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Creating disruptive technologies to solve challenges in microfluidics

An interview with Dr Katherine Elvira, University of Victoria




In our first interview of 2021, we spoke with Dr Katherine Elvira, Canada Research Chair in New Materials and Techniques for Health Applications, Michael Smith Foundation for Health Research Scholar (in partnership with the Pacific Alzheimer Research Foundation) and an Assistant Professor in the Department of Chemistry at the University of Victoria, British Columbia. Her research group, The Elvira Lab, is involved in a wide variety of microfluidic studies, ranging from fundamental droplet stability studies to blue-sky research for Alzheimer's, which we explore further below.



Overcoming fundamental challenges in microfluidics

The need to understand fundamental microfluidic challenges drives a significant portion of our research. This focus naturally led to our investigation of droplet behavior under different oil/surfactant conditions. We did this because the causes of droplet failure and how they are affected by a surfactant and a device's surface chemistry are often not explored in the microfluidic literature.

One of our publications (https://aip.scitation.org/doi/10.1063/1.4917343) aimed to address this gap in the literature. This paper describes multiple oil/surfactant conditions and different droplet failure modes that arise due to wetting and surface affinity, shear forces and interfacial tension, surfactant properties, and phase properties. We also highlighted recurring challenges associated with PolyDimethylSiloxane (PDMS ). PDMS is extensively used in the fabrication of microfluidics chips. However, it often requires surface derivatization to be suitable for a droplet system, and derivitization has to be done using specialized treatments that may lack long-term stability. Nested glass microcapillaries offer an alternative to PDMS, but manually aligning the capillaries can be time-consuming and laborious.

To overcome these limitations, we have developed a more accessible capillary assembly method using 3D printing techniques. This new plug-and-play approach is easy to use and extremely robust. To avoid surfactant issues being a possible variable during testing, we used Sphere Fluidics' biocompatible surfactant, Pico-Surf™. Pico-Surf™ is one of the most stable surfactants used in literature and can be relied on to perform well. So, if you are looking for a fluorous surfactant, and it's usable for your system, I recommend using Pico-Surf™.


Harnessing microfluidics to treat Alzheimer's disease

On the other side of the spectrum, we are working on a project that goes beyond microfluidic fundamentals and into the realm of blue-sky research. Funded by The New Frontiers in Research Fund (NFRF), this high-risk, high-reward research project aims to transform how the pharmaceutical industry develops drugs to treat Alzheimer's disease.

As the brain is one of the most highly protected organs in the body, designing drugs that can penetrate the blood-brain barrier is a continual challenge. We are modelling the blood-brain barrier on a chip to tackle this, using microfluidic technologies to build these systems from the bottom up, starting with creating the cell membrane, then quantifying a drug's interaction with each cellular component. This new technology will help determine how each component of the endothelial cells making up the blood-brain barrier affects the ability of drugs to treat Alzheimer's disease.

Detection limitations are the main obstacle we face in this project, but this is a typical microfluidic challenge. While fluorescent detection is a highly-sensitive method, most drugs are not fluorescent or do not fluoresce in the range detected with traditional microscopy. To develop a more applicable system, we are exploring different detection methods such as molecular recognition. Molecular recognition involves tagging a drug to make it fluorescent, but this alters the molecule and may subsequently change how it interacts with the artificial cells. However, there is a lot of exciting research based on non-fluorescent detection and incorporating this into our work is an ongoing project.


Wider research and impact priorities

In addition to drug discovery and development, The Elvira Lab is also involved in biomaterials production. In one biomaterial development project, we have constructed prototissues using droplets containing bovine serum albumin proteins that we have functionalized to show collective behaviors (https://chemrxiv.org/articles/preprint/Programmed_Assembly_of_Bespoke_Prototissue_Spheroids). In another project, we are building microspheres for in vitro drug delivery using microfluidic technologies. This is a rapidly expanding area of research with huge potential in the biomedical field.

Overall, the purpose of our lab is to have an impact outside of academia. As academics and scientists, this mindset is crucial to facilitate the practical application and commercialization of microfluidic research. This practical perspective will also help develop more applicable plug-and-play microfluidic systems that scientists can use across fields. Subsequently extending the capabilities of many labs and supporting groundbreaking discoveries.


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