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A D-optimal design was used to identify and model variables that affect the transit time of wound exudate through an illustrative dressing used for negative pressure wound therapy. Many authors have addressed the clinical benefits of negative pressure wound therapy, but limited information is available on how to assess performances of dressings. In this paper, the transit time of wound exudate through a dressing was chosen as a model parameter to show how experimental design (DOE) can be used for this purpose. Results demonstrated that rate of exudate production, temperature and dressing thickness were the variables with the largest impact on transit time. The DOE approach could be used to model other dressing properties, like for example capability of absorbing excess exudate or breathability.

International audience; CSEM has developed new sol-gel based sensitive layers enabling the optical detection of volatiles and dissolved analytes with enhanced performances. These sol-gel films exhibit a hierarchical nanoporous structure. Dedicated optical readers have been developed to interrogate the optical signal of the sensitive sol-gel patches. Applications of this technology, focusing yet on O2, CO2, and pH detection, are illustrated with practical cases in aeronautics and environmental, health, and process monitoring.

The three year EU project SMARTER-SI that ends in January 2018 has tested a new concept for small lot manufacturing for SMEs which we call the Cooperative Foundry Model (CFM). During previous research, all RTOs have completed building blocks, i.e. components or parts of systems which are readily available and characterized by their high Technology Readiness Level (TRL). These building blocks are combined and integrated in so-called Application Experiments (AEs), thereby creating innovative Smart Systems that serve the SMEs' needs. Four pre defined AEs have been presented before [1] and in this paper, six additional AEs will be presented: i) a smart sensor for pneumatic combined clutch and brakes, ii) smart well plates for tissue engineering integrating continuous, non-invasive TEER iii) microclimate sensor for moisture applications, iv) LTCC-Si-Pressure Sensor, v) miniaturized capillary electrophoresis system for bio analysis, and vi) a MEMS sensor module for respiratory applications. Finally, a brief description of ongoing standardization efforts is presented.

Additive manufacturing (AM) is currently at the heart of the digital manufacturing trends. It englobes more than 15 different technologies. They are relying on the fabrication of a part made from mainly 1 or sometimes 2 materials with only 1 fabrication technology. In this study, we are developing technologies and materials to create 3D components on substrates or on 3D objects to form new components with an increase of functionality and complexity. We are particularly focusing on the realization of hybrids millimeter scale components for application in watch and medical field.

The three year EU project SMARTER-SI that started in February 2015 has developed and tested a new production platform for smart systems that offer SMEs and “mid-cap” companies help to manufacture small and medium volumes. The ultimate goal of this project is to test a new concept for small lot production, which we call the Cooperative Foundry Model (CFM). The CFM is tested by combining components or parts of systems (building blocks) already developed by the RTOs involved in the project in so-called Application Experiments (AEs), thereby creating innovative Smart Systems which serve SMEs' product needs. During the first two years, four predefined AEs have been developed that consist of i) a multi-parametric point of care testing (POCT) device, ii) a dew-point measurement system, iii) a CO 2 measurement system, and iv) a portable device that can be used to screen water quality.

A pH sensor based on polymethylmethacrylate (PMMA) optical fibers has been developed for on-body monitoring in biological fluids. Detection relies on evanescent wave absorption in a thin film deposited on the fiber core. The sensitive film was prepared using sol–gel technology from a mixture of tetraethyl orthosilicate (TEOS) and methyltriethoxysilane (MTES) or phenyltriethoxysilane (PTES), forming a porous hybrid organic–inorganic layer upon drying. The so-called ORMOSILs (organically modified silicate) were doped with bromophenol blue (BB) and the formulation was optimized to suppress dye leaching by varying the fraction of organic precursor, the sol aging time and the drying conditions. The molecular structure of the films was examined by Fourier-transformed infrared (FTIR) spectroscopy, and their optical responses characterized with UV–VIS absorption spectroscopy. Homogeneous crack-free films were obtained with an optimal MTES content of 50%. Leaching from these films was greatly reduced, with more than 80% of dyes remaining after 2 months in phosphate buffered saline (PBS) buffer. The entrapped indicator showed pronounced increase of apparent pKa and a broader response range compared to the free form in solution. The sensor demonstrated good sensitivity from pH 3 to 9, with an optical signal variation of 3.5 dB. It showed sensitivity to ionic strength variations, but not to temperature in the range between 20 and 50 °C. Reversible pH monitoring between pH 5 and 8 with a precision of 0.2 pH unit was demonstrated in human serum as a model biological fluid, without degradation of the sensing fiber over 24 h. This simple and low cost device will be particularly valuable to support diagnosis and the evaluation of therapies for wound healing.

