Nano-sized Drug Carrier Based On Polydopamine

Compared with traditional formulations, polymer nanoparticles possess the following characteristics: a large drug loading, convenient to use, easy to absorb and degrade in vivo.It has attracted widely attention that polylactic–co-glycolic acid(PLGA) as the drug carrier,which has biodegradability. PLGA nanoparticles has solved several problems:short half-life of the drug, frequently dosing and instability in vivo. Thus, PLGA-NPs can improve the patients’ compliance. However, it has shorter cycle time and a serious drug burst release.Dopamine(DOPA,3,4-hydroxy phenylethylamine) has good adhesion with a variety of materials. The adhesion mechanism occurs when it self-polymerize to form the polydopamine(PDA) in aerobic alkaline environment. PDA has good hydrophilcity, biocompatibility, stability and biodegradation.So it can be considered to prepare polydopamine nanoparticles and used as a material of surface modification to improve the brust release of PLGA-NPs to extend the long cycle time in vivo.The research content is as follows:(1) We prepared blank PDA nanoparticles(PDA-NP) and Alendronate sodium(ALD)-loaded nanoparticle(PDA-ALD-NP) in an alkaline solution taking advantage of DOPA. We measured the sizes and zeta potential of PDA-NP and PDA-ALD-NP utilizing a dynamic light scattering(DLS), the result showd that the average sizes were less than 102 nm and had narrow size distribution, also, the zeta potentials were around-25 mV. We observed the morphology of the two nanoparticles making use of Scanning electron microscope(SEM), the results showed that both PDA-NP and PDA-ALD-NP were smooth and round.The UV-Vis spectrophotometry detected the drug loading of PDA-ALD-NP was 5.3%±1.2%. The release in vitro displayed that the PDA-ALD-NP could significantly slow down the release of ALD. In addition, we also studied the stability in vitro of PDA-ALD-NP and found that PDA-ALD-NP was able to maintain a certain degree of stability in aqueous solution and fetal bovine serum(FBS).Tribological investigation showed PDA-ALD-NP had better tribological performance.In addition, empolying MTT method to inspect the biocompatibility of DOPA and two types of nanoparticles.(2)Using PLGA as materials, DOPA as a material of surface modification,doxorubicin(DOX) and resveratrol(Res) as model drugs,DOX-loaded PLGA nanoparticles(PLGA-DOX-NP), DOX-loaded PLGA nanoparticles with surface modificated PDA(PDA-PLGA-DOX-NP), Res-loaded PLGA nanoparticles(PLGA-Res-NP) and Res-loaded PLGA nanoparticles with surface modificated PDA(PDA-PLGA-Res-NP) were prepared by emulsion solvent evaporation method.We use Transmission Electron Microscopy(TEM) to observe its morphology, DLS to inspect its particle size distribution and zeta potential, UV-Vis to detecte drug loadings, the dynamic dialysis method to investigate in vitro drug release, otherwise to investigate its stability in aqueous solution and FBS.The research results displayed as follows: all the four nanoparticles had smaller size, good size distribution, better spherical morphology and dispersivity.That drug loadings of drug-loaded PLGA nanoparticle with modified polydopamine were smaller.In vitro release curve could be seen that PDA-PLGA-DOX-NP and PDA-PLGA-Res-NP improved drug burst release due to surface modification of PDA.Stability test could indicated that PDA-the PLGA-DOX-NP and PDA-PLGA- Res-NP could maintain a certain degree of stability in aqueous solution and fetal bovine serum(FBS).In addition,We inspected the antitumor effect of loaded-adriamycin nanoparticlesand the toxicity of blank nanoparticles on MCF-7 cell by MTT method.