Congratulations to Nicholas van Heijst, the 2023 Ross Hallett Memorial Scholarship in Biophysics Winner!

Posted on Wednesday, June 21st, 2023

Nicholas van Heijst obtained his Honours BSc in Nanoscience from the University of Guelph. He joined the Dutcher Lab as an undergraduate student in 2019, completed his MSc in 2021, and is currently a PhD student in the Dutcher Lab.

For his undergraduate research project, Nicholas worked on a nanoparticle sizing technique called resistive pulse sensing. The system measures the flow of particles through a single nanosized pore, with the signal appearing as dips in the current or resistive pulses. This instrument is susceptible to plugging of the nanopore and had frustrated other students in the lab, but Nicholas determined the optimal conditions to avoid the plugging of the nanopore, which allowed him to collect high-quality data.

In his MSc research, Nicholas used surface plasmon resonance (SPR) imaging to measure binding of bioactive compounds to phytoglycogen (PG) nanoparticles immobilized on the SPR sensor surface. In particular, he measured the binding of concanavalin A (ConA) to both native and acid-hydrolyzed PG particles, demonstrating that acid hydrolysis did not adversely affect the binding process. Nicholas is co-first author on a 2022 Biomacromolecules paper on this work. 

In his PhD research, Nicholas is focusing on improving the solubility of hydrophobic bioactive compounds through their association with PG. This is a major challenge in introducing many bioactive compounds into the largely hydrophilic environment of the human body. Nicholas has achieved a spectacular increase (by a factor of > 108!) in the solubility in water of a very hydrophobic carotenoid, astaxanthin (ASX), and he has done this only through its physical association with PG. The ASX-PG complex is also extraordinarily stable in water, with no loss in its UV absorption signal over several months. Nicholas compared the preparation of the ASX-PG complex using three different techniques and identified nitrogen evaporation as the best method. He is the first author on a manuscript that we are writing on his work. Moving forward, Nicholas is focusing on determining the mechanisms of interaction, e.g., hydrogen bonding, hydrophobic effect, that are responsible for this dramatic increase in water solubility and stability. To do this, he is using a variety of experimental techniques: UV-Vis spectroscopy, to quantify the solubility, stability and nature of the aggregation of ASX in the ASX-PG complex; infrared spectroscopy and SPR imaging, to confirm the association of ASX with PG; and nuclear magnetic resonance spin echo, to assess the association of ASX with the outer surface of the PG particles. He is also comparing the results for ASX with those for other carotenoids and hydrophobic bioactives that lack the ability to form hydrogen bonds with the PG particles, as well as testing hydrophobically modified versions of PG. Nicholas’ experimental work also overlaps nicely with his fellow graduate student Ben Morling’s computational work on these systems. Nicholas’ work provides a new strategy for using PG to improve the solubility of hydrophobic compounds, which is an exciting new avenue of research in the Dutcher Lab. 

Nicholas is also a great communicator of his research results and has given talks at the Canadian Association of Physicists Congress and the American Physical Society March Meeting. His thoughtful, articulate and thorough approach to his research has allowed him to accomplish a lot, and he has been awarded several major scholarships and awards for his academic and research excellence, including the Ontario Graduate Scholarship and the Nanoscience Graduation Medal. Outside the lab and classroom, Nicholas enjoys playing volleyball and he avidly follows F1 racing. 

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