Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PhD : selection by topics

Life Sciences >> Biotechnology, biophotonics
3 proposition(s).

Ultrasensitive Biomolecular detection based on nanoPhotonics

Département Microtechnologies pour la Biologie et la Santé (LETI)

Laboratoire Chimie des Matériaux et des Interfaces



There is strong market pressure to develop integrated, fast and ultra-sensitive biosensors capable of extracting information at the molecular level, in the context of in situ or portable systems intended for use in routine or personalized health care applications. Such devices could make it possible to perform biological protocols without amplification, their high sensitivity enabling single molecule detection (SMD). This thesis aims at developing original biosensor architectures allowing ultra-fast and ultra-sensitive acquisition, by exploiting the unique properties of nanowire photodetector networks associated with quantum dots biocompatible markers in order to improve their sensitivity and specificity; while limiting their sensitivity to environmental disturbances (high signal-to-noise ratio); and without prejudice to the future ability to integrate this technology very densely (submicron photodetection pixel pitch). We propose to demonstrate the detection of light emission by fluorophores or quantum dots grafted on biomolecules, in the visible spectral domain, by AsGa nanowire photodetector arrays. A first prototype will have to be sized and manufactured to operate at wavelengths selected from commercial fluorescent markers or QDs. A multi-wavelength prototype will be considered as a perspective. The performance of the prototype will be qualified before and after microfluidic integration, then the performance of the biosensor will be characterized to target the detection of single molecules. In addition to a knowledge oriented towards nano-physics, the candidate will have to be interested in biological applications, as well as in integration of the detector prototype into a functional microfluidic device.

Improving CO2 fixation by microalgae through a combined genetic, metabolic and process engineering approach





Improving CO2 fixation by microalgae is a challenge for the developing microalgae industry. There is great interest in this improvement, as it will significantly increase the biomass productivity of microalgae reducing the cost of cultivation and more specifically as a vector in in flue gas bioremediation. Promising candidates with increased rates of photosynthesis were obtained in a previous study. They will be screened in this PhD thesis for their increased ability to fix CO2. The best mutant(s) will be thoroughly characterized. First, a genetic approach through complementation studies will be performed. Then, the metabolites produced during photosynthesis will be determined and measured to produce a map to understand the basis of the CO2 fixation increase. And finally, these mutants will be grown in fully instrumented photobioreactors to adopt a process approach. This line of attack using diverse and complementary techniques (genetics, metabolics and process) will allow the understanding and improvement of CO2 fixation by microalgae.

Hyperspectral microscopy and single-shot optical coherence tomography with a static Fourier transform imaging spectrometer

Département Microtechnologies pour la Biologie et la Santé (LETI)

Laboratoire Imagerie et Systèmes d'Acquisition



Fourier Transform Spectroscopy measures the degree of coherence of light to recover the spectrum. A Fourier Transform spectrometer is said static when the fringe pattern is recorded in a single shot with no displacement of mechanical parts. Recently this concept was extended to Hyperspectral Imaging (HSI) for Space applications using a new configuration of static interferometer positioned in front of a focal plane array. Aside from HSI, another possibility that has not yet been investigated is to use this static interferometer for Optical Coherence Tomography (OCT). This PhD project is a collaboration between the Department of Astrophysics of the University of Grenoble and CEA Leti. We propose to investigate this new OCT approach, and its coupling to HSI in a fast bimodal system that could address many applications in Diagnostic and Bioimaging. The student will work on the development of a microscope integrating this new kind of interferometer, as well as the numerical processing of the interference patterns. Applications from students with a solid background in optics and data processing are welcome. A strong interest in biophotonics, and bioimaging is expected.

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