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Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications
Published on: February 6, 2016
Mechanisms of quantum dot nanoparticle cellular uptake
Leshuai W Zhang1, Nancy A Monteiro-Riviere
1Center for Chemical Toxicology Research and Pharmacokinetics, Department of Clinical Science, North Carolina State University, Raleigh, North Carolina 27606, USA.
Summary
Quantum dots (QDs) are useful in medicine but their cell uptake mechanism was unclear. This study reveals QDs enter cells via lipid rafts and specific pathways, showing low toxicity at certain doses.
Area of Science:
- Nanotechnology
- Cell Biology
- Biomedical Engineering
Background:
- Quantum dots (QDs) offer excellent photoemission and photostability for biomedical uses.
- Understanding QD toxicity and cellular uptake mechanisms is crucial for safe application.
- QD nanoparticles (655 nm emission) feature a CdSe core, ZnS shell, and ellipsoid shape.
Purpose of the Study:
- To elucidate the cellular uptake mechanism of QD nanoparticles in human epidermal keratinocytes (HEKs).
- To investigate the role of different endocytic pathways in QD internalization.
- To assess the toxicity and cellular effects of QD exposure.
Main Methods:
- Utilized QD nanoparticles with carboxylic acid surface coating.
- Investigated uptake pathways using lipid rafts, clathrin, and caveolae markers.
- Employed 24 endocytic interfering agents to map QD entry routes.
- Assessed QD toxicity using live/dead cell assays and observed effects on actin filaments.
Main Results:
- QD uptake was mediated by lipid rafts, not clathrin or caveolae.
- Internalization occurred via early endosomes, progressing to late endosomes/lysosomes.
- QD entry pathways are primarily regulated by G-protein-coupled receptor and LDL/scavenger receptors.
- Low toxicity observed at 20 nM QD dose in HEKs after 48 hours; actin filament formation induced, unlike cadmium's depolymerization effect.
Conclusions:
- QD nanoparticle uptake in HEKs is a specific process involving lipid rafts and defined endocytic pathways.
- QD nanoparticles demonstrate low toxicity at specific concentrations and doses.
- Surface properties (coating, size, charge) significantly influence QD cellular uptake for biomedical applications like cancer treatment and drug delivery.
