Modeling and Characterization of MEMS Thermal Biosensors

2004 ◽  
Author(s):  
Li Wang ◽  
David M. Sipe ◽  
Qiao Lin
Keyword(s):  
Flow Rate ◽  
Flow Injection ◽  
Output Voltage ◽  
Enzymatic Reaction ◽  
Injection Mode ◽  
Optimal Flow ◽  
Flow Through ◽  
Heat Transfer Effects ◽  
Substrate Concentrations

In this paper, a closed-form analytical model, which considers the coupling of heat transfer effects and enzymatic reaction kinetics, is developed to describe the behavior of MEMS thermal biosensors for substrate detection either in flow-injection mode or flow-through mode. Simulation results show that the maximum thermopile output voltage is saturated at higher substrate concentrations for flow-injection mode. For flow-through mode, there exists an optimal flow rate which corresponds to the maximum thermopile output voltage. The optimal flow rate is inversely proportional to the concentration of the substrate involved in the reaction. A prototype MEMS thermal biosensor is fabricated and tested. The validity of the models is verified by comparison to the experimental results.

A MEMS Thermal Biosensor for Metabolite Measurements

2005 ◽  
Author(s):  
Li Wang ◽  
Qiao Lin
Keyword(s):  
Flow Rate ◽  
Flow Injection ◽  
Temperature Sensor ◽  
Metabolite Concentration ◽  
Microfluidic Channels ◽  
Enzymatic Reactions ◽  
Thin Membranes ◽  
Flow Through ◽  
On Chip ◽  
Heat Released

We present a MEMS differential thermal biosensor integrated with microfluidics for metabolite concentration measurements either in flow-injection or flow-through modes. The biosensor consists of two identical freestanding polymer thin membranes, resistive on-chip heaters, and a metal thermoelectric differential temperature sensor between the two membranes. Integrated with polymer microfluidic channels and chambers, the biosensor allows efficient handling and measurements of small volumes (~1 μl) of liquid samples. Calibrated with on-chip resistive heaters, the biosensor shows a sensitivity of 1.2 V/W and time constant of 0.58 s. Enzyme-functionalized beads are packed in the chambers and interacted with metabolite solutions. The heat released from the enzymatic reactions is detected by the temperature sensor and used to measure the metabolite concentration. The biosensor demonstrated a glucose concentration resolution of 0.12 mM for flow-injection mode, and 0.48 mM for flow-through mode with a flow rate of 0.5 ml/h. It is found that there exists an optimal flow rate that corresponds to the maximum thermopile output voltage when the biosensor works in the flow-through mode.

Computer Simulation of Amperometric Biosensor Response to Mixtures of Compounds

2002 ◽  
Vol 7 (2) ◽  
pp. 3-14 ◽  
Author(s):  
R. Baronas ◽  
J. Christensen ◽  
F. Ivanauskas ◽  
J. Kulys
Keyword(s):  
Computer Simulation ◽  
Enzymatic Reaction ◽  
Diffusion Equations ◽  
Response Data ◽  
Finite Difference Technique ◽  
Stationary Diffusion ◽  
Biosensor Array ◽  
Menten Kinetic ◽  
Biosensor Response

A mathematical model of amperometric biosensors has been developed. The model bases on non-stationary diffusion equations containing a non-linear term related to Michaelis-Menten kinetic of the enzymatic reaction. The model describes the biosensor response to mixtures of multiple compounds in two regimes of analysis: batch and flow injection. Using computer simulation, large amount of biosensor response data were synthesised for calibration of a biosensor array to be used for characterization of wastewater. The computer simulation was carried out using the finite difference technique.

Stabilization of the Speed of the Hydraulic Motor Through Throttle Compensation for Volume Losses

2020 ◽  
Vol 26 (3) ◽  
pp. 126-130
Author(s):  
Krasimir Kalev
Keyword(s):  
Flow Rate ◽  
Hydraulic Drive ◽  
Pressure Change ◽  
Operating Conditions ◽  
Drive System ◽  
Inlet Pressure ◽  
Schematic Diagram ◽  
Hydraulic Characteristics ◽  
Hydraulic Motor ◽  
Flow Through

AbstractA schematic diagram of a hydraulic drive system is provided to stabilize the speed of the working body by compensating for volumetric losses in the hydraulic motor. The diagram shows the inclusion of an originally developed self-adjusting choke whose flow rate in the inlet pressure change range tends to reverse - with increasing pressure the flow through it decreases. Dependent on the hydraulic characteristics of the hydraulic motor and the specific operating conditions.

