CN106581688A - Medicine carrier based on graphene and preparation method of same - Google Patents

Abstract

The invention provides a medicine carrier based on graphene, wherein reduced graphene oxide is coated with polydopamine with surface modification by mesoporous silicon dioxide, thickness of a mesoporous silicon dioxide layer being 2-50 nm and thickness of a polydopamine layer being 1-30 nm. In the medicine carrier based on graphene, the reduced graphene oxide is coated with the polydopamine, so that biocompatibility is improved and photo-thermal absorption performance of the medicine carrier is improved. Through external modification of the mesoporous silicon layer on the reduced graphene oxide coated with polydopamine, the photo-thermal performance and photo-acoustic imaging performance of the material are improved, and supporting load of the medicine is also increased. Meanwhile, the silicon-base material is beneficial to multifunctional modification, so that the medicine carrier based on graphene can achieve multi-functions such as imaging, therapy and medicine supporting.

Description

A kind of graphene-based drug carrier and preparation method thereof

technical field

The invention belongs to the field of biomedical materials, and in particular relates to a graphene-based drug carrier and a preparation method thereof.

Background technique

The key to the successful realization of photothermal therapy is the selection of near-infrared light-absorbing materials with excellent performance. Light-absorbing materials not only require high-intensity absorption of near-infrared light, but also need to convert the absorbed light energy into heat and release it. In addition, these materials must be biocompatible and of appropriate size for enrichment at the tumor site through active targeting. At present, many nanomaterials with strong absorption in the near-infrared region have been applied in photothermal therapy and verified at the level of cells or living bodies. They mainly include inorganic nanomaterials such as noble metal nanomaterials, carbon-based nanomaterials, and other metal nanomaterials, as well as organic materials such as near-infrared dyes and conjugated polymers. The shape of noble metal photothermal materials is easy to change after the temperature rises, which affects its photothermal stability; other metal nanomaterials are mainly semiconductor nanomaterials. Due to the poor biological metabolism of metal nanoions, the metabolic pathways and Toxicity also requires systematic investigation and testing. In addition, the light-to-heat conversion efficiency of semiconductor nanoparticles is low. Although some methods to improve the light-to-heat conversion efficiency have been proposed, obtaining semiconductor nanoparticles with uniform shape, stable size and good performance often involves high-temperature reactions. There are some unavoidable problems in the application of simple organic small molecules in photothermal therapy, such as their optical properties are unstable under the action of heat, they are prone to photobleaching, and the drugs will be excreted quickly after intravenous administration. Based on this, researchers combine these small molecules with other macromolecules in the form of aggregates to form nanomicelles or vesicles, which can effectively improve the stability of small organic molecules. However, such small organic molecules, such as ICG and porphyrin, are encapsulated in polymers by means of non-covalent bonds, or self-assembled to form nano-aggregates, which are more likely to occur under relatively high-intensity laser irradiation and during biological cycles. Or less certain release, resulting in the stability is still not high. In addition to the above-mentioned photothermal materials, there is also a class of dopamine melanin photothermal reagents that have recently attracted extensive attention from researchers. However, pure polydopamine is difficult to form nanomaterials and cannot obtain higher drug loading.

Among carbon-based nanomaterials, simple graphene oxide or reduced graphene oxide has low photothermal conversion efficiency, and the surface is easy to adsorb proteins, resulting in oxidative stress, which has certain limitations as a drug carrier.

Graphene is a flat film of hexagonal honeycomb lattice composed of carbon atoms with sp2 hybrid orbitals. It is only one carbon atom thick and has many excellent physical and chemical properties. The intermediate product of graphene—graphene oxide (GO) is easier to modify due to its large number of oxygen-containing functional groups, and is highly respected in the field of biomedicine. Due to the photothermal effect exhibited by the presence of a large number of conjugated structures in GO, GO can be used as a drug carrier to enhance additional synergistic therapeutic means after administration. However, graphene oxide without any surface modification has poor stability in physiological environment due to surface charge effect and non-specific adsorption protein characteristics, which will cause damage to some organs of animals (such as lungs). Moreover, GO drug loading often efficiently loads drug molecules with aromatic ring structures through π-π stacking, so the type of drug and the amount of drug loaded are limited. Functional modification and modification of GO to improve its performance is the premise and key to the application of GO in the biological field.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a graphene-based drug carrier.

