Simultaneous Identification of Spectral Properties and Sizes of Multiple Particles in Solution with Subnanometer Resolution

Karabudak, Engin; Brookes, Emre; Lesnyak, Vladimir; Gaponik, Nikolai; Eychmüller, Alexander; Walter, Johannes; Segets, Doris; Peukert, Wolfgang; Wohlleben, Wendel; Demeler, Borries; Cölfen, Helmut

doi:10.1002/anie.201603844

Cited by 49 publications

(49 citation statements)

References 31 publications

(83 reference statements)

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“…Recently, it was demonstrated that MWL-AUC in combination with 2DSA can be used to determine the spectral properties and sizes of multiple but discrete quantum dot species. 37 Further studies shall be focused on MWL analysis to derive the size dependent extinction spectra for all species in polydisperse PSDs. AUC together with PCSA will then allow studying the quantum size effect for continuous distributions of semiconductor NPs.…”

Section: Discussionmentioning

confidence: 99%

2D analysis of polydisperse core–shell nanoparticles using analytical ultracentrifugation

Walter

Gorbet

Akdas

et al. 2017

Analyst

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Accurate knowledge of size, density and composition of nanoparticles (NPs) is of major importance for their applications. In this work the hydrodynamic characterization of polydisperse core-shell NPs by means of analytical ultracentrifugation (AUC) is addressed. AUC is one of the most accurate techniques for the characterization of NPs in the liquid phase because it can resolve particle size distributions (PSDs) with unrivaled resolution and detail. Small NPs have to be considered as core-shell systems when dispersed in a liquid since a solvation layer and stabilizer shell will significantly contribute to the particle’s hydrodynamic diameter and effective density. AUC measures the sedimentation and diffusion transport of the analytes, which are affected by the core-shell compositional properties. This work demonstrates that polydisperse and thus widely distributed NPs pose significant challenges for current state-of-the-art data evaluation methods. Existing methods either have insufficient resolution or do not correctly reproduce the core-shell properties. First, we investigate the performance of different data evaluation models by means of simulated data. Then, we propose a new methodology to address the core-shell properties of NPs. This method is based on the parametrically constrained spectrum analysis and offers complete access to the size and effective density of polydisperse NPs. Our study is complemented using experimental data derived for ZnO and CuInS2 NPs, which do not have a monodisperse PSD. For the first time, the size and effective density of such structures can be resolved with high resolution by means of a two-dimensional AUC analysis approach.

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Section: Discussionmentioning

confidence: 99%

2D analysis of polydisperse core–shell nanoparticles using analytical ultracentrifugation

Walter

Gorbet

Akdas

et al. 2017

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“…SEDFIT, ULTRASCAN and SEDANAL offer a possibility for the analysis of this experiment type with special implemented methods. In ULTRASCAN and SEDANAL, it is even possible to analyze multiwavelength (MWL) data obtained by the MWL-detector (Karabudak et al 2016;Walter et al 2015). However, all analysis methods do not yet consider the difference in density created by the overlay solution.…”

Section: Introductionmentioning

confidence: 99%

Analytical band centrifugation revisited

Schneider

Cölfen

2018

Eur Biophys J

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Analytical band centrifugation (ABC) is a powerful tool for the analysis of macromolecules and nanoparticles. Although it offers several advantages over the sedimentation velocity (SV) experiment like a physical separation of the individual components and the possibility to perform chemical reactions, its analysis is still very restricted. Therefore, we investigated the integration of ABC data as an alternative approach, as this results in data similar to SV, which can then be evaluated by many established evaluation programs. We investigated this method using two different test systems, myoglobin as a biopolymer with significant diffusion and 100 nm polystyrene latex as a large particle with negligible diffusion, and found some limiting issues. These are namely, broadening of the initial boundary by diffusion of the sample, which can be taken into account and the dynamic density gradient between the solvent in the sector and the overlaid solution, which deforms the initial band upon movement through the gradient and is currently not taken into account. We show the influence these two factors have on the evaluation and show that it is possible to calculate the time-dependent change in solvent density and viscosity in the AUC cell using the integrated form of Fick's second law. We conclude that taking the dynamic density gradient into account will open ABC for the sophisticated methods based on the analysis of the whole sedimentation boundary and not just the determination of an average sedimentation coefficient.

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“…The potential for MWL-AUC has drawn particular attention to the study of metallic and semiconductor nanoparticles, owing to the extraordinary size and shape dependent optical properties at the nano scale. AUC has the capability to resolve nanoparticle size distributions with Angstrom resolution, and with MWL detection, to also probe spectral properties in dispersion [16,17].…”

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confidence: 99%

LED based near infrared spectral acquisition for multiwavelength analytical ultracentrifugation: A case study with gold nanoparticles

Pearson

Cölfen

2018

Analytica Chimica Acta

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Simultaneous Identification of Spectral Properties and Sizes of Multiple Particles in Solution with Subnanometer Resolution

Cited by 49 publications

References 31 publications

2D analysis of polydisperse core–shell nanoparticles using analytical ultracentrifugation

2D analysis of polydisperse core–shell nanoparticles using analytical ultracentrifugation

Analytical band centrifugation revisited

LED based near infrared spectral acquisition for multiwavelength analytical ultracentrifugation: A case study with gold nanoparticles

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