Characterization and analysis of real-time capillary convective PCR toward commercialization.

Almost all the reported capillary convective polymerase chain reaction (CCPCR) systems to date are still limited to research use stemming from unresolved issues related to repeatability, reliability, convenience, and sensitivity. To move CCPCR technology forward toward commercialization, a couple of critical strategies and innovations are discussed here. First, single- and dual-end heating strategies are analyzed and compared between each other. Especially, different solutions for dual-end heating are proposed and discussed, and the heat transfer and fluid flow inside the capillary tube with an optimized dual-end heating strategy are analyzed and modeled. Second, real-time CCPCR is implemented with light-emitting diode and photodiode, and the real-time fluorescence detection method is compared with the post-amplification end-point detection method based on a dipstick assay. Thirdly, to reduce the system complexity, e.g., to simplify parameter tuning of the feedback control, an internal-model-control-based proportional-integral-derivative controller is adopted for accurate temperature control. Fourth, as a proof of concept, CCPCR with pre-loaded dry storage of reagent inside the capillary PCR tube is evaluated to better accommodate to point-of-care diagnosis. The critical performances of improved CCPCR, especially with sensitivity, repeatability, and reliability, have been thoroughly analyzed with different experiments using influenza A (H1N1) virus as the detection sample.