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Book ChapterDOI

Design and Analysis of MEMS based Cantilever Sensor for the Detection of Cardiac Markers in Acute Myocardial Infarction

01 Jan 2009-pp 810-812
TL;DR: In this paper, a geometric variation of the cantilever was proposed to improve the sensitivity of the microcantilever and to eliminate the disadvantages while improving the sensitivity simultaneously.
Abstract: Piezo-resistive actuation of a microcantilever induced by biomolecular binding such as DNA hybridization and antibody-antigen binding is an important principle useful in biosensing applications. As the magnitude of the forces exerted is small, increasing the sensitivity of the microcantilever becomes critical. In this paper, we are considering to achieve this by geometric variation of the cantilever. The sensitivity of the cantilever was improved so that the device can sense the presence of antigen even if the magnitude of surfacestresses over the microcantilever was very small. We consider a ‘T-shaped’ cantilever that eliminates the disadvantages while improving the sensitivity simultaneously. Simulations for validation have been performed using Intellisuite software (a MEMS design and simulation package). The simulations reveal that the T-shaped microcantilever is almost as sensitive as a thin cantilever and has relatively very low buckling effect. Simulations also reveal that with an increase in thickness of the cantilever, there is a proportional decrease in the sensitivity.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a hybrid microelectromechanical system (MEMS) vortex flowmeter was used to detect frequency of vortices development in a 40mm-diameter tubular pipe.
Abstract: This paper presents construction and performance of a novel hybrid microelectromechanical system (MEMS) vortex flowmeter. A miniature cantilever MEMS displacement sensor was used to detect frequency of vortices development. 3-mm-long silicon cantilever, protruding directly out of a trailing edge of a trapezoidal glass-epoxy composite bluff body was put into oscillatory motion by vortices shed alternately from side surfaces of the obstacle. Verified linear measurement range of the device extended from 5 to 22 m/s; however, it could be broadened in absence of external 50-Hz mains electrical interfering signal which required bandpass frequency-domain digital sensor signal processing. The MEMS vortex sensor proved its effectiveness in detection of semilaminar airflow velocity distribution in a 40-mm-diameter tubular pipe.

11 citations


Cites methods from "Design and Analysis of MEMS based C..."

  • ...Deflection of a MEMS cantilever, induced by a tiny force of molecular binding between antibody and antigen, is a principle used in MEMS biosensors [4]....

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Journal ArticleDOI
TL;DR: In this article, an E-shaped model for micro cantilevered biosensor is designed using COMSOL multiphysics specifically for detection of Malaria protozoan parasites.
Abstract: In this paper, the presented work aims to provide a designed model based on Finite element method for detection of Malaria protozoan parasites. Micro-cantilevers are next generation highly efficient biosensors for detection and prevention of any disease. Here, an E-shaped model for micro cantilevered biosensor is designed using COMSOL Multiphysics specifically for detection of Malaria. Microcantilever materials viz Au, Cu, Si and Pt are used for sensing Malaria protozoan with proper optimization of device structure. The studies were carried out for stress developed and displacement occurred due to force applied through these protozoan biomolecules and varying beam length. Further, the designed structure was analyzed for different beam materials available for biosensor and it was found that Au is best suitable material for detection of malaria protozoan parasites since it has best sensitivity profile among presented materials. The results were also verified through analytical approach and it was found that both results obtained through simulation and analytical methods do closely agree with each other.

7 citations


Cites background or methods from "Design and Analysis of MEMS based C..."

  • ...Several research groups have also shown the possibility of using Micro-Cantilevers for the diagnosis of prostate cancer [2,5,6], myocardial infarction [7], and glucose monitoring [8]....

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  • ...Piezoresistive, piezoelectric, thermal expansion or capacitive effects are the various method for detection [4,7]....

