Multiplexed Remote SPR Detection of Biological Interactions through Optical Fiber Bundles The development of sensitive methods for in situ detection of biomarkers is a real challenge to bring medical diagnosis a step forward. The proofofconcept of a remote multiplexed biomolecular interaction detection through a plasmonic optical fiber bundle is demonstrated here. The strategy relies on a fiber optic biosensor designed from a 300 xc2xb5m diameter bundle composed of 6000 individual optical fibers. When appropriately etched and metallized, each optical fiber exhibits specific plasmonic properties. The surface plasmon resonance phenomenon occurring at the surface of each fiber enables to measure biomolecular interactions, through the changes of the retroreflected light intensity due to lightplasmon coupling variations. The functionalization of the microstructured bundle by multiple protein probes was performed using new polymeric 3Dprinted microcantilevers. Such soft cantilevers allow for immobilizing the probes in micro spots, without damaging the optical microstructures nor the gold layer. We show here the potential of this device to perform the multiplexed detection of two different antibodies with limits of detection down to a few tenths of nanomoles per liter. This tool, adapted for multiparametric, realtime, and label free monitoring is minimally invasive and could then provide a useful platform for in vivo targeted molecular analysis.

Spectral Phase Shift Interferometry for Refractive Index Monitoring in MicroCapillaries In this work, we demonstrate spectral phaseshift interferometry operating in the nearinfrared wavelength range for refractive index (RI) monitoring of fluidic samples in microcapillaries. A detailed theoretical model was developed to calculate the phasesensitive spectral reflectivity when lowcost rectangular glass microcapillaries, filled with samples with different refractive indices, are placed at the end of the measurment arm of a Michelson interferometer. From the phasesensitive spectral reflectivity, we recovered the cosineshaped interferometric signal as a function of the wavelength, as well as its dependence on the sample RI. Using the readout radiation provided by a 40nm wideband light source with a flat emission spectrum centered at 1.55 xc2xb5m and a 2 xc3x97 1 fiberoptic coupler on the common inputoutput optical path, experimental results were found to be in good agreement with the expected theoretical behavior. The shift of the microcapillary optical resonances, induced by RI variations in the filling fluids (comparing saline solution with respect to distilled water, and isopropanol with respect to ethanol) were clearly detected by monitoring the positions of steep phase jumps in the cosineshaped interferometric signal recorded as a function of the wavelength. By adding a few optical components to the instrumental configuration previously demonstrated for the spectral amplitude detection of resonances, we achieved phasesensitive detection of the wavelength positions of the resonances as a function of the filling fluid RI. The main advantage consists of recovering RI variations by detecting the wavelength shift of xe2x80x9csharp peaksxe2x80x9d, with any amplitude above a threshold in the interferometric signal derivative, instead of xe2x80x9cwide minimaxe2x80x9d in the reflected power spectra, which are more easily affected by uncertainties due to amplitude fluctuations.