An integrated platform for a very sensitive detection of cocaine based on a refractometric biosensor is demonstrated. The system uses a waveguide grating biosensor functionalized with a cocaine multivalent antigen-carrier protein conjugate. The immunoassay scheme consists of the competitive binding of cocaine-specific antibodies to the immobilized conjugates. A 1000-fold enhancement of the sensor's sensitivity is achieved when using gold conjugated monoclonal antibodies instead of free antibodies. Together with the optimization of the assay conditions, the setup is designed for a quick identification of narcotics using automated sampling. The results show that the presence of cocaine in a liquid sample could be identified down to a concentration of 0.7 nM within one minute. This value can be reduced even further when longer binding time is allowed (0.2 nM after 15 min). Application of the system to detection of narcotics at airport security control points is discussed.

An analytical detection platform was developed to evaluate the induced toxicity in cell cultures exposed to foreign agents like growth factors or nanoparticles. Connecting a biosensing detection device to the cell culture flasks allows analyzing the composition of cell medium in real-time. The analysis relies on the quantification of inflammatory cytokines released by cells into the cell culture medium, by means of solid-phase immunoassays analyzed with the wavelength interrogated optical sensing (WIOS) instrument. A fluidic system for in situ measurements allows detecting cytokines in real-time, with a sensitivity of 1-100 ng/mL depending on the cytokine. In addition, integration of an in-line optical absorbance measurement unit, in combination with the standard AB cell proliferation assay, provides information on the cell viability in the culture. Fluidic connections between the cell culture flasks, the optical biosensor and the absorbance measurement unit simultaneously allow quantifying up to three cytokines (interleukin 8, interleukin 6 and the monocyte chemotactic protein), assessing cellular proliferation, and thus discriminating between naïve cells and cells exposed to foreign agents such as growth factors (tumor necrosis factor alpha) or nanoparticles. This analytical tool presents a high potential for assessing the cytotoxicity of nanoparticles and other chemicals in vitro.

Nanostructuring waveguides by means of block-copolymer assisted lithography has as effect an increase in the total surface area. The non-specific adsorption of proteins on the nanostructured surfaces was monitored by wavelength-interrogated optical sensing and an increase in the sensitivity of the detection as compared to flat chips was observed. A model of the adsorption process confirmed the obtained experimental results and allowed the design of experimental approaches through which the detection sensitivity can be further improved.

An optical biosensor was developed to monitor the release of inflammatory cytokines by cells, aiming at the assessment of nanoparticle toxicity in vitro . Combined with optical detection, a label-free immunoassay allows quantifying the chemokine Interleukin 8 (IL-8) in cell culture medium, and discriminating between naive and stressed cells. Parallel detection of several cytokines involved in the inflammatory process provides a reliable analysis of the cellular immune response to stress caused by foreign agents like nanoparticles. Fluidic channels between the cell culture and the detection device leads to an integrated detection platform, allowing continuous monitoring of cellular events.

An immunosensor was developed for the detection of sulfonamide antibiotics in milk. Detection relied on a competitive immunoassay format, using immunoreagents previously developed for the generic detection of sulfonamide antibiotics and evaluated by enzyme-linked immunosorbent assay. The immunoassay was implemented onto a microsystem platform, the wavelength interrogated optical sensing device, which uses the evanescent field to probe changes at the interface of a waveguiding layer, and thus allows sensitive detection of biomolecule adsorption. The immunoreagents were immobilized onto the surface of the waveguide chip, and a fluidic cell allowed flowing analyte and detection solutions above the surface. Sulfapyridine was used as reference sulfonamide and detected with the immunosensor in buffer and in milk with a limit of detection (IC(90)) of 0.2+/-0.1 microg L(-1) and 0.5+/-0.1 microg L(-1), respectively. The analysis time was below 30 min, including regeneration of the sensing surface, with minimum sample preparation required. The reproducibility of the detection was better than 10%. A blind assay allowed identifying milk samples that were contaminated with different sulfonamide antibiotics at or above the maximum residue limits established by the European Union for these compounds (100 microg L(-1)). Thus, the developed immunosensor presents great potential as a generic sensing device for the fast and early detection of food contaminants on the field by non-skilled users.

Major research efforts are focusing on the development of multi-analyte-residue analysis and the design of user-friendly analytical devices for continuous or on-site measurements. Advances in microtechnology and nanotechnology make possible novel analytical solutions to meet these needs. With specific bioreceptors and antibodies, immunosensors may become excellent analytical tools. A portable wavelength-interrogated optical system (WIOS) exploits class-selective bioreceptors for simultaneous screening of the most frequently used antibiotics in the veterinary field (e.g., sulfonamides, fluoroquinolones, β-lactams and tetracyclines). The label-free sensor uses the evanescent-wave principle, by which changes in the refractive index close to the modified chip surface are detected by scanning the resonance condition at which a light wave is coupled in the waveguide through a conveniently designed grating. The bioreagents used in this study were developed to detect a wide range of congeners of each selected family of antibiotics below the maximum residue limit (MRL) values established for milk samples. The WIOS made it possible to detect more than 30 different antibiotics and it was successfully applied to analyze different antibiotic residues in milk samples.

