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Novel glycidyl-terminated organosilicon coupling agents possessing a trialkoxysilyl head group and a very long hydrocarbon chain (C22) were synthesized. Their ability to afford densely packed self-assembled monolayers (SAMs) grafted on silica-based surfaces was investigated. Transmission FT-IR spectra showed that the most regular films were obtained by using trichloracetic acid as the catalyst (10 M%). Atomic force microscopy (AFM) and optical ellipsometry were consistent with well ordered monolayers exhibiting a marked decrease of the surface roughness. Epifluorescence microscopy revealed that these SAMs possessed a better surface reactivity than monolayers obtained with the commercially available (3-glycidoxypropyl) trimethoxysilane (GPTS) upon grafting of a fluorescent probe (dansylcadaverin). Moreover, direct attachment of fluorescent antibodies (RAG-TRITC) through covalent binding led to higher mean fluorescence intensities, showing that these new SAMs possess high potential for the immobilization of biological molecules.

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We present the development of new Polydimethylsiloxane (PDMS) chips, which are coupled with Love acoustic wave sensors to realize a detection cell of bio-organisms in liquid media. Three generations of biocompatible PDMS chips have been developed. Built-in thermistors allow a thermal control (±0.05°C). Unlike the usual assemblies, this chip is maintained by pressure on the sensor and not sticked on its surface. This technique makes it entirely removable and cleanable. Therefore, the surface of the sensor can be functionalized or regenerated. The realization of these chips is quick and inexpensive.We here outline the development of these different cells and present characteristics of the resulting microsensors, depending on the chip configuration. Real-time responses during antibodies immobilization are presented and analyzed. Antibodies at typical concentration of 45μg/ml are successfully fast detected, with response times from 350s for static down to 90s for dynamic detection setup, with similar sensitivity. Discussions on the mechanical fluid behaviour at the near sensor surface allow to better understand these results and to investigate further developments aiming at improving the quality of the fluid stream in order to even increase future sensor characteristics.