Our Research

Florescent and Luminescent Molecules, Macromolecules and Nanomaterials

The global goal of the Petoud team is to provide new reagents and tools (luminescent reagents and oligonucleotides) for biological analysis and imagery. It combines expertise in the design, synthesis and characterization of organic and inorganic molecules, macromolecules and nanomaterials.

As a complement, the group has established an extensive expertize in visible and near-infrared spectroscopy (absorbance and luminescence), biochemistry, cellular and small animal imaging.

Luminescent Reporters and Photons Converter Based on Lanthanides Targeted for Applications

The creation of novel luminescent reporters and sensors based on lanthanide cations emitting in the visible and in the near-infrared is one of the major component of the research program. Our objective is to design, synthesize and study lanthanide complexes and materials which possess novel or improved luminescence properties that address requirements of analysis in biological conditions where a significant fluorescent background is present. In addition, we test and use the resulting reporters in practical applications such as bioanalytical assays and imagery at the cellular and small animal levels.

Our long term goal is to expand the field of application of lanthanide compounds by synthesizing antennae that will allow us to sensitize a larger number of lanthanide cations with more diverse emission wavelengths and to create novel types of reporters and sensors suitable for the detection of biological molecules and biological activity. This specifically includes the development of near-infrared (NIR) emitting lanthanide compounds. In order to generate the luminescence of lanthanide, these cations must be sensitized by an “antenna”. This entity must harvest as many photons as possible and transfer the resulting energy to the lanthanide cations. Quest for novel antenna (synthesis and rationalization of the energy transfer process) is a part of our work.

The complementary aspect of this research is the use of these compounds in practical applications with a special interest for cellular and small animal imaging. Projects also include the creation of novel equipments (microscopy and macroscopy) that will allow the use of the lanthanide compounds in these conditions. We have also interest in coupling optical and magnetic imaging agents.

To achieve these goals, we are currently investigating different families of lanthanide compounds: small molecule complexes, dendrimers, nanocrystals, metal-organic frameworks, micelles and microemulsions. Examples of these are depicted below.

In addition, the Petoud team is responsible for the optical platform at the CBM. The goal of this platform is to provide to internal and external user advanced spectroscopic instrumentation and, if required, the corresponding training to the users.

Modified Oligonucleotides

Novel oligonucleotides are developed with the purpose to obtain tools for basic research, in vitro diagnostics, cellular and animal imaging, as well as potential therapeutic agents.

Thus, depending of the intended applications, the oligonucleotides should possess several of the following properties: to be able to form specific and stable complexes with their targets and either to induce irreversible modifications of the targets (by cleavage or cross-linking reactions) or to produce a modified signal, in the presence of the target, that can be used as a proof of interaction. Furthermore, for the applications in cultured cells and in vivo the oligonucleotides must be devoid of toxicity, resistant to nucleases and capable of reaching their targets inside of the cells.

Oligonucleotides made of natural nucleosides are devoid of the required properties for these applications. In order to provide them with more adapted properties, we chemically modify the different structural units of their backbones (nucleic bases, internucleotidic linkages, sugar moieties). To these oligonucleotides, that ensure the specific recognition of the targets, are covalently attached various ligands (intercalating agents, cleavage and cross-linking reagents, visible and NIR labels….) in order to provide them with additional properties. The development of conjugates with optimized properties depends on parameters between both entities. The chemical synthesis of these new oligonucleotide series requires the development of new reagents and synthetic methods. Examples of recent achievements are described in the selected publications and illustrations reported below.

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