 0.4 micro-filtration membrane to obtain a filtrate, and the filtrate is dialyzed through a dialysis bag with a molecular weight cut-off of 1000 Da to remove unreacted experimental materials to obtain a second solution; the second solution in the dialysis bag is poured out, subjected to a rotary evaporation to remove 90% of the liquid water, and then dried in a vacuum to obtain the B-CDs, and the B-CDs are stored at 4° C. away from light, or the B-CDs are dispersed in water to obtain a B-CDs aqueous dispersion for subsequent experiments; (2) preparation of carboxylated Fe 3 O 4 magnetic nanoparticles: adding ferric chloride and ferrous chloride with a molar ratio of 2:1 into a 250 mL reaction flask to prepare a 100 mL mixed solution, adding 10 mL of ammonia water with a mass concentration of 25% into the 250 mL reaction flask under N 2 protection to obtain a third solution, stirring the third solution rapidly to cause a second reaction, adjusting a pH of the third solution to alkaline with HCl, after 10 minutes of the second reaction, adding 10 mL of trisodium citrate solution to the third solution to obtain a fourth solution; and then placing the 250 mL reaction flask in a water bath at 80° C. continuously stirring the fourth solution for a third reaction for 30 minutes to obtain a first reaction production; wherein the first reaction product is centrifuged, washed and dried to obtain the carboxylated Fe 3 O 4 magnetic nanoparticles; the carboxylated Fe 3 O 4 magnetic nanoparticles are stored at 4° C. away from light, or dispersed in water to prepare a Fe 3 O 4 aqueous dispersion for subsequent experiments; (3) preparation of magnetic molecularly imprinted core-shell polymers: adding 2 mL of the B-CDs aqueous dispersion to 18 mL of aqueous dispersion containing 0.8 mL of the Fe 3 O 4 aqueous dispersion to obtain a fifth solution, stirring the fifth solution for a fourth reaction for 30 minutes, adding template molecules (the phycoerythrin) and 20 μL of 3-aminopropyltriethoxysilane to the fifth solution to obtain a sixth solution, continuously performing a fifth reaction on the sixth solution for 1 hour, then adding 40 μL of ammonia water and 40 μL of tetraethyl silicate to the sixth solution to obtain a seventh solution, and continuously performing a sixth reaction on the seventh solution away from light for 12 hours to obtain a second reaction product; wherein the second reaction product is centrifuged, and washed three times with a solution consisting of ethanol and acetonitrile at a volume ratio of 8:2 to remove the template molecules to obtain a product, and then Fe 3 O 4 /B-CDs/SiO 2 -MIPs are obtained from the product by centrifugation, washing and drying; the Fe 3 O 4 /B-CDs/SiO 2 -MIPs are dispersed in water to prepare a Fe 3 O 4 /B-CDs/SiO 2 -MIPs aqueous dispersion for use; (4) at room temperature and under a magnetic stirring, adding the phycoerythrin with a plurality of molar concentrations to the Fe 3 O 4 /B-CDs/SiO 2 -MIPs aqueous dispersion to form a plurality of homogeneous mixtures and then incubating the plurality of homogeneous mixtures away from light for 5 minutes; wherein fluorescence emission spectra of the plurality of homogeneous mixtures are measured; by fitting a linear relationship between ratios I phycoerythrin /I B-CDs of fluorescence emission peak intensities of the phycoerythrin and the B-CDs and the plurality of molar concentrations of the phycoerythrin, the ratiometric fluorescent sensor for the phycoerythrin is constructed.

2 . The method for preparing the ratiometric fluorescent sensor for the phycoerythrin based on the magnetic molecularly imprinted core-shell polymer according to claim 1 , wherein, in step (1), a size of each of the aminated B-CDs is 1-5 nm.

3 . The method for preparing the ratiometric fluorescent sensor for the phycoerythrin based on the magnetic molecularly imprinted core-shell polymer according to claim 1 , wherein, in step (2), a size of each of the carboxylated Fe 3 O 4 magnetic nanoparticles is 10-30 nm.

4 . The method for preparing the ratiometric fluorescent sensor for the phycoerythrin based on the magnetic molecularly imprinted core-shell polymer according to claim 1 , wherein, in step (3), a mass concentration of the B-CDs is 1-10 mg/mL, a mass concentration of the carboxylated Fe 3 O 4 magnetic nanoparticles is 5-20 mg/mL, and the plurality of molar concentrations of the phycoerythrin is 0.5-1 μM.

5 . The method for preparing the ratiometric fluorescent sensor for the phycoerythrin based on the magnetic molecularly imprinted core-shell polymer according to claim 1 , wherein, in step (4), a linear detection range of the molar concentrations of the phycoerythrin is 1-500 nM, and a detection limit of the phycoerythrin is 1-10 nmol/L.

Assignees

• Univ Qingdao

Inventors

• Jin Hui
• Gui Rijun
• Fu Yongxin
• Bu Xiangning

Classifications

• C09K11/06 Primary

  containing organic luminescent materials · CPC title

• C09K11/025

  non-luminescent particle coatings or suspension media · CPC title

• G01N2021/6439

  with indicators, stains, dyes, tags, labels, marks · CPC title

• C09K2211/14

  Macromolecular compounds · CPC title

• G01N21/6486

  Measuring fluorescence of biological material, e.g. DNA, RNA, cells (G01N21/6428 takes precedence) · CPC title