Method for preparing porous drug carrier by using carbon nanotube composite calcium carbonate

Abstract

The invention discloses a new technology which can select a carbon nano tube as a carrier, nano calcium carbonate (CaCO3) capable of regulating and controlling a tumor microenvironment is prepared on the surface through an in-situ deposition technology, a drug carrier (CNTs / CaCO3) is formed by the carbon nano tube (CNTs) loaded with the CaCO3, and the effect of killing cancer cells is achieved in combination with an anti-tumor drug. The composite material is subjected to x-ray diffraction analysis, and the result shows that the carbon nano tube is successfully coated with calcium carbonate; the research on the drug loading performance of the composite material further shows that the drug loading rate of the composite material is high. The prepared material CNTs / CaCO3 can wrap a drug to reach a tumor area, calcium carbonate is decomposed in a slightly acidic environment in a tumor, and drug release is accelerated while the pH value of the tumor microenvironment is adjusted. Therefore, the compound has a wide application prospect in the aspect of biological medicine.

Description

Technical Field

[0001] The invention belongs to the field of biomedical materials, and specifically relates to a method and application of an anti-tumor drug carrier prepared by using calcium carbonate composite carbon nanotubes. Background Art

[0002] Cancer is one of the diseases that endanger human health. Current treatment methods include surgical treatment, radiotherapy, chemotherapy, etc. Chemotherapy has a wide range of applications and a high usage rate. Its main feature is to deliver anti-tumor drugs to the cancerous site through the body's circulatory system to achieve the effect of accurately killing cancer cells, but its side effects are large, because anti-tumor drugs will damage or even kill normal cells in the body during circulation, and the drug concentration is constantly diluted during the circulation process. When reaching tumor cells, the drug concentration is reduced and cancer cells cannot be killed, thereby greatly reducing the treatment effect. Therefore, it is very important to prepare efficient and suitable drug carriers. Therefore, in this experiment, we intend to study a new type of drug carrier to load anti-tumor drugs. By avoiding the drawbacks of existing methods, modifying the drug carrier, reducing the release of drugs that have not reached the tumor lesion, reducing the toxic side effects of anti-tumor drugs, and enhancing the effect of tumor treatment.

[0003] Studies have found that a slightly acidic environment can promote the spread of cancer cells. Therefore, adjusting the pH and changing the slightly acidic environment of the tumor to prevent cancer cells from invading other normal cells is an effective auxiliary means of chemotherapy drugs. Calcium carbonate is a typical inorganic compound with a wide range of sources and is widely used in chemical, medical, and food industries. In particular, nano-scale CaCO3 is stable at neutral pH and degrades into Ca at acidic pH. 2+ and CO2, have been proposed as a pH-sensitive chemotherapy drug delivery system. In recent work, Achilefu et al. prepared monodispersed CaCO3 nanoparticles and found that they have good regulation ability in the tumor microenvironment (slightly acidic) and have potential therapeutic effects. Carbon nanotubes have significant properties such as high biocompatibility, high drug loading efficiency and low side effects, and have received great attention in biomedical applications. When reaching the tumor site, the calcium carbonate-loaded carbon nanotubes release drugs and induce cancer cell apoptosis. At the same time, the CaCO3 component decomposes in a slightly acidic environment and neutralizes the pH, which has the effect of regulating the tumor microenvironment. Sufficient drug release can also effectively kill tumor cells and achieve the purpose of treatment. Summary of the invention

[0004] The present invention uses ultrasound and in-situ deposition technology to load calcium carbonate on carbon nanotubes to form a drug carrier, and then introduces anti-tumor drugs such as doxorubicin through a soaking method after centrifugal washing to successfully construct an anti-tumor system. The material wraps the drug to reach the tumor area, and the calcium carbonate decomposes in the slightly acidic environment of the tumor, adjusting the pH value of the tumor microenvironment while accelerating the release of the drug, achieving the effect of killing cancer cells.

[0005] The specific steps include:

[0006] Step 1, dissolving dicyandiamide and ferrous sulfate heptahydrate in ethanol, stirring to dissolve, drying, and grinding to obtain powder.

[0007] Step 2: Take the powder prepared in step 1 and place it in a magnetic boat, place it in a tube furnace, and set appropriate time and temperature for carbonization.

