| Objective:To perpare a kind of mesoporous silica nanoparticles, which was as a carrier and modified by PEG.We take Cypate that has the function of near-infrared fluorescence imaging and photothermal effect and doxorubicin what as a kind of chemotherapy drugs as the model drugs for Cancer theranostics,then we committed to perpare a kind of multifunctional nanoparticles that was hydrophilic and has the function of near-infrared fluorescence imaging and has the effect of photothermal and chemotherapy.Methods:There has many methods to prepare mesoporous silica currently, we use the template method, CTAB as the template, TEOS as the silicon source, APTES as the amino agent,all these were mixed in the aqueous solution of a certain pH. Then the mesoporous silica was used as the monomer with Cypate on it by an amide coupling reaction,then to increase its hydrophilicity by reaction of the PEG molecule via an amide introduction, finally, doxorubicin was entrapped mesoporous silica by dipping.At this experiment. (1) To use dynamic light scattering, SEM, TEM, nitrogen adsorption experiments, FTIR, and other testing methods for the size, zeta potential, morphology, specific surface area, mesoporous pore size distribution, amide bond and drug loading of the multifunctional nanoparticles. (2)The absorbance and fluorescent spectrums of Cypate or DOX were measured using UV-Vis spectrophotometer and fluorescences pectrophotometer, respectively.We studied the chem-stability, photostability at different media and the release behavior of Cypate and DOX using dialysis method respectively. (3)DPBF fluorescence probe method was used to evaluate the ability of generating singlet oxygen.MTT method was used to evaluate the cytotoxicity of blank material, free Cypate/DOX or DOX@ SiO2 or Cypate/SiO2 and Cypate/DOX-SiO2 with or without photoirradiation To use UV-Vis spectrophotometer and fluorescence spectrophotometer to explore the cellular uptake. The UV-Vis spectrophotometer also was applied to explore the mechanism of endocytosis of nanoparticles. AO staining and DHE staining were used to visually reflect the ability of generating singlet oxygen. (4)4T1 tumor- bearing nude mice were established as the tumor model, and then in vivo fluorescence imaging technique was applied to investigate the distribution and imaging of micelles in nude mice bearing 4T1 tumor.4T1 tumor-bearing mice were established as the tumor model, using fluorescence spectrophotometer to investigate the distribution of Cypate in mice and using HPLC to investigate the distribution of DOX in mice. (5)The antitumor effect of the Cypate/DOX-SiO2 were evaluated using 4T1 tumor-bearing mice with or without photoirradiation.Results:(1) We have prepared blank nanoparticles:average particle size of 39.4±2.1 nm,zeta potential of 44.2±2.8 mv,PDI of 0.218,pore diameter of 2.6nm and specific surface area of 290.5 m2/g.And we have prepared multifunctional nanoparticles:average particle size of 44.3±1.6 nm,zeta potential of 12.7±4.8 mv,PDI of 0.158.Drug loading of Cypate and DOX was 10% and 15%, respectively. (2) The multifunctional nanoparticles have good stability in fluorescence and ultraviolet-visible absorption. Furthermore, we demonstrated the release behavior of Cypate and DOX from ICG/DOX Micelles at pH 7.4 and 5.0 at 37℃ to find the multifunctional nanoparticles have obviously slow release effect. (3) In vitro studies, multifunctional nanoparticles have shown good tumor cell killing capacity at high concentrations, the effect is better than the single-package doxorubicin and silica nanoparticles coupled Cypate, indicating that the multifunctional nanoparticles contained two drugs has a synergistic effect. (4) In vivo studies,NIRF imaging show that the Cypate/DOX-SiO2 nanoparticles have an enhanced imaging and long residence time in tumor site. In studies of tissue distribution,it showed the highest concentration in the tumor site.All these data indicated good effect of anticancer. (5) In vivo anticancer therapy,it showsed that the Cypate/SiO2 group under photoirradiation can eliminate the tumor, but after a period of time the tumor will regenerate. DOX@ SiO2 group can inhibit the tumor growth but it is hard to eliminate the tumor. The Cypate/DOX-SiO2 group under photoirradiation can well eradiciate tumor, and inhibit the regeneration of tumor.Conclusions:In summary, we have developed multifunctional nanoparticles for cancer near-infrared fluorescence imaging and therpy.The average size of it was 44.3±1.6 nm,it’s zeta potential was 12.7±4.8 mv,and the PDI was 0.158.After analysis, the nanoparticles has good chemical stability and photo stability, and has a good slow release effect. In vitro studies show multifunctional nanoparticles have good ability of killing tumor cells.The cellular uptake ability of Cypate and doxorubicin compared to the free drug has improved significantly. The results in NIF imaging, multifunctional nanoparticles show enhanced imaging and longer retention time. In vivo antitumor studies,the synergistic effect of DOX and Cypate eliminate the tumor and avoids the problem of relapse. |
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