Assessment and Improvement of the Thermal Performance of a Polycarbonate Micro Continuous Flow Polymerase Chain Reactor (CFPCR)

2007 ◽  
Author(s):  
Pin-Chuan Chen ◽  
Michael W. Mitchell ◽  
Dimitris E. Nikitopoulos ◽  
Steven A. Soper ◽  
Michael C. Murphy
Keyword(s):  
Thin Film ◽  
Liquid Crystal ◽  
Temperature Distribution ◽  
Thermal Management ◽  
Continuous Flow ◽  
Infrared Camera ◽  
Amplification Efficiency ◽  
Temperature Zone ◽  
Temperature Distributions ◽  
Polymerase Chain

BioMEMS are compact devices that use microfabrication to miniaturize benchtop instrumentation. Due to the requirement for uniform temperature distributions over restricted areas, thermal isolation, and faster heating and cooling rates in a limited space, thermal management is a key to ensuring successful performance of BioMEMS devices. The continuous flow polymerase chain reactor (CFPCR) is a compact BioMEMS device that is used to amplify target DNA fragments using repeated thermal cycling. The temperature distribution on the backside of a micro CFPCR was measured using thermochromic liquid crystals and an infrared camera. In the liquid crystal experiment, the performance of a 5 mm thick polycarbonate micro CFPCR with thin film heaters attached directly to the bottom polycarbonate surface over each temperature zone was studied. Natural convection was used as a cooling mechanism. The temperature distribution in the renaturation zone was dependent on the positions of the feedback thermocouples in each zone. Three different thermocouple configurations were assessed and the liquid crystal images showed that a best case 3.86°C temperature difference across the zone, leading to a 20% amplification efficiency compared to a commercial thermal cycler [5]. The device was modified to improve the temperature distribution: a thinner substrate, 2 mm, reduced the thermal capacitance; grooves were micro-milled in the backside to isolate each temperature zone; and three separate copper heating stages, combining the thin film heaters with copper plates, applied uniform temperatures to each zone [10]. Infrared camera images showed that the temperature distributions were distinct and uniform with a ±0.3 °C variations in each temperature zone, improving amplification efficiency to 72%. Good thermal management for PCR amplification can’t only increase its reliability and yield efficiency, but also accelerate the entire analytical process.

A Thermal System for a High Throughput Continuous Flow Polymerase Chain Reaction Device (CFPCR)

2008 ◽  
Author(s):  
P.-C. Chen ◽  
D. S. Park ◽  
B. H. You ◽  
N. Kim ◽  
T. Park ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
High Throughput ◽  
Continuous Flow ◽  
Thermal Environment ◽  
Infrared Camera ◽  
Thermal System ◽  
Uniform Temperature ◽  
Chain Reaction ◽  
Copper Strip ◽  
Polymerase Chain

A thermal system used to evaluate a high throughput 96 continuous flow polymerase chain reactor (CFPCR) array was designed, fabricated, and tested. Each polymerase chain reactor (PCR) in the array required three different temperature zones to realize denaturaiton at 90°C–94°C, renaturation at 50°C–70°C, and extension at 72°C; a total of 288 temperature zones were required for the 96 CFPCR array. In an initial configuration, 18 copper strips were used to define the 288 temperature zones. Each copper strip was controlled by a PID feedback control loop. Numerical simulations were used to understand the thermal crosstalk phenomena between the micromilled copper strips, which were tightly packed since the high throughput micro-titer plate format restricted each CFPCR to a square 8 mm on a side. The lowest achievable temperature in each renaturation zone in this complicated thermal environment was also identified. Thermal crosstalk limited the minimum renaturation temperature to 61.1°C. An infrared camera was used to investigate the temperature uniformity over a 0.25 mm thick polycarbonate sheet mounted on the thermal system. The temperature distribution was not uniform due to poor contact between the copper strips and device, warm air accumulated between the packed copper strips, and greater heat transfer around the boundaries of the device. More work is required to overcome these limitations and achieve a more uniform temperature distribution for a multi well CFPCR.