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01 Jan 2013
TL;DR: Zhang et al. as mentioned in this paper investigated the properties of symmetric hammerhead microcantilevers vibrating laterally in viscous liquid media, and the results showed that, with a fixed head area, the resulting resonance frequency and mass sensitivity will first increase and then decrease, because the total kinetic energy will first decrease and then increase.
Abstract: THEORETICAL ANALYSIS OF LATERALLY VIBRATING HAMMERHEAD MICROCANTILEVER SENSORS IN A VISCOUS LIQUID Jinjin Zhang, B.E., M.E. Marquette University, 2013 Dynamically driven prismatic microcantilevers excited in the in-plane flexural mode have been investigated and used in liquid-phase sensing applications. However, the performance is restricted due to their limited surface sensing area and higher stiffness in shorter and wider prismatic microcantilevers. To increase the surface sensing area, and further improve sensing characteristics, it has been proposed to investigate symmetric hammerhead microcantilevers vibrating laterally in viscous liquid media. In this work, a theoretical model is proposed and the characteristics of the microcantilevers with symmetric shaped hammerheads (isosceles trapezoid, semi-circle, uniform rectangle and composite rectangle) are investigated. In the analysis, the stem of the structure is modeled as an Euler-Bernoulli beam while the head is modeled as a rigid body. Since the arbitrary, symmetric head has a varying width, 2b2(x), in the length direction, a new semi-analytical expression for the hydrodynamic function in terms of the Reynolds number, Re(x), and aspect ratio, h/[2b2(x)] is obtained and the resonance frequency, quality factor and mass sensitivity are investigated as a function of both the hammerhead microcantilever geometry and liquid media properties. For the investigated geometries, the results show that, for a hammerhead microcantilever with a fixed head area, as the mass center of the head moves towards the support end of the stem, the resulting resonance frequency and mass sensitivity will first increase and then decrease, because the total kinetic energy will first decrease and then increase. The quality factor will keep increasing, due to a more rapid decrease in the energy dissipation. It is also found that, hammerhead microcantilevers with wider heads tend to have higher quality factors. For instance, the highest quality factors are found for the hammerhead microcantilevers with the isosceles trapezoid-shaped, uniform rectangular and composite rectangular head as 140, 72 and 129, respectively, due to the possible shift of the mass center of the head towards the support end of the stem. Such trends can be used to optimize sensor device geometry and frequency stability. By further increasing the surface sensing area (additional mass), the resonance frequency and the mass sensitivity will significantly decrease. Such trade-offs must be considered when designing the geometry of the hammerhead microcantilever devices. For appropriately designed hammerhead microcantilevers, the improvement in the sensing area and quality factor are expected to yield much lower limits of detection in (bio) chemical sensing applications.

4 citations


Cites background from "Design and Analysis of MEMS based C..."

  • ...There have been several attempts to theoretically model a transversely vibrating rectangular hammerhead microcantilever in a vacuum [22, 35-36, 60, 69, 104-109]....

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  • ...These applications range from detecting toxic gases [6-18], such as mercury vapor [6-9], volatile organic compounds [10,11], to detection of specific biological compounds applications such as the detection of bacillus anthracis spores[19], specific antigens [20], myocardial infarction [21, 22] and glucose monitoring [23]....

