CN109157862B

CN109157862B - Mixed solution capable of separating out microspheres under action of highly converged laser beam

Info

Publication number: CN109157862B
Application number: CN201810974483.3A
Authority: CN
Inventors: 胡春光; 李帅; 高晓晴; 韩梦柯; 马国腾; 李宏斌; 胡晓东; 胡小唐
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2018-08-24
Filing date: 2018-08-24
Publication date: 2020-10-27
Anticipated expiration: 2038-08-24
Also published as: CN109157862A

Abstract

The invention relates to a mixed solution capable of separating out microspheres under the action of a highly converged laser beam, which is characterized by being a mixed solution of a phosphate buffer solution and isopropanol. According to the volume ratio, the mixture ratio of the phosphate buffer solution to the isopropanol is as follows: 1:3.5-6.

Description

Mixed solution capable of separating out microspheres under action of highly converged laser beam

Technical Field

The invention relates to a mixed solution capable of separating out microspheres under the action of a highly converged laser beam.

Background

The optical tweezers stably capture micron-scale particles near a focus by utilizing a three-dimensional potential well formed by highly converged laser beams, have the characteristics of nano-scale spatial resolution, piconiu-scale mechanical resolution, non-contact and no damage, are widely applied to the fields of cell biology, unimolecular biology, physics, colloid science and the like, and capture and control cells in capillary vessels of ears of living mice to dredge vascular blockage, capture polystyrene/silicon dioxide microspheres and further study protein unfolding/folding kinetic characteristics and the like. However, the above researches are all based on the capture and manipulation of micron-sized particles by optical tweezers, and the powerful functions of the optical tweezers should not be limited thereto, so that the technology of controllably preparing and manipulating microparticles by using the optical tweezers is to be explored by the researchers.

There have been many efforts and advances in the art of preparing and manipulating microparticles using optical tweezers. TERUKI SUGIYAMA et al uses optical tweezers to capture and aggregate nano particles, polymers, molecular clusters and the like to form micron-to-millimeter-grade substances, and uses the optical tweezers to research the crystallization of glycine in heavy water and the like; hagay Shpaisman et al controllably prepare spherical and elongated colloidal particles of specified size using optical tweezers.

Most of the light spots converged by the optical tweezers in the above researches are focused on the interface of liquid and air, and few researches on the preparation of particles by focusing the inside of the solution are needed; in addition, the above preparation techniques are either in a supersaturated state of a single solution or in a solution system in which a chemical reaction is being carried out, that is, the application range is not wide enough.

Disclosure of Invention

The invention aims to provide a mixed solution capable of precipitating microspheres under the action of a highly focused laser beam, the mixed solution can be used as a manipulation object of an optical tweezers system, the mixing proportion is set according to the principle of being beneficial to precipitating solution substances, and the dissolved substances are dissolved in one solution but not dissolved or slightly dissolved in the other solution. The mixed solution of two kinds of prepared solutions is irradiated by the optical tweezers, the light spot converged by the optical tweezers is in the solution, the focused light spot of the optical tweezers is in the mixed solution, namely, the interface between the non-solution and the air, the mixed solution is locally heated by the aid of the laser light spot converged at high degree, so that the solubility of the mixed solution in the area to dissolved substances is reduced, the dissolved substances are crystallized and separated out, and micron-scale spherical structure crystal particles can be controllably prepared and controlled by changing the laser light intensity, the laser beam direction and the laser irradiation time. The technical scheme is as follows:

a mixed solution capable of separating out microspheres under the action of a highly converged laser beam is a mixed solution of phosphate buffer solution and isopropanol, and the proportion of the phosphate buffer solution to the isopropanol is as follows according to the volume ratio: 1:3.5-6.

Preferably, the ratio of the phosphate buffer solution to the isopropanol is as follows: 1:4.

The invention provides a new system of mixed solution of two solutions, such as mixed solution of phosphate buffer solution and isopropanol organic solvent, and the volume ratio is 1:4, the mixing proportion is set according to the principle of being favorable for the precipitation of dissolved substances, wherein the dissolved substances are dissolved in one solution but are not dissolved or slightly dissolved in the other solution; the laser convergence light spot is in the mixed solution, the mixed solution is locally heated by means of the highly converged laser light spot, so that the solubility of the mixed solution near the light spot to dissolved substances is reduced, the dissolved substances are crystallized and separated out, and the prepared crystal particles are spherical under the action of the highly converged light beam light spot.

Drawings

FIG. 1 is a controllable microsphere preparation and manipulation device based on optical tweezers.

In the figure: 1. a 1064nm laser; 2. a half-wave plate; 3. a polarization beam splitter prism; 4. a laser collection cylinder; 5. a piezoelectric driven mirror; 6. a dichroic mirror; 7. soaking the objective lens in water; 8. a three-dimensional displacement table; 9. a sample cell; 10. 780nm illumination source; 11. a lens; 12. a CCD camera.

FIG. 2 is a diagram of the effect of the letter "TJU" on the controlled preparation and manipulation of microspheres based on optical tweezers.

FIG. 3 shows that the volume ratio of the two is 1:4 and 1: the growth morphology of the microspheres in 100s under the condition of 6 is changed.

Detailed Description

The mixed solution and the application scenario of the present invention will be described with reference to the following embodiments and drawings.

