Past colloquia and seminars


DNA Origami for Super-resolution Microscopy and Label Free Sensing

Academic or specialist Thesis defense

This talk presented in the context of my PhD thesis, summarize a journey driven by the quest for better imaging techniques and the exploration of innovative methods to advance microscopy.
Since the breakthrough of techniques that push the boundaries of imaging resolution beyond diffraction limits, there has been an increasing interest in exploring innovative techniques that extend the knowledge gained from fluorescence microscopy. This search for improved easy-to-use techniques that can push the boundaries of the scientific knowledge, including the more diverse and useful information motivated the research summarized on this thesis.
Central to this pursuit lies DNA origami, a versatile tool offering precise arrangement of diverse components at nanoscale distances. Exploiting this property enables the study of interactions between different entities at single molecule level. For instance, across this work it is used to nanometrically engineer and locate a single FRET pair with a specified separation distance. This work aims to take advantage of this powerful methodology synergistically with other technologies and materials.
Guided by this vision, the talk is organized around two key projects. The first one is based on the creation of a novel fluorescence microscopy technique and the utilization of DNA origami for nanoscale object manipulation, with its associated data processing. The primary objective was on the development of a lifetime-based super-resolution technique using a commercially available setup, and we designed a DNA origami structure used for the proof of principle. We achieve this by combining different techniques including confocal microscopy, DNA-PAINT, fluorogenic imagers, and FRET [1].
The second project revolves around an in-depth exploration of two-dimensional monolayers of molybdenum disulfide (MoS_2) as a potential fluorescence quenching surface, with the aim of including it into three-dimensional super-resolution measurements. Previous studies have drawn parallels between MoS_2 monolayers and graphene in terms of their quenching capabilities, yet despite the extensive research on this material, a comprehensive characterization of this phenomenon is lacking [2]. In light of this, our aim is to meticulously study and characterize the fluorescence quenching effect exhibited by MoS_2, with the ultimate goal of integrating it into the expanding repertoire of materials utilized as quenching layers, specifically aiming for three-dimensional super-resolution.
[1] Super-Resolved FRET Imaging by Confocal Fluorescence-Lifetime Single-Molecule Localization Microscopy (Small Methods 2023)
[2] Super-resolved Optical Mapping of Reactive Sulfur-Vacancies in Two-Dimensional Transition Metal Dichalcogenides (ACSNano 2021)

When? 19.12.2023 16:00
Where? PER 08 0.51
Chemin du Musée 3
1700 Fribourg
speaker Germán Chiarelli
Groupe Professeur Acuna
Contact Département de Physique, Groupe Acuna
Prof. Guillermo Acuna
Chemin du Musée 3
1700 Fribourg