4th Annual Mountain West
Biomedical Engineering Conference
September 5-6, 2008
Abstract Details
Presented By: | Sundberg, Scott |
Affiliated with: | University of Utah, Biomedical Engineering |
Authors: | Scott O. Sundberg, Carl T. Wittwer and Bruce K. Gale |
From: | Biomedical Engineering, Pathology and Mechanical Engineering Departments at the University of Utah |
Title
Abstract
Introduction: The digital polymerase chain reaction (PCR) is capable of detecting single DNA molecules and is the ultimate quantitative tool. Rare mutations within an excess of normal DNA can be detected and genetic allelic imbalance can be quantified. This process is expensive and difficult because of the thousands of reactions necessary. Dilutions are typically used to achieve single DNA copy reactions whereas single DNA reactions are accomplished in the spinning disc platform by using a thousand or more micro-sized wells to limit the DNA using an inexpensive rotating disc to partition the sample. Materials and Methods: A knife plotter was used to pattern a thin, black, single-sided adhesive vinyl sheet (75 microns thick) with a spiraling channel having 1000 wells, facing radially outward and tangential along the spiral with dimensions of 0.5 mm x 0.5 mm for a 20 nl volume on a disc that is 90 mm in diameter. This patterned sheet was then thermally bonded to a PETG sheet (125 microns thick) and a metalized mylar was adhered to the adhesive side of the vinyl sheet by running them through a laminator at 130 °C, thus creating the rotating disc. Amplified DNA solution was pipetted into an inlet port towards the center of the disc and a centrifuge was used to spin the solution into the disc at 3000 rpm. The disc was interrogated using a CCD camera image to determine volume variation between wells by measuring the surface area of each well. Results: Each well was filled to capacity with no noticeable volume change occurring radially along the disc from shear force after the disc was spun. The well volume standard deviation was found to have a 10% tolerance. Conclusions: The spinning disc platform is capable of accurately partitioning a sample and can now be used for digital PCR applications. The spinning disc platform is an improvement over other volume limiting platforms because it requires no valving or pumping and a rapid air thermal cycler can be used to increase speed and throughput.