PhD Thesis Defense | Zuzanna Lawera

Bridging Nanotechnology and Neurobiology: Voltage-Sensing and Photothermal Control of Neural Activity Using Semiconductor and Metallic Nanocrystals

November 7, 12:00

CFM Auditorium

Candidate: Zuzanna Lawera

Supervisor:  Prof. Marek Grzelczak and Prof. Rafael Yuste

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SUMMARY

Driven by the need for minimally invasive, high-resolution neural interfaces, this dissertation bridges nanotechnology and neurobiology by developing nanoscale tools for the optical detection and modulation of neuronal activity. Focusing on semiconductor quantum dots and plasmonic gold nanocrystals, the work presents complementary approaches to “read” and “write” neural signals. Designed to either report changes in membrane potential or deliver light-driven stimuli, these nanomaterials hold potential to overcome limitations of conventional techniques used in neurobiology.

New nanoscale tools for minimally invasive, high-resolution detection and modulation of neural activity.

To establish a reproducible model for testing nanoscale probes, a genetically engineered line of self-spiking human embryonic kidney (HEK293) cells was employed. These cells provided a simplified yet reliable system for evaluating optical reporters. For voltage sensing, spherical quantum wells (SQWs) were synthesized and functionalized for aqueous stability. Their membrane localization was verified by fluorescence microscopy, and their responses were tested in spiking HEK cultures. While the nanocrystals remained photostable and correctly targeted membranes, fluorescence modulation during action potentials was below detection thresholds, highlighting the need for brighter probes and faster, more sensitive imaging.

In parallel, gold nanocrystals with controlled morphologies were explored as photothermal actuators. Upon illumination, these plasmonic particles converted light into localized heating sufficient to trigger neuronal firing in brain tissue slices. The ability to induce single or burst action potentials demonstrated the feasibility of light-based neuromodulation.

Overall, this research outlines key design principles and technical challenges for nanomaterial-based neural interfaces, paving the way toward next-generation tools that enable non-invasive, high-precision monitoring and control of neural activity.