Biofunctionalized tilted Fiber Bragg Gratings for label-free immunosensing.

We present a study aimed at developing a label-free optical fiber biosensor for detection and quantification of biomolecules in real-time. The biosensor based on a Tilted Fiber Bragg Grating (TFBG) transduces a binding event between the probe and target molecules into a change in the refractive index of the medium surrounding the fiber. This work describes the experimental results obtained with three methods for immobilizing biomolecular probes on a TFBG silica cladding surface. Bovine serum albumin (BSA) and anti-BSA are used to assess the performances of the TFBG based biosensor in each configuration.

Supramolecular interactions between beta-cyclodextrin and hydrophobically end-capped poly(ethylene glycol)s: a quartz crystal microbalance study.

In this study, the supramolecular interactions occurring between beta-cyclodextrin-based surfaces and macromolecular chains modified at one end with naphthyl, adamantyl, or phenyladamantyl hydrophobic groups were investigated by means of a quartz crystal microbalance. beta-Cyclodextrin-functionalized gold electrodes were obtained through the amide-coupling reaction between mono-6-deoxy-6-amino-beta-cyclodextrin and 11-mercaptoundecanoic acid self-assembled monolayer allowing the reproducible preparation of densely grafted surfaces with host properties. The interaction data obtained for the three different modified poly(ethylene glycol)s are in good agreement with our previous studies performed by high performance liquid chromatography and surface plasmon resonance. This evidences that the driving force for the supramolecular interaction is based on the inclusion of the hydrophobic terminal group of the chains within the cyclodextrin cavities. The reversibility of the inclusion process was proven through the regeneration of the original host properties of the sensing surfaces using sodium dodecylsulfate as a competitor for the desorption of the poly(ethylene glycol) chains.