Dynamic Cellular Uptake of Mixed-Monolayer Protected Nanoparticles (original) (raw)
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ACS nano, 2015
Correlation of the surface physicochemical properties of nanoparticles with their interactions with biosystems provides key foundational data for nanomedicine. We report here the systematic synthesis of 2, 4, and 6 nm core gold nanoparticles (AuNP) featuring neutral (zwitterionic), anionic, and cationic headgroups. The cellular internalization of these AuNPs was quantified, providing a parametric evaluation of charge and size effects. Contrasting behavior was observed with these systems: with zwitterionic and anionic particles, uptake decreased with increasing AuNP size, whereas with cationic particles uptake increased with increasing particle size. Through mechanistic studies of the uptake process we can attribute these opposing trends to a surface-dictated shift in uptake pathways. Zwitterionic NPs are primarily internalized through passive diffusion, while the internalization of cationic and anionic NPs is dominated by multiple endocytic pathways. Our study demonstrates that size...
ACS Nano, 2020
Here we use cryo soft X-ray tomography (cryo SXT), which delivers 3D ultrastructural volumes of intact cells without chemical fixation or staining, to gain insights about nanoparticle uptake for nanomedicine. We initially used dendritic polyglycerol sulfate (dPGS) with potential diagnostic and therapeutic applications in inflammation. Although dPGS coated gold nanoparticle (dPGS-AuNP) uptake followed a conventional endocytic/degradative pathway in human lung epithelial cell lines (A549), by cryo SXT we detected ~5% of dPGS-AuNP in the cytoplasm, a level undetectable by confocal light microscopy. We also observed ~5% of dPGS-AuNP in a rarely identified sub-cellular site, namely lipid droplets, which are important for cellular energy metabolism. Finally, we also found substantial changes in the quantity of cytoplasmic organelles upon dPGS-AuNP uptake over the 1-6 h incubation period; the number of small vesicles and mitochondria significantly increased and the number of multivesicular bodies and the number and volume of lipid droplets significantly decreased. Although nearly all organelle numbers at 6 h were still significantly different from controls, most appeared to be returning to normal levels. To test for generality, we also examined cells after uptake of gold nanoparticles coated with a different agent, polyethyleneimine (PEI), used for nucleic acid delivery. PEI nanoparticles did not enter lipid droplets, but they induced similar, albeit less pronounced changes in the quantity of cytoplasmic organelles. We confirmed these changes in organelle quantities for both nanoparticle coatings by confocal fluorescence microscopy. We suggest this cytoplasmic remodeling could reflect a more common cellular response to coated gold nanoparticle uptake.
Effect of Physico-Chemical Properties of Nanoparticles on Their Intracellular Uptake
International Journal of Molecular Sciences, 2020
Cellular internalization of inorganic, lipidic and polymeric nanoparticles is of great significance in the quest to develop effective formulations for the treatment of high morbidity rate diseases. Understanding nanoparticle–cell interactions plays a key role in therapeutic interventions, and it continues to be a topic of great interest to both chemists and biologists. The mechanistic evaluation of cellular uptake is quite complex and is continuously being aided by the design of nanocarriers with desired physico-chemical properties. The progress in biomedicine, including enhancing the rate of uptake by the cells, is being made through the development of structure–property relationships in nanoparticles. We summarize here investigations related to transport pathways through active and passive mechanisms, and the role played by physico-chemical properties of nanoparticles, including size, geometry or shape, core-corona structure, surface chemistry, ligand binding and mechanical effect...
Insight into nanoparticle cellular uptake and intracellular targeting
Journal of Controlled Release, 2014
Collaborative efforts from the fields of biology, materials science, and engineering are leading to exciting progress in the development of nanomedicines. Since the targets of many therapeutic agents are localized in subcellular compartments, modulation of nanoparticle-cell interactions for efficient cellular uptake through the plasma membrane and the development of nanomedicines for precise delivery to subcellular compartments remain formidable challenges. Cellular internalization routes determine the post-internalization fate and intracellular localization of nanoparticles. This review highlights the cellular uptake routes most relevant to the field of nontargeted nanomedicine and presents an account of ligand-targeted nanoparticles for receptor-mediated cellular internalization as a strategy for modulating the cellular uptake of nanoparticles. Ligand-targeted nanoparticles have been the main impetus behind the progress of nanomedicines towards the clinic. This strategy has already resulted in remarkable progress towards effective oral delivery of nanomedicines that can overcome the intestinal epithelial barrier. A detailed overview of the recent developments in subcellular targeting as a novel platform for next-generation organelle-specific nanomedicines is also provided. Each section of the review includes prospects, potential, and concrete expectations from the field of targeted nanomedicines and strategies to meet those expectations.
