Cationic Nanoparticles Have Superior Transvascular Flux into Solid Tumors: Insights from a Mathematical Model
ABSTRACT Despite their great promise, only a few nanoparticle formulations have been approved for clinical use in oncology. The failure of nano-scale drugs to enhance cancer therapy is in large part due to inefficient delivery. To overcome this outstanding problem, a better understanding of how the physical properties (i.e., size, surface chemistry, and shape) of nanoparticles affect their transvascular transport in tumors is required. In this study, we developed a mathematical model for nanoparticle delivery to solid tumors taking into account electrostatic interactions between the particles and the negatively-charged pores of the vessel wall. The model predictions suggest that electrostatic repulsion has a minor effect on the transvascular transport of nanoparticles. On the contrary, electrostatic attraction, caused even by small cationic charges (surface charge density less than 3 × 10(-3) C/m(2)) can lead to a twofold or more increase in the transvascular flux of nanoparticles into the tumor interstitial space. Importantly, for every nanoparticle size, there is a value of charge density above which a steep increase in transvascular transport is predicted. Our model provides important guidelines for the optimal design of nanoparticle formulation for delivery to solid tumors.
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ABSTRACT: Limited drug distribution is partially responsible for the efficacy gap between preclinical and clinical studies of nano-sized drug carriers for cancer therapy. In this study, we examined the transport behavior of cationic micelles formed from a triblock copolymer of poly(D,L-lactide-co-glycolide)-block-branched polyethyleneimine-block-poly(D,L-lactide-co-glycolide) using a unique in vitro tumor model composed of a multilayered cell culture (MCC) and an Ussing chamber system. The Cy3-labeled cationic micelles showed remarkable Cy3 distribution in the MCC whereas charge-shielded micelles with a poly(ethylene glycol) surface accumulated on the surface of the MCC. Penetration occurred against convectional flow caused by a hydraulic pressure gradient. The study using fluorescence resonance energy transfer (FRET) showed that the cationic micelles dissociate at the interface between the culture media and the MCC or possibly inside of the first-layer cells and penetrates into the MCC as unimers. The penetration and distribution were energy-dependent and suppressed by various endocytic inhibitors. These suggest that cationic unimers mainly utilized clathrin-mediated endocytosis and macropinocytosis for cellular entry and a significant fraction were exocytosed by an unknown mechanism.Nano Today 12/2014; 9(6):695-704. DOI:10.1016/j.nantod.2014.10.003 · 18.43 Impact Factor
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ABSTRACT: Novel polymeric nanoparticles (NPs) specifically designed for delivering chemotherapeutics in the body and aimed at improving treatment activity and selectivity, cover a very relevant area in the field of nanomedicine. Here, we describe how to build a polymer shell of Hyaluronan (HA) and Polyethyleneimine (PEI) on biodegradable NPs of poly(lactic-co-glycolic) acid (PLGA) through electrostatic interactions and to achieve NPs with unique features of sustained delivery of a docetaxel (DTX) drug cargo as well as improved intracellular uptake. A stable PEI or HA/PEI shell could be obtained by careful selection of layering conditions. NPs with exquisite stability in salt and protein-rich media, with size and surface charge matching biological requirements for intravenous injection and endowed with sustained DTX release could be obtained. cytotoxicity, uptake and activity of both PLGA/PEI/HA and PLGA/PEI NPs were evaluated in CD44(+) (A549) and CD44(-) (Calu-3) lung cancer cells. In fact, PEI-coated NPs can be formed after degradation/dissociation of the surface HA because of the excess hyaluronidases overexpressed in tumour interstitium. There was no statistically significant cytotoxic effect of PLGA/PEI/HA and PLGA/PEI NPs in both cell lines, thus suggesting that introduction of PEI in NP shell was not hampered by its intrinsic toxicity. Intracellular trafficking of fluorescently labeled RHO-PLGA/PEI/HA and RHO-PLGA/PEI NPs demonstrated an increased time-dependent uptake only for RHO-PLGA/PEI/HA NPs in A549 cells as compared to Calu-3. As expected, RHO-PLGA/PEI NP uptake in A549 cells was comparable to that observed in Calu-3 cells. RHO-PLGA/PEI/HA NPs internalized into A549 cells showed a preferential perinuclear localization. Cytotoxicity data in A549 cells suggested that the delivery of DTX through PLGA/PEI/HA NPs exerted a more potent antiproliferative activity than free DTX. Furthermore, DTX-PLGA/PEI NPs, as hypothetical result of hyaluronidase-mediated degradation in tumor interstitium, were still able to improve the cytotoxic activity of free DTX. Taken together, results lead us to hypothesize that biodegradable NPs coated with a PEI/HA shell represent a very promising system to treat CD44 overexpressing lung cancer. In principle, this novel nanocarrier can be extended to different single drugs and drug combinations taking advantage of the shell and core properties.Journal of Nanobiotechnology 04/2015; 13(1):29. DOI:10.1186/s12951-015-0088-2 · 4.08 Impact Factor
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ABSTRACT: Employing green methods in the design and synthesis of functionalized metallic nanoparticles poses significant challenges in terms of maintaining product integrity (size, shape, dispersity, and colloidal stability). In this study, the direct synthesis of cationic gold nanoparticles (GNPs) capped by low molecular weight (Mw 600) polyethylenimine was investigated. Specifically, three separate HAuCl4 reduction pathways were used to produce robust GNPs with sizes ranging from 4 to 20 nm in diameter with excellent size control. The inclusion of carbon dioxide as a nontoxic, nonflammable, and inexpensive component led to decreases in particle size and an increase in the colloidal stability of the GNPs. Furthermore, the thermally reversible reaction of CO2 with amines provides means to control the solvent pH through carbamate structures and, hence, the controllable formation of particle aggregates. The effects of pH, PEI concentration, and reduction method on the particle core size and stability were determined via transmission electron microscopy, UV–vis absorption spectra, and dynamic light scattering.ACS Sustainable Chemistry & Engineering 05/2013; 1(7):826–832. DOI:10.1021/sc400028t