[0008] Step 3, taking the powder obtained by carbonization in step 2, washing with acid, filtering and drying to obtain carbon nanotube powder.

[0009] Step 4, take a beaker, add the carbon nanotube powder and CaCl2 in step 3, ultrasonically treat, then introduce carbon dioxide, heat and stir for several hours.

[0010] Step 5, centrifugally wash the solid matter in the beaker to obtain CNTs / CaCO3 drug carriers, stir and mix with anti-tumor drugs such as DOX at room temperature, allow the drugs to adsorb to the carriers, remove free components, passivate, collect, and successfully construct a composite drug delivery system.

[0011] Preferably, the amounts of substances added in step 1 are 5-10 g of dicyandiamide, 0.1-0.5 g of ferrous sulfate heptahydrate, and 50-70 mL of ethanol, respectively. The stirring time is 2-4 h, and the drying temperature is 60-80° C.

[0012] Preferably, the temperature set in step 2 is 500-900° C. and the time is 60-120 min.

[0013] Preferably, in step 3, the concentration of hydrochloric acid is 0.5-2 mol / L, the pickling time is 1-2 h, and the drying temperature is 60-80°C.

[0014] Preferably, in step 4, the mass ratio of carbon nanotubes to CaCl2 is 1:1-1:5, and the reaction is heated and stirred for 12-48 hours.

[0015] Compared with the prior art, the present invention has the following significant advantages:

[0016] (1) The carbon nanotubes used in the present invention have good biocompatibility and can be used as a load for anti-tumor drugs such as DOX.

[0017] (2) The drug carrier is modified by the present invention. When the drug carrier reaches the tumor site, the CaCO3 component decomposes in a slightly acidic environment, which can effectively adjust the pH value of the tumor microenvironment and reduce the metastasis and spread of tumor cells.

[0018] (3) The composite of calcium carbonate and carbon nanotubes according to the present invention effectively improves the drug loading rate, and sufficient drug release can effectively kill tumor cells and achieve a therapeutic effect.

[0019] (4) The present invention uses calcium carbonate to encapsulate anti-tumor drugs, and precisely regulates the release of drugs in the tumor area, thereby reducing the toxic side effects on normal cells in the body's circulatory system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the XRD diagram of the carbon nanotube composite calcium carbonate porous material of the present invention. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the embodiments and drawings.

[0022] Preparation steps of carbon nanotubes: weigh 5g of dicyandiamide and 0.278g of ferrous sulfate heptahydrate, dissolve them in 50ml of ethanol, and stir for 2h to dissolve them; put the obtained solution into a 70℃ oven for drying, and grind the powder obtained after drying into powder with an agate mortar; spread the powder on a magnetic boat, and carbonize it in a tubular furnace, first calcining at 500℃ for 60min, and then heating to 900℃ for 120min; the powder obtained after carbonization is put into 1mol / L hydrochloric acid for pickling for 1h; the pickled powder is filtered 3-4 times to obtain a black solid powder, which is dried and stored in an 80℃ oven.

[0023] Step 1, prepare a beaker, add 20-50 mg of CNTs and 50-100 mL of ethanol, and perform ultrasonic treatment for 1-3 h.

[0024] Step 2, add CaCl2 in a mass ratio of 1:1-1:5 to CNTs to the beaker in step 1, ultrasonicate for 1 hour, introduce carbon dioxide at a flow rate of 0.5-2 L / min for 20 seconds, and heat and stir for 12-48 hours.

[0025] Step 3, centrifugally wash the solid matter in the beaker to obtain CNTs / CaCO3 drug carriers, stir and mix with anti-tumor drugs such as DOX at room temperature, allow the drugs to adsorb to the carriers, remove free components, passivate, collect, and successfully construct a composite drug delivery system.

[0026] The CNTs / CaCO3 prepared in each example is as follows Figure 1 As shown, the appearance of XRD characteristic peaks indicates that calcium carbonate has been doped into carbon nanotubes.

[0027] Embodiment 1:

[0028] Step 1, prepare a beaker, add 30 mg of CNTs and 100 mL of ethanol into it, and perform ultrasonic treatment for 1 h.

[0029] Step 2, add 30 mg of CaCl2 to the beaker in step 1, ultrasonicate for 1 h, introduce carbon dioxide at a flow rate of 1 L / min for 20 s, and heat and stir for 24 h.

