Method for preparing porous drug carrier with tumor microenvironment regulation function by utilizing moso bamboo powder compounded with calcium carbonate

Abstract

The invention discloses a new technology which can utilize calcium carbonate (CaCO3) to wrap a biomass material moso bamboo powder (BP) to form a drug carrier (BP-coated CaCO3), and the drug carrier is combined with an anti-tumor drug to achieve the effect of killing cancer cells. The preparation method comprises the following steps: wrapping the moso bamboo powder with a layer of CaCO3 through a simple one-step method, carbonizing to form a drug carrier, enriching the pore structure of the moso bamboo powder, facilitating drug loading, and introducing doxorubicin (DOX) and other anti-tumor drugs through a soaking method to successfully construct the anti-tumor system. The composite material is subjected to infrared (IR) and X-ray photoelectron spectroscopy (XPS) characterization, and the result shows that the antitumor drugs such as DOX and the like are attached to the BP-coated CaCO3 porous material. According to the material prepared by the invention, the moso bamboo powder with the porous structure provides more attachment sites for the medicine, in addition, calcium carbonate wraps the medicine, reaches a tumor area, is decomposed in a slightly acidic environment, adjusts the pH value, promotes the release of the medicine and reduces the toxic and side effects of the medicine in vivo, so that the material has a wide application prospect in the aspect of tumor treatment.

Description

Technical Field

[0004] The invention belongs to the field of composite material preparation, and particularly relates to a method for preparing a porous drug carrier with a tumor microenvironment regulating function by utilizing bamboo powder and composite calcium carbonate. Background Art

[0005] 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 transport 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 cannot kill cancer cells, 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 circumventing the drawbacks of existing methods, modifying the drug carrier, reducing the release of drugs that have not reached the tumor lesion site, reducing the toxic side effects of anti-tumor drugs, and enhancing the effect of tumor treatment.

[0006] 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, has 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. However, the use of calcium carbonate alone is prone to agglomeration, so we need to find a suitable carrier. Bamboo powder, as a biomass material, is a good drug carrier. This natural organic component greatly reduces some potential risks in the process of tumor treatment. In addition, the drug carrier formed by combining it with calcium carbonate is carbonized to form a fluffy porous structure, which provides attachment space for anti-tumor drugs. When reaching the tumor site, the porous biomass bamboo powder releases the encapsulated drug and induces cancer cell apoptosis. At the same time, the CaCO3 component is also released in a slightly acidic environment, neutralizing the pH and effectively preventing cancer cells from invading other normal cells. Summary of the invention

[0007] The present invention utilizes bamboo powder, a porous green biomass component, to modify the drug carrier by introducing calcium carbonate, loads anti-tumor drugs, and enters the tumor area in the body, which can well improve the tumor micro-acid environment. The decomposition of calcium carbonate in the micro-acid environment will promote the release of drugs, achieving the effect of inducing cancer cell apoptosis.

[0008] The specific steps include:

[0009] Step 1: Place the chopped bamboo in a polytetrafluoroethylene tank and mix with ZrO2 balls. Ball milling is performed at a speed of 500 r / min for several hours.

[0010] Step 2: Add calcium chloride into a beaker and dissolve it with ethanol. Add BP to the ethanol solution of calcium chloride and stir evenly at room temperature.

[0011] Step 3: Take another beaker and weigh a certain amount of ammonium bicarbonate. Seal the two small beakers with tin foil and pierce holes. Transfer them to a vacuum oven and react for several hours.

[0012] Step 4: Wash the solid matter in the beaker by centrifugation to obtain the BP@CaCO3 drug carrier. Take a certain amount of the above substances for carbonization treatment. Soak the carbonized porous material in anti-tumor drugs such as DOX and stir and mix them at room temperature to allow the drugs to be adsorbed into the porous structure. Remove the free components, purify and collect them, and successfully construct a composite drug delivery system.

[0013] Preferably, the bamboo powder used in step 1 is obtained by grinding, specifically grinding the chopped bamboo and ZrO2 in a polytetrafluoroethylene tank for 3-6 hours.

[0014] Preferably, the amount of substances added in step 2 is 0.5-1g of calcium chloride, 1-2g of bamboo powder, and 50-100ml of alcohol (99.5%) or water.

[0015] Preferably, in step 3, the amount of ammonium bicarbonate is 10-15 g, and the reaction time is 20-40 h at 43°C.

