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IBEC Seminar: Martí Duocastella
Wednesday, November 15, 2023 @ 12:00 pm–1:00 pm
Toward the next generation of 3D optical microscopes: faster, deeper, and label-free
Martí Duocastella, Departament de Fisica Aplicada, Universitat de Barcelona
Three-dimensional (3D) optical microscopy is the tool of choice for characterizing the structure and dynamics of biological systems at sub-cellular resolution. However, most microscope architectures are tailored to capture two-dimensional (2D) information from moderately thin samples labeled with fluorophores. Due to constraints posed by light scattering and the requirement for mechanical focus translation, existing systems provide shallow penetration depth and low volumetric imaging speed, thus falling short of unraveling biological complexity inside medium-sized organisms or even organoids. In this talk, I will discuss our efforts to overcome these issues and achieve sub-millisecond imaging at potentially millimeter depths and without labels. Our strategy consists of focusing, modulating, and guiding light by exploiting the acousto-optic effect, that is, ultrasound-induced refractive index gradients. The unique interaction between ultrasound and light enables rapid 3D light control, making it suitable for the development of inertia-free light sheet microscopes that lack mechanically moving parts and offer imaging rates of tens of volumes per second. It also facilitates illumination encoding in single-pixel cameras, enabling scanless 2D imaging at 5 kHz. Interestingly, applying ultrasonic waves in a scattering medium acts as an instantaneous waveguide embedded in the medium, helping to redirect light toward a 7-fold deeper focus. I will discuss the advantages and pitfalls of these acousto-optic technologies and illustrate them with applications, including imaging of spheroids and flowing samples.
Martí Duocastella is a Serra Hunter full professor in the Department of Applied Physics at Universitat de Barcelona (UB) and leader of the Dynamic Optical Systems Lab. He completed his PhD in Physics at UB in 2010 and then moved to Princeton University as a postdoctoral research associate, where he also became the vice-president of Research and Development of the startup company TAG Optics. In 2014 he joined Istituto Italiano di Tecnologia as a researcher (group leader), until returning to Barcelona as a faculty member in 2019. His research focuses on novel optical methods for three-dimensional (3D) light engineering, with applications in materials science, sensing, and biology. He is an ERC Consolidator Grant awardee.
In 2012, he was appointed a Ramon Y Cajal (RyC) researcher, but after two years as a RyC, he decided to move back to Switzerland where in 2015 was awarded an ERC starting grant to study and control self-assembly processes of metal-organic based crystalline materials. In 2019, he was appointed as an ICREA professor and since August 2020 his group is located at the University of Barcelona (UB)