Damien Dresse Introduction The possibility to modify and control the surface wettability of different materials has attracted signicant scientic and technological interest. Particularly for biological systems (implantable microdevices in the body or microfluidic systems) the hydrophobic and hydrophilic nature of a surface plays a key role on the mediation of solute (e.g. protein) adsorption and cell adhesion [1,2]. Also, surface roughness may amplify hydrophobicity as observed with superhydrophobicity of self-cleaning surfaces like some plant leaves, e.g., lotus [3]. Such an effect can be desirable for channel flows since it can reduce resistance to the flow [4]. Moreover, the clinical use of so-called non-fouling surfaces requires the ability to effectively interface with the biological milieu in a non-immunogenic and stable manner [5]. So to address this twofold request of surfaces having a tuneable physical behaviour towards a liquid sample as well as a natural compatibility with biomarkers carried within the sample suitable polymer films have been developped by Plasma Enchanced Chemical Vapor Deposition (PECVD). These polymers films also have practical uses in the surface modification of all kinds of materials such as binding of biomaterials, dyeing of textiles, catalyst preparation, printability of polymers, adhesion improvement of composite, wettability improvement of materials etc. [5-9]. PECVD films provide unique advantages due to the ability to control topography and film thickness on the micro and nanoscale, and control surface chemistry in a precise manner through chemical coupling and precursors tayloring. The present article is illustrating this technology through the case of application of SEMOFS. SEMOFS is an European project whose aim is to develop technologies, demonstrators and bioprotocols for the polymer based integrated probe card. It applies a label-free optical detection based on surface plasmon resonance (SPR) [10], where biochemical interactions at the sensor surface are monitored by observing the resonant behaviour of surface waves at a thin metal film. Both active and passive optical components (light source, waveguide, detector) as well as fluidic elements for active liquid transport and immobilised biological material (e.g. antibodies) will be integrated in the card. This new type of biosensor concept will

A bio-chemical sensor system based on wavelength interrogation of integrated optical sensor chips is presented. The combination of a non-mechanical scanning approach with sensor chips of high quality and stability allows fast and accurate multi-channel measurements. The emphasis of the present paper lies in presenting detailed design considerations, and in reporting the application of the system to several high sensitivity sensing tasks. An excellent performance of the sensor is demonstrated for bulk refractometry and affinity measurements. The bulk refractometric measurements show a detection limit of

In the frame of the European project PROETEX, CSEM continued to develop applications in the field of smart garment for monitoring vital signs and environment of the wearer. This European integrated project grouped 23 partners from all over Europe. The objectives of the project were to develop smart garments for firefighters and rescuers that will help them and their headquarters to know the location, the capacity, and the encountered risks of emergency personnel on the intervention’s field. The smartness was given by the network of integrated sensors and the communication capacities of the developed garments. The inner garments integrated life sign monitoring sensors for heart rate (HR), respiration rate, body temperature, etc. The outer garments were equipped with sensors to determine environmental risks (chemical, temperature), the situation of the rescuer (activity, attitude, localization), and the control system with a communication module. The system was tested in the laboratory and the intervention’s field. In the laboratory, it was compared with reference measurement systems and proved its functionality. Then it was tested with firefighters and rescuers in training situations with exercises of real rescue and fire operations. It proved its ability to provide relevant information to the management of emergency personnel during operation. Integration of sensors in garments is an emerging technology that will find applications not only for monitoring people in extreme situations but also for monitoring people during sport training or for monitoring patients and elderly people at home.

A microchip-based flow confinement method for rapid delivery of small sample volumes to sensor surfaces is described. For flow confinement, a sample flow is joined with a perpendicular makeup flow of water or sample medium. Under laminar flow conditions, the makeup flow confines the sample into a thin layer above the sensing area and increases its velocity. This can benefit mass transport limited processes such as DNA hybridization or heterogeneous immunoassays. For proof of concept, this method was applied to a high-affinity immunoassay with excess capture antibody. Rabbit IgG was immobilized onto a silicon nitride waveguide. Cy5-labeled anti-rabbit IgG was hydrodynamically pumped over the immobilized zone through an attached 3D-PDMS flow cell with 20-microm-deep microchannels. The degree of confinement was adjusted through the volume flow rate of the confining flow. Evanescent field-based fluorescence detection enabled monitoring of the binding event. Assays were allowed to reach equilibrium to enable sensorgram normalization for inter-run comparison. The corresponding assay completion times could be reduced from 55 min for static drop conditions to 13 min for 25:1 flow confinement (ratio of confining to sample flow). For typical analytical applications, where equilibrium formation is not required, the faster response should translate to very short analysis times. Concurrently with the faster binding, sample consumption was reduced by 96% compared to conventional whole-channel sample delivery. Diffusional loss of analyte into the confining layer was identified as the main limitation of flow confinement, particularly for long sensing pads.

