PhD Defense by Helena M. D. Danielsen
Title: A Thermoplasmonic Platform for Investigating Membrane Repair
Abstract: The cell membrane is crucial for cell survival, and to maintain its integrity, cells have developed robust plasma membrane repair (PMR) mechanisms. Although the nature of this intricate machinery is not fully understood, certain proteins, such as annexins, have been implicated in playing a pivotal role in PMR. To study these mechanisms, a novel optical platform utilizing thermoplasmonic heating was developed to locally puncture individual cells. The findings revealed that the recruitment of annexins A5 and A2 to the injury site is vital for the process of wound resealing. In addition, the thermoplasmonic method was extended to intracellular membrane ruptures, revealing a large-scale reorganization of the actin cytoskeleton following puncture of the nuclear envelope. Specifically, the influx of extracellular calcium was identified as a key factor influencing this reorganization process. Overall, the thermoplasmonic method holds promising potential for the nanoscale study of both plasma membrane and nuclear repair, two intricate processes that are essential for the survival of metastatic cancer cells and the development of therapeutic strategies for various degenerative diseases.