Study On Theconstruction Of Polydopamine-mediated Different Surface-modified Nanoparticles And Their Biological Behavior In Vitro And In Vivo

Study on the construction of Polydopamine-mediated DifferentSurface-modified Nanoparticles and Their Biological Behavior in vitroand in VivoThe nature of a particle's surface significantly affects their behavior and fate in the physiological environment.A pre-understanding and a simple controlling of the surface coatings' interactions with biological systems are of vital importance.In recent years,nanosystems including nano-sized drug delivery systems for treatment and nanoscale diagnostic reagents such as polymeric NPs,liposomes,quantum dots(QDs),nano-hydroxyapatite and graphene show a great application prospect in the diagnosis and treatment of the disease.However,their clinical applications are still limited by their poor biocompatibility such as hydrophobicity,hemolysis and toxicity.In order to reduce the self-toxicity of nanosystems,improve their pharmacokinetic profiles and enhance their cellular internalization ability,we present a simple and uniform surface modification strategy mediated by polydopamine(pD),which canmodify nanoparticles with different coatings to improve their biocompatibility,the ability to interact with cells,their pharmacokinetic profiles and reduce toxic side effects.Herein,we prepared PLGA nanoparticles with good uniformity in particle size and good stability,then we successfully modified model PLGA NPs with three surface modifiers: bovine serum albumin(BSA),poly-L-lysine(PLL)and polyethylene glycol(PEG)respectively via polydopamine(pD)endowing new surface properties.The particle size,particle size distribution,zeta potential and drug loading of LTX-loaded NPs(PLGA,pD-PLGA,BSA-pD-PLGA,PLL-pD-PLGA and PEG-pD-PLGA)were determined.And the surface modification of nanoparticles was further confirmed by transmission electron microscopy(TEM),x ray photoelectron spectroscopy(XPS),nuclear magnetic resonance(1H-NMR)and infrared spectroscopy(FTIR).In summary,the increase in particle size and the change of zeta potential,morphology,surface components,1H-NMR spectrum and FT-IR absorptionspectrum suggested that NPs withdifferent coatingsassisted bypolydopamine were prepared successfully.In order to investigate the effects of three kinds of surface coating(BSA,PEG,PLL)on the stability of nanoparticles,we carried out the experiment of serum stability.The results showed that BSA and PEG coating could maintain the stability of nanoparticles in serum.The PLL shell with low positive charge density could still adsorb serum protein to a certain degree,which lead to the increase of particle size and size distribution.In addition,in vitro drug release studies revealsthatBSA coating showed a delay in drug release,which brought us a tip that proteinsshells like BSA or its analogue might delay the release of high protein-binding rate drugs like taxane.The effects of the above three kinds of surface coating on the antitumor activity and the uptake efficiency of cancer cells were studied by using the human breast cancer cell line MCF-7 and human lung cancer cell line A549 as the cell model.The study on cell viability of blank NPs showed that BSA coating had good biocompatibility.In addition,when the particle concentration is higher than 250?g/m L,PLL coating showed slight toxicity,which may be the results that its low positive charge density on the surface was compensated bythe negatively charged plasma protein.Meanwhile,PLLcoated NPs exhibited higher and slightly pH-dependent antitumoractivity.The cells still ingested more PLLcoated NPs than negative ones though its low positive charge density.Moreover,these results reveals that the increase ofpositive charge from p H 7.4 to 6.3 for PLL coated NPscanimprove internalization of NPs to some extent inthe acidic tumor microenvironment.And the extent of this improvement varies depending on the type of cell(MCF-7 obviously and A549 slightly here).PLL coated NPs exhibit excellent cellular uptake and slightlypH-dependent intracellular uptake which isbeneficial to meet the treatment needs in the acidic tumor micro environment.In this paper,UPLC-MS/MS method was used to determine the concentration of LTX in plasma samples.Male Sprague-Dawley(SD)rats were used as experimental animals.After intravenous administration,drug time curve was draw and the pharmacokinetic parameters were calculated to evaluate the effects of different surface coatings on the pharmacokinetic behavior of NPs in rats.Results showed that PEG coated NPs displayed good pharmacokinetic profiles as expected.BSA coated NPs could inhibit the plasma proteins' adsorption thus prolong their circulation time and enhance their AUC(0-?)to some extent.Despite the lower AUC and t1/2z compared with the negatively charged NPs,the AUC of PLL coated NPs was 1.5-fold greater than that of LTX solution(2642.77±133.50?g/L·h vs 1701.01±53.90?g/L·h,p< 0.05)and the t1/2z values of PLL coated NPs was 1.6-fold higher compared to LTX solution(11.51±3.34 h vs 7.23±0.48 h,p<0.05).Finally,the male Kunming mice were used as the experimental animals,and DiR was used as the fluorescent dye.The effects of different surface coatings on the tissue distribution of nanoparticles in mice were investigated.Results showed that the sum of organ distribution for PLL coated NPs was less than that of negatively charged NPs.It is speculated that a portion of the positively charged particles might beinternalized by blood cells or be bound to the polyanions on the surface of the vessel wall.In addition,the distribution of PEG nanoparticles in liver and spleen was not as rapid as that of BSA coated nanoparticlesbut gradually increased after 1h.This result confirms the advantage of PEG,meanwhile indicating that all the foreign particles cannot avoid the ultimatefate of opsonization and engulfmentby the reticuloendothelial system(RES).