The capability to deliver light to specific locations within the brain using optogenetic tools has opened up new possibilities in the field of neural interfacing. In this context, optical fibers are commonly inserted into the brain to activate or mute neurons using photosensitive proteins. While chronic optogenetic stimulation studies are just beginning to emerge, knowledge gathered in connection with electrophysiological implants suggests that the mechanical mismatch of conventional optical fibers and the cortical tissue may be a significant contributor to neuroinflammatory response. Here, we present the design and fabrication of physiologically responsive, mechanically adaptive optical fibers made of poly(vinyl alcohol) (PVA) that may mitigate this problem. Produced by a one-step wet-spinning process, the fibers display a tensile storage modulus E′ of ∼7000 MPa in the dry state at 25°C and can thus readily be inserted into cortical tissue. Exposure to water causes a drastic reduction of E′ to ∼35 MPa on account of modest swelling with the water. The optical properties at 470 and 590 were comparable with losses of 0.7±0.04 dB/cm at 470 nm and 0.6±0.1 dB/cm at 590 nm in the dry state and 1.1±0.1 dB/cm at 470 nm and 0.9±0.3 dB/cm at 590 nm in the wet state. The dry end of a partially switched fiber with a length of 10 cm was coupled with a light-emitting diode with an output of 10.1 mW to deliver light with a power density of >500 mW/cm2 from the wet end, which is more than sufficient to stimulate neurons in vivo. Thus, even without a low-refractive index cladding, the physiologically responsive, mechanically adaptive optical fibers presented here appear to be a very useful new tool for future optogenetic studies.

A novel approach for accomplishing robust integrated optical biosensors is presented. The principle is based on a symmetric grating coupler structure with the inherent feature of compensating disturbances originating from different kinds of mechanical instabilities. The complete sensor system has no moving parts and provides the high sensitivities typical for integrated optical sensors based on grating couplers. The feasibility of this approach is demonstrated by determining the refractive index of liquids as well as by measuring the specific binding of biomolecules (anti-chicken IgG) to immobilized chicken IgG on the sensor chip surface.

The EU FP7 SWAN-iCare project aims at developing an integrated autonomous device for the monitoring and the personalized management of chronic wounds, mainly diabetic foot ulcers and venous leg ulcers. Most foot and leg ulcers are caused by diabetes and vascular problems respectively but a remarkable number of them are also due to the co-morbidity influence of many other diseases (e.g. kidney disease, congestive heart failure, high blood pressure, inflammatory bowel disease). More than 10 million people in Europe suffer from chronic wounds, a number which is expected to grow due to the aging of the population. The core of the project is the fabrication of a conceptually new wearable negative pressure device equipped with Information and Communication Technologies. Such device will allow users to: (a) accurately monitor many wound parameters via non-invasive integrated micro-sensors, (b) early identify infections and (c) remotely provide an innovative personalized two-line therapy via non-invasive micro-actuators to supplement the negative pressure wound therapy. This paper describes the main components of the SWAN-iCare system and its potential impact in the area of wound management.

Real-time, on-body measurement using minimally invasive biosensors opens up new perspectives for diagnosis and disease monitoring. Wearable sensors are placed in close contact with the body, performing analyses in accessible biological fluids (wound exudates, sweat). In this context, a network of biosensing optical fibers woven in textile enables the fabric to measure biological parameters in the surrounding medium. Optical fibers are attractive in view of their flexibility and easy integration for on-body monitoring. Biosensing fibers are obtained by modifying standard optical fibers with a sensitive layer specific to biomarkers. Detection is based on light absorption of the sensing fiber, placing a light source and a detector at both extremities of the fiber. Biosensing optical fibers have been developed for the in situ monitoring of wound healing, measuring pH and the activity of proteases in exudates. Other developments aim at the design of sensing patches based on functionalized, porous sol-gel layers, which can be deposited onto textiles and show optical changes in response to biomarkers. Biosensing textiles present interesting perspectives for innovative healthcare monitoring. Wearable sensors will provide access to new information from the body in real time, to support diagnosis and therapy.

A novel approach based on the use of gray-tone masks to shape arbitrary profiles is described. Tapered structures in thick polyimide as well as blazed gratings and Fresnel microlenses in fused silica substrates have been fabricated. The 3D shaping capability of this technology is illustrated by a high efficiency of 75% obtained for the lenses. This technology involves one appropriate mask, a photolithographic exposure and an etching step; it is realized on conventional equipment and is therefore cost effective.