Another object of the present invention is to propose a preparation method of the graphene-based drug carrier.

The third object of the present invention is to propose the application of the graphene-based drug carrier.

The technical scheme that realizes the above-mentioned purpose of the present invention is:

A graphene-based drug carrier, which is reduced graphene oxide coated by polydopamine surface-modified mesoporous silica, wherein the thickness of the mesoporous silica layer is 2-50 nm, and the thickness of the polydopamine layer is 1~30nm.

As an organic conjugated polymer with strong absorption in the near infrared, polydopamine has good stability and biocompatibility in the application of photothermal therapy. Conjugated polymers obtained by oxidative polymerization of monomers are usually hydrophobic, and will form aggregated nanoparticles in aqueous solution, which will affect their application at the biological level. The present invention uses the mesoporous material to chemically modify the surface of the conjugated macromolecule so that it has good stability in the physiological environment.

Preferably, the thickness of the mesoporous silicon dioxide layer is 5-20 nm, the thickness of the dopamine layer is 3-20 nm, and the size of the coated reduced graphene oxide is 20-300 nm.

A preparation method of a graphene-based drug carrier, comprising the steps of:

S1 Disperse graphene oxide in a buffer solution with a pH value of 8.0-9.0, then add dopamine hydrochloride, and react at 50-90°C for 4-48 hours to obtain polydopamine-coated reduced graphene oxide;

S2 Disperse the polydopamine-coated reduced graphene oxide obtained in step S1 in an aqueous solution, add a cationic surfactant, adjust the pH value to 10-12, add organosilane, and react at room temperature for 12-36 hours to obtain a graphene-based drug carrier .

Further, in step S1, the size of the graphene oxide is 20-300 nm, and the buffer solution with a pH value of 8.0-9.0 is a tris buffer solution.

Wherein, in step S1, the mass ratio of graphene oxide to dopamine hydrochloride is 1-3:1; after adding dopamine hydrochloride, react at 60-70° C. for 12-24 hours.

Wherein, in step S2, the cationic surfactant is selected from cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, cationic polyacrylamide, benzalkonium chloride, benzalkonium bromide , the concentration of the cationic surfactant in the aqueous solution is 0.002-0.2mol/L.

Wherein, in step S2, the concentration of the polydopamine-coated reduced graphene oxide dispersed in the aqueous solution is 0.005-1 mg/mL, and the mass ratio of the organosilane to the polydopamine-coated reduced graphene oxide is 0.1-1.

Wherein, in step S2, the organosilane is one or more of ethyl orthosilicate, 3-aminopropyltriethoxysilane, and γ-mercaptopropyltrimethoxysilane.

Wherein, after the reaction in step S2, the product is washed with methanol and/or ethanol and centrifuged. Use one or more of NaOH, Na ₂ CO ₃ , KOH, NaHCO ₃ to adjust the pH value.

Application of the graphene-based drug carrier of the present invention in the preparation of photothermal therapy reagents.

The beneficial effects of the present invention are:

The graphene-based drug carrier provided by the present invention is coated with polydopamine on the outside of the reduced graphite oxide, thereby improving the biocompatibility and improving the photothermal absorption performance of the drug carrier. The photothermal conversion efficiency of pure graphene oxide or reduced graphene oxide is not high, and the surface is easy to adsorb protein, resulting in oxidative stress, which has certain limitations as a drug carrier. Modification of the mesoporous silicon layer on the outside of reduced graphene oxide coated with polydopamine can improve the photothermal performance and photoacoustic imaging performance of such materials, as well as increase the drug loading capacity. At the same time, silicon-based materials are conducive to multifunctional modification, making this based Graphene drug carriers can realize multiple functions of imaging and therapy as well as loading drugs.

