Characterization of nanoparticle uptake by endothelial cells

doi:10.1016/S0378-5173(01)00923-1

International Journal of Pharmaceutics

Volume 233, Issues 1–2, 21 February 2002, Pages 51-59

https://doi.org/10.1016/S0378-5173(01)00923-1 Get rights and content

Abstract

Endothelium is an important target for drug or gene therapy because of its important role in the biological system. In this paper, we have characterized nanoparticle uptake by endothelial cells in cell culture. Nanoparticles were formulated using poly dl-lactide-co-glycolide polymer containing bovine serum albumin as a model protein and 6-coumarin as a fluorescent marker. It was observed that the cellular uptake of nanoparticles depends on the time of incubation and the concentration of nanoparticles in the medium. The uptake of nanoparticles was rapid with confocal microscopy demonstrating their localization mostly in the cytoplasm. The mitogenic study demonstrated biocompatability of nanoparticles with the cells. The study thus demonstrates that nanoparticles could be used for localizing therapeutic agents or gene into endothelial cells. Nanoparticles localized in the endothelium could provide prolonged drug effects because of their sustained release characterics, and also could protect the encapsulated agent from enzymatic degradation.

Introduction

Endothelium is an important target for drug or gene therapy because it is involved in a number of normal and pathophysiologic conditions such as angiogenesis, atherosclerosis, tumor growth, myocardial infarction, limb and cardiac ischemia, restenosis, etc. (Nabel, 1991, Dass and Su, 2000, Martin and Murray, 2000, Parikh and Edelman, 2000). Various therapeutic approaches have been investigated to modify the endothelium to counteract the disease conditions (Nabel, 1995). Vascular endothelial cells are a particularly important target for functional genes because of their large population and contiguity with the blood stream (Yao et al., 1991). Different systems such as drug-conjugates and immunoliposomes have been studied to actively target therapeutic agents to the endothelium (Scherpereel et al., 2001, Stahn et al., 2001). In this paper, we have characterized the uptake of biodegradable nanoparticles by endothelial cells in cell culture, and have proposed strategies for endothelial delivery of nanoparticles in vivo.

Section snippets

Materials

Poly (dl-lactide-co-glycolide) (PLGA, MW 143 900, copolymer ratio 50:50) was purchased from Birmingham Polymers, Inc. (Birmingham, AL). Bovine serum albumin (BSA, Fraction V), polyvinyl alcohol (PVA, average MW 30 000–70 000), heparin sodium salt (Grade I-A from porcine intestinal mucosa), Triton-X 100 were purchased from Sigma Chemical Co. (St. Louis, MO). 6-Coumarin was obtained from Polyscience, Inc. (Warrington, PA). Fetal bovine serum (FBS, non heat-inactivated), 1× trypsin–EDTA, and

Results and discussion

The nanoparticle size ranged from 277 to 372 nm with the mean hydrodynamic diameter of 321 nm and polydispersity of 0.132, suggesting uniformity of the particle size distribution (Fig. 1). The ζ potential of nanoparticles was −10.37 mV. The BSA loading in the particles was 21% w/w (70% entrapment efficiency) and the dye loading was 0.53 μg/mg nanoparticles, suggesting that almost all the dye added to the formulation got entrapped into nanoparticles. In the previous studies, we have shown that

Conclusions

In this study, we have shown a rapid uptake of nanoparticles by endothelial cells. The uptake depends on the concentration of nanoparticles, and the particles were seen to localize mainly in the cytoplasm. Nanoparticles are biocompatible with the cells, as they did not affect the cell viability in a 48 h mitogenic assay. Nanoparticles could be used to target drugs or genes to the endothelium to achieve sustained therapeutic effect.

Acknowledgements

Grant support from the National Institutes of Health, Heart, Lung, and Blood Institute (HL 57234) and the Nebraska Research Initiative, Gene Therapy Program is appreciated.

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View full text

Characterization of nanoparticle uptake by endothelial cells

Abstract

Introduction

Section snippets

Materials

Results and discussion

Conclusions

Acknowledgements

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Matrix Biol.

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