Highly Stable Positively Charged Dendron-Encapsulated Gold Nanoparticles

Cho, Tae Joon; MacCuspie, Robert I.; Gigault, Julien; Gorham, Justin M.; Elliott, John T.; Hackley, Vincent A.

doi:10.1021/la5002013

Cited by 54 publications

(63 citation statements)

References 63 publications

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“…The zeta potential distributions of AuNP batches #1−#5 are given in Figure S10. The high zeta potential values are superior to previously reported values from +5 to +45 mV, [13,16,37] and ensure a high colloidal stability of MUTAB-AuNPs. The results are summarized in Table S1.…”

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confidence: 67%

Rapid Cationization of Gold Nanoparticles by Two‐Step Phase Transfer

et al. 2015

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Cationic gold nanoparticles offer intriguing opportunities as drug carriers and building blocks for self‐assembled systems. Despite major progress on gold nanoparticle research in general, the synthesis of cationic gold particles larger than 5 nm remains a major challenge, although these species would give a significantly larger plasmonic response compared to smaller cationic gold nanoparticles. Herein we present the first reported synthesis of cationic gold nanoparticles with tunable sizes between 8–20 nm, prepared by a rapid two‐step phase‐transfer protocol starting from simple citrate‐capped particles. These cationic particles form ordered self‐assembled structures with negatively charged biological components through electrostatic interactions.

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confidence: 67%

Rapid Cationization of Gold Nanoparticles by Two‐Step Phase Transfer

et al. 2015

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“…However, such materials would be quite challenging to produce, given the high unpredictability of biological entities. Perhaps more readily available would be ENM reference materials (with well-defined and consistent physicochemical properties) that have been validated for use as positive or negative controls in multiple toxicity assays; such materials are already being pursued by the research community (153). Validation of such materials is not trivial and would require rigorous comparative studies using robust assays that have been examined for ENM interference (10,11).…”

Section: Modifications Of the Automated Fadu Assaymentioning

confidence: 99%

Emerging metrology for high-throughput nanomaterial genotoxicology

Nelson

Wright

Ibuki

et al. 2016

MUTAGE

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The rapid development of the engineered nanomaterial (ENM) manufacturing industry has accelerated the incorporation of ENMs into a wide variety of consumer products across the globe. Unintentionally or not, some of these ENMs may be introduced into the environment or come into contact with humans or other organisms resulting in unexpected biological effects. It is thus prudent to have rapid and robust analytical metrology in place that can be used to critically assess and/or predict the cytotoxicity, as well as the potential genotoxicity of these ENMs. Many of the traditional genotoxicity test methods [e.g. unscheduled DNA synthesis assay, bacterial reverse mutation (Ames) test, etc.,] for determining the DNA damaging potential of chemical and biological compounds are not suitable for the evaluation of ENMs, due to a variety of methodological issues ranging from potential assay interferences to problems centered on low sample throughput. Recently, a number of sensitive, high-throughput genotoxicity assays/platforms (CometChip assay, flow cytometry/micronucleus assay, flow cytometry/γ-H2AX assay, automated ‘Fluorimetric Detection of Alkaline DNA Unwinding’ (FADU) assay, ToxTracker reporter assay) have been developed, based on substantial modifications and enhancements of traditional genotoxicity assays. These new assays have been used for the rapid measurement of DNA damage (strand breaks), chromosomal damage (micronuclei) and for detecting upregulated DNA damage signalling pathways resulting from ENM exposures. In this critical review, we describe and discuss the fundamental measurement principles and measurement endpoints of these new assays, as well as the modes of operation, analytical metrics and potential interferences, as applicable to ENM exposures. An unbiased discussion of the major technical advantages and limitations of each assay for evaluating and predicting the genotoxic potential of ENMs is also provided.

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“…Now, through a series of stability studies we can conclude that Au-PEI25kB, the branched and highest-M r PEI gold conjugates, exhibited the most stable behavior, in general, and has improved stability compared to that of citrate-stabilized AuNPs in PBS, DMEM, and acidic solution and after the lyophilization−reconstitution cycle. A comparison of the stability of the Au-PEI25kB to our previously developed positively charged dendron-stabilized AuNP (Au-PCD), 50 which contained a disulfide linker and three branched polyethylene glycol chains with trimethylammonium termini (M r ≈ 2.6kD), demonstrates that the PEI conjugate is relatively less stable in physiological salt media (PBS and DMEM) and the lyophilization−reconstitution cycle. However, the PEI conjugate demonstrated better stability than Au-PCD under strongly acidic conditions.…”

Section: Conjugation Mechanism Studymentioning

confidence: 99%

Unexpected Changes in Functionality and Surface Coverage for Au Nanoparticle PEI Conjugates: Implications for Stability and Efficacy in Biological Systems

et al. 2015

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Cationic polyethylenimine conjugated gold nanoparticles (AuNP-PEI) are a widely studied vector for drug delivery and an effective probe for interrogating NP-cell interactions. However, an inconsistent body of literature currently exists regarding the reproducibility of physicochemical properties, colloidal stability, and efficacy for these species. To address this gap, we systematically examined the preparation, stability, and formation mechanism of PEI conjugates produced from citrate-capped AuNPs. We considered the dependence on relative molar mass, Mr, backbone conformation, and material source. The conjugation mechanism of Au-PEI was probed using attenuated total reflectance FTIR and X-ray photoelectron spectroscopy, revealing distinct fates for citrate when interacting with different PEI species. The differences in residual citrate, PEI properties, and sample preparation resulted in distinct products with differentiated stability. Overall, branched PEI (25 kDa) conjugates exhibited the greatest colloidal stability in all media tested. By contrast, linear PEI (25 kDa) induced agglomeration. Colloidal stability of the products was also observed to correlate with displaced citrate, which supports a glaring knowledge gap that has emerged regarding the role of this commonly used carboxylate species as a "place holder" for conjugation with ligands of broad functionalities. We observed an unexpected and previously unreported conversion of amine functional groups to quaternary ammonium species for 10 kDa branched conjugates. Results suggest that the AuNP surface catalyzes this conversion. The product is known to manifest distinct processes and uptake in biological systems compared to amines and may lead to unintentional toxicological consequences or decreased efficacy as delivery vectors. Overall, comprehensive physicochemical characterization (tandem spectroscopy methods combined with physical measurements) of the conjugation process provides a methodology for elucidating the contributing factors of colloidal stability and chemical functionality that likely influence the previously reported variations in conjugate properties and biological response models.

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Highly Stable Positively Charged Dendron-Encapsulated Gold Nanoparticles

Cited by 54 publications

References 63 publications

Rapid Cationization of Gold Nanoparticles by Two‐Step Phase Transfer

Rapid Cationization of Gold Nanoparticles by Two‐Step Phase Transfer

Emerging metrology for high-throughput nanomaterial genotoxicology

Unexpected Changes in Functionality and Surface Coverage for Au Nanoparticle PEI Conjugates: Implications for Stability and Efficacy in Biological Systems

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