The Study Of Self-assembled Nanoparticles Of Hydrophobically Modified Carboxymethyl Curdlan Conjugates As The Novel Antitumor Drug Delivery Carrier

In this study,we synthesized novel polymeric amphiphiles by deoxycholic acid (DOCA) hydrophobically modified CM-curdlan and prepared self-assembled nanoparticles.Epirubicin(EPB),as a model antitumor drug,was physically entrapped inside DCMC self-aggregated nanoparticle.The load capability and release behavior were investigated.The antitumor effect of EPB loaded DCMC nanoparticles was examined by cell culture in vitro.In order to providing a novel antitumor drug carrier,the safety of cartier was examined by animal experiment.The main content of this research are shown as follows.A series of DOCA-modified-CM-curdlan were synthesized and characterized by conductometric titration,FTIR,~1H NMR,and XRD.The degree of DOCA substitution (DS),as spectrophotometrically determined,was 2.1,3.2,4.1,or 6.3 DOCA group per hundred sugar residues of CM-curdlan.The physicochemical properties of the self-aggregated nanoparticals in aqueous media were investigated using ~1H NMR, dynamic light scattering(DLS),zeta potential,scanning electron microscope(SEM), transmission electron microscopy(TEM) and fluorescence spectroscopy.DCMC conjugates provided monodispersed self-aggregated nanoparticles in water,with mean diameter decreasing from 192 to 347 nm with DOCA DS increasing.Zeta potential of DCMC self-aggregated nanoparticles exhibited near -60 mV in distilled water and -26 to -36 mV in PBS,Indicating these nanoparticles were covered with negatively charged CM-curdlan shells.The critical aggregation concentration(cac) of the DCMC were dependent on the degree of substitution(DS) of DOCA and were slightly lower in PBS than in distilled water.The mean diameter and cac were affected by electrolytes and pH of the media.The SEM and TEM images demonstrated that the self-assembled nanoparticles were spherical shape.The EPB was physically entrapped inside the DCMC self-aggregated nanoparticles by transmembrane ammonium sulfate gradients method.The loading content of EPB increased with increasing drug-to-carrier ratio.The loading efficiency of EPB could achieve 41.6%-61.3%.The TEM images showed the EPB loaded DCMC nanoparticles were almost spherical in shape and had a coarser surface compared with blank DCMC nanoparticles.We believed this is because some EPB were adsorbed to surface of nanoparticles.The size of EPB loaded DCMC nanoparticles increased with EPB-loading centent increasing from 6.56%-19.26%.The release behavior of EPB from DCMC nanoparticles was studied in vitro by dialysis method and the results showed that EPB release correlated with the pH of the release media and drug loading content.The release rate decreased with pH of release media and loading content increasing.The study of cell cytotoxicity in vitro showed blank DCMC self-aggregated nanoparticles have no antitumor activity even concentration at 100μg/mL.However,the EPB loaded DCMC self-aggregated nanoparticles and free EPB have antitumor activity at EPB concentration 0.1～10μg/mL in vitro,moreover the cytotoxicity of the EPB loaded DCMC self-aggregated nanoparticles were higher than free EPB.Flow cytometry and confocal image analysis revealed that EPB loaded DCMC nanoparticles exhibited greater extent of cellular uptake than free EPB.It was confirmed in vivo toxicity studies that blank DCMC self-aggregated nanoparticles did not induce unexpected side effects and EPB loaded DCMC nanoparticles was safer than free EPB.These results indicated the DCMC self-aggregated nanoparticles as drug carrier was safe and EPB entrapped in DCMC nanoparticles could reduce its side effects.DCMC could be a promising carrier for antitumor drugs delivery.