Nanomedicine, 2013
Quantification of gold nanoparticle cell uptake under controlled biological conditions and adequate resolution Aim: We examined cellular uptake mechanisms of fluorescently labeled polymer-coated gold nanoparticles (NPs) under different biological conditions by two quantitative, microscopic approaches. Materials & methods: Uptake mechanisms were evaluated using endocytotic inhibitors that were tested for specificity and cytotoxicity. Cellular uptake of gold NPs was analyzed either by laser scanning microscopy or transmission electron microscopy, and quantified by means of stereology using cells from the same experiment. Results: Optimal inhibitor conditions were only achieved with chlorpromazine (clathrin-mediated endocytosis) and methyl-cyclodextrin (caveolinmediated endocytosis). A significant methyl-cyclodextrin-mediated inhibition (63-69%) and chlorpromazine-mediated increase (43-98%) of intracellular NPs was demonstrated with both imaging techniques, suggesting a predominant uptake via caveolin-medicated endocytois. Transmission electron microscopy imaging revealed more than 95% of NPs localized in intracellular vesicles and approximately 150-times more NP events/cell were detected than by laser scanning microscopy. Conclusion: We emphasize the importance of studying NP-cell interactions under controlled experimental conditions and at adequate microscopic resolution in combination with stereology.
ACS Nano, 2011
Numerous studies have examined how the cellular delivery of gold nanoparticles (AuNPs) is influenced by different physical and chemical characteristics; however, the complex relationship between AuNP size, uptake efficiency and intracellular localization remains only partially understood. Here we examine the cellular uptake of a series of AuNPs ranging in diameter from 2.4 to 89 nm that are synthesized and made soluble with poly(ethylene glycol)-functionalized dithiolane ligands terminating in either carboxyl or methoxy groups and covalently conjugated to cell penetrating peptides. Following synthesis, extensive physical characterization of the AuNPs was performed with UVÀvis absorption, gel electrophoresis, zeta potential, dynamic light scattering, and high resolution transmission electron microscopy. Uptake efficiency and intracellular localization of the AuNPÀpeptide conjugates in a model COS-1 cell line were probed with a combination of silver staining, fluorescent counterstaining, and dual mode fluorescence coupled to nonfluorescent scattering. Our findings show that AuNP cellular uptake is directly dependent on the surface display of the cell-penetrating peptide and that the ultimate intracellular destination is further determined by AuNP diameter. The smallest 2.4 nm AuNPs were found to localize in the nucleus, while intermediate 5.5 and 8.2 nm particles were partially delivered into the cytoplasm, showing a primarily perinuclear fate along with a portion of the nanoparticles appearing to remain at the membrane. The 16 nm and larger AuNPs did not enter the cells and were located at the cellular periphery. A preliminary assessment of cytotoxicity demonstrated minimal effects on cellular viability following peptide-mediated uptake.
Nonendosomal cellular uptake of ligand‐free, positively charged gold nanoparticles
Cytometry Part A, 2010
Gold nanoparticles (GNPs) have interesting optical properties, such as exceptionally high quantum yields and virtually limitless photostability. Therefore, they show the potential for applications as biomarkers especially suitable for in vivo and long‐term studies. The generation of GNPs using pulsed laser light rather than chemical means provides nanoparticles, which are remarkably stable in a variety of media without the need of stabilizing agents or ligands. This stabilization is achieved by partial oxidation of the gold surface resulting in positively charged GNPs. However, little is known about cellular uptake of such ligand‐free nanoparticles, their intracellular fate, or cell viability after nanoparticle contact. The current work is aimed to explore the response of a bovine cell line to GNP exposure mainly using laser scanning confocal microscopy (LSCM) supported by other techniques. Cultured bovine immortalized cells (GM7373) were coincubated with GNP (average diameter 15 nm...
The Journal of Physical Chemistry C, 2019
The study of interactions between Au nanostructures and living cells is a fundamental aspect that can be applied for the promising applications in nanomedicine. In the present work, we performed coarse-grained molecular dynamics (MD) simulations to observe the internalization pathways of Au nanostructures (nanosphere, nanocage, nanorod, nanoplate, and nanohexapod) into an idealized mammalian plasma membrane at an unprecedented level of complexity. Compared with the simple lipid bilayer model consisting of two lipid species, the different cellular uptake pathways of the AuNP were found. We highlight that the complexity of the lipid bilayer models plays an important role in the uptake pathway of nanoparticles (NPs). The permeability of aggregated AuNPs was much less than the NP counterpart. Spherical AuNPs showed pronounced size and surface charge dependence in their translocation through the plasma membrane. The translocation rates of different Au nanostructures were also evaluated and we found that Au nanohexapod exhibited highest cellular uptake. Understanding the interrelationship between size, shape, surface charge, and aggregation of Au nanostructures provides a clear view on the design of Au nanostructures for developing new diagnostic strategies and drug delivery. 1