scholarly journals An Innovative Rapid Thermal Cycling Device for Polymerase Chain Reaction

2008 ◽  
Vol 2 (2) ◽  
Author(s):  
Shadi Mahjoob ◽  
Kambiz Vafai
Keyword(s):  
Heat Transfer ◽  
Polymerase Chain Reaction ◽  
Temperature Distribution ◽  
Thermal Cycling ◽  
Thermal Management ◽  
Uniform Temperature ◽  
Chain Reaction ◽  
Temperature Ramp ◽  
Polymerase Chain ◽  
Thermal Cycler

Polymerase chain reaction (PCR) is the most commonly used molecular biology technique to amplify nucleic acid (DNA and RNA) in vitro. This technique is highly temperature sensitive and thermal management has an important role in PCR operation in reaching the required temperature set points at each step of the process (denaturing, annealing and elongation). In this work, an innovative microfluidic PCR thermal cycling device is designed to increase the heating∕cooling thermal cycling speed while maintaining a uniform temperature distribution throughout the substrate containing the aqueous nucleic acid sample. The device design is incorporating the jet impingement and micro-channel thermal management technologies utilizing a properly arranged configuration filled with a porous medium. Porous Inserts are attractive choices in heat transfer augmentation. They provide a very large surface area for a given volume which is a key parameter in heat transfer processes. Various effective parameters that are relevant in optimizing this flexible thermal cycler are investigated such as thermal cycler configuration, thickness of inlet and exit fluid channels, fluid flow rate and velocity, the porous matrix material and properties, and utilization of thermal grease. An optimized case is established based on the effects of the cited parameters on the temperature ramp, temperature distribution and the required power for circulating the fluid in the thermal cycler. The results indicate that the heating∕cooling temperature ramp (temperature change per heating∕cooling cycling time) of the proposed device is considerably higher (150.82◻C∕s) than those in literature. In addition, the proposed PCR offers a very uniform temperature in the substrate while utilizing a low power.

Experimental Investigation of Hard Turning Mechanisms by PCBN Tooling Embedded Micro Thin Film Thermocouples

2012 ◽  
Author(s):  
Linwen Li ◽  
Bin Li ◽  
Xiaochun Li ◽  
Kornel F. Ehmann
Keyword(s):  
Thin Film ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Chip Formation ◽  
Hard Turning ◽  
Cutting Temperature ◽  
Temperature Distributions ◽  
Field Distributions ◽  
Thin Film Thermocouples ◽  
Cutting Zone

Temperature-distribution measurements in cutting tools during the machining process are extremely difficult and remain an unresolved problem. In this paper, cutting temperature distributions are measured by thin film thermocouples (TFTCs) embedded into Polycrystalline Cubic Boron Nitride (PCBN) cutting inserts in the immediate vicinity of the tool-chip interface. Using these measurements, steady and dynamic phenomena during hard turning as well as the chip morphology and formation process were analyzed based on the cutting temperature distributions in the insert. The relationship between the cutting temperature-field distributions in the PCBN insert and the segmented chip formation is analyzed using temperature-distribution mapping. It is shown that the temperature-distribution in the cutting zone depends on the shearing band distribution in the chip and the thermal transfer rate from the heat generation zone to the cutting tool. Furthermore, it became evident that the material flow stress and the shearing bands greatly affect not only the chip formation morphology but also the cutting temperature field distributions in the cutting zone of the cutting insert.

