CN109233806B - Method for preparing silicon dioxide particles containing methylene blue with high fluorescence intensity by heat treatment assistance - Google Patents

Abstract

The invention provides a method for preparing methylene blue-containing silica particles with high fluorescence intensity by heat treatment assistance, belonging to the technical field of chemical raw material preparation. Adding ammonia water, methylene blue and ethyl orthosilicate into a mixed solution containing water and ethanol, stirring for 4 hours, centrifuging and washing, drying the prepared silica particles containing the methylene blue at 70 ℃ for 24 hours, and treating at 120-180 ℃ for 24 hours to obtain the silica particles containing the methylene blue with high fluorescence intensity. The method has simple process, low raw material price and easy industrial production, and the obtained particles have good biocompatibility and high fluorescence intensity.

Description

Method for preparing silicon dioxide particles containing methylene blue with high fluorescence intensity by heat treatment assistance

Technical Field

A method for preparing methylene blue-containing silica particles with high fluorescence intensity by heat treatment assistance belongs to the technical field of chemical raw material preparation.

Background

The dye molecule has higher application value in the aspects of fluorescent sensors, biological fluorescent markers, cell tracing, solid-state lasers and the like, and the realization of the performances is related to the aggregation state of the dye molecule. In a high-concentration solution or solid powder, dye molecules such as methylene blue molecules are easy to form an aggregation state, and the interaction between the aggregation state molecules can cause the occurrence of a fluorescence quenching effect, so that a fluorescence signal is weakened, and the fluorescence signal of the methylene blue is almost undetected. Only in relatively dilute aqueous solutions, e.g. with concentrations of methylene blue molecules below 10^-6The fluorescence signal of methylene blue can be detected every liter, which causes the application of methylene blue molecules in the related field to be greatly limited.

In recent years, research reports of dye molecules on the aspect of aggregation luminescence are very many, researchers mainly regulate and control the aggregation state of molecules in modes of molecular rotation limitation, intra-molecular coplanar or J-aggregate formation and the like among high-concentration dye molecules or solid aggregation state molecules, inhibit a non-radiative energy conversion mechanism for weakening a fluorescence signal, greatly reduce the probability of fluorescence quenching of the aggregation state of the dye molecules, and improve the fluorescence luminescence efficiency of the dye molecules. However, the research carried out in this respect mainly focuses on limited kinds of molecules, such as rhodamine B dye molecules, silole-like small molecules and branched polymer-like derivatives thereof, which have excellent performance, but high price, complex preparation process and certain limitations in biocompatibility. The methylene blue is used as a dye molecule, has low price and low toxicity, has a light-emitting range in a near infrared region, and is beneficial to the wide application of the methylene blue in related fields. The methylene blue is adsorbed into the particles, the interaction between the methylene blue molecules can be limited through the interaction between the methylene blue and the matrix, for example, the fluorescence intensity of the methylene blue is obviously improved after the methylene blue is adsorbed to the carrier by montmorillonite (Journal of Colloid and Interface Science 339(2009) 416-426), and the fluorescence signal of the methylene blue is also obviously improved in hydroxyapatite/silica composite particles containing the methylene blue (Applied Physics A113 (2013) 583-589). However, a method for preparing methylene blue-containing silica particles having high fluorescence intensity by heat-treating the methylene blue-containing silica particles has not been reported so far.

Disclosure of Invention

The invention aims to provide a method for preparing methylene blue-containing silica particles with high fluorescence intensity by heat treatment assistance, which is characterized by comprising the following steps:

step 1, sequentially adding ammonia water and methylene blue into a mixed solution containing water and ethanol, stirring for 15 minutes, then adding ethyl orthosilicate, wherein the volume ratio of the water to the ethanol to the ammonia water to the ethyl orthosilicate is 5:26.74:0.72:1, the concentration of the methylene blue is 2.32 millimole per liter, stirring for 4 hours, then carrying out centrifugal separation to obtain a sediment, washing the sediment twice with ethanol, and then washing once with an acetate buffer solution with the pH =3.6, wherein the volume ratio of the ethanol to the acetate buffer solution to the ethyl orthosilicate is 34.88:1 and 5.81:1 respectively, and then drying the sediment obtained through the centrifugal separation at 70 ℃ for 24 hours to obtain silica particles containing the methylene blue;

and 2, treating the silica particles containing methylene blue prepared in the step 1 at the temperature of 120-180 ℃ for 24 hours to obtain the silica particles containing methylene blue with high fluorescence intensity.

