The Construction And Antitumor Activity Study Of Nano-drug Delivery System

There are more and more people dying of cancer today.People often feel powerless in the face of cancer invasion.Currently,the methods of cancer treatment are usually based on surgical interventions,RT,neoadjuvant chemotherapy?ChT?,hormone therapy?HT?or molecularly targeted therapy?MT?.In addition,in each of the cancer treatment options,the toxic and side effects generated during the treatment process can make the patient feel painful.Therefore,it is very urgent to find a method that not only can suppress the deterioration of cancer but also will not cause side effects to other normal tissues.Christian de Duve reported on a new method of treating cancer by destroying the lysosomal membrane to kill cancer cells and won the Nobel Prize for medicine.That is,lysosomes are defined as"suicide packets".In short,when a certain drug enters the lysosome of a cancer cell,the permeability of the lysosomal membrane increases under the action of the drug,and after the increase,certain specific tissue proteins are released from lysosomes to the cytoplasm,causing apoptosis or apoptosis-like pathways.This method of killing cancer cells can also effectively overcome the drug resistance of cancer cells.Therefore,the use of lysosomes as a potential therapeutic target has attracted more and more attention.Among nanomaterials,hollow mesoporous silica nanomaterials?HMSN_S?have been widely used because of their excellent biocompatibility,large surface area,large pore volume,and adjustable pore size.In addition,the surface of the HMSN_S can be further modified by the target substance.As a surface modification material,dopamine has great potential in constructing the bridges between HMSN_S and target substances.Targeted substances usually have a specific recognition function on a certain part of cancer cells,so the use of targeted substances for targeted therapy has become one of the hot spots in current medical research.In the process of making drug delivery systems using nanomaterials for drug delivery,the poor solubility and non-specificity of most anticancer drugs limits their clinical application.Nanoparticles made from drug conjugates have the advantages of high drug loading and passive tumor targeting capabilities.Based on the above,we have constructed two different Nano-drug delivery systems.One is the use of HMSN_S loaded with DOX and treatment with sodium bicarbonate,followed by poly-dopamine?pDA?modification on the surface and further attachment of folic acid?FA?to synthesize a targeted Nano-drug delivery system.The second is to use an amide bond to bind the two DOX molecules and then make the nanoparticles by ultrasound.The details are as follows:?1?The construction of a targeted pH-responsive Nano-delivery systemHMSNs were prepared according to the method previously used in the research group and loaded with doxorubicin?DOX?and treated with sodium bicarbonate?NaHCO₃?,then modifying pDA and FA to synthesize the Nano-drug delivery system BGNSs@pDA-FA.First,we characterized the successful synthesis of the material through transmission electron microscopy?TEM?,Zeta potential,and changes in color during the fabrication of the material.Then,the vitro release experiments confirmed that BGNSs and BGNSs@pDA-FA will only release the drug in the weakly acidic environment within the tumor.In addition,it was observed by the ultrasound imaging experiment that when the PBS solution was at a pH of 7.4,almost no bubbles were generated in the material.Bubbles will only occur at pH 5.0.However,the results of both in vitro release and ultrasound imaging demonstrate that BGNSs@pDA-FA produces fewer drugs and bubbles than BGNSs,because the modified pDA blocks the production of drugs and bubbles,but this is not affects the anti-cancer effect of the material on the cells.?2?Inhibitory effect of BGNSs@pDA-FA on MCF-7,MCF-7/ADR and MCF-10A cellsMCF-7,MCF-7/ADR and MCF-10A cells were used to investigate the effect of BGNSs@pDA-FA on cells.In vitro cytotoxicity assay,CLSM assay,LMP assay,Casepase-3 enzyme activity assay,folate competition assay,and lactate dehydrogenase assay?LDH?were used to study the mechanism of BGNSs@pDA-FA.In vitro cytotoxicity experiments showed that BGNSs@pDA-FA exhibits better anti-cancer effects and has smaller side effects on normal tissues.CLSM experiments confirmed that most of the materials in this study entered lysosomes,and a few entered the cytoplasm.The LMP assay confirmed that BGNSs@pDA-FA did produce bubbles and increased LMP.In addition,in order to verify how the BGNSs@pDA-FA caused cancer cell death,the Casepase-3 enzyme activity assay and LDH assay were performed to verify that BGNSs@pDA-FA causes cancer cell death through apoptosis or similar apoptosis pathway.Folic acid competition experiments characterized the successful binding of folic acid in BGNSs@pDA-FA and played an important role in the expression of folate receptors on the surface of cancer cells.In summary,BGNSs@pDA-FA played a better anticancer effect.?3?The construction of amide bond-based drug delivery system and its anti-cancer researchIn this paper,two DOX were successfully linked together through amide bonds by a one-pot method.The drug-drug-binding nanomaterial DCD was then prepared by sonication.The amide bond will be break down and releases DOX In the presence of lysosomal amidase.Compared to free DOX,it has controlled release ability,a better anti-cancer effect and smaller side effects on normal tissues.In this paper,the successful synthesis of DCD was characterized by TEM,fluorescence spectroscopy,dynamic light scattering?DLS?,mass spectrometry,hydrogen spectroscopy and carbon spectroscopy.In vitro release experiments showed that DCD nanomaterials release DOX only in the presence of amidase.So under physiological conditions,DCD does not produce drug leakage.The cytotoxicity assay of DCD confirmed that the maximum half-inhibitory concentration?IC50?of DCD and free DOX was 8.16 and 2.30?g/mL after incubating24 h with MCF-7 cells,respectively.The IC50 was 4.53 and 0.91?g/mL after incubating 48 h.After incubation with MCF-7/ADR for 24 h,the IC50 was 46.6 and60.1?g/mL,respectively,and after incubation for 72 h,they were 3.33 and 6.30?g/mL,respectively.After incubation with MCF-10A cells for 24 hours,the IC50 were 4.05 and2.28?g/mL,respectively,and after incubation for 48 h,they were 1.53 and 0.93?g/mL,respectively.The above data shows that the anti-cancer efficiency of DCD is better than that of free DOX,and the side effects on normal tissues are also smaller than that of DOX.Casepase-3 enzyme activity and LDH experiments confirmed that cell death caused by DCD was through apoptosis or apoptotic pathways rather than necrosis.Therefore,the use of the drug itself to form nano-materials has a good prospect in the treatment of cancer.