Zwitterionic copolymer surface chemistry and an example of tracking of single QD targeted to cannabinoid receptor CB1R on the membrane of neurons. (Tasso et al, ACS Nano, 2015)

Our group is focused on the synthesis, the characterisation and the applications of a material : semiconductor nanometric sized particles, also known as quantum dots (QD). The team, hosted in LPEM, is located in the heart of Paris at the Ecole Supérieure de Physique et de Chimie Industrielles de la ville de Paris (ESPCI).

We bring together within one group the competences necessary for the synthesis and the characterization (chemical and physical) of semiconductor nanocrystals; for their applications in building blocks for renewable energy sources; for their use as fluorescent probes for in vivo imaging or biotechnological applications; and for the development of novel imaging techniques for the detection of these nanoparticles in diffuse media.

Nanoparticles synthesis and characterisation

We synthesize semiconductor nanocrystals (NCs) of various compositions, with emission wavelengths ranging from 350nm to 1500nm. We strive to control their shape, their size, their crystal structure and their surface ligands. The NCs are characterized at ESPCI with various techniques including TEM, STEM, Xray diffraction, and fluorescence spectroscopy. The latter can be performed between 4K and 300K, on ensemble or on single particle, with spectral and temporal resolution.

Measure of the radial pressure in core/shell structures with a 0.3 nm resolution
Control of the cristalline structure in core/shell QDs
Towards non blinking QDs
First synthesis of CdSe nanoplatelets with thickness controlled at the atomic monolayer level
Supraconductivity of lead nanoparticles
Synthesis of core/shell NIR Cd-free QDs

Probes for in vivo imaging

We are developing several original surface chemistries to make the QD water soluble and as biocompatible as possible. We couple macromolecules to QDs, and use them as fluorescent probes for in vivo and cell imaging. We work the probe surface chemistry to make probes for multimodal imaging and probes that can change fluorescence upon finding its target. One of our major challenges is to keep the probe size below 20nm diameter.

Multimodal imaging
Protocol for the synthesis and functionalization of QDs for in vivo imaging
Fluorescent bar codes on magnetic beads
Ligand exchange
Reduced toxicity QDs
A novel surface chemistry for live cell functional imaging

Building blocks for renewable energy devices

Semiconductor NCs with small (few nanometer) dimension(s) at least in one direction have unique optical and electrical properties. Part of our team takes advantage of these unique properties to design devices (solar cells, LED) with NPs as active compound.

Imaging fluorescent probes in diffuse media

We have developed several methods to visualize cells marked with fluorescent nanoparticles. These methods include structured illumination and adaptive optics. We can test our probes and their fluorescent properties easily in vitro and in vivo (cell culture).

Fast full-field optical sectioning
Comparing different optical sectioning techniques