| In recent years, with the development of bionanotechno logy in the field of medicine,the nanoscale drug delivery system has played an increasingly important role in reducing adverse reaction of anti-tumor drugs, realizing the drug controlled release and active targeting. In this study, two different nanoscale drug delivery systems were designed and synthesized, and their anti-tumor efficacy was investigated in vitro,(1) Multifunctional Polymer-drug Conjugated Nanoparticle Drug Delivery SystemObjective: A novel nanoscale drug delivery system was fabricated by conjugating galactose-based polymer, methoxy-poly(ethylene glycol)-block-poly(6-0-methacryloyl-D-galactopyranose) (mPEG-b-PMAGP) with doxorubicin (DOX) via an acid-labile carbamate linkage, which are featured with pH responsive and hepatoma targeting. Methods: The chemical structure of resultant conjugates was characterized by the Fourier Transform Infrared Spectrometer (FT-IR) and 1H NMR Spectroscopy(1H NMR). The self-assembling properties of mPEG42-b-PbMAGP2O-co-DOX conjugates were detected by fluorescence spectrum, dynamic laser light scattering instrument (DLS) and transmission electron microscopy (TEM). The pH-responsive DOX release profiles of mPEG42-b-PMAGP2O-co-DOX nanoparticles were examined in the condition of different release media (PBS, pH = 5.0, 6.5, 7.4) in vitro by a dialysis method. The cellular uptake behavior of mPEG42-b-PMAGP20-co-DOX nanoparticles was evaluated by confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) in qualitative and quantitative analysis, respectively. The in vitro anti-tumor efficacy of mPEG42-b-PMAGP2O-co-DOX nanoparticles against HepG2 and MCF-7 cells was verified using the MTT assay. Results: The critical micelle concentration (CMC) of the polymer-drug conjugates was 1.58 × 10-2 mg/ml; the diameter of mPEG42-b-PMAGP20-co-DOX nanoparticles was 54.84 ± 0.58 nm; and the TEM image showed that the structure of the obtained nanoparticles was completely spherical-shaped and the diameter was approximately 20-30 nm. The cumulative release of DOX from the nanoparticles was 26.58 % during 72 h in the neutral condition (pH 7.4), while the corresponding values increased to 43.61% and 76.48% in the acidic conditions (pH 6.5 and 5.0), respectively. The mPEG42-b-PMAGP20-co-DOX nanoparticles which contain galactose functional groups exhibited higher cellular uptake efficacy by HepG2 cells (ASGP receptor overexpressing cancer cell line) than by MCF-7 and A549 cancer cells (ASGP receptor deficient cancer cell lines) under the same condition. In addition, the mPEG42-b-PMAGP20-co-DOX nanoparticles exhibited higher cytotoxicity to HepG2 cells than to MCF-7 cells under the same condition too. Conclusions: This polymer-drug conjugate could self-assemble into nanoparticles in aqueous solution.The mPEG42-b-PMAGP2O-co-DOX nanoparticles can achieve significantly pH-responsive drug release and hepatoma targeting.(2) Multifunctional Mesoporous Silica Nanoparticle Drug Delivery SystemObjective: A novel nanoscale drug delivery system was designed and synthesized by modifying hyaluronic acid (HA) onto the surface of mesoporous silica nanoparticles (MSNs) via disulfide bonds. Methods: The structure and property of MSNs before and after modification were detected by TEM, FT-IR, TGA and N2 adsorption-desorption analysis. Doxorubicin hydrochloride (DOX HCl), as a model drug,was encapsulated into MSNs and MSN/SS/HA nanoparticles under the same condition, respectively. The drug loading (DL%) and encapsulation efficiency (EE%)of MSNs and MSN/SS/HA nanoparticles were determined by a fluorescence spectrophotometer,and the in vitro drug release profiles were examined through a dialysis method in the phosphate buffer solution with or without the presence of GSH.The cellular uptake behavior of MSNs/SS/HA@DOX nanoparticles was evaluated by confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) in qualitative and quantitative analysis, respectively. The in vitro cytotoxicity of MSNs/SS/HA@DOX nanoparticles against HeLa and L02 cells was verified using the MTT assay. Results: The TEM image revealed that both of blank and modified MSNs were generally in spherical shape and exhibited porous structure. In addition,after modification with HA via disulfide linkage, the average diameter of MSNs/SS/HA nanoparticles increased from 25 nm to 40 nm. The results also revealed that HA was successfully conjugated onto the surface of MSNs and played a certain modification effect on the pore of MSNs. Both DL% and EE% of MSN/SS/HA nanoparticles were higher than MSNs. The cumulative release of DOX from MSN/SS/HA@DOX nanoparticles was approximately 31.02% during 72 h in the absence of GSH, while in the release medium containing 2μM and 10 mM GSH, the corresponding values increased to 32.06% and 81.66%, respectively. In addition, only 29.5% of DOX was leaked out from MSNs/SS/HA@DOX nanoparticles during 24 h in the absence of GSH (PBS, pH 7.4), while about 88.8% of DOX was released from MSNs@DOX. MSNs/SS/HA@DOX nanoparticles exhibited higher cellular uptake efficacy by HeLa cells (CD44 overexpressing cell line) than by L02 cells (CD44 deficient cell line) and showed DOX dose-dependent toxicity to the both kinds of cells. Moreover, the MSNs/SS/HA@DOX nanoparticles exhibited higher cytotoxicity to HeLa cells than to L02 cells under the same condition. Conclusions: The MSN/SS/HA@DOX nanoparticles can achieve significantly redox-responsive and sustained drug release and they could enhance the cellular uptake efficacy and cytotoxicity to cancer cells and possess tumor-targeting function. |
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