Evanescent Waveguide Sensor for On-Chip Biomolecular Detection

This work presents analysis and development of an evanescent waveguide sensor system, which integrates an amorphous silicon photodiode and a glass-diffused waveguide. Design of the system includes a study of thickness and refractive index of the transparent electrode of the diode, which are crucial parameters for the optimization of the optical coupling between the waveguide and the photodetector. Preliminary electro-optical measurements on the fabricated device show excellent system performances, and suggest its use for on-chip detection in lab-on-chip applications

Comparison of Two Low-Power Electronic Interfaces for Capacitive Mems Sensors

The paper discusses the importance and the issues of interfacing capacitive sensors. Two architectures applicable for interfacing capacitive sensors are presented. The first solution was designed to interface a capacitive humidity sensor designed and built for a humidity-dependent monolithic capacitor developed at Budapest University of Technology and Economics. The second case presents the possible read-out solutions for a SOI-MEMS accelerometer. Both of the architectures were built and tested in a discrete implementation to qualify the methods before the integrated realization. The paper presents a detailed comparison of the two methodsComment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

Organic and CMOS biosensors for detection of telomerase expression

Organic and CMOS biosensors for detection of telomerase expressio

Microelectromechanical Systems and Devices

The advances of microelectromechanical systems (MEMS) and devices have been instrumental in the demonstration of new devices and applications, and even in the creation of new fields of research and development: bioMEMS, actuators, microfluidic devices, RF and optical MEMS. Experience indicates a need for MEMS book covering these materials as well as the most important process steps in bulk micro-machining and modeling. We are very pleased to present this book that contains 18 chapters, written by the experts in the field of MEMS. These chapters are groups into four broad sections of BioMEMS Devices, MEMS characterization and micromachining, RF and Optical MEMS, and MEMS based Actuators. The book starts with the emerging field of bioMEMS, including MEMS coil for retinal prostheses, DNA extraction by micro/bio-fluidics devices and acoustic biosensors. MEMS characterization, micromachining, macromodels, RF and Optical MEMS switches are discussed in next sections. The book concludes with the emphasis on MEMS based actuators

Integration of biomolecular logic principles with electronic transducers on a chip

Boolean operations applied in biology and integrated with electronic transducers allow the development of a new class of digital biosensors for the detection of multiple input signals simultaneously and in real-time. With the help of Boolean functions (AND, OR, etc.), an electrical output signal will be directly delivered, representing a ”1” or “0” binary notation, corresponding to a “true” or “false” statement, respectively. Such digital biosensors have the future potential to create medical devices and systems for intelligent or smart diagnostics. The present thesis describes the realization of different enzyme-based biomolecular logic gates combined with electronic transducers for the possible application in medicine or food industry. In a first concept, a so called BioLogicChip is developed combining a “sense-act-treat” function integrated on one chip. The present system exemplarily mimics an “artificial pancreas” designed as a closed-loop drug-release system. A glucose sensor is constructed as enzyme-based AND logic gate, a temperature-depending hydrogel imitates the actuator function switching ON and OFF with its shrinking or swelling property, and an additional insulin sensor is developed to monitor and control the release of the drug (here: insulin) from the actuator. In this study, the results of the individual components such as the amperometric glucose sensor, the temperature-dependent hydrogel and the amperometric insulin sensor are presented, which are necessary to create such BioLogicChip. Moreover, a digital adrenaline biosensor is developed to proof the catheter position during adrenal vein sampling. The sensor consists of an oxygen electrode modified by a bi-enzyme system with the enzymes laccase and pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH) to realize substrate-recycling principle to detect low adrenaline concentrations (in the nanomolar concentration range). The sensor`s behavior at different pH values and at different temperatures is studied. Measurements in Ringer`s solution are performed. In addition, the sensitivity of the biosensor to other catecholamines such as noradrenaline, dopamine and dobutamine is investigated. Furthermore, the adrenaline biosensor is successfully examined in human blood plasma. Finally, “proof-of-principle” experiments have been performed by combining the adrenaline biosensor with Boolean operations to get a rapid qualitative statement of the presence or absence of adrenaline, thus validating the correct position of the catheter in a YES/NO form. This adrenaline biosensor is further miniaturized as a thin-film platinum adrenaline biosensor. Here, the bioelectrocatalytical measurement principle is applied by immobilization of the enzyme PQQ-GDH to detect adrenaline in the nanomolar concentration range, too. The measurement conditions such as pH value, glucose concentration in the analyte solution and temperature are optimized with regard to a high sensitivity and low detection limit. Also, this sensor has been verified towards other catecholamines (noradrenaline, dopamine and dobutamine). The platinum thin-film adrenaline biosensor is successfully applied in blood plasma for the detection of different spiked adrenaline concentrations. Furthermore, the developed adrenalin biosensor is able to detect the concentration difference between adrenal blood and peripheral blood. In contrast to the above-mentioned amperometric biosensor examples for biomolecular gates, also a field-effect-based platform is given attention in this thesis. The field-effect electrolyte-insulator-semiconductor (EIS) sensor consists of a layer structure of Al/p-Si/SiO2/Ta2O5 and is used to create an acetoin biosensor for the first time to control different fermentation processes. The sensor chip is modified by the enzyme acetoin reductase from B. clausii DSM 8716T for the catalytical reaction of (R)-acetoin to (R,R)-butanediol and meso-butanediol, respectively, in the presence of NADH. The linear measurement range, the optimal immobilization strategy (cross-linking by using glutaraldehyde and adsorptive binding) as well as the optimal working pH value and long-term stability are investigated by means of constant-capacitance measurements. Finally, the acetoin sensor was successfully applied in wine probes to detect different spiked acetoin concentrations. The sensor shows opportunities to be further developed as digital acetoin biosensor