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Work Package 3

Characterisation of fluorescent particles

The aim of this workpackage is to establish and validate measurement techniques for the traceable optical characterisation of fluorescent nanomaterials, especially for the key fluorometric parameter fluorescence quantum yield. In addition, for selected materials, also other spectroscopic methods for the determination of parameters controlling the signaling behavior of fluorescent nanoparticles will be assessed, such as the number of fluorophores per particle, the number of selected surface functionalities or the number of proteins adsorbed onto such particles in representative biological systems thereby completing the studies performed in WP2, WP4, and WP5.

The need for comparable, quantitative and traceable fluorescence measurements follows from the extremely limited number of fluorescence–based assays with approval from the Food and Drug Administration (FDA). This is despite the recognised strong potential of fluorescence techniques and the recent efforts concerning the standardisation of fluorescence measurements.

Techniques to determine the signal-relevant optical properties of nanoobjects

The aim of this task is the traceable determination of the fluorescence quantum yield of nano-objects in different environments including biological systems.

As for all fluorescent nanoparticles, the size of the (environment-dependent) fluorescence quantum yield is one of the most important parameters for determining their signaling behavior. This workpackage aims to develop a reliable metrological approach.
Different techniques will be used:

  • Relative measurement of fluorescence quantum yields using common absorption and fluorescence spectrometers as example for common laboratory equipment
  • Absolute measurement of fluorescence quantum yields using an integrating sphere setup

The output of this work package will be traceable methods for the determination of the fluorescence quantum yields of well characterised fluorescent nanomaterials differing in material and size and the derivatisation of limitations of common laboratory equipment (conventional absorption and fluorescence spectrometers) for such measurements.

Techniques to determine selected analytical parameters of fluorescent nano-objects

The aim of this task is the development of spectroscopic methods for the determination of parameters controlling the signaling behavior of fluorescent nanoparticles such as the number of fluorophores per particle, the number of selected surface functionalities or the number of proteins adsorbed onto such particles in representative biological systems thereby completing the studies performed in the first work package of WP3 and the measurements in WP2, WP4, and WP5.