Further, the preparation method of the graphene-based drug carrier is simple, the reaction conditions are mild, and the cost is low.

Description of drawings

Fig. 1 is the transmission electron micrograph of the drug carrier based on graphene of embodiment 2 of the present invention;

Fig. 2 is the nitrogen adsorption-desorption isotherm and the pore size distribution figure of the drug carrier based on graphene in Example 2 of the present invention;

Fig. 3 is the photothermal heating curve of the drug carrier based on graphene in Example 2 of the present invention;

4 is a diagram showing the relationship between the concentration of graphene oxide, polydopamine-coated reduced graphene oxide, and graphene-based drug carrier and cell survival rate in Example 2 of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The graphene oxide used in the examples was purchased from Nanjing Xianfeng Nano Material Technology Co., Ltd.

Unless otherwise specified, the materials in the examples were prepared according to existing methods, or were directly purchased from the market.

Experimental example 1:

Mix 10mL graphene oxide (2mg/mL aqueous dispersion) and 10mg dopamine hydrochloride, add 0.1mL 1M tris buffer solution, and react at 60°C for 24 hours to obtain polydopamine-coated reduced graphene oxide, denoted as pRGO . The thickness of the polydopamine layer was observed by atomic force microscopy within 10 nm.

0.8mL 0.2M cetyltrimethylammonium bromide solution, then add 0.18mL NaOH (0.1mol/L) to make the pH of the solution 11, add 0.06mL tetraethyl orthosilicate, react for 24h, The obtained mesoporous silicon material has a thickness of 5-10 nm.

Embodiment 2: Preparation of graphene-based drug carrier

Mix 10 mL of graphene oxide (2 mg/mL) aqueous dispersion and 10 mg of dopamine hydrochloride, add 0.1 mL of 1 mol/L tris buffer solution, and react at 60 ° C for 24 hours to obtain polydopamine-coated reduced graphene oxide;

The obtained polydopamine-coated reduced graphene oxide 0.1mg was dispersed in 20mL aqueous solution, the concentration was 0.005mg/mL, 0.8mL of 0.2M cetyltrimethylammonium bromide solution was added, and then 0.18mL of NaOH ( 0.1mol/L) to make the pH of the solution 11; add 0.06mL tetraethyl orthosilicate and react for 24h. After centrifugation and washing with ethanol and water, graphene-based drug carriers were obtained.

Embodiment 3: Preparation of graphene-based drug carrier

Mix 10 mL of graphene oxide (1 mg/mL) and 10 mg of dopamine hydrochloride, add 0.1 mL of 1 mol/L tris buffer solution, and react at 90°C for 12 hours to obtain polydopamine-coated reduced graphene oxide;

Disperse 0.1 mg of the obtained polydopamine-coated reduced graphene oxide in 20 mL of aqueous solution, the concentration is 0.005 mg/mL, 0.8 mL of 0.2 mol/L cetyltrimethylammonium bromide solution, and then add 0.18 mL of NaOH (0.1M), add 0.1mL tetraethyl orthosilicate, react for 24h, centrifuge and wash to obtain the graphene-based drug carrier.

Fig. 1 is the scanning electron micrograph of the drug carrier based on graphene of the present embodiment, can see obvious mesoporous structure; Fig. 2 is its nitrogen adsorption-desorption isotherm and pore size distribution curve, can find out its ratio from the figure The surface area reaches 1154m ² /g, and the pore diameter is 3.82nm.

Test Example 1 Photothermal effect test

The reduced graphene oxide pRGO, the mesoporous silica-coated reduced graphene oxide pRGO@MS prepared in Example 2, the graphene oxide GO, and the phosphate buffer PBS were respectively irradiated with near-infrared light.

Figure 3 is the photothermal curve of graphene oxide, polydopamine-coated reduced graphene oxide pRGO, and the graphene drug carrier pRGO@MS prepared in Example 2. It can be seen that the photothermal effect of the material is significantly improved after polydopamine modification , the modified mesoporous silicon layer has little effect on its photothermal effect.

