Staff member


Rodica Alis Olea

PhD Student
Nanoscopy for Nanomedicine
aolea@ibecbarcelona.eu
+34 934 020 514
Staff member publications

Baranov, M. V., Olea, R. A., van den Bogaart, G., (2019). Chasing uptake: Super-resolution microscopy in endocytosis and phagocytosis Trends in Cell Biology 29, (9), 727-739

Since their invention about two decades ago, super-resolution microscopes have become a method of choice in cell biology. Owing to a spatial resolution below 50 nm, smaller than the size of most organelles, and an order of magnitude better than the diffraction limit of conventional light microscopes, superresolution microscopy is a powerful technique for resolving intracellular trafficking. In this review we discuss discoveries in endocytosis and phagocytosis that have been made possible by super-resolution microscopy – from uptake at the plasma membrane, endocytic coat formation, and cytoskeletal rearrangements to endosomal maturation. The detailed visualization of the diverse molecular assemblies that mediate endocytic uptake will provide a better understanding of how cells ingest extracellular material.

Keywords: Endocytosis, Endosomes, Organelles, Super-resolution microscopy, Trafficking


Feiner-Gracia, N., Olea, R. A., Fitzner, R., El Boujnouni, N., Van Asbeck, A. H., Brock, R., Albertazzi, L., (2019). Super-resolution imaging of structure, molecular composition, and stability of single oligonucleotide polyplexes Nano Letters 19, (5), 2784-2792

The successful application of gene therapy relies on the development of safe and efficient delivery vectors. Cationic polymers such as cell-penetrating peptides (CPPs) can condense genetic material into nanoscale particles, called polyplexes, and induce cellular uptake. With respect to this point, several aspects of the nanoscale structure of polyplexes have remained elusive because of the difficulty in visualizing the molecular arrangement of the two components with nanometer resolution. This limitation has hampered the rational design of polyplexes based on direct structural information. Here, we used super-resolution imaging to study the structure and molecular composition of individual CPP-mRNA polyplexes with nanometer accuracy. We use two-color direct stochastic optical reconstruction microscopy (dSTORM) to unveil the impact of peptide stoichiometry on polyplex structure and composition and to assess their destabilization in blood serum. Our method provides information about the size and composition of individual polyplexes, allowing the study of such properties on a single polyplex basis. Furthermore, the differences in stoichiometry readily explain the differences in cellular uptake behavior. Thus, quantitative dSTORM of polyplexes is complementary to the currently used characterization techniques for understanding the determinants of polyplex activity in vitro and inside cells.

Keywords: dSTORM, Gene delivery, Polyplexes, Stability, Super-resolution microscopy