| Abstract: |
Colloids provide manifold opportunities for targeted product design due to their tuneable properties with respect to size, shape, composition, surface and spectral characteristics. The determination of structure-property relationships is however quite challenging as most particulate samples exhibit pronounced polydispersity with respect to their disperse properties. Analytical ultracentrifugation (AUC) is a fractionating and highly accurate method for the multidimensional analysis of nanoparticles as it allows the combination of spectral information with hydro- and thermodynamic properties.[1-4]
So far, the characterization of fluorescent nanoparticles by AUC was limited, as the formerly commercially available fluorescence detector for AUC could not provide any spectral information.[5] With a newly developed multiwavelength emission detector in our group, it is possible to extract spectra of fluorescent particles and biomolecules alongside their sedimentation and diffusion coefficients from a single centrifugal run.[6] Experiments with fluorescence labelled proteins are used to show the capabilities of the new setup for the determination of the molar mass and the frictional properties of biomolecules, while for fluorescent silica particles the characterization of size and spectral properties can be demonstrated.
In order to illustrate the advantage of the centrifugation based method over bulk measurements, narrowly distributed quantum dots showing size- and structure-dependent shifts of their fluorescence spectra are investigated.[6] With our novel multiwavelength emission detector and the established extinction based detector for AUC, a comprehensive platform for the holistic characterization of fluorescent colloids is now available. Notably, our detection system further provides access to the highly promising field of species selective Raman characterization.
References:
1. J. Walter et al., ACS Nano, 2014, 8, 8871-8886.
2. J. Walter et. al. Anal. Chem., 2015, 87, 3396-3403.
3. J. Walter and W. Peukert, Nanoscale, 2016, 8, 7484-7495.
4. J. Pearson et al., Anal. Chem., 2018, 90, 1280-1291.
5. I. K. MacGregor et al., Biophys. Chem., 2004, 108, 165-185.
6. S. E. Wawra et al., Nanoscale Advances, 2019, 1, 4422-4432. |
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