Functionalized nanoporous coatings prepared by sol-gel processes are excellent sensing interfaces. Indeed, the high surface area combined with the specific functionalization using organic dyes and biologic entities has led to highly sensitive and selective optical (bio)sensors for gaseous or diluted species. Thus, biochips and optical fibers modified with functionalized nanoporous sensitive layers have been developed for environmental (e.g. gas detection, selective recognition of pesticides) and healthcare applications (e.g. wound monitoring).

Polymer nanocomposite gratings with a 363 nm period and a 12 nm step height were replicated using a glass master in a rapid, low-pressure imprint process. The composite materials were based on a UV-curable acrylated hyperbranched polymer and nanosized SiO2 particles. The influence of particle fraction up to 25 vol%, process pressure and UV intensity on the grating geometry was analyzed using atomic force microscopy. The period of the grating was found to be identical to that of the glass master for all investigated conditions. It was shown that the gel point of the nanocomposite was an important factor that determined the stability as well as the dimensions of the imprinted structure. However, a distortion of the grating was observed with increasing fraction of SiO2, which was correlated to the increased internal stress of the composite. Wavelength interrogated optical sensors were produced by depositing a high refractive index TiO2 layer on the composite gratings. The laser signal strength of the polymer sensors was equal to that of the reference high precision glass sensor with 10-12 g/mm2 sensitivity. The strength was lower for the nanocomposites due to propagation losses argued to result from residual porosity.

The concern for “food safety” surely emerged very early in human history, contributing to the establishment of certain rules and customs. In today’s technologically developed countries, food safety is subject to strict laws that regulate the presence of undesired substances in food. In particular, in the milk industry, levels of residues of veterinary medicinal products, of which antibiotics represent a significant part, are regulated by European Council (EC) Regulation no. 2377/90. More precisely, a series of four antibiotic families are found to be of particular interest due to their routine use for treatment in bacterial infection and/or prophylactic purposes: fluoroquinolones, sulfonamides, β-lactams, and tetracyclines. Their excessive use in dairy diet in recent decades gave rise to stronger bacterial resistance, which consequently represents a serious problem in the efficiency of classic antibacterial treatment in humans [1]. In this context, there is a considerable need for developing sensing devices able to detect a series of antibiotic families simultaneously. A few dipstick format tests [1] commercially available that are cheap, fast, and reliable currently offer an interesting alternative to expensive conventional chromatographic techniques. However, those systems are not fully automated and are unable to detect more than two antibiotic families per single test. The present work reports the development of a lab-on-a-chip (LOC) test system for multiplexed detection of four antibiotic families in raw milk. A fabricated microfluidic cartridge is prefilled with the solutions necessary for immunoassays, and the whole detection sequence is operated automatically by external pump-and-valve combinations. The immunoassay principle is based on a competitive assay format, and the resulting refractive index changes at the sensor surface are probed using the wavelength interrogated optical sensing (WIOS) method. The multiplexed sensing system that was consequently developed was adapted for the simultaneous detection of sulfonamides, fluoroquinolones, β-lactams, and tetracyclines. The whole test procedure is fast (less than 10 min), easy to handle (automated actuation), and cost-effective due to the use of novel photosensitive materials in a “one-step” fabrication process.

Continuous health monitoring often requires hospitalization, which can become an expensive and inconvenient choice for the patient. In this perspective, wearable sensors that allow in situ biosensing constitute a very promising technology. This work aims to develop immunosensors for continuous monitoring of the wound healing process, based on pH changes, as well as on the concentrations of inflammatory proteins such as the C-reactive protein (CRP). Sensing principles include the use of responsive hydrogels that swell in response to changes in the surroundings, and the use of functional surfaces that specifically recognize the target protein. The detection principle is based on an optical signal, using the evanescent field of light propagating along a waveguide, probing refractive index changes. An optical sensing system that can be integrated in a wound dressing patch has been designed, including a white light source (LED), and a spectrometer for detection. The sensor was successfully tested in the laboratory with biological samples (blood serum), demonstrating reversible pH measurements between pH 6-8, and detection of changes in the concentration of CRP between 1 and 100 μg/ml. The sensor will later be integrated into wound dressings or bandages, forming a sensing patch that is connected via optical fibres and electrical wires to the detection system and power supply. This novel technology will be particularly valuable in applications such as the supervision of skin grafts and ulcer treatments.

