Advanced thermoplasmonic tools for the study of thermal biology at the single cell level – PlasmoTherm

Thermodynamics on the nanoscale (hereinafter nanothermics) is a branch of nanotechnology that currently demonstrates a gain of interest favored by the development of novel thermal microscopy techniques. As any field of science features thermal-induced processes, the applications of nanothermics are numerous and diversified, lying at the interface between thermics, nanooptics, nanochemistry, fluid dynamics, phase transitions, magnetism, etc.

Gold nanoparticles are currently playing a dominant role in nanothermics as they can act as nanosources of heat, under illumination at their plasmonic resonance resonance wavelength due to strong optical absorption. In other words, they stand for the most fundamental tool one can play with for applications in nanothermics. The area of research that benefits from the use of gold nanoparticles as nanosources of heat is termed thermoplasmonics. Some biomedical applications have already been developed in thermoplasmonics (cancer therapy, drug and gene release, photoacoustic imaging) and the area of interest of this burgeoning thematics is now reaching applications in physics and chemistry.

The aim of this project is to tackle pioneer experiments in thermoplasmonics for biology. In a first part, we will implement new functionalities on our current experimental setup in order to enable the efficient study of living cells. In particular, we will mount a confocal fluorescence imaging functionality and a temperature regulation stage. In a second part, we will address a concrete problem in thermal biology at the single cell level. All the experiments will be based on the local heating of living cells using gold nanoparticles, along with the use of a thermal microscopy technique we recently developed, and suited for cell imaging. The first biological problem that we will address is the thermal induced (de)polymerization of microtubules in living cells. This text-book case will enable us to demonstrate the capabilities of our approach based on the association of gold nanoparticles and thermal imaging. The second biological problem will aim at uncovering why neurons tend to grow toward infrared light, an intriguing phenomenon that have been proposed to originate from a thermal effect and that is at the basis of an active branch of research called 'optical neuronal guidance'.