Martin Kjærulf Rasmussen

PhD defence by Martin Kjærulf Rasmussen

On Wednesday 27 January, Martin Kjærulf Rasmussen will defend his PhD thesis "Capture, characterization and reactions of nanoparticles in a diffusiophoretic trap".

Time: 27 January at 13:00

Place: Zoom, registration is required here:

Supervisor: Associate Professor Rodolphe Marie, DTU Health Tech
Co-Supervisor: Jonas Nyvold Pedersen, DTU Health Tech

Members of assessment committee:
Associate Professor Martin Dufva, DTU Health Tech
Senior Research Scientist Christophe Ybert, CNRS, Institut Lumière Matière
Professor Fredrik Höök, Chalmers University

Associate Professor Line Hagner Nielsen, DTU Health Tech

Nanometer-sized biocolloids including synthetic liposomes and naturally occurring exosomes are promising for drug delivery in cancer treatment and as biomarkers for early stage diagnosis of cancer. Characterizing nanoparticles properties such as size, zeta potential and surface characteristics is, however, challenging and requires several independent experimental measurements.  

This work presents a diffusiophoretic trap for concentrating nanoparticles from a dilute solution and measuring their size and zeta potential in a one-step measurement with a salt gradient in a nanochannel. The salt gradient causes oppositely directed particle and fluid transport that trap particles. Within minutes, the particle concentration increases more than two orders of magnitude. A model for the spatial distribution of a single or an ensemble of nanoparticles is developed and returns both the particle size and surface charge. Reagents can be introduced while nanoparticles are trapped, and reactions on the particle surfaces can therefore be monitored in real-time. Therefore, the diffusiophoretic trap is demonstrated as a label-free sensor for real-time sensing of ligands using the methods high surface charge sensitivity. This is an important analysis procedure for designing nanoparticle based drug delivery systems, for which size, charge and surface modifications play a major role in their efficiency. Similarly, nanometer-sized exosomes excreted from cells in the body can be analyzed as biomarkers for development of early stage cancer diagnostics. Finally the diffusiophoretic trap is also shown to be able to analyze nanoparticle-nanoparticle reactions such as liposome fusion for modeling of membrane fusion.  


Wed 27 Jan 21
13:00 - 16:00


DTU Sundhedsteknologi