Study of fluid flow through a channel deformed by piezoelement

2018 ◽  
Vol 13 (3) ◽  
pp. 1-10 ◽  
Author(s):  
I.Sh. Nasibullayev ◽  
E.Sh Nasibullaeva ◽  
O.V. Darintsev
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Boundary Conditions ◽  
Flow Rate ◽  
Contact Surface ◽  
Piezoelectric Element ◽  
Neumann Boundary ◽  
Differential Pressure ◽  
Physical Parameters ◽  
Flow Through

The flow of a liquid through a tube deformed by a piezoelectric cell under a harmonic law is studied in this paper. Linear deformations are compared for the Dirichlet and Neumann boundary conditions on the contact surface of the tube and piezoelectric element. The flow of fluid through a deformed channel for two flow regimes is investigated: in a tube with one closed end due to deformation of the tube; for a tube with two open ends due to deformation of the tube and the differential pressure applied to the channel. The flow rate of the liquid is calculated as a function of the frequency of the deformations, the pressure drop and the physical parameters of the liquid.

scholarly journals Characterization of Two NMN Deamidase Mutants as Possible Probes for an NMN Biosensor

2021 ◽  
Vol 22 (12) ◽  
pp. 6334
Author(s):  
Alessandra Camarca ◽  
Gabriele Minazzato ◽  
Angela Pennacchio ◽  
Alessandro Capo ◽  
Adolfo Amici ◽  
...  
Keyword(s):  
Enzymatic Reaction ◽  
Promising Candidate ◽  
Beneficial Effects ◽  
Steady State Fluorescence ◽  
Nicotinamide Mononucleotide ◽  
Recognition Elements ◽  
Steady State Fluorescence Spectroscopy ◽  
Similar Affinity ◽  
Micromolar Range

Nicotinamide mononucleotide (NMN) is a key intermediate in the nicotinamide adenine dinucleotide (NAD+) biosynthesis. Its supplementation has demonstrated beneficial effects on several diseases. The aim of this study was to characterize NMN deamidase (PncC) inactive mutants to use as possible molecular recognition elements (MREs) for an NMN-specific biosensor. Thermal stability assays and steady-state fluorescence spectroscopy measurements were used to study the binding of NMN and related metabolites (NaMN, Na, Nam, NR, NAD, NADP, and NaAD) to the PncC mutated variants. In particular, the S29A PncC and K61Q PncC variant forms were selected since they still preserve the ability to bind NMN in the micromolar range, but they are not able to catalyze the enzymatic reaction. While S29A PncC shows a similar affinity also for NaMN (the product of the PncC catalyzed reaction), K61Q PncC does not interact significantly with it. Thus, PncC K61Q mutant seems to be a promising candidate to use as specific probe for an NMN biosensor.

scholarly journals Hot Box Investigations of a Ventilated Bioclimatic Wall for NZEB Building Façade

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1327
Author(s):  
Dwinanto Sukamto ◽  
Monica Siroux ◽  
Francois Gloriant
Keyword(s):  
Energy Efficiency ◽  
Flow Rate ◽  
Experimental Setup ◽  
Air Flow Rate ◽  
Space Thickness ◽  
Zero Energy ◽  
Interior Space ◽  
Air Space ◽  
Thermal Metrology

The building sector is the largest consumer of energy, but there are still major scientific challenges in this field. The façade, being the interface between the exterior and interior space, plays a key role in the energy efficiency of a building. In this context, this paper focuses on a ventilated bioclimatic wall for nearly zero-energy buildings (NZEB). The aim of this study is to investigate an experimental setup based on a hot box for the characterization of the thermal performances of the ventilated wall. A specific ventilated prototype and an original thermal metrology are developed. This paper presents the ventilated prototype, the experimental setup, and the experimental results on the thermal performances of the ventilated wall. The influence of the air space thickness and the air flow rate on the thermal performances of the ventilated wall is studied.

scholarly journals Tyrosinase Nanoparticles: Understanding the Melanogenesis Pathway by Isolating the Products of Tyrosinase Enzymatic Reaction

