Download the internship proposal

Type of internship

M2 internship / last year of engineering school

Internship date or duration

6 months, from February 2026.

Context

Photothermal therapeutic nanoagents aim at converting optical energy into heat to induce hyperthermia and a stress response in targeted biological tissues. From an external optical excitation, the energy is absorbed by the nanoagents, transformed into heat and then transferred to the surrounding medium. At the macroscopic scale, a continuous laser excitation leads to a global heating until a steady state is reached. However, this macroscopic point-of-view ignores the nanoscale spatial heterogeneity of the temperature distribution while strong thermal gradients could induce localized therapeutic effects.

Photoacoustic imaging (introductory video: https://youtu.be/2f3V0DQNLYg) maps optical absorption based on a transformation of absorbed optical energy into ultrasound waves, when a transient optical excitation is used. The optical energy transformed into heat induces a transient pressure increase in the nanoscale layer surrounding each nanoagent. Recently, we demonstrated that the macroscopic light-to-heat conversion efficiency of photothermal nanoagents can be precisely measured with quantitative photoacoustic spectroscopy [1]. For this purpose, we determined the photoacoustic coefficient of nanoparticle suspensions with a home-build photoacoustic spectrometer [2].

To characterize the nanoscale temperature distribution, we now propose to combine the pulse excitation of photoacoustic imaging with a continuous heating of the nanoparticles in suspension. This novel nanothermometry method is expected to pave the way for a systematic evaluation of photothermal particles for their capacity to induce efficient nanoscale heating. The project is in collaboration with the laboratory PHENIX (Sorbonne Université) and has been funded by the ANR in 2025.

[1] T. Lucas et al., Nanoscale, vol. 15, no 42, p. 17085‑17096, 2023, doi: 10.1039/D3NR03727D.
[2] T. Lucas et al., Sensors, vol. 22, no 17, p. 6543, 2022, doi: 10.3390/s22176543.

Objective

The objective of this internship is to perform experiments to measure the nanoscale temperature increase around photothermal agents using quantitative photoacoustic spectroscopy. For this purpose, we will benefit from the photoacoustic spectrometer developed at the LIB and the algorithms to analyze the photoacoustic signal.

Tasks

The intern will be in charge of:

• the implementation of the experimental set-up and the acquisition sequence, together with research engineers at the LIB;
• the acquisition of data on nanoparticle suspensions;
• signal processing to analyze the collected data;
• the derivation of a simple model of thermal transfer to better understand the experimental results.

Skills

Experimental skills to design the set-up (together with research engineers) and perform experiments, but also programming and signal processing skills (Matlab and python). Moreover, the internship involves a theoretical study of the thermal transfer and photoacoustic equations to derive a simple model to be better understand the experimental results.

This internship may lead to a thesis.

Compensation

Monthly internship stipend (according to current French regulations), and partial reimbursement of monthly public transport costs (≃€550–600/month total).

Contact

Candidates are invited to send their CV, cover letter, and transcripts from the last two academic years to: Jérôme GATEAU, jerome.gateau[at]sorbonne-universite.fr

Location

This internship will be carried out at the Laboratory of Biomedical Imaging (LIB), 15 rue de l’École de Médecine, 75006 Paris, France.