Introduction The Physical Objects Measurable with Grating-Based Optical Sensors Particles Thin Films Living Cells Applications to Areas of Human Activity Medicine Environment Process Monitoring Military Space Incoupling Mode Sensors The Optical Theory of OWLS (Optical Waveguide Lightmode Spectroscopy) The Structure of the Planar Grating Coupler Sensor Chip Instrumentation Sensor Fabrication Immunosensors Based on OWLS Detection OWLS Assays on Living Cells Electrochemical-OWLS, Fluoro-OWLS Outcoupling Mode Sensors Chirped Grating Couplers (CGS) Light Pointer Wavelength-Interrogated Optical Sensing (WIOS) Combination of Wavelength-Interrogated Optical Sensing and Fluorescence Detection Array Sensors Resonant Waveguide Grating (RWG) Sensors Referencing Sensor Fabrication Applications Keywords: label-free sensor; grating coupler; OWLS; WIOS; RWG; biosensor; evanescent field sensor; optical sensor

This paper describes a new technology platform for polymeric micro optical fluidic systems. The platform consists of active and passive optical and fluidic elements for a surface plasmon resonance (SPR) biosensor for the detection of proteins. The platform includes the integration of polymer light emitting diodes, polymer photodiodes as well as polymer based fluidic valves and pressure generation elements. Surface functionalization for micro optical and micro fluidic parts as well as advanced manufacturing methods are other important parts of the presented technology platform.

The optoelectronic version of an existing industrial 2 /spl mu/m CMOS process has been developed. With the new technology, single mode strip waveguides, photodiodes and waveguide-to-photodiode couplers have been integrated together with standard CMOS devices. Thanks to a modular approach, the properties of the core process have not been altered. The bandwidth of the basic system, consisting of a curved waveguide coupled to a photodiode and a transimpedance amplifier, is higher than 1.5 MHz at a wavelength of 780 nm. As an example, an unbalanced interferometer with on-chip amplifier has been qualified. >

Novel sensor chips for evanescent wave sensing have been developed and investigated for various (bio-) chemical applications. A preferred integrated optical sensing scheme requires an array of independent sensing pads being present on the chip, each one of them having two different regions for in- and out coupling of the optical readout beam. We present a novel chip type, where this goal is achieved by thickness variations of the waveguiding film and one single grating period. The sensor chips consisted of a 300 nm thick Ta2O5 waveguide deposited on a glass substrate structured with a uniform grating of 360 nm period. By this optical structure a first coupling angle was defined. Sensing pads with a different coupling angle were realized by etching the film at selected regions down to a thickness of about 150 nm. The performance of the novel chips was demonstrated in various refractometric sensing applications. The experiments included cover medium refractive index variation as well as monitoring of affinity binding of small molecules. A very high resolution of 3x10-8 in the effective refractive index was achieved. The emphasis of this paper is on describing this approach and on presenting optical chip characterization methods together with modeling results.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Introduction La telemedecine s'etend a tous les domaines de la sante, dont la cicatrisation des plaies chroniques. Les plaies de pied diabetique et les ulceres veineux representent une part importante de ces plaies. Materiels et methodes Ce poster presente la description preliminaire du projet Europeen FP7-ICT-2011-8 qui vise a elaborer un systeme de soins pour plaies chroniques intitule SWAN-iCare. Resultats De septembre 2012 a septembre 2016, un consortium de cliniciens et de scientifiques va elaborer un nouveau systeme de prise en charge des plaies chroniques : le systeme SWAN-iCare, dedie principalement aux plaies de pied diabetique et aux ulceres veineux. Ce dispositif reposera sur un traitement par pression negative realisable au domicile du patient, couple a un monitoring a distance de la cicatrisation a partir : – de capteurs situes au voisinage de la plaie pour mesurer certaines caracteristiques physico-chimiques de l'exsudat impactant sur la cicatrisation (pH, taux de proteases…). – de mesure de la pression plantaire pour les plaies de pied diabetique ou de la dorsiflexion pour les ulceres veineux, ou encore d'un suivi de l'oxygenation de la plaie ou de la glycemie capillaire. Le but est d'offrir pour des plaies dites « difficile a cicatriser » un outil de monitoring pour le centre de cicatrisation en charge du patient, afin d'ameliorer la prise en charge globale de ces plaies de pronostic incertain. Les resultats presentes ici tracent les grandes lignes de ce projet, dans les limites du respect de la propriete intellectuelle. Conclusion Dans un avenir proche, on peut s'attendre au developpement du traitement par pression negative pour les plaies chroniques, associe a des systemes de monitoring a distance reposant sur des capteurs pour differentes caracteristiques des plaies concernees.

A new scheme for integrated optical fluorescence sensing is presented. The principle is based on a planar waveguide containing multiple sensing units, each consisting of a single-pad grating coupler structure. Single-pad means that all the following functions are incorporated in one single pad: laser light input, excitation of the labeled analyte molecules, efficient collection of the emitted fluorescent light into the waveguide, background suppression, and coupling the guided wave out to the detector. The results demonstrate a high efficiency of the fluorescence light excitation and collection, as well as a good suppression of the volume background.

