Magnetic fluorescent Raman double-encoding composite microspheres and preparation method and application thereof

A Raman double-coded, composite microsphere technology, applied in the direction of microsphere preparation, Raman scattering, fluorescence/phosphorescence, etc., can solve the problems of difficult precise control, less SERS signal, etc., and achieve low cost, high luminous efficiency, light reduction Effects of low reproducibility and instability of small Raman signals

Inactive Publication Date: 2015-09-16
FUDAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current SERS substrates mainly have rough surfaces of gold or silver, nanoparticles or aggregates deposited on the surface of dielectric microspheres, and high SERS activity has always been a resea

Method used

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  • Magnetic fluorescent Raman double-encoding composite microspheres and preparation method and application thereof
  • Magnetic fluorescent Raman double-encoding composite microspheres and preparation method and application thereof
  • Magnetic fluorescent Raman double-encoding composite microspheres and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Example 1: Preparation of MF Microspheres of Different Sizes

[0043] 1. Preparation of MF balls with a particle size of 4 μm

[0044] Take 0.625g of melamine, 4.9ml of formaldehyde solution, disperse in 60ml of deionized water, pre-polymerize at 70°C for 0.5h, add 1μl of formic acid, continue mechanical stirring for 2h, let stand, remove the upper emulsion, and repeatedly wash the product with ethanol and water centrifuge , and vacuum-dried to prepare MF microspheres with a particle size of 4 μm.

[0045] 2. Preparation of MF balls with a particle size of 0.4 μm

[0046] The content of formic acid in the above reaction conditions was changed to 50 μl to obtain MF microspheres with a particle size of 0.4 μm.

Embodiment 2

[0047] Example 2: Mixed adsorption of FMF microspheres and ferrofluid with different feeding ratios

[0048] Mix FMF microspheres and ferrofluid mass ratios in 9:1, 6:1, 3:1, 1:1, 1:3 and 1:6 in 20ml of ethanol, and incubate in a shaker at 30°C and 180rpm 3h, the obtained product was first centrifuged and washed to separate the unadsorbed magnetic fluid, and then magnetically separated to remove the FMF microspheres that did not absorb enough magnetic fluid. It was found that the magnetic enrichment rate of 3:1 feed ratio was faster (about 40s), and the magnetic enrichment rate did not increase significantly with the increase of feed ratio, and the excessive magnetic fluid adsorbed on the surface would hinder the subsequent deposition of silver nanoparticles.

Embodiment 3

[0049] Example 3: Detection of different concentrations of 4-ABT by double-coded composite microspheres

[0050] The obtained composite microspheres were dried, and 10 mg microspheres were mixed with 15 ml different concentrations (10 -11 -10 -3 g / L) of 4-ABT ethanol solution was added to the centrifuge tube, and incubated in a shaker for 2 hours. Afterwards, the SERS signal of the sample was detected by a Raman spectrometer.

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Abstract

The invention belongs to the technical field of functional material, and specifically relates to magnetic fluorescent Raman double-encoding composite microspheres and a preparation method and an application thereof. The composite microspheres are prepared by the steps: adding fluorescein in a condensation reaction of melamine and formaldehyde to form fluorescent melamine resin microspheres, after a magnetic fluid is physically adsorbed on the surface, depositing silver nanoparticles by a chemical deposition method to form core-shell structural microspheres with the fluorescent melamine resin microspheres as a core and the magnetic fluid and the silver nanoparticles as a shell, then fixing Raman labeled molecules and coating with an SiO2 shell layer to form the composite microspheres denoted as the FMF/Fe3O4-NPs/Ag-NPs/SiO2 composite microspheres. The composite microspheres are labeled with the fluorescein, have the micron-scale microsphere particle size, can be used as a single-microsphere Raman enhancement substrate, and are applied to Raman detection. The method is simple in operation and controllable in process, can increase the encoding capacity of the composite microspheres by labeling of different fluoresceins and adsorption of various Raman report molecules, and can be used for anti-fake marks for coatings/printing inks and the like.

Description

technical field [0001] The invention belongs to the technical field of functional materials, and in particular relates to a magnetic fluorescence Raman-enhanced double-coded composite microsphere, a preparation method thereof, and an anti-counterfeiting application in the field of paint and ink. Background technique [0002] Coatings are an important class of materials in modern industry, mainly including traditional coating products based on natural substances and modern coating products based on synthetic chemical products, which are widely used in modern life. Coating is also an indispensable material in home decoration and plays a very important role in decoration. As another important material in modern industry, ink is mainly composed of colorants, binders and other auxiliary components. It can express patterns, characters, etc. on the substrate through printing. It has great potential in the fields of books, architectural decoration and electronic circuit board printi...

Claims

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Application Information

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IPC IPC(8): B01J13/02G01N21/64G01N21/65
Inventor 汪长春李锐敏
Owner FUDAN UNIV
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