[0016] Preferably, in step 4, 1-2 g of the carbonized material is mixed with an anti-tumor drug such as DOX at room temperature and stirred evenly, and then separated and purified to obtain a composite material.

[0017] Compared with the prior art, the present invention has the following significant advantages:

[0018] (1) The present invention uses the natural ingredient BP, whose porous structure is conducive to the loading of anti-tumor drugs such as DOX.

[0019] (2) The drug carrier is modified by the present invention, and when it reaches the tumor site, the CaCO3 component is decomposed in a slightly acidic environment, which can effectively adjust the pH value.

[0020] (3) The present invention uses calcium carbonate to encapsulate anti-tumor drugs, and precisely regulates the release of drugs in the tumor area, thereby reducing toxic side effects on normal cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 These are the IR graphs of BP and BP@CaCO3.

[0022] Figure 2 These are the XPS images of BP and BP@CaCO3. Specific implementation method:

[0023] The present invention is further described in detail below in conjunction with the embodiments and drawings.

[0024] Preparation steps of bamboo powder: put the bamboo powder into a polytetrafluoroethylene tank, mix it with ZrO2 balls, and ball mill it at a speed of 500r / min for several hours to obtain the BP required for the experiment, which was then stored in a vacuum drying dish.

[0025] Step 1, prepare a glass beaker, add 0.5-1g calcium chloride, 50-100ml alcohol (99.5%) or water, after the calcium chloride is completely dissolved, add 1-2g BP, and stir at room temperature for 5h;

[0026] Step 2, take another beaker, add 10-15g of ammonium bicarbonate into it, seal the two small beakers with tin foil, pierce holes, transfer to a vacuum oven at 43°C and react for 20-40h;

[0027] Step 3, transfer BP@CaCO3 to a tube furnace and carbonize at 450 °C for 3 h;

[0028] Step 4, mixing the carbonized bamboo powder and anti-tumor drugs such as DOX at room temperature, filtering and washing to remove free components, and forming a composite material.

[0029] BP@CaCO3 prepared in each embodiment is as follows Figure 1 As shown, at 1460cm -1 and 876cm -1 The characteristic peak of calcium carbonate appears, indicating that calcium carbonate has been successfully coated on bamboo powder. Figure 2 As shown in the figure, the XPS full spectrum and C spectrum once again prove that our material preparation is successful and can be used as a drug carrier to induce cancer cell apoptosis.

[0030] Embodiment 1:

[0031] Step 1, prepare a 150ml glass beaker, add 0.5g calcium chloride and 100ml water into it, after the calcium chloride is completely dissolved, add 1g BP, and stir at room temperature for 5h;

[0032] Step 2, take another 100 ml beaker, add 15 g of ammonium bicarbonate into it, seal the two small beakers with tin foil and pierce holes, transfer them to a vacuum oven at 43 ° C for reaction for 30 hours;

[0033] Step 3, transfer BP@CaCO3 to a tube furnace and carbonize at 450 °C for 3 h;

[0034] Step 4, the carbonized bamboo powder and anti-tumor drugs such as DOX are stirred and mixed at room temperature, and free components are removed by filtration and washing to form a composite material.

[0035] Embodiment 2:

[0036] Step 1, prepare a 150ml glass beaker, add 0.5g calcium chloride and 100ml alcohol (99.5%) into it, after the calcium chloride is completely dissolved, add 1g BP, and stir at room temperature for 5h;

[0037] Step 2, take another 100 ml beaker, add 15 g of ammonium bicarbonate into it, seal the two small beakers with tin foil, pierce holes, transfer to a vacuum oven at 43 ° C for 30 hours;

[0038] Step 3, transfer BP@CaCO3 to a tube furnace and carbonize at 450 °C for 3 h;

[0039] Step 4: Carbonized bamboo powder and anti-tumor drugs such as DOX are stirred and mixed at room temperature, and free components are removed by filtration and washing to form a composite material.

