Capillary-based fully integrated and automated system for nanoliter polymerase chain reaction analysis directly from cheek cells

A miniaturized, integrated and automated system based on capillary fluidics has been developed for nanoliter DNA analysis directly from cheek cells. A ll steps for DNA analysis, including injecting aqueous reagents and DNA sam ples, mixing the solutions together, thermal cell lysis, polymerase chain r eaction (PCR), transfer and injection of PCR product, separation, sizing an d detection of those products are performed in a capillary-based integrated system. A small amount of cheek cells collected by a plastic toothpick is directly dissolved in the PCR cocktail in a plastic vial or mixed on-line w ith a small volume of PCR cocktail (125 nl) in the capillary. After thermal cell lysis and PCR in a microthermal cycler, the DNA fragments are mixed w ith DNA size standards and transferred to a micro-cross for injection and s eparation by capillary gel electrophoresis. Programmable syringe pumps, swi tching valves, multiposition and freeze-thaw valves are used for microfluid ic control in the entire system. This work establishes the feasibility of p erforming all the steps of DNA analysis from real samples in a capillary-ba sed nanoliter integrated system. (C) 2001 Elsevier Science B.V. All rights reserved.