In a complex field such as bio-molecular diagnostics it is significant to know the behaviour of molecules in each assay before they are available for real time testing on devices. With numerous deadly diseases around mankind, behaviour of bio-molecules associated with each of these diseases becomes a first priority for the molecular diagnostics. The purpose of this review is to highlight the behaviour of enzymatic molecules using vibrations in conjunction with Micro-Electro-Mechanical Systems (MEMS) structures, which can be used as a diagnostic tool in a rapidly growing field of medical discipline. The authors introduce piezo-electric actuators in the experimental set-up that is used to accelerate the enzymatic molecular reaction in minute quantities of the reactant. The discussion for the above method is well supported by a body of literature from both biomedical and mechanical engineering. These enzymes are made to interact with their respective anti-bodies, whose reaction can be detected using many methods among which fluorescence spectroscopy is of preference and further detected using specific MEMS structures whose changes are detected through optical means. The results described here are intended to give a methodological approach to the creation of device in the future in the medical field for the detection of bio-molecules. Experimental results include pictures taken during shaking with piezo-electric stacks; fluorescence spectrometer results confirming a reaction between the enzyme and its anti-body and the biochemical reaction-taking place on the surface of the cantilever beams. The intent of this review is to better understand the behaviour of an enzymatic molecule under the influence of vibrations. With insight into the principles underlying the operation of the vibration experiment, the results could help to evaluate the value of a device that could be used in the molecular diagnostics in a simpler, faster and less expensive way.
Medical applications often require the detection of specific peptides that are indicators of patients' specific medical conditions. The identification of such peptides is to some extent cumbersome and requires specialized equipment, specialized personnel and the results of the test may come as false negative or false positive. This paper presents the experimental results that directed towards the developments of a device and measurement system that is precisely detecting the reaction time between a peptide and a corresponding reaction match. A series of reaction signatures are identified and presented in the paper. Besides, SEM analysis of the peptides after the reaction confirms the existence of the signatures as the ones recorded by the authors. The proposed device could be miniaturized and a potential solution of the optical-based measurement system is presented and discussed. Serious challenges such as packaging or peptide manipulation are also discussed. The configuration of the sensing element is essential in producing the desired sensitivity of the device. A sensitivity analysis is carried out to prove that concentrations of fraction of ppm are detectable through this method.
This paper describes the design of a novel electrostatically actuated optical attenuator that uses the electrostatic actuation of a cylindrical waveguide. The optical MEMS device consists of an electrostatically actuated waveguide positioned in a V-groove and overhanging at the end to act as a cantilever. The optical fiber waveguide can be sputtered with a thin film of gold that acts as a good electrode. The electrostatic force between the electrodes actuates the input fiber under the application of a voltage and causes misalignment between the input and output fibers and thereby attenuates the amount of light transmitted to the output fiber. Electrostatic modeling of the system presented in this paper is simple and sufficiently accurate. The proposed analytical model takes into consideration the geometry of the cylindrical electrodes. The geometrical relationship of the cantilever beam to the range of the biasing voltage is also discussed. The paper presents the variation of deflection of the waveguide and the variation of power loss with respect to the applied voltages. The obtained results clearly demonstrate the efficient use of the proposed method and modeling approach.
A simple and novel way of attenuation is presented to investigate the feasibility of affecting the coupling cylindrical waveguides. Piezoelectric polymers such as PVDF (Poly Vinyledene Fluoride) are very attractive for many applications as they exhibit good piezoelectric and pyroelectric responses and low acoustic impedance. Moreover, their properties can be tailored according to the desired requirements. PVDF actuators are proposed because of their low cost and simple process of fabrication. In this paper, cylindrical waveguides are actuated by means of a piezoelectric actuator using PVDF (Poly Vinylidene Fluoride) material. The presented results include the design and analysis of a new cylindrical waveguide based attenuator with PVDF actuation. The presented results include the influence of PVDF (Poly Vinylidene Fluoride) actuation on the optical coupling efficiency. The paper also includes the parametric study on the variation of the geometry of PVDF film with respect to the coupling efficiency. The results also include the variation of deflection and power loss through cylindrical waveguides for various applied voltages. The paper demonstrates a simple and novel application of PVDF film for optical microsystem.
This paper explores a novel way of sensing the angular velocity rate change of MEMS based gyroscopes with optical methods. In the capacitive sensing mechanism, displacement due to angular rate induces differential capacitance, requiring many supporting filtering and amplification sub-systems and circuits in the device to eliminate the noise. One of the most important aspects of using optical sensing elements with MEMS technology is the elimination of capacitive sensing used in conventional MEMS based gyroscopes. Conventional bulky optical gyroscopes based on Sagnac effect, with very small drift-rate parameters, is difficult to be implemented with MEMS technology due to the requirement of large area enclosed by the laser ring and fiber optic paths. Light interference effect of optical properties can permit the phase shift measurement of the light wavelength. In this paper, the combination of optical and mechanical systems is studied for estimating angular acceleration rate by Coriolis Effect.
This article describes and provides valuable information for companies and universities with strategies to start fabricating MEMS for RF/Microwave and millimeter wave applications. The present work shows the infrastructure developed for RF/Microwave and millimeter wave MEMS platforms, which helps the identification, evaluation and selection of design tools and fabrication foundries taking into account packaging and testing. The selected and implemented simple infrastructure models, based on surface and bulk micromachining, yield inexpensive and innovative approaches for distributed choices of MEMS operating tools. With different educational or industrial institution needs, these models may be modified for specific resource changes using a careful analyzed iteration process. The inputs of the project are evaluation selection criteria and information sources such as financial, technical, availability, accessibility, simplicity, versatility and practical considerations. The outputs of the project are the selection of different MEMS design tools or software (solid modeling, electrostatic/electromagnetic and others, compatible with existing standard RF/Microwave design tools) and different MEMS manufacturing foundries. Typical RF/Microwave and millimeter wave MEMS solutions are introduced on the platform during the evaluation and development phases of the project for the validation of realistic results and operational decision making choices. The encountered challenges during the investigation and the development steps are identified and the dynamic behavior of the infrastructure is emphasized. The inputs (resources) and the outputs (demonstrated solutions) are presented in tables and flow chart mode diagrams.