Determination of ζ‐potential, charge, and number of organic ligands on the surface of water soluble quantum dots by capillary electrophoresis

Voráčová, Ivona; Klepárnı́k, Karel; Lišková, Marcela; Foret, František

doi:10.1002/elps.201400459

Cited by 30 publications

(13 citation statements)

References 31 publications

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“…When compared to methotrexate, quantum dots clearly showed a more effective electrostatic modulation, which could be attributed to higher particle charge and lower ionic strength of the solution. Specifically, the high exposed charge is due to the carboxylic functionalization, where several groups result in a negative net charge that ranges from −5 to −15 depending on pH and ionic strength [ 41 ]. Moreover, the low ionic strength solution (0.01 × PBS) has a Debye length 10 times greater than the 1 × PBS.…”

Section: Resultsmentioning

confidence: 99%

Silicon Nanofluidic Membrane for Electrostatic Control of Drugs and Analytes Elution

et al. 2020

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Individualized long-term management of chronic pathologies remains an elusive goal despite recent progress in drug formulation and implantable devices. The lack of advanced systems for therapeutic administration that can be controlled and tailored based on patient needs precludes optimal management of pathologies, such as diabetes, hypertension, rheumatoid arthritis. Several triggered systems for drug delivery have been demonstrated. However, they mostly rely on continuous external stimuli, which hinder their application for long-term treatments. In this work, we investigated a silicon nanofluidic technology that incorporates a gate electrode and examined its ability to achieve reproducible control of drug release. Silicon carbide (SiC) was used to coat the membrane surface, including nanochannels, ensuring biocompatibility and chemical inertness for long-term stability for in vivo deployment. With the application of a small voltage (≤ 3 V DC) to the buried polysilicon electrode, we showed in vitro repeatable modulation of membrane permeability of two model analytes—methotrexate and quantum dots. Methotrexate is a first-line therapeutic approach for rheumatoid arthritis; quantum dots represent multi-functional nanoparticles with broad applicability from bio-labeling to targeted drug delivery. Importantly, SiC coating demonstrated optimal properties as a gate dielectric, which rendered our membrane relevant for multiple applications beyond drug delivery, such as lab on a chip and micro total analysis systems (µTAS).

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Section: Resultsmentioning

confidence: 99%

Silicon Nanofluidic Membrane for Electrostatic Control of Drugs and Analytes Elution

et al. 2020

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“…The electric potential formed at this interface is defined as zeta potential (ζ ). 123 To determine the zeta potential an electrical voltage is applied in a special cuvette containing the charged NPs in suspension. The NPs move towards the electrode of opposite polarity at a constant velocity that is proportional to surface charges and consequently the zeta potential.…”

Section: Dynamic Light Scattering and Zeta Potentialmentioning

confidence: 99%

“…124 In addition, a modification process on QDs' surface (e.g., ligand addition) could be also evaluated using zeta potential analysis. 123 Ipe et al 125 reported the use of DLS and zeta potential techniques to confirm the protein cytochrome P450 BSβ conjugation with CdS and CdSe QDs. Upon protein conjugation to CdS QDs' surface, for example, increasing in the hydrodynamic diameter (near to three-fold) and modification in the nanoparticles charge from about ζ = −28 to −5 mV were observed.…”

Section: Dynamic Light Scattering and Zeta Potentialmentioning

confidence: 99%

(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

Pereira¹,

Monteiro²,

Albuquerque³

et al. 2019

J. Braz. Chem. Soc.

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Quantum dots (QDs) are semiconductor nanocrystals, which present unique photophysical properties, enabling their application as new fluorescent platforms for biomedical sciences. Colloidal QDs are end-capped with organic or inorganic compounds, not only to prevent their agglomeration but also to provide reaction sites for the attachment of targeting (bio)molecules, nanoparticles or other interfaces, for specific biological purposes. The (bio)conjugation can involve non-covalent or covalent interactions, which can be accomplished through different strategies. The final assembly needs to maintain its chemical and optical stability and biochemical functionality. Although a relative good comprehension of the experimental procedures has been established, the bioconjugation process is still a challenge. The present manuscript aims to review the main (bio)conjugation strategies successfully applied to QDs, describing the steps necessary to prepare stable targeting fluorescent nanoplatforms, as well as some usual methods used to evaluate and optimize this process.

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“…At the aim to clarify these aspects it is important to remind that the electrophoretic behavior of AuNP has been described as strongly depending on the experimental conditions adopted in terms of buffer ionic strength, colloid surface charge and hydrophilic coatings which surely influence the ζ‐potential. For ζ < 25 mV at 25°C, the dependence of the electrophoretic mobility on particle size is expressed as a function of ( kR ), where k is the reciprocal of the electric double layer thickness and R is the particle hydrodynamic radius .…”

Section: Resultsmentioning

confidence: 99%

Improved separation and size characterization of gold nanoparticles through a novel capillary zone electrophoresis method using poly(sodium4‐styrenesulfonate) as stabiliser and a stepwise field strength gradient

et al. 2017

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A novel capillary zone electrophoresis (CZE) method was developed for an improved separation and size characterization of pristine gold nanoparticles (AuNP) using uncoated fused-silica capillaries with UV-Vis detection at 520 nm. To avoid colloid aggregation and/or adsorption during runs, poly(sodium 4-styrenesulfonate) (PSS) was added (1%, w/v) in the running buffer (CAPS 10 mM, pH 11). This polyelectrolyte conferred an enhanced stabilization to AuNP, both steric and electrostatic, exalting at the same time their differences in electrophoretic mobility. Resolution was further and successfully improved through a stepwise field strength gradient by the application of 25 kV for the first 5 min and then 10 kV. Migration times varied linearly with particles diameters showing relative standard deviations better than 1% for daily experiments and 3% for interday experiments. A comparison with the size distribution obtained by transmission electron microscopy (TEM) allowed assessing that the electrophoretic profile can reasonably be considered as representative of the effective size heterogeneity of each colloid. Finally, the practical utility of the proposed method was demonstrated by measuring the core diameter of a gold colloid sample produced by chemical synthesis which was in good agreement with the value obtained by TEM measurements.

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Determination of ζ‐potential, charge, and number of organic ligands on the surface of water soluble quantum dots by capillary electrophoresis

Cited by 30 publications

References 31 publications

Silicon Nanofluidic Membrane for Electrostatic Control of Drugs and Analytes Elution

Silicon Nanofluidic Membrane for Electrostatic Control of Drugs and Analytes Elution

(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

Improved separation and size characterization of gold nanoparticles through a novel capillary zone electrophoresis method using poly(sodium4‐styrenesulfonate) as stabiliser and a stepwise field strength gradient

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