Composite Nanodots Based on Carbon Nanodots and Preparation Method Thereof

Abstract

The present invention discloses a preparation technique of composite nanodots based on carbon nanodots, and their use in the field of fluorescent imaging, wherein, the main components of the composition are carbon nanodots, which are material with superior biocompatibility characteristics, and supporting component is methylene blue, and particle diameter range is 100-500 nanometers, and the zeta potential is −35 to 10 millivolts. The above said techniques for preparation of composite nanodots are safe, quick and simple, low cost, and easy to perform for industrialized production. Composite carbon nanodots have good biocompatibility and safety, high fluorescence imaging sensitivity, and they are promising in gaining wider use in the fields of biomedical imaging, targeting diagnosis and therapy, drug screening and optimization, and in vivo labelling and tracing, and have potential value in personalized medicine.

Claims

1. Composite nanodots based on carbon nanodots, characterized in that; the main components of the composition are carbon nanodots, and methylene blue is used as a support ligand.

2. Composite nanodots based on carbon nanodots according to claim 1, characterized in that; the carbon sources of the carbon nanodots in the composite nanodots are any of wolfberry leaching agents, soy milk, or dietary milk.

3. Composite nanodots based on carbon nanodots according to claim 1, characterized in that; the grain size range of the composite nanodots is 100-500 nanometers, and the zeta potential range is −30 to 10 millivolts.

4. Composite nanodots based on carbon nanodots according to claim 1, characterized in that; the concentration of methylene blue in composite carbon nanodots is 10 micrograms/milliliter.

5. A preparation method of composite nanodots based on carbon nanodots according to claim 1, characterized in that; it comprises the operation steps of: a. forming a solution of the above said carbon sources and 0.5 milligrams/millilitres of methylene blue by means of mixing in the ratio of 0.1:1 to 10:1 by volume, diluting the mixture 1-10 folds with ultra-pure water, and thus obtaining a precursor solution; b. placing the above said precursor solution in a microwave reaction instrument, and setting the instrument parameters as follows: temperature: 100-180° C., time: 30-300 minutes; c. reacting for more than 30 minutes, obtaining a clear solution as a result of centrifugal separation, and obtaining crude product of composite carbon nanodots; d. applying purification on the crude product of composite nanodots.

6. Method of preparation of composite nanodots based on carbon nanodots according to claim 5, characterized in that; purification is applied on the crude product of composite nanodots using ultrafiltration purification.

7. Method of preparation of composite nanodots based on carbon nanodots according to claim 5, characterized in that; purification is applied on the crude product of composite nanodots using dialysis purification.

8. Use of the composite nanodots based on carbon nanodots according to claim 1 in the field of fluorescence biological imaging.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a flow chart of the preparation technique of composite carbon nanodots;

[0018] FIG. 2a shows the particle size distribution of the composite carbon nanodots given in embodiment 1;

[0019] FIG. 2b shows the zeta potential phenogram of the composite carbon nanodots given in embodiment 1;

[0020] FIG. 3a shows the particle size distribution of the composite carbon nanodots given in embodiment 2;

[0021] FIG. 3b shows the zeta potential phenogram of the composite carbon nanodots given in embodiment 2;

[0022] FIG. 4a shows the particle size distribution of the composite carbon nanodots given in embodiment 3;

[0023] FIG. 4b shows the zeta potential phenogram of the composite carbon nanodots given in embodiment 3;

[0024] FIG. 5a shows the fluorescence spectogram of the composite carbon nanodots given in embodiment 1 at the excitation wavelength between 340-440;

[0025] FIG. 5b shows the fluorescence spectogram of the composite carbon nanodots given in embodiment 1 at the excitation wavelength of 650;

[0026] FIG. 6a shows the fluorescence spectogram of the composite carbon nanodots given in embodiment 2 at the excitation wavelength between 340-440;

[0027] FIG. 6b shows the fluorescence spectogram of the composite carbon nanodots given in embodiment 2 at the excitation wavelength of 650;

[0028] FIG. 7a shows the fluorescence spectogram of the composite carbon nanodots given in embodiment 3 at the excitation wavelength between 340-440;

[0029] FIG. 7b shows the fluorescence spectogram of the composite carbon nanodots given in embodiment 3 at the excitation wavelength of 650;

[0030] FIG. 8 is a comparison chart of the in vitro fluorescent imaging effects of only the carbon nanodots and the composite carbon nanodots;

[0031] FIG. 9 is a comparison chart of fluorescent imaging effects of intravenous injection of the composite carbon nanodots of embodiment 1 on rat tail, before injection and 3.5 hours after injection.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Below given specific descriptions about the present invention through embodiments are only for better understanding of the invention, and do not form any limitation in the protection scope of the invention disclosed in the claims, and persons skilled in the related technical field can make some non-essential changes and modifications on the present invention according to the contents of the above said description.

