On-chip quantitative PCR using integrated real-time detection by capillary electrophoresis.

Quantitative PCR (qPCR) has been widely used for the detection and monitoring of a variety of infectious diseases. PCR and CE were integrated into a microfluidic chip that was designed to achieve rapid real-time amplicon sampling, separation, and quantitation without requiring various probes. A novel chip design allows the overlapped execution of PCR and CE, minimizing the time required for CE analysis after each PCR cycle. The performance of the on-chip qPCR method was demonstrated using a 45-minutes model assay protocol for the phiX174 bacteriophage, and the multiplexing capability of the method was demonstrated by adding a second target, E. coli genomic DNA, to the model assay. The results indicate good sensitivity, reproducibility, and linearity over the tested assay range, 50 to 2 × 10(4) copies/25 µL reaction. Based on this performance, the on-chip qPCR method should be applicable to a wide variety of infectious disease detection and monitoring assays with the addition of suitable sample preparation protocols.

Fully automated rapid quantification of Hepatitis C Virus RNA in human plasma and serum by integrated on-chip RT-qPCR and capillary electrophoresis.

The quantification of hepatitis C virus (HCV) is essential for the management of chronic hepatitis C therapy. We have developed a fully automated microfluidic RT-qPCR system for rapid quantitative detection of HCV RNA in human EDTA-plasma and serum, and the performance of the method was assessed. The platform for the assay, µTASWako g1 Fully Automated Genetic Analyzer, performs automated sample preparation and RNA extraction, followed by amplification and detection on an integrated RT-qPCR-CE (capillary electrophoresis (CE)) microfluidic chip. The total assay time from sample input to data output is less than 120 minutes. The HCV assay has a linear quantitative range of 15 to 107 IU/mL, with a limit of detection (LOD) of 10.65 IU/mL in EDTA-plasma and 12.43 IU/mL in serum. The assay has a reproducibility of SD ≤ 0.16 log10 IU/mL and an accuracy of ≤ 0.22 log10 IU/mL difference when compared to the assigned values. The main HCV genotypes 1 to 6 are detected with an accuracy of ± 0.3 log10 IU/mL. The assay is specific for HCV RNA and is free of interference from non-HCV pathogens, elevated levels of anti-viral and anti-bacterial drugs, and common endogenous interferents. In the linear quantitative range, the assay is highly correlated with the Roche cobas AmpliPrep/cobas TaqMan HCV Test, version 2.0 (r2 = 0.949). As the assay is highly sensitive, accurate and specific, and provides reliable quantification of HCV in plasma and serum, it can potentially be applicable for monitoring the therapy and management of HCV infection.

Cytometric analysis of protein expression and apoptosis in human primary cells with a novel microfluidic chip-based system.

BACKGROUND: Work with primary cells is inherently limited by source availability and life span in culture. Flow cytometry offers extensive analytical opportunities but generally requires high cell numbers for an experiment. METHODS: We have developed assays on a microfluidic system, which allow flow cytometric analysis of apoptosis and protein expression with a minimum number of fluorescently stained primary cells. In this setup, the cells are moved by pressure-driven flow inside a network of microfluidic channels and are analyzed individually by two-channel fluorescence detection. For some assays the staining reactions can be performed on-chip and the analysis is done without further washing steps. RESULTS: We have successfully applied the assays to evaluate (a) activation of E-selectin (CD62E) expression by interleukin-1beta in human umbilical vein endothelial cells (HUVECs), (b) induction of CD3 by phorbol-12-myristate-13-acetate in freshly prepared human peripheral blood lymphocytes, and (c) staurosporine-induced apoptosis in HUVEC and normal human dermal fibroblasts. CONCLUSIONS: Results obtained with the microfluidic system are in good correlation with data obtained using a standard flow cytometer, but demonstrate new dimensions in low reagent and cell consumption.