Time-of-Flight Secondary Ion Mass Spectrometry Investigation of the Orientation of Adsorbed Antibodies on SAMs Correlated to Biorecognition Tests

The adsorption of an antiglutamate dehydrogenase (Anti-GDH) antibody on different surfaces was studied to probe its orientation and bioactivity. Three different situations were investigated: physisorption on a −COOH-terminated thiols self-assembled monolayer (SAM) on gold, covalent grafting on the same SAM using NHS-EDC activation, and physisorption on a −CH₃ SAM. The orientation of the antibody was investigated combining time-of-flight secondary ion mass spectrometry and principal component analysis. Several orientations are proposed for each case and compared to the results of biorecognition measurements with the antigen (GDH). At each step, protein layers were characterized ex-situ with polarization-modulated infrared reflection absorption spectroscopy and in situ (i.e., in the liquid phase) with quartz crystal microbalance with dissipation monitoring. Biorecognition measurements showed interesting correlations with proposed protein orientations. The role of hydrophobic and/or electrostatic interactions and that of covalent bonding are discussed to underline the influence of the orientation on the bioactivity of adsorbed Anti-GDH

ARMEN: Assistive robotics to maintain elderly people in natural environment

International audienceThis document presents the research project ARMEN aiming at the conception of an assistive robot very simple to use and providing advanced functions to help maintaining disabled or elderly people at home. The document presents the robot SAM and the functions of navigation, of emotion detection from speech, of image understanding, the knowledge representation and the avatar conceived for the supervision of the robot in an intuitive way. The document presents the results of the technical evaluations made showing the interest and potential of these functions for practical applications. The document presents the clinic evaluations that will take place soon to validate the development made with elderly and handicapped people in a therapeutic setting. The protocol used for these evaluations is described before the presentation of conclusions evoking the perspective of the project

Probing the Orientation of β‑Lactoglobulin on Gold Surfaces Modified by Alkyl Thiol Self-Assembled Monolayers

The adsorption of a globular protein on chemically well controlled surfaces was investigated in order to correlate its orientation to the surface properties. To this end, three different alkyl thiols, differing by their end group (−COOH, −CH₃, and −NH₂), were used to build up self-assembled monolayers (SAMs) on gold substrates. β-Lactoglobulin (βLG) was then adsorbed on these SAMs by immersion in a phosphate buffer solution. The surface modification with alkyl thiols and the subsequent adsorption of proteins were characterized <i>ex situ</i> by polarization modulated infrared reflection–absorption spectroscopy (PM-IRRAS) and X-ray photoelectron spectroscopy (XPS). The adsorption behavior of proteins was also monitored <i>in situ</i> using quartz crystal microbalance with dissipation measurements (QCM-D). Direct evidence regarding the protein orientation in the adsorbed state was obtained by means of time-of-flight secondary ion mass spectrometry (ToF-SIMS). Principal component analysis (PCA), performed on the ToF-SIMS results, enables to separate the samples and shows that the proteins display different distributions of amino acids at the surface depending on the conditioning thiol layer. Our results revealed that the adsorption mode of the protein is influenced by the thiol end groups, and specific orientations of the protein on the surface are proposed for the different substrates

High level functions for the intuitive use of an assistive robot

Conference of 2013 IEEE 13th International Conference on Rehabilitation Robotics, ICORR 2013 ; Conference Date: 24 June 2013 Through 26 June 2013; Conference Code:101627International audienceThis document presents the research project ARMEN (Assistive Robotics to Maintain Elderly People in a Natural environment), aimed at the development of a user friendly robot with advanced functions for assistance to elderly or disabled persons at home. Focus is given to the robot SAM (Smart Autonomous Majordomo) and its new features of navigation, manipulation, object recognition, and knowledge representation developed for the intuitive supervision of the robot. The results of the technical evaluations show the value and potential of these functions for practical applications. The paper also documents the details of the clinical evaluations carried out with elderly and disabled persons in a therapeutic setting to validate the project

An intelligent robotics modular architecture for easy adaptation to novel tasks and applications

International audienceIndustrial robots significantly contributed to the increase of quality and productivity in the industry. Still, their deployment and use remain complex and expensive, limiting their main market to mass production in large factories. This article introduces an intelligent robotics framework intended to solve this issue. It relies on a four-layer modular architecture associating a components-agnostic orchestrator coordinating software modules accessed through a standard middleware, and different hardware running the required functions. This architecture is implemented for performing various tasks in autonomy or in collaboration with a human operator, the different components being turned on and adapted on-demand according to the use-case requirements. We illustrate the proposed concept on four robotic sequences: the assembly of a representative gear unit with one arm, the same application with two robots, the Robothon® Grand Challenge and the insertion of deformable objects in a rail

Graphene synthesis and antibody immobilization techniques for iImmunosensors

The principle of antigen–antibody interaction is exploited for immunosensor development. Over the years, immunosensors have been fabricated for different applications, and the fabrication process has benefited from the use of nanomaterials. Graphene, a single-atom-thick layer of carbon, has been used to coat the sensing electrodes of immunosensors; antibodies are then immobilized onto the graphene-modified electrodes to produce graphene-based immunosensors. Here, we describe several techniques for producing graphene and its derivatives. We also focus on approaches for antibody immobilization on these graphene-modified electrodes