Novel methods for super-resolution fluorescence imaging

Super-resolution fluorescence microscopy techniques are able to image (biological) structures with a spatial resolution of tens of nm, one order of magnitude better than standard fluorescence microscopy. In our group we develop novel methods that extend the application of super-resolution microscopy. A few years ago we were able to image for the first time directly-labelled DNA with a spatial resolution below 40 nm. Currently, we use correlative super-resolution fluorescence imaging and atomic force microscopy (AFM) to develop and validate novel labelling methods in super-resolution microscopy. Overally, we are focused on the development of advanced combinations of these two techniques for imaging, nanomanipulation and nanomechanical characterization, to answer questions in biology and materials science.

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In situ correlative AFM and super-resolution fluorescence imaging (ChemPhysChem 2014).

 

Single-cell real-time imaging of bacterial death processes

 

We are also interested in using advanced microscopy to study bacterial death processes at the single-cell level and with temporal resolution. We have developed labelling strategies to follow the effects of photodynamic treatment in bacteria in real-time. Moreover, using combined fluorescence and AFM, we have studied mechanically-induced bacterial death, which is relevant in the context of mechano-bactericidal nanomaterials, and quantified the forces involved in this process. The mechanistic understanding provided by these advanced microscopy methods may help in the design and implementation of improved bactericidal strategies.

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Mechanically-induced bacterial death (probably overdramatized)

(ACS Applied Materials & Interfaces 2020)

 

This project aims at developing a new type of light-responsive proteins capable of generating singlet oxygen, a particular form of reactive oxygen species that plays a crucial role in cell signalling and phototherapeutic applications. The possibility to have precise genetic control of the protein localization and thus the site of singlet oxygen generation is attracting much interest given its strong potential for applications in advanced microscopy, optogenetics and photodynamic therapy. A key aspect of this emerging field that combines photonics and genetics is the development of new and better photosensitizing proteins. The objectives of this research line are to understand singlet oxygen photosensitization by proteins (in particular flavoproteins and GFP-like proteins), engineer new and better mutants, and use them in applications such as photodynamic therapy or electron microscopy. This project is carried out in collaboration with the group of Prof. Santi Nonell at Institut Químic de Sarrià in Barcelona.

Genetically-encoded singlet oxygen photosensitizers

 

Bacteria expressing photosensitizing fluorescent proteins (Photochemical & Photobiological Sciences 2012)

Bacteria expressing photosensitizing fluorescent proteins

(Photochemical & Photobiological Sciences 2012).

 

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