Test Example 2 Loading drug test

Graphene oxide GO, reduced graphene oxide RGO, polydopamine-coated reduced graphene oxide pRGO, and the graphene-based drug carrier prepared in Example 1 and Example 2 are loaded on doxorubicin, that is, the carrier is put into the doxorubicin In an aqueous solution (2 mg/mL) of the drug, stirred overnight, centrifuged and washed to remove unloaded drug. The calculated drug loads are 40mg/mg, 22mg/mg, 78mg/mg, 144mg/mg, 145mg/mg respectively. The results show that the modification of the polydopamine layer and the modification of the mesoporous silicon layer have played a huge role in increasing the drug loading capacity, and at the same time greatly improved the photothermal performance, endowing the material itself with significance in the application of drug carriers.

Test Example 3 Toxicity Evaluation Test

Toxicity evaluation of graphene oxide GO, polydopamine-coated reduced graphene oxide pRGO prepared by reacting for 24 hours in Experimental Example 1, and graphene-based drug carrier pRGO@MS prepared in Example 2 was performed with the CCK-8 kit, and the results are shown in the figure 4, the modification of polydopamine and mesoporous silicon reduces the toxicity of graphene oxide and improves its biocompatibility.

The above embodiments are only descriptions of preferred implementations of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, ordinary engineers and technicians in the field may make various modifications to the technical solutions of the present invention. and improvements, all should fall within the scope of protection determined by the claims of the present invention.

Claims (10)

1. A drug carrier based on graphene, characterized in that, The reduced graphene oxide is coated with polydopamine whose surface is modified with mesoporous silicon dioxide, wherein the thickness of the mesoporous silicon dioxide layer is 2-50 nm, and the thickness of the polydopamine layer is 1-30 nm. 2. The drug carrier based on graphene according to claim 1, characterized in that, the thickness of the mesoporous silica layer is 5-20nm, the thickness of the dopamine layer is 3-20nm, and the size of the reduced graphene oxide 20-300nm. 3. A preparation method based on graphene-based drug carrier, characterized in that, comprising steps: S1 Disperse graphene oxide in a buffer solution with a pH value of 8.0-9.0, then add dopamine hydrochloride, and react at 50-90°C for 4-48 hours to obtain polydopamine-coated reduced graphene oxide; S2 Disperse the polydopamine-coated reduced graphene oxide obtained in step S1 in an aqueous solution, add a cationic surfactant, adjust the pH value to 10-12, add organosilane, and react at room temperature for 12-36 hours to obtain a graphene-based drug carrier . 4. The preparation method according to claim 3, characterized in that, in step S1, the size of the graphene oxide is 20-300 nm, and the buffer solution with a pH value of 8.0-9.0 is a tris buffer solution. 5. The preparation method according to claim 3, characterized in that, in step S1, the mass ratio of graphene oxide to dopamine hydrochloride is 1-3:1; after adding dopamine hydrochloride, react at 60-70°C for 12 ~24 hours. 6. preparation method according to claim 3, is characterized in that, in step S2, described cationic surfactant is selected from hexadecyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, The concentration of cationic polyacrylamide, benzalkonium chloride, benzalkonium bromide, and cationic surfactant in the aqueous solution is 0.002-0.2mol/L. 7. The preparation method according to claim 3, characterized in that, in step S2, the concentration of the polydopamine-coated reduced graphene oxide dispersed in the aqueous solution is 0.005-1 mg/mL, and the organosilane and polydopamine The mass ratio of the coated reduced graphene oxide is 0.1-1. 8. The preparation method according to claim 3, characterized in that, in step S2, the organosilane is ethyl orthosilicate, 3-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxy One or more of silanes. 9. The preparation method according to claim 3, characterized in that, after the reaction in step S2, the product is washed with methanol and/or ethanol, and centrifuged. 10. The application of the graphene-based drug carrier according to claim 1 or 2 in the preparation of photothermal therapy reagents.