Limiting Performance of High Throughput Continuous Flow Micro-PCR

2004 ◽  
Author(s):  
Pin-Chuan Chen ◽  
Masahiko Hashimoto ◽  
Michael W. Mitchell ◽  
Dimitris E. Nikitopoulos ◽  
Steven A. Soper ◽  
...  
Keyword(s):  
Continuous Flow ◽  
High Flow ◽  
Linear Velocity ◽  
Amplification Efficiency ◽  
Temperature Zone ◽  
Electrokinetic Flow ◽  
Element Analysis ◽  
Steady State Temperature ◽  
Rapid Amplification ◽  
Flow Velocities

Continuous flow polymerase chain reaction (CFPCR) devices are compact reactors suitable for microfabrication and the rapid amplification of target DNAs. For a given reactor design, the amplification time can be reduced simply by increasing the flow velocity through the isothermal zones of the device; for flow velocities near the design value, the PCR cocktail reaches thermal equilibrium at each zone quickly, so that near ideal temperature profiles can be obtained. However, at high flow velocities there are penalties of an increased pressure drop and a reduced residence time in each temperature zone for the DNA/reagent mixture, potentially affecting amplification efficiency. This study was carried out to evaluate the thermal and biochemical effects of high flow velocities in a spiral, 20 cycle CFPCR device. Finite element analysis (FEA) was used to determine the steady-state temperature distribution along the micro-channel and the temperature of the DNA/reagent mixture in each temperature zone as a function of linear velocity. The critical transition was between the denaturation (95°C) and renaturation (55°C-68°C) zones; above 6 mm/s the fluid in a passively-cooled channel could not be reduced to the desired temperature and the duration of the temperature transition between zones increased with increased velocity. The amplification performance of the CFPCR as a function of linear velocity was assessed using 500 and 997 base pair (bp) fragments from λ-DNA. Amplifications at velocities ranging from 1 mm/s to 20 mm/s were investigated. Alternative design of PCR was investigated. Shuttle PCR has a single straight channel and a DNA plug, driven by electrokinetic flow, will move forward and backward in the microchannel to achieve the repetitive thermal cycles. Thermal performance, independent insulated temperature blocks, and molecular and thermal diffusion were evaluated.

Neuro-Genetic Optimization of Temperature Control for a Continuous Flow Polymerase Chain Reaction Microdevice

2006 ◽  
Vol 129 (4) ◽  
pp. 540-547 ◽  
Author(s):  
Hing Wah Lee ◽  
Parthiban Arunasalam ◽  
William P. Laratta ◽  
Kankanhalli N. Seetharamu ◽  
Ishak A. Azid
Keyword(s):  
Polymerase Chain Reaction ◽  
Temperature Distribution ◽  
Reaction Zone ◽  
Temperature Control ◽  
Continuous Flow ◽  
Microfluidic Channels ◽  
Genetic Optimization ◽  
Chain Reaction ◽  
Fea Simulation ◽  
Polymerase Chain

In this study, a hybridized neuro-genetic optimization methodology realized by embedding finite element analysis (FEA) trained artificial neural networks (ANN) into genetic algorithms (GA), is used to optimize temperature control in a ceramic based continuous flow polymerase chain reaction (CPCR) device. The CPCR device requires three thermally isolated reaction zones of 94°C, 65°C, and 72°C for the denaturing, annealing, and extension processes, respectively, to complete a cycle of polymerase chain reaction. The most important aspect of temperature control in the CPCR is to maintain temperature distribution at each reaction zone with a precision of ±1°C or better, irrespective of changing ambient conditions. Results obtained from the FEA simulation shows good comparison with published experimental work for the temperature control in each reaction zone of the microfluidic channels. The simulation data are then used to train the ANN to predict the temperature distribution of the microfluidic channel for various heater input power and fluid flow rate. Once trained, the ANN analysis is able to predict the temperature distribution in the microchannel in less than 20min, whereas the FEA simulation takes approximately 7h to do so. The final optimization of temperature control in the CPCR device is achieved by embedding the trained ANN results as a fitness function into GA. Finally, the GA optimized results are used to build a new FEA model for numerical simulation analysis. The simulation results for the neuro-genetic optimized CPCR model and the initial CPCR model are then compared. The neuro-genetic optimized model shows a significant improvement from the initial model, establishing the optimization method’s superiority.

