A micro circulating PCR chip using a suction-type membrane for fluidic transport

Abstract

A new micromachined circulating polymerase chain reaction (PCR) chip is reported in this study. A novel liquid transportation mechanism utilizing a suction-type membrane and three microvalves were used to create a new microfluidic control module to rapidly transport the DNA samples and PCR reagents around three bio-reactors operating at three different temperatures. When operating at a membrane actuation frequency of 14.29 Hz and a pressure of 5 psi, the sample flow rate in the microfluidic control module can be as high as 18 microL/s. In addition, an array-type microheater was adopted to improve the temperature uniformity in the reaction chambers. Open-type reaction chambers were designed to facilitate temperature calibration. Experimental data from infrared images showed that the percentage of area inside the reaction chamber with a thermal variation of less than 1 degrees C was over 90% for a denaturing temperature of 94 degrees C. Three array-type heaters and temperature sensors were integrated into this new circulating PCR chip to modulate three specific operating temperatures for the denaturing, annealing, and extension steps of a PCR process. With this approach, the cycle numbers and reaction times of the three separate reaction steps can be individually adjusted. To verify the performance of this circulating PCR chip, a PCR process to amplify a detection gene (150 base pairs) associated with the hepatitis C virus was performed. Experimental results showed that DNA samples with concentrations ranging from 10(5) to 10(2)copies/microL can be successfully amplified. Therefore, this new circulating PCR chip may provide a useful platform for genetic identification and molecular diagnosis.

The Dropletisation of Bio-Reactions

“…These designs fall into three broad categories: well-based [17][18][19], single-phase continuous flow [20][21][22][23][24] and dropletbased devices [25][26][27][28][29][30]. Droplet-based designs possess several distinct advantages over other designs for the handling of biological samples, most notably for the case of single cell analysis (Fig.…”

Multichannel oscillatory-flow multiplex PCR microfluidics for high-throughput and fast detection of foodborne bacterial pathogens

“…Since its introduction (Kopp et al 1998), dynamic continuous-flow PCR devices have been realized by different structure designs and different fluidic geometries (Frey et al 2007;Ohashi et al 2007;Chien et al 2009;Hartung et al 2009;Pjescic et al 2010;Zhang and Xing 2010;Peham et al 2011). Among them, the oscillatoryflow PCR devices have obtained increasing attention in recent years, due to their salient features such as cycle number/dwell time flexibility, ease of real-time detection implementation, large footprint reduction, and ability to process multiple samples in parallel.…”

A Self-Contained Portable Polymerase-Chain-Reaction System Integrated with Electromagnetic Mini-Actuators for Bi-Directional Fluid Transport

“…PCR mixture circulates in the channel loop with three specific temperature zones. Bi-directional flow is another concept of accomplishing thermal cycles by rapidly oscillating PCR mixture between different temperature zones [16][17][18][19][20][21].…”

“…1(c)). Note that since the actuators can be easily driven with DC voltages, the proposed approach eliminates the need of bulky equipments for driving fluid, such as syringe pumps/injectors [15,19], special power supplies [17], or air compressors [16,21]. Figures 3(b) and 3(c) are the schematic illustration of the combined configuration viewed along the xdirection indicated in Fig.…”