In the past decade, microfluidics has grown to take new, freer, more application-driven forms. These include capillary-driven, open microfluidics, and hanging drop microfluidic systems. Understanding fundamental fluid mechanics and transport phenomena in these new microstructures gives rise to new functionalities not hitherto possible with conventional channel networks. In this talk, we will discuss how fluid mechanics and mass transfer modelling plays a key role in the design, optimisation, and operation of several emerging microfluidic-based technologies. We will provide examples of theory-guided technological developments from our laboratory and from our collaborators in the field of on-chip 3D tissue culture, microfluidic probes, and capillary-driven microfluidics. Thomas Gervais is assistant professor of engineering physics and biomedical engineering at Polytechnique Montréal since 2013. His research focuses on fundamental fluid mechanics and mass transfer in microstructures, with an emphasis on developing miniature systems for the interrogation of cancer tissues. He holds a bachelor degree in engineering physics from Polytechnique Montreal and a Ph.D. in bioengineering from MIT. Besides research and teaching, he is also a seasoned populariser of science, having written over 100 popular science articles, 35 short TV documentaries, and appeared in over 75 episodes of various French Canadian Science TV shows in the past decade. He also works as consultant in the field of scientific communications and to solve challenging transport problems in the natural resources and high tech industries.