[0033] The raw materials used in the preparation of the present invention are all commercially available.

[0034] Embodiment 1: 2 milliliters of wolfberry leaching agent and 2 milliliters of methylene blue solution (0.5 milligrams/milliliters) are mixed, and then diluted 1 fold using ultra-pure water to obtain a precursor solution. The precursor solution is then placed in a 5 milliliter special glass bottle for use in microwave reaction instruments, and afterwards, the bottle is placed in a microwave reaction instrument, and the reaction conditions are set to 180 degrees centigrade and 30 minutes. The reaction system is allowed to wait for 50 minutes, and then centrifugated, and the supernatant liquid is retained, and composite carbon nanodots are obtained following ultrafiltration. The methylene blue concentration measured in composite nanodots using ultraviolet spectrophotometer standard curve method is 5.6 micrograms/milliliter. Measurements are made by a laser particle analyzer according to dynamic light scattering principle, and the composite carbon nanodot grain size distribution is found as 179±77.1 nanometers (See, FIG. 2a), while the surface zeta potential is found as 6.85±2.20 millivolts (See, FIG. 2b). The fluorescence properties of composite carbon nanodots are measured by a fluorescence detector device Imaging of composite carbon nanodots and unloaded blank comparative groups in a fluorescence field confirmed that the composite carbon nanodots can remarkably increase the contrast and resolution of fluorescent imaging Under extremely low concentrations, relatively strong fluorescent response signal is obtained (See FIGS. 5a and 5b), which can be used in the fields of bio-labelling and medical imaging.

[0035] Embodiment 2: 10 milliliters of freshly brewed soy milk and 1 milliliter of methylene blue solution (0.5 milliliter/milliliters) are mixed, and then diluted 10 folds using ultra-pure water to obtain a precursor solution. The precursor solution is then placed in a 5 milliliter special glass bottle for use in microwave reaction instruments, and afterwards, the bottle is placed in a microwave reaction instrument, and the reaction conditions are set to 100 degrees centigrade and 5 hours. The reaction system is allowed to wait for 60 minutes, and then centrifugated, and the supernatant liquid is retained, and composite carbon nanodots are obtained following ultrafiltration. The methylene blue concentration measured in composite carbon nanodots using ultraviolet spectrophotometer standard curve method is 8.6 micrograms/milliliter. Measurements are made by a laser particle analyzer according to dynamic light scattering principle, and the grain size distribution of the composite carbon nanodots loaded on methylene blue are found as 197.9±79.7 nanometers (See, FIG. 3a), while the surface zeta potential is found as 31 21.5±4.36 millivolts (See, FIG. 3b). The fluorescence properties of composite carbon nanodots measured by a fluorescence detector device are shown in FIGS. 6a and 6b.

[0036] Embodiment 3: 1 milliliter of dietary milk and 10 milliliters of methylene blue solution (0.5 milligrams/milliliters) are mixed, and then diluted 5 folds using ultra-pure water to obtain a precursor solution. The precursor solution is then placed in a 5 milliliter special glass bottle for use in microwave reaction instruments, and afterwards, the bottle is placed in a microwave reaction instrument, and the reaction conditions are set to 160 degrees centigrade and 2 hours. The reaction system is allowed to wait for 1 hour, and then centrifugated, and the supernatant liquid is retained, and composite carbon nanodots are obtained following dialysis. The methylene blue concentration measured in composite carbon nanodots using standard curve method is 1.8 micrograms/milliliter. Measurements are made by a laser particle analyzer according to dynamic light scattering principle, and the grain size distribution of the composite carbon nanodots loaded on methylene blue are found as 434.4±196.8 nanometers (See, FIG. 4a), while the surface zeta potential is found as 4.92±2.88 millivolts (FIG. 4b). The fluorescence properties of composite carbon nanodots measured by a fluorescence detector device are shown in FIGS. 7a and 7b.

[0037] The present invention provides composite nanodots that are loaded on methylene blue and their use in the field of fluorescent imaging The combination of the composite nanodots based on carbon nanodots and the fluorescent dyes form composite fluorescent carbon nanodots, and the obtained composite nanometer fluorescence imaging materials have favourable biocompatibility and safety characteristics, provide high fluorescent imaging sensitivity, and in the fluorescent field, after being stimulated by near infrared light, they produce a fluorescent signal response as shown in FIG. 8. As indicated by in vivo imaging experiments on rats in near infrared light field, compared to blank groups (not loaded with carbon nanodots), the composite carbon nanodots loaded on methylene blue can remarkably increase the contrast and resolution of in vivo fluorescent imaging in animals (See, FIG. 9). They are promising in gaining wider use in the fields of biomedical imaging, targeting diagnosis and therapy, drug screening and optimization, and in vivo labelling and tracing, and also, they have potential value in the field of personalized medicine, and therefore, they are expected to have wide usage prospects in the field of biomedical imaging.