Investigating the Detection of Lipids gel/fluid Phase Transition by Change of Scattering Light and Coupling Factor into Optical Microresonators

International audienceThe present paper describes biophotonic sensors realized by way of inexpensive processes. As hybrid silica/polymer resonators, they are suited to detect biological molecules in gel/fluid phase transition at infinitesimal concentrations (sphingomyelin lipids). The photonic structure is made of specific amplified deep UV210 photoresist-polymer waveguides coupled by a sub-wavelength gap with racetrack microresonators allowing a minimal dependence in temperature. Then, temperature dependent wavelength shifts characterizing the optical resonances of the device have been evaluated, highlighting a quite low thermal feature of the sensor advantageous for relevant applications. With an appropriate vesicle lipid deposition process, specific in biology, together with an apt experimental bio-thermo-photonic protocol, the dynamic evolution of the sphingomyelin lipid phase transition has been assessed. The ability to detect their gel/fluid transition phase and melting temperature has been demonstrated with a mass product factor value 1.4×10 7 lower than that of classical methods. The equilibrium regimes of the resonators and the scattered part of the light are clearly highlighted as markedly modified by the dynamic of the sphingomyelin during its own phase transition