Nanoobjects microscopy

Mechanobiological studies of ultrasound-mediated cell junction interruption using fluorescence super-resolution microscopy
Chmyrov A.1, Huang Y.-S.1, Ntziachristos V.1
1 Institute for Biological and Medical Imaging, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
E-mail: andriy.chmyrov@helmholtz-muenchen.de

The ability to spatiotemporally dissemble and re-assemble the intercellular adhesion allows the researchers and tissue engineers to break and build multicellular biosystems in a specific manner. Examples of clinical applications include a precise spatiotemporal modulation of tissue integrity through complete opening and recovery of cell junctions at the blood-brain barrier (BBB) for efficient drug delivery [1]. Although various kinds of strategies have been developed to facilitate the efficiency of drug delivery across the BBB to date, a safer and more efficient way is still desperately in need due to the complexity of the brain. Therefore, either too firm or too loose state of the cell junctions leads to the imbalances of the health conditions. 
One of the suitable tools for achieving this goal is the microbubble-engaged ultrasound irradiation. However, a clear understanding of the mechanism has been limited due to the complexity and the meticulous scale in the signal regulations and architectural changes therein. Among the reasons that there are still many unanswered questions in the field is an insufficient spatial resolution of the images obtained. For instance, how the tight junctions (TJ) proteins redistribute due to the ultrasound irradiation is still unclear. The fluorescence super-resolution microscopy, which normally yields the lateral resolution in the 20~50 nm range, is an excellent tool to tackle this problem
Based on our expertise and experience in fluorescence super-resolution imaging, we plan to establish a multi-functional super-resolution imaging platform integrated with Stimulated Emission Depletion (STED) microscopy [2], soundwave, and microfluidic cell culture systems to investigate the spatiotemporal correlations between the molecular and architectural events in ultrasound-mediated TJ modulation.

1.	Konofagou E. Optimization of the Ultrasound-Induced Blood-Brain Barrier Opening // Theranostics-2012.-2(12)-P. 1223-1237.
2.	Sahl S.J., Hell S.W., Jakobs S. Fluorescence nanoscopy in cell biology // Nat. Rev. Mol. Cell Biol.-2017.-18.-P. 685-701.