Size dependent fluorescence and Raman characterization of nanoparticles by means of a novel analytical ultracentrifuge
Final Report Abstract
Knowledge about the size, density, shape and optical properties of nanoparticles is of crucial importance, as product properties are directly correlated via structure-property relationships. The coupled analysis of these particle characteristics still represents a considerable metrological challenge. In this project, a new multiwavelength emission detector was developed for the analytical ultracentrifuge (MWE-AUC), which allows the measurement of the size- or composition-dependent fluorescence properties of nanoparticles and macromolecules directly in solution and without further purification or time-consuming sample preparation. The development features an advanced detector design with outstanding performance concerning the spectral resolution and range flexibility as well as the quality of the data acquired. The excitation by a 520 nm laser is complemented with a 405 nm laser, which can be changed in a few minutes. An external spectrograph with three switchable tunable gratings permits optimisation of the spectral resolution in an order of magnitude range from 0.14 nm to 2.0 nm. The developed system offers a low systematic signal noise and permits the assessment and control of inner filter effects, an important aspect when studying concentrated samples. A large signal dynamic range permits studying samples in a broad concentration range of at least five orders of magnitude. Our system was validated by complementary studies on two biological systems, fluorescent BSA (bovine serum albumin) and GFP (green fluorescent protein), using the commercial Optima AUC with absorbance detection and our custom-built multiwavelength absorbance detection system (MWL-AUC) for comparison. The capabilities of the MWE-AUC with respect to multiwavelength characterisation were demonstrated by studies on gold nanoclusters, which exhibit specific fluorescence depending on their structure, and CdSe/CdS quantum dots, where size- and structure-dependent shifts of their fluorescence spectra could be analyzed as well. Overall, this project depitcs an important step in the in-depth investigation of the size-, shape- and composition-dependent multiwavelength emission properties of colloids, as the unique combination of fluorescence detection and hydrodynamic characterization by sedimentation provides direct access to structure-property relationships.
Publications
-
A multiwavelength emission detector for analytical ultracentrifugation. Nanoscale Advances, 1(11), 4422-4432.
Wawra, Simon E.; Onishchukov, Georgy; Maranska, Maria; Eigler, Siegfried; Walter, Johannes & Peukert, Wolfgang
-
Optical and Hydrodynamic Characterization of Nanoparticles Via Analytical Ultracentrifugation. Dissertation, Friedrich-Alexander-Universität Erlangen-Nürnberg, 2022.
Simon Wawra
-
Development of an advanced multiwavelength emission detector for the analytical ultracentrifuge [Data set]. Zenodo
Vanessa Lautenbach, Georgy Onishchukov, Simon E. Wawra, Uwe Frank, Lukas Hartmann, Wolfgang Peukert & Johannes Walter
-
Development of an advanced multiwavelength emission detector for the analytical ultracentrifuge. Nanoscale Advances, 6(10), 2611-2622.
Lautenbach, Vanessa; Onishchukov, Georgy; Wawra, Simon E.; Frank, Uwe; Hartmann, Lukas; Peukert, Wolfgang & Walter, Johannes