In this paper a microchip-based “flow confinement” method for sample delivery is validated for the first time by applying it to immunoassays on optical waveguides. With binding ligands in the sample flow and receptors immobilized on the waveguide it results in faster binding.

The simulation of the coupling efficiency of fluorescence sources immobilized in the evanescent field of a waveguide mode has allowed the dimensioning of a sensing waveguide platform based on a silicon substrate exhibiting maximum fluorescence efficiency. The incoupling of the excitation light and the outcoupling of the fluorescence signal are performed by means of a corrugation grating. The presence of the highly reflective silicon surface under the waveguide grating causes interferences in the fluorescence output signal which depend on the wavelength and on the radiation angle. A theoretical modeling of the grating coupling under these conditions has led to the achievement of high incoupling efficiency at the excitation wavelength, and simultaneously to high outcoupling efficiency at the wavelength of the fluorescence peak. An experiment was performed with fluorescein at the surface of a 160 nm thick silicon nitride waveguide film on a silicon substrate with a 2100 nm thick buffer layer of silica. The measured outcoupled spectra fit well with the calculated spectra taking into account the output grating coupling, the fluorescence spectrum, and fluorescence coupling. These waveguide grating structures are applied to the detection of immunological reactions.

High resolution optical encoders take advantage of diffraction and interference properties of light. In such components, the scale is a phase grating that diffracts light into several orders; an optical reading system makes two of them to interfere. In state of the art systems, the orders interfere after they have been spatially separated from other orders; this leads to cumbersome reading heads. A compact, fully diffractive optical reading system was designed and realized. This reading system was used for the realization of rotation encoders. Using the competences of the Eureka EU 922 FOTA project partners, the encoder phase gratings were successfully realized and the reading system was implemented in standard rotation encoder housings. Without interpolation the encoder gives 480'000 pulses per revolution with a repeatability of 2.5 pulses.

The practical usefulness of multimode guided wave optics has been overshadowed by the powerful trend of optical communications towards single mode technologies. Although multimode integrated optic technology lends itself to a very restricted palette of optical functions, it can perform elementary functions at a cost which falls dramatically as the number of identical samples increases unlike that of all-fibre and micro-optic components. Glass integrated optics brings the additional advantage of stability versus external physical parameters.

Optical sensing techniques can be considered as powerful information sources on the biochemistry of tissue, blood, and physiological fluids. Various sensing modalities can be considered: spectroscopic determination of the fluorescence or optical absorption of the biological medium itself, or more generally, of a reagent in contact with the biological medium. The principle and realization of the optical sensor developed are based on the use of polished fibers: the cladding of a monomode fiber is removed on a longitudinal section. The device can then be inserted into an hypodermic needle for in-vivo measurements. Using this minute probe, local measurements of the tissue biochemistry or metabolic processes can be obtained. The sensing mechanism is based on the propagation of the evanescent wave in the tissues or reagent: the proximity of the fiber core allows the penetration of the model field tail into the sensed medium, with a uniquely defined field distribution. Single or multi-wavelength analysis of the light collected into the fiber yields the biochemical information. Here an example of this sensing technology is discussed. In-vitro measurement of bilirubin in gastric juice demonstrates that the evanescent wave optical sensor provides a sensitivity which matches the physiological concentrations. A device is proposed for in-vivo monitoring of bilirubin concentration in the gastro-oesophageal tract.

By patterning the iron oxide film of a conventional iron oxide mask it is possible to obtain a binary phase grating of high diffraction efficiency and high transmission that can be used in high-resolution displacement sensors.

Periodically corrugated optical waveguides on glass with non-collinear coupling have been investigated both theoretically and experimentally. For a TE or TM polarized guided mode of a planar waveguide obliquely incident on a grating pad, there are four characteristic angles corresponding to the coupling with TE and TM reflected modes fulfilling the Bragg condition. The reflectivity is obtained by solving the coupled mode equations for the non-collinear case. The modelling shows that integrated passive functions such as polarization splitting and interference can be achieved. The polarization interference element uses the property that the coupling coefficients TM-TE and TE-TE are equal at defined incidence angles. Since the angle between the two reflected TE beams is only a few minutes of arc, the two beams can interfere. The waveguides are made by K+ ion exchange in BK7 glass for 3 hours at 380°C. The structure was designed for use at a wavelength of 633 nm and uses a 485 nm period grating which was fabricated by holographic exposure and plasma etching techniques in a 50 nm TiO2 layer e-beam evaporated onto the glass surface. The reflectivity of the grating structure was studied experimentally and compared with theory. The diffraction angles are within 30 " of arc of the predicted angles. The measured reflectivities reached 20 %. The feasibility of realizing an integrated optic preprocessing circuit for polarization interferometry has been demonstrated.