A Study of LED C-Like Linear Tube by Micromachining Technique for LCD Backlight Applications

2009 ◽  
Vol 419-420 ◽  
pp. 189-192
Author(s):  
Chao Heng Chien ◽  
Zhi Peng Chen
Keyword(s):  
Thin Film ◽  
Liquid Crystal ◽  
Thermal Management ◽  
Liquid Crystal Display ◽  
Thin Film Transistor ◽  
Light Sources ◽  
Cold Cathode ◽  
Optical Efficiency ◽  
Light Emitting ◽  
Fabrication Cost

In order to make the liquid crystal display (LCD) panel thinner, brighter and no-Hg containing, the light emitting diodes (LEDs) are generally beginning to replace conventional cold cathode florescent lamp (CCFL) as light sources for LCD backlight unit (BLU). The thermal management and cost are consideration caused by more LEDs used for larger size BLU. For saving the fabrication cost and considering the luminous uniformity of most commercial BLU, a novel C-like linear tube is fabricated by precision and micromachining technique. The LED C-like linear tube is not only decreasing LEDs for BLU but also increasing the optical efficiency for emitting the light into the BLU. The C-like linear tube is proposed to replace CCFL tube for thin film transistor (TFT) LCD applications.

Liquid Crystal Thermography of an On-Chip Polymerase Chain Reaction Micro-Thermocycler

2006 ◽  
Author(s):  
Tracy Helen Fung ◽  
Shih-Hui Chao ◽  
Joseph E. Peach ◽  
Deirdre R. Meldrum
Keyword(s):  
Polymerase Chain Reaction ◽  
Liquid Crystal ◽  
Temperature Distribution ◽  
Dna Amplification ◽  
Temperature Sensitive ◽  
Chain Reaction ◽  
Liquid Crystal Thermography ◽  
Polymerase Chain ◽  
On Chip

Microscale liquid crystal thermography is a technique to measure temperature distribution of microfabricated devices in real-time. This method utilizes a microscope to image the color map of a layer of temperature-sensitive encapsulated thermochromic liquid crystals (TLC) coated on a microfabricated device. This paper describes the TLC coating process on microscale devices, the characteristics of colorimetric hysteresis, and the calibration of temperature measurements. The calibrated measurements have been applied for characterization of an on-chip polymerase chain reaction (PCR) microscale thermocycler where precise and dynamic temperature control is essential for efficient DNA amplification. Tests on the micro-thermocycler were done around the ranges centered at 30 °C and 95 °C. The results illustrate the effects on the temperature distribution due to micro-thermocycler geometry, and provide important insight for micro-thermocycler design.

scholarly journals Thermal Analysis of Cold Plate with Different Configurations for Thermal Management of a Lithium-Ion Battery

Batteries ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 17
Author(s):  
Seyed Saeed Madani ◽  
Erik Schaltz ◽  
Søren Knudsen Kær
Keyword(s):  
Thermal Analysis ◽  
Temperature Distribution ◽  
Lithium Ion Battery ◽  
Thermal Management ◽  
Electric Vehicles ◽  
Heat Dissipation ◽  
Lithium Ion ◽  
Cold Plate ◽  
Liquid Cooling ◽  
Cooling Design

Thermal analysis and thermal management of lithium-ion batteries for utilization in electric vehicles is vital. In order to investigate the thermal behavior of a lithium-ion battery, a liquid cooling design is demonstrated in this research. The influence of cooling direction and conduit distribution on the thermal performance of the lithium-ion battery is analyzed. The outcomes exhibit that the appropriate flow rate for heat dissipation is dependent on different configurations for cold plate. The acceptable heat dissipation condition could be acquired by adding more cooling conduits. Moreover, it was distinguished that satisfactory cooling direction could efficiently enhance the homogeneity of temperature distribution of the lithium-ion battery.

Sign in / Sign up

Export Citation Format

Share Document