Minisymposium

Professor Jan van Hest, Eindhoven University of Technology, NL

Topological control in nanomedicine

Abstract: The efficacy of nanoparticles employed in drug delivery is affected by a range of features such as their size, surface properties and shape. Over the past years we have developed a range of methods to construct polymer vesicles, or polymersomes, with a range of different topologies. In this lecture two examples will be presented. First, by a combination of extrusion and a dialysis-induced shape change process, we were able to construct from a batch of large spherical vesicles, smaller spheres and tubes. After surface modification with T cell activating antibodies we could determine which shape was most effective in triggering a cellular response. The same particle library was furthermore used to control particle distribution in vivo. The second topic that will be discussed regards our class of nanoparticles with photodynamic and photothermal (PDT/PTT) features, which are used to kill cancer cells. By creating an anisotropic coverage of the PDT/PTT units on the polymersome chassis not only therapeutic efficacy was installed but also the propensity of the particles to act as nanomotors. This leads to an improved activity and deeper tissue penetration. Both topics will show the versatility of topological control on nanomedicine efficacy.

Professor Renato Zenobi, ETH Zürich, CH

Nanoscale Chemical Imaging using Tip-Enhanced Raman Spectroscopy

Tip-enhanced Raman Spectroscopy (TERS), introduced in the year 2000, is a nanoscale chemical analysis and imaging method with a spatial resolution down to a few nm, even at ambient conditions [1]. TERS relies on the enhancement of the local electromagnetic field by a plasmonic metal nanostructure that is scanned over the sample by means of a scanning probe microscope, using either AFM or STM feedback. Analogous to SERS, the local electromagnetic field of Raman scattered light is enhanced by many orders of magnitude in TERS. In this fashion, TERS is a variant of scanning probe microscopy that provides localized chemical information.

The working principle, experimental realization, and capabilities of TERS will be introduced [1], with special emphasis on how to avoid artifacts and how to best define the spatial resolution. I will then discuss recent applications of TERS to the spatially resolved chemical analysis and imaging of molecular systems. Examples from recent TERS studies in our laboratory will be chosen, focusing on catalysis [2], biological membranes [3], and the nanostructure of photovoltaic cells [4].

[1] T. Schmid, L. Opilik, C. Blum, and R. Zenobi, Angew. Chem. Int. Ed. 52, 5940-5954 (2013); F. Shao and R. Zenobi, Anal. Bioanal. Chem. 411, 37-61 (2019).

[2] Z.-F. Cai, T. Käser, N. Kumar, and R. Zenobi, J. Phys. Chem. Lett. 13, 4864-4870 (2022); Z.-F. Cai, J.P. Merino, W. Fang, N. Kumar, J.O. Richardson, S. De Feyter, and R. Zenobi, J. Am. Chem. Soc. 144, 538-546 (2022); Z.-F. Cai, N. Kumar, and R. Zenobi, CCS Chemistry 5, 55-71 (2023).

[3] Y. Pandey, N. Kumar, G. Goubert, and R. Zenobi, Angew. Chem. Int. Ed. 50, 19041- 19046 (2021); Y. Pandey, A. Ingold, N. Kumar, and R. Zenobi, Nanoscale 16 (2024)

10578-10583. C. Xu, T. Käser, N. Kumar, and R. Zenobi, J. Phys. Chem. Lett. (ASAP) - doi: 10.1021/acs.jpclett.4c01994.

[4] S. Bienz, G. Spaggiari, D. Calestani, G. Trevisi, D. Bersani, R. Zenobi, and N. Kumar, ACS Appl. Mater. Interf. 16, 14704-14711(2024).

Professor Marcy Zenobi-Wong, ETH Zürich, CH

Engineering scaffold voids to advance tissue formation

The human body is permeated by physiological spaces at the organ, tissue, cell and molecular level. These spaces provide critical means of transport, communication, signal propagation, morphogen diffusion, cellular crosstalk, and localized biochemical reactions. Constriction of these spaces, such as arterial occlusion or tissue fibrosis, are associated with pathologies.  Given the omnipresent nature of such spaces within tissues and organs, the scaffold’s negative ‘void’ space becomes a critical factor in designing scaffolds for tissue engineering.  Here we describe the implementation of filamented light (FLight) Biofabrication to exert control over a scaffold’s internal 3D architecture.   Examples from the musculoskeletal system are discussed.