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01 Jan 2010
TL;DR: In this paper, a hybrid microelectromechanical system (MEMS) vortex sensor was used to detect frequency of vortices development in a 40mm-diameter tubular pipe.
Abstract: —This paper presents construction and performanceof a novel hybrid microelectromechanical system (MEMS) vortexflowmeter. A miniature cantilever MEMS displacement sensorwas used to detect frequency of vortices development. 3-mm-longsilicon cantilever, protruding directly out of a trailing edge of atrapezoidal glass-epoxy composite bluff body was put into oscilla-tory motion by vortices shed alternately from side surfaces of theobstacle. Verified linear measurement range of the device extendedfrom 5 to 22 m/s; however, it could be broadened in absence ofexternal 50-Hz mains electrical interfering signal which requiredbandpass frequency-domain digital sensor signal processing. TheMEMS vortex sensor proved its effectiveness in detection of semil-aminar airflow velocity distribution in a 40-mm-diameter tubularpipe. [2010-0164] Index Terms —Bluff body, flow sensor, frequency, laminar, tur-bulent, vortex. I. I NTRODUCTION M EASURING and monitoring flow rates in fluids iscrucial in many laboratory research routines as wellas in industrial practice. Although several successful methodshave been introduced so far [1], vortex flowmeters relyingon Karman vortex street phenomenon have been extensivelydeveloped in recent times due to current progress in micro-electronic sensor and integrated circuit technology. Vortex flowmeasurement relies on repetitive alternate generation of vor-tices behind the nonstreamlined obstacle (the bluff body) putinto the turbulent path of fluid. Vortices are generated at theseparation surface where a jump change of fluid velocity takesplace, leading to the fluid boundary layer detachment. It hasbeen theoretically shown that in ideal conditions, the frequencyof vortex shedding is proportional to the fluid velocity overthe wide range of Reynolds number values. Main advantagesof the vortex anemometry include no moving parts in thedevice construction, elevated accuracy, low pressure drop, fastresponse time, direct measurement of flow velocity, as wellas weak interferences brought in by temperature, density, andviscosity variations. Recent developments in the vortex flowmonitoring involve application of tandem bluff body vortexshedders [2] and advanced techniques for vortices sensing,relying on microelectromechanical transducers [3].
References
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Journal Article
TL;DR: Results of this study show that cTnI is an effective marker for the retrospective diagnosis of AMI, and consideration should be given to its use in place of CK-MB.
Abstract: Serial plasma concentrations of myoglobin, creatine kinase MB (CK-MB) isoenzyme, and cardiac troponin I (cTnI) were measured in 25 patients with a confirmed diagnosis of acute myocardial infarction (AMI), and 74 patients who were suspected of AMI but were subsequently ruled out for this diagnosis. The cutoff concentration for the cTnI assay was optimally determined to be 2.5 ng/mL. Of the three markers, myoglobin had the highest clinical sensitivity (50 percent) when blood was collected between 0 to 6 h after the onset of chest pain. Assays for all serum markers used had high clinical sensitivity (> 93 percent) 6 to 24 h after onset. The CK-MB remained highly sensitive for 48 h, while cTnI was sensitive for up to 72 h. Between 72 and 150 h, cTnI had a clinical sensitivity of 70 percent as compared to 21 percent and 18 percent for myoglobin and CK-MB, respectively. The clinical specificity of cTnI for non-AMI patients was equivalent to CK-MB and significantly higher than for myoglobin. The clinical efficiency of cTnI for all samples was better than either CK-MB or myoglobin, owing mainly to the wider diagnostic window. The specificity of cTnI for 59 patients with chronic renal failure, skeletal muscle trauma and disease was better than all of these markers including cardiac troponin T (cTnT). Results of this study show that cTnI is an effective marker for the retrospective diagnosis of AMI, and consideration should be given to its use in place of CK-MB.

108 citations

Journal ArticleDOI
TL;DR: In this article, an analytical modeling of a piezoelectric multi-layer cantilever used as a micro-electro-mechanical-system (MEMS) chemical sensor is presented.
Abstract: This paper presents an analytical modeling of a piezoelectric multi-layer cantilever used as a micro-electro-mechanical-system (MEMS) chemical sensor. Selectively coated microcantilevers have been developed for highly sensitive chemical sensor applications. The proposed piezoelectric chemical sensor consists of an array of multi-layer piezoelectric cantilevers with voltage output in the millivolt range that replaces the conventional laser-based position-sensitive detection systems. The sensing principle is based upon changes in the deflection induced by environmental factors in the medium where a microcantilever is immersed. Bending of the cantilever induces the potential difference on opposite sides of the piezoelectric layer providing an information signal about the detected chemicals. To obtain an application specific optimum design parameters and predict the cantilever performance ahead of actual fabrication, finite element analysis (FEM) simulations using CoventorWare (a MEMS design and simulation program) were performed. Analytical models of multi-layer cantilevers as well as simulation concept are described. Both mechanical and piezoelectric simulation results are carried out. The cantilever structures are analyzed and fabrication process steps are proposed.

50 citations

Journal ArticleDOI
TL;DR: The performance of the flow-through amperometric sensor based on semi-permeable dialysis tubing implemented in silicon is presented in this paper, where the sensor is designed in the form to be an integral component of a lab-on-a-chip systems and it has been successfully incorporated into an integrated microdialysis system.
Abstract: In this paper, the performance of the flow-through amperometric sensor based on semi-permeable dialysis tubing implemented in silicon is presented. The sensor is designed in the form to be an integral component of a lab-on-a-chip systems and it has been successfully incorporated into an integrated microdialysis system. Results concerning glucose sensors based on a flow-through sensor implemented in silicon operating as part of the integrated microdialysis system are presented. Moreover, comparison of the performances of the glucose sensor implemented in Perspex in the earlier work and the sensor implemented in silicon are discussed.

31 citations

Journal ArticleDOI
TL;DR: Myoglobin and hFABP provide little clinical value when measured on admission in patients presenting with chest pain, and both performed poorly in those patients who were cTnI negative on admission.
Abstract: Introduction: Patients presenting with chest pain do so at varying times following its onset. In addition, their histories can be unreliable, making the interpretation of time-dependent biochemical...

27 citations