2021 ◽  
Vol 22 (2) ◽  
pp. 734
Author(s):  
Paul K. Varghese ◽  
Mones Abu-Asab ◽  
Emilios K. Dimitriadis ◽  
Monika B. Dolinska ◽  
George P. Morcos ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Large Scale ◽  
Magnetic Beads ◽  
Enzymatic Reaction ◽  
Oculocutaneous Albinism ◽  
Transmission Electron ◽  
Hill Kinetics ◽  
Rate Limiting ◽  
Human Tyrosinase

Human Tyrosinase (Tyr) is the rate-limiting enzyme of the melanogenesis pathway. Tyr catalyzes the oxidation of the substrate L-DOPA into dopachrome and melanin. Currently, the characterization of dopachrome-related products is difficult due to the absence of a simple way to partition dopachrome from protein fraction. Here, we immobilize catalytically pure recombinant human Tyr domain (residues 19–469) containing 6xHis tag to Ni-loaded magnetic beads (MB). Transmission electron microscopy revealed Tyr-MB were within limits of 168.2 ± 24.4 nm while the dark-brown melanin images showed single and polymerized melanin with a diameter of 121.4 ± 18.1 nm. Using Hill kinetics, we show that Tyr-MB has a catalytic activity similar to that of intact Tyr. The diphenol oxidase reactions of L-DOPA show an increase of dopachrome formation with the number of MB and with temperature. At 50 °C, Tyr-MB shows some residual catalytic activity suggesting that the immobilized Tyr has increased protein stability. In contrast, under 37 °C, the dopachrome product, which is isolated from Tyr-MB particles, shows that dopachrome has an orange-brown color that is different from the color of the mixture of L-DOPA, Tyr, and dopachrome. In the future, Tyr-MB could be used for large-scale productions of dopachrome and melanin-related products and finding a treatment for oculocutaneous albinism-inherited diseases.

scholarly journals A combined flow injection/reversed phase chromatography – high resolution mass spectrometry workflow for accurate absolute lipid quantification with 13C- internal standards

The Analyst ◽  
2021 ◽  
Author(s):  
Harald Schoeny ◽  
Evelyn Rampler ◽  
Yasin El Abiead ◽  
Felina Hildebrand ◽  
Olivia Zach ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Flow Injection ◽  
High Resolution Mass Spectrometry ◽  
Reversed Phase ◽  
Internal Standards ◽  
Lipid Quantification ◽  
High Resolution Mass ◽  
Resolution Mass

We propose a fully automated novel workflow for lipidomics based on flow injection- followed by liquid chromatography high resolution mass spectrometry (FI/LC-HRMS). The workflow combined in-depth characterization of the lipidome...

scholarly journals Spectral Decomposition of the Flow and Characterization of the Sound Signals through Stenoses with Different Levels of Severity

2021 ◽  
Vol 8 (3) ◽  
pp. 41
Author(s):  
Fardin Khalili ◽  
Peshala T. Gamage ◽  
Amirtahà Taebi ◽  
Mark E. Johnson ◽  
Randal B. Roberts ◽  
...  
Keyword(s):  
Pressure Fluctuations ◽  
High Energy ◽  
Sound Sources ◽  
Severity Level ◽  
Non Invasive ◽  
Flow Through ◽  
Severity Of The Disease ◽  
Proper Orthogonal ◽  
Different Levels

Treatments of atherosclerosis depend on the severity of the disease at the diagnosis time. Non-invasive diagnosis techniques, capable of detecting stenosis at early stages, are essential to reduce associated costs and mortality rates. We used computational fluid dynamics and acoustics analysis to extensively investigate the sound sources arising from high-turbulent fluctuating flow through stenosis. The frequency spectral analysis and proper orthogonal decomposition unveiled the frequency contents of the fluctuations for different severities and decomposed the flow into several frequency bandwidths. Results showed that high-intensity turbulent pressure fluctuations appeared inside the stenosis for severities above 70%, concentrated at plaque surface, and immediately in the post-stenotic region. Analysis of these fluctuations with the progression of the stenosis indicated that (a) there was a distinct break frequency for each severity level, ranging from 40 to 230 Hz, (b) acoustic spatial-frequency maps demonstrated the variation of the frequency content with respect to the distance from the stenosis, and (c) high-energy, high-frequency fluctuations existed inside the stenosis only for severe cases. This information can be essential for predicting the severity level of progressive stenosis, comprehending the nature of the sound sources, and determining the location of the stenosis with respect to the point of measurements.

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