title: 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.
authors.affiliation: Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Liang-Ju
authors.initials: LJ
authors.lastname: Chien
authors.forename: Jung-Hao
authors.initials: JH
authors.lastname: Wang
authors.forename: Tsung-Min
authors.initials: TM
authors.lastname: Hsieh
authors.forename: Ping-Hei
authors.initials: PH
authors.lastname: Chen
authors.forename: Pei-Jer
authors.initials: PJ
authors.lastname: Chen
authors.forename: Da-Sheng
authors.initials: DS
authors.lastname: Lee
authors.forename: Ching-Hsing
authors.initials: CH
authors.lastname: Luo
authors.forename: Gwo-Bin
authors.initials: GB
authors.lastname: Lee
mesh_terms: D005591:Chemical Fractionation / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017022:Flow Injection Analysis / Q000295:instrumentation* / Q000379:methods; D006361:Heating / Q000295:instrumentation; D008567:Membranes, Artificial; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation / Q000379:methods; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D012313:RNA / Q000235:genetics* / Q000302:isolation & purification*; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000295:instrumentation* / Q000379:methods; D012680:Sensitivity and Specificity; D013396:Suction / Q000295:instrumentation* / Q000379:methods
chemical_list: D008567:Membranes, Artificial; D012313:RNA