The mixed solution of two kinds of prepared solutions is irradiated by the optical tweezers, the light spot converged by the optical tweezers is in the solution, the focused light spot of the optical tweezers is in the mixed solution, namely, the interface between the non-solution and the air, the mixed solution is locally heated by the aid of the laser light spot converged at high degree, so that the solubility of the mixed solution in the area to dissolved substances is reduced, the dissolved substances are crystallized and separated out, and micron-scale spherical structure crystal particles can be controllably prepared and controlled by changing the laser light intensity, the laser beam direction and the laser irradiation time.

Two solutions used in the experiment for preparing microspheres were phosphate buffered saline PBS (commercially available, PBS has PH of 7.2-7.4, and contains potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium chloride and potassium chloride as main components) and isopropanol (commercially available, molecular weight is 60.10, isopropanol content is not less than 99.9%, and water content is 0.01%), when the volume ratio of the two solutions is 1: 1, no microspheres are generated; when the volume ratio of the phosphate buffer solution to the isopropanol organic solvent is 1:3. 1: 4. 1: 5. 1: 6. 1: when 8, microspheres are generated, but the growth rates of the microspheres in the two solutions are different under the condition of different volume ratios, and when the volume ratio of the two solutions is 1: at 4, the microspheres grew fastest. In FIG. 3, the volume ratio of the two is 1:4 and 1: the growth morphology of the microspheres in 100s under the condition of 6 is changed.

The experimental device shown in fig. 1 is used as an optical tweezers operation platform. The device comprises a diode-pumped neodymium-doped yttrium vanadate optical fiber coupling solid-state laser for outputting 1064nm wavelength continuous waves, a water immersion objective with the numerical aperture of 1.2, the working distance of 0.28mm and the amplification factor of 63, a half-wave plate, a polarization beam splitting prism, a piezoelectric driving reflector, a three-dimensional displacement platform and an optical tweezers system consisting of dichroic mirrors; 18 x 0.17mm coverslip and 24 x 50 x 0.17mm slide glass; phosphate buffer solution and isopropanol organic solvent are used for injecting into the sample cell in the experiment; the CCD camera, the 780nm illumination light source, the lens and the dichroic mirror form an illumination imaging light path.

The 1064nm linearly polarized gaussian beam was focused by a high numerical aperture objective lens (NA ═ 1.2) to form an optical trap near the sample stage. The mixed liquid of phosphate and isopropanol is irradiated by the highly converged laser beam, the radiant heat generated by the laser accelerates the precipitation of phosphate crystals, and the phosphate crystals are captured and converged by the action of optical trapping force to form spherical particles. And displaying and recording the state of the stored microspheres in real time through a 780nm illumination light source and a CCD imaging module. The size and position of the microsphere can be controlled through a half-wave plate, a polarization beam splitter prism, a laser collecting cylinder, a piezoelectric driving reflector and a three-dimensional displacement platform. The specific operation steps of the embodiment are as follows:

(1) initializing an optical tweezers system, adjusting the power of a laser 1 under the action of a half-wave plate 2, a polarization beam splitter prism 3 and a laser collecting cylinder 4 to enable the power of a collimated laser beam of an incident light path to be 1w, and focusing the collimated laser beam by a high numerical aperture objective lens 7 to form a focusing light spot with the diameter of 1um for stably capturing crystal particles;

(2) preparing a sample cell, connecting 18 × 0.17mm cover glass and 24 × 50 × 0.17mm glass slide through a sealing film, placing the glass slide on an electric heating plate, heating at 100 ℃ for 30 seconds, and bonding the glass slide and the glass slide together by the melting action of the sealing film to form a sample cell 9 structure;

(3) preparing a sample, namely mixing a phosphate buffer solution and an isopropanol organic solvent in a volume ratio of 1:4, mixing, injecting into a sample cell 9, sealing two ends with vacuum grease to prevent the sample from flowing out, and placing on a sample table 8 for experiment;

(4) locally heating a phosphate buffer solution and an isopropanol mixed solution by means of a highly converged laser spot to reduce the solubility of the mixed solution near the laser spot to a dissolved substance phosphate, so that the dissolved substance phosphate is crystallized and separated out; capturing and converging the phosphate crystals in the optical trap to form spherical particles by means of the action of optical trap force; observing the prepared phosphate microspheres through a CCD12 interface, and controlling the particle size, the preparation speed and the particle position of phosphate crystal particles by adjusting the laser intensity, the laser beam direction and the laser irradiation time; the change in the microspheres was recorded and stored by means of the illumination source 10 and the CCD 12.

Claims

1. A method for preparing microspheres under the action of a highly focused laser beam, comprising the steps of: (1) preparing a mixed solution of phosphate buffer solution and isopropanol, wherein the ratio of the phosphate buffer solution to the isopropanol is as follows according to the volume ratio: 1: 3.5-6; (2) placing the prepared mixed solution into a sample cell of an optical tweezers system; (3) irradiating the mixed solution by using optical tweezers, converging light spots by using the optical tweezers in the solution, and crystallizing and separating out dissolved substances under the action of locally heating the mixed solution by using the highly converged laser light spots; and (4) capturing and converging the crystallized particles by means of the action of light trapping force to form micron-scale spherical structure particles, namely microspheres, and realizing controllable preparation and control of the microspheres by changing the laser intensity, the laser beam direction and the laser irradiation time.

2. The method for preparing microspheres according to claim 1, wherein the ratio of phosphate buffer to isopropanol is: 1:4.