A digital PCR system based on the thermal cycled chip with multi helix winding capillary

Abstract

This paper presents a digital PCR system based on a novel thermal cycled chip, which wraps microchannels on a trapezoidal structure made of polydimethylsiloxane (PDMS) in a multi-helix manner for the first time. It is found that compared to the single helix chip commonly used in previous reports, this kind of novel multi-helix chip can make the surface temperature in the renaturation zone more uniform, and even in the case of rapid fluid flow, it can improve the efficiency of the polymerase chain reaction. What’s more, the winding method of multi helix (such as double helix, six helix and eight helix) can obtain better temperature uniformity than the winding of odd helix (such as single helix and three helix). As a proof of concept, the temperature-optimized double-helical chip structure is applied to continuous-flow digital PCR and there is no need to add any surfactant to both the oil phase and reagent. In addition, we successfully analyzed the fluorescence signal of continuous-flow digital PCR by using CMOS camera. Finally, this method is applied for the absolute quantification of the clinical serum sample infected by HBV. The accuracy of the test results has been confirmed by commercial instruments.

A three-in-one microfluidic droplet digital PCR platform for absolute quantitative analysis of DNA

“…For example, a capillary-based strategy was developed to generate droplets stored in tubes followed by amplification in a continuous flow manner and digital readout through cytometers. 4,[6][7][8] This strategy provides a chip-free droplet generation method but shows low practicability due to complicated settings when connecting the capillary to the control system. Therefore, microfluidic chips implementing droplet generation and storage were proposed for realizing integrated ddPCR, where polydimethylsiloxane (PDMS) and glass were employed as chip materials.…”

Multiplex Molecular Point-of-Care Test for Syndromic Infectious Diseases

“…Since experience-based empiric treatment is a possible driver of over-broad and unnecessary antibiotic usage, rapid POC diagnostic testing has become a promising solution to this problem. Molecular tests, such as polymerase chain reaction (PCR) and other nucleic acid-based amplification technologies (NAATs), have gradually replaced or augmented traditional laboratory techniques for pathogen identification in the form of POC testing, because these tests can detect fastidious or uncultivable microorganisms that indicate possible poly-microbial infection [ 10 – 12 ]. The successful migration of molecular diagnostics from universal laboratories to the clinical setting.…”