The invention has the beneficial effects that:

1. the selected reagent has low price, simple process method and device and easy industrialized production;

2. the fluorescence intensity of the silicon dioxide particles containing methylene blue can be regulated and controlled through simple heating treatment;

3. the methylene blue and the silicon dioxide are low-toxicity substances, the biocompatibility is good, and the prepared silicon dioxide particles containing the methylene blue have high fluorescence intensity and can be used in the fields of fluorescent display, solid-state lasers, fluorescent sensors and the like.

Drawings

FIG. 1 is a fluorescence spectrum of a particle sample (wavelength of excitation light source: 532 nm, energy: 10 microwatts). (a) Silica particles containing methylene blue having high fluorescence intensity prepared by example 1; (b) the silica particles containing methylene blue with high fluorescence intensity prepared by the method of example 2; (c) the resulting methylene blue-containing silica particles prepared by comparative example 1.

Detailed Description

The present invention is further illustrated by the following examples.

Example 1

(1) Sequentially adding 92 ml of absolute ethyl alcohol, 17.2 ml of water, 2.48 ml of concentrated ammonia water and 0.10 g of methylene blue into a beaker, stirring for 15 minutes, adding 3.44 ml of ethyl orthosilicate, stirring for 4 hours, performing centrifugal separation to obtain a precipitate, washing the precipitate twice with 120 ml of ethanol, washing once with 20 ml of acetate buffer solution with pH =3.6, and drying the precipitate obtained through centrifugal separation at 70 ℃ for 24 hours to obtain silicon dioxide particles containing the methylene blue;

(2) and (2) treating the silica particles containing methylene blue prepared in the step (1) at 180 ℃ for 24 hours to prepare the silica particles containing methylene blue with high fluorescence intensity.

Example 2

(1) Sequentially adding 92 ml of absolute ethyl alcohol, 17.2 ml of water, 2.48 ml of concentrated ammonia water and 0.10 g of methylene blue into a beaker, stirring for 15 minutes, adding 3.44 ml of ethyl orthosilicate, stirring for 4 hours, performing centrifugal separation to obtain a precipitate, washing the precipitate twice with 120 ml of ethanol, washing once with 20 ml of acetate buffer solution with pH =3.6, and drying the precipitate obtained through centrifugal separation at 70 ℃ for 24 hours to obtain silicon dioxide particles containing the methylene blue;

(2) and (2) treating the silica particles containing methylene blue prepared in the step (1) at 120 ℃ for 24 hours to prepare the silica particles containing methylene blue with high fluorescence intensity.

Comparative example 1

(1) Adding 92 ml of absolute ethyl alcohol, 17.2 ml of water, 2.48 ml of concentrated ammonia water and 0.10 g of methylene blue into a beaker in sequence, stirring for 15 minutes, adding 3.44 ml of ethyl orthosilicate, stirring for 4 hours, performing centrifugal separation to obtain a precipitate, washing the precipitate twice with 120 ml of ethanol, washing once with 20 ml of acetate buffer solution with pH =3.6, and drying the precipitate obtained through centrifugal separation at 70 ℃ for 24 hours to obtain the silica particles containing the methylene blue.

Claims (1)

1. A method for preparing a silica particle containing methylene blue with high fluorescence intensity by heat treatment assistance is characterized by comprising the following steps:

step 1, sequentially adding ammonia water and methylene blue into a mixed solution containing water and ethanol, stirring for 15 minutes, then adding ethyl orthosilicate, wherein the volume ratio of the water to the ethanol to the ammonia water to the ethyl orthosilicate is 5:26.74:0.72:1, the concentration of the methylene blue is 2.32 millimole per liter, stirring for 4 hours, then carrying out centrifugal separation to obtain a sediment, washing the sediment twice with ethanol, and then washing once with an acetate buffer solution with the pH =3.6, wherein the volume ratio of the ethanol to the acetate buffer solution to the ethyl orthosilicate is 34.88:1 and 5.81:1 respectively, and then drying the sediment obtained through the centrifugal separation at 70 ℃ for 24 hours to obtain silica particles containing the methylene blue;

and 2, treating the silica particles containing methylene blue prepared in the step 1 at the temperature of 120-180 ℃ for 24 hours to obtain the silica particles containing methylene blue with high fluorescence intensity.

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