Kevin Braeckmans
Having obtained a Master degree in Physics at Ghent University (Belgium) in 1999, he joined the Laboratory of General Biochemistry and Phsyiscal Pharmacy (Ghent University) to perform research on advanced optical microscopy methods for pharmaceutical applications. During his Ph.D. he was involved in the development of a new type of encoded microcarriers for diagnostic applications. This research contributed to the establishment of a spin-off company Memobead Technologies, which now has been taken over by a Swiss company (Biocartis). For this work he has received the first price for Young Biotechnology Researcher from the Funds of Biotechnology (FBBF, Belgium) in 2005. During his Ph.D. he also performed research on the development of new methods for quantitative fluorescence recovery after photobleaching (FRAP) measurements in biological and pharmaceutical materials. Having obtained his Ph.D. in 2004, he received a fellowship of the Fund for Scientific Research – Flanders as a post-doctoral researcher. In 2005 he joined the group of prof. Braüchle (Lehrstuhl für Physikalische Chemie I) at the Ludwig-Maximilians Universität München where he was involved in the development of algorithms and software for single particle tracking analysis. Later on he returned to the Laboratory of General Biochemistry and Physical Pharmacy (Ghent University) to continue his research on advanced microscopy methods. In 2008 he became a professor at the Faculty of Pharmaceutical Sciences of Ghent University where he is currently leading the Biophotonic Imaging Group, which is hosted by the Laboratory of General Biochemistry and Physical Pharmacy. His current research topics involve the development of novel microscopy techniques for measuring molecular dynamics and their application to the study of extra- and intracellular barriers for drug and gene delivery.
http://www.ugent.be/fw/en/research/pharmaceutics/biofys/contact/staff/loc_index/braeckmans
Introduction to Single Particle Tracking
Single particle tracking (SPT) is a fluorescence microscopy method capable of visualising the movement of individual fluorescently labelled molecules or nanoparticles with high temporal and spatial resolution. Although the molecules are below the optical resolution limit and have a very low intensity, their movement can be visualised using an efficient illumination and detection system. In a pharmaceutical context, SPT can play an important role by characterising the dynamic behaviour of individual drug molecules in e.g. living cells. By analyzing the movement of individual molecules, SPT can reveal details of the dynamics that are more difficult to resolve by ensemble averaging techniques. Thus, SPT is a powerful complementary tool to other fluorescence microscopy techniques such as FRAP (fluorescence recovery after photobleaching) and FCS (fluorescence correlation spectroscopy).
In this lecture, the layout of an SPT set-up and the data analysis will be discussed. From the hardware side, usually an epi-fluorescence set-up is being used with widefield laser illumination in combination with a fast and sensitive CCD camera. Additionally, suitable algorithms and software are needed to localize the individual particles in each frame of an SPT movie. This set of coordinates can subsequently be used to calculate the trajectories of individual particles by comparing corresponding features. Finally, the individual trajectories can be analyzed in terms of the mode of motion (diffusion, directed transport, restricted diffusion) and the relevant quantitative parameters (diffusion coefficient, transport velocity, compartment size). Some examples will be given of how motion trajectories can give insight into the particle biophysical behaviour.