[0030] Step 3, the solid matter in the beaker was washed by centrifugation to obtain CNTs / CaCO3 drug carrier, which was mixed with DOX by stirring at room temperature to allow the drug to adsorb onto the carrier, and the free components were removed, passivated, and collected to successfully construct a composite drug delivery system.

[0031] Embodiment 2:

[0032] Step 1, prepare a beaker, add 30 mg of CNTs and 100 mL of ethanol into it, and perform ultrasonic treatment for 1 h.

[0033] Step 2, add 60 mg of CaCl2 to the beaker in step 1, ultrasonicate for 1 h, introduce carbon dioxide at a flow rate of 1 L / min for 20 s, and heat and stir for 24 h.

[0034] Step 3, the solid matter in the beaker was washed by centrifugation to obtain CNTs / CaCO3 drug carrier, which was mixed with DOX by stirring at room temperature to allow the drug to adsorb onto the carrier, and the free components were removed, passivated, and collected to successfully construct a composite drug delivery system.

[0035] Embodiment 3:

[0036] Step 1, prepare a beaker, add 30 mg of CNTs and 100 mL of ethanol into it, and perform ultrasonic treatment for 1 h.

[0037] Step 2, add 30 mg of CaCl2 to the beaker in step 1, ultrasonicate for 1 h, introduce carbon dioxide at a flow rate of 1 L / min for 20 s, and heat and stir for 24 h.

[0038] Step 3, the solid matter in the beaker was washed by centrifugation to obtain CNTs / CaCO3 drug carrier, which was mixed with OXA at ​​room temperature to adsorb the drug onto the carrier, and the free components were removed, passivated, and collected to successfully construct a composite drug delivery system.

[0039] Comparative Example 1:

[0040] This comparative example is basically the same as Example 1, except that the heating and stirring time is 12 h.

[0041] The results show that the surface of the carbon nanotube composite material prepared in this comparative example is covered with less calcium carbonate, the encapsulation effect is not good, the uneven encapsulation of calcium carbonate causes the risk of drug penetration during transportation, and the drug loading performance is reduced.

[0042] Comparative Example 2:

[0043] This comparative example is substantially the same as Example 2, except that carbon dioxide is then introduced at a flow rate of 2 L / min for 20 s.

[0044] In this comparative example, it was measured that after the influx of carbon dioxide at a flow rate of 0.5 L / min for 20 seconds, the amount of calcium carbonate encapsulated was significantly less than that of carbon dioxide at 1.0 L / min, indicating that a small amount of carbon dioxide introduced will affect the amount of calcium carbonate generated.

[0045] Comparative Example 3:

[0046] This comparative example is basically the same as Example 3, except that the anticancer drug contained is different, and DOX is used as the anticancer drug contained.

[0047] The results showed that the drug loading of this comparative example was significantly decreased, indicating that the molecular weight of the anticancer drug would affect the drug loading of the drug carrier for the anticancer drug.

Claims

1. A composite material for regulating the tumor microenvironment in response to pH, characterized in that: The following steps are involved: Step 1, dissolving dicyandiamide and ferrous sulfate heptahydrate in ethanol, stirring to dissolve, drying, and grinding to obtain powder. Step 2: Take the powder prepared in step 1 and place it in a magnetic boat, place it in a tube furnace, and set appropriate time and temperature for carbonization. Step 3, taking the powder obtained by carbonization in step 2, acid-washing, filtering and drying to obtain carbon nanotube powder. Step 4, take a beaker, add the carbon nanotube powder and CaCl2 in step 3, ultrasonically treat, then introduce carbon dioxide, heat and stir for several hours. Step 5, centrifugally wash the solid matter in the beaker to obtain CNTs / CaCO3 drug carriers, stir and mix with anti-tumor drugs such as DOX at room temperature, allow the drugs to adsorb to the carriers, remove free components, passivate, collect, and successfully construct a composite drug delivery system.

2. The carbon nanotube composite material prepared as claimed in claim 1, characterized in that The reaction time is 12-48 hours.

3. The added carbon nanotube powder and CaCl2 as claimed in claim 1, characterized in that: The mass ratio is 1:1-1:

5.

4. The loaded anti-tumor drug according to claim 1, characterized in that Including cytotoxic drugs, hormone drugs, biological response modifiers, monoclonal antibody drugs, other types of drugs, adjuvant drugs, etc.

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