Low loss passive integrated optic interferometric sensors might successfully compete with optical fibre sensors in short path length applications such as distance measurement, force and perhaps also low performance rotation sensors. They are inherently polarization maintaining, stable, low cost and versatile.There is yet an important function which remains to be practically solved in integrated optics on passive substrates: the phaseshifting allowing a waveguide interferometer to delivering non degenerate optical power signals, ie, sine and cosine functions of the input optical phase difference.The proposed device achieving this function is a single process ion exchanged circuit on glass using a low mode number imaging waveguide caisson. The proposed configuration can be applied to all kinds of interferometers. 1. INTRODUCTION Since the early days of integrated optics the directional coupler formed by two neigh­ bouring waveguide sections1 has been considered as a key component for all singlemode fiber communication, and more recently, sensor systems. Until recently their main use was for amplitude modulation and switching purpose. There was only little concern about the re­ lationship between the power signals at the two output ports of a coupler and the optical phase at its input ports. Since the advent of coherent optical communications and, more recently, of integrated optic interferometry for sensors (e.g. in distance measurement) there has been a growing interest for such an element as a true wave mixer capable of retrieving the phase difference between two incoming beams. It is well known that a 2 x 2 port 3 dB directional coupler only delivers two degenerate power signals of the input phase shift, which means that the direction of a displacement can not be determined and that interpolation can not be performed accurately. In order to allow, e.g., phase tracking in coherent communication and fringe counting and interpolation in interferometry, the mixing coupler should supply at least two non-degenerate power signals, i.e., sine and cosine functions of the input phase difference.This is what occurs in a 3-fiber fused coupler2 delivering a three-phase output. In integrated optics the analysis of a 3-waveguide coupler was achieved3 but no experimental evidence has been published yet. Non degenerate integrated optic interferometers have been reported. Rather than being true singlemode circuits they are planarizations of bulk optic configurations using singlemode planar waveguides4 • 5 . The integration is in one dimension and leaves open the question of the phase front alteration due to various inhomogeneous disturbances within the waveguide material with possible consequences on the optical power modulation depth.Actual singlemode guided wave optics provides a perfect spatial coherence over long and topologically complex waveguide routes and offers unique features for multiple wave inter­ ference. One of these properties is that of waveguide multiple imaging first demonstrated by Ulrich6 . The phase relationship between the sub-images of a fourfold waveguide imaging section is such that the latter delivers four optical power signals in quadrature7 . This means in particular that in a balanced mixer the unknown and possibly fluctuating power signal component can be optically cancelled out. Such a waveguide section was demonstrated by means of a flat-core fibre7 .The purpose of the present contribution is to analyse the imaging capability of an integrated optic section singlemode in depth and multimode in width, hereafter called "caisson". It will be theoretically and experimentally shown that a low mode number wave­ guide caisson, i.e., a rather short section (less than 10 mm), can achieve sufficiently good and low loss fourfold imaging of input singlemode waveguides to be used as an inter­ ferometric mixer for most industrial applications which nowadays use bulk interferometry. The technology used is the fairly simple and well characterized ion exchange technique in glasses.

A glass etching technology with a HF solution and a chromium mask is presented. The technology allows the etching of semi-circular grooves as deep as 250 μm within a few microns with good surface quality. Two etched substrates can be superposed to obtain a cicular channel that can be filled with plastic to obtain a waveguide. The design of the mask permits the fabrication of guided wave plumbing platforms of light distribution, coupling and intersection circuits compatible with hard clad silica or plastic fibers. The feasability of a coupling platform is demonstrated. The technology also permits the positioning of optical fibers in front of integrated optic circuits.

A multiplexed immunoassay-based antibiotic sensing device integrated in a lab-on-a-chip format is described. The approach is multidisciplinary and involves the convergent development of a multi-antibiotic competitive immunoassay based on sensitive wavelength interrogated optical sensor (WIOS) technology and a polymer-based self-contained microfluidic cartridge. Immunoassay solutions are pressure-driven through external and concerted actuation of a single syringe pump and multiposition valve. Moreover, the use of a novel photosensitive material in a 'one step' fabrication process allowed the rapid fabrication of microfluidic components and interconnection port simultaneously. Pre-filled microfluidic cartridges were used as binary response rapid tests for the simultaneous detection of three antibiotic families - sulfonamides, fluoroquinolones and tetracyclines - in raw milk. For test interpretation, any signal lower than the threshold value obtained for the corresponding Maximum Residue Limit (MRL) concentration (100 microg L(-1)) was considered negative for a given antibiotic. The reliability of the multiplexed detection system was assessed by way of a validation test carried out on a series of six blind milk samples. A test accuracy of 95% was calculated from this experiment. The whole immunoassay procedure is fast (less than 10 minutes) and easy to handle (automated actuation).