[0040] Embodiment 3:

[0041] Step 1, prepare a 150ml glass beaker, add 0.5g calcium chloride and 100ml alcohol (99.5%) into it, after the calcium chloride is completely dissolved, add 1g BP, and stir at room temperature for 5h;

[0042] Step 2, take another 100 ml beaker, add 15 g of ammonium bicarbonate into it, seal the two small beakers with tin foil and pierce holes, transfer them to a vacuum oven at 43 ° C for reaction for 20 hours;

[0043] Step 3, transfer BP@CaCO3 to a tube furnace and carbonize at 450 °C for 3 h;

[0044] Step 4: Carbonized bamboo powder and anti-tumor drugs such as DOX are stirred and mixed at room temperature, and free components are removed by filtration and washing to form a composite material.

[0045] Embodiment 4:

[0046] Step 1, prepare a 150ml glass beaker, add 0.5g calcium chloride and 100ml alcohol (99.5%) into it, after the calcium chloride is completely dissolved, add 1g BP, and stir at room temperature for 5h;

[0047] Step 2, take another 100 ml beaker, add 15 g of ammonium bicarbonate into it, seal the two small beakers with tin foil, pierce holes, transfer to a vacuum oven at 43 ° C and react for 40 hours;

[0048] Step 3, transfer BP@CaCO3 to a tube furnace and carbonize at 450 °C for 3 h;

[0049] Step 4, mixing the carbonized bamboo powder and anti-tumor drugs such as DOX at room temperature, filtering and washing to remove free components, and forming a composite material.

[0050] Comparative Example 1:

[0051] This comparative example is basically the same as Example 1, the only difference is that the solvent selected is water.

[0052] The results showed that BP was unevenly dispersed in water and the calcium carbonate coating effect was poor. The uneven coating of calcium carbonate made the drug at risk of penetration during transportation. In addition, excessive calcium carbonate would increase the burden of cell decomposition and affect the neutralization of the pH value in the slightly acidic environment of the tumor in the later stage. This is because due to the polarity effect, BP is not easy to combine with water, and the density of water is large, BP is not easy to precipitate, which is not conducive to the formation of calcium carbonate.

[0053] Comparative Example 2:

[0054] This comparative example is substantially the same as Example 1, the only difference being that alcohol is selected as the solvent.

[0055] The results showed that BP had a good dispersion effect in water. After the reaction in the vacuum oven, the encapsulation effect of calcium carbonate in the reaction with alcohol as the solvent was significantly higher than that in water. This was because the density of alcohol was smaller than that of water, BP was easy to precipitate, and because of the polarity effect, the two combined better.

[0056] Comparative Example 3:

[0057] This comparative example is basically the same as Example 1, except that the reaction time in the vacuum oven is 20 h.

[0058] In this comparative example, it was measured that after 20 hours of reaction, the amount of calcium carbonate coated on BP was significantly less than that after 30 hours of reaction, indicating that the reaction time was too short, affecting the formation of calcium carbonate.

[0059] Comparative Example 4:

[0060] This comparative example is basically the same as Example 1, except that the reaction time in the vacuum oven is 40 h.

[0061] This comparative example measured that after 40 hours of reaction, the amount of calcium carbonate coated on BP was more than that after 30 hours of reaction, but the increase was not obvious, indicating that within the reaction time limit of 30 hours, the amount of calcium carbonate attached to BP was close to saturation, and even if the time was increased, it would not have a greater impact.

Claims

1. A porous drug-carrying material for anti-tumor use prepared based on biomass raw materials, characterized in that: The following steps are involved: Step 1: Place the chopped bamboo in a polytetrafluoroethylene tank, mix it with ZrO2 balls, and ball-mill for several hours to obtain the BP required for the experiment, which is then stored in a vacuum drying dish. Step 2: Add calcium chloride into a beaker and add a solvent (water, ethanol) to dissolve it, add BP to the calcium chloride solution, and stir evenly at room temperature; take another beaker and weigh a certain amount of ammonium bicarbonate, seal two small beakers with tin foil and pierce holes, transfer them to a vacuum oven, and react for several hours. Step three, transfer BP@CaCO3 to a tubular furnace for carbonization. After the reaction is completed, stir and mix the carbonized bamboo powder with anti-tumor drugs such as DOX at room temperature, and filter and wash to remove free components to form a composite material.

2. The BP used as claimed in claim 1, characterized in that The ball milling time is 3-6 hours.

3. Adding BP to a solvent as claimed in claim 1, characterized in that The solution of choice is alcohol (99.5%) or water.

4. The method of transferring BP@CaCO3 to a vacuum oven as claimed in claim 1, characterized in that The reaction time is 20-40 hours.

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