Automated chip-based device for simple and fast nucleic acid amplification

Abstract

A chip-based PCR device is presented that is capable of rapid temperature ramping and handling sample volumes in the microliter range. The PCR chip comprises a microchannel thermally connected to three temperature zones. Inside this microchannel, the PCR sample plug is driven and precisely positioned by a ferrofluidic actuator for more than 40 cycles within 5 min. Computer simulations predict that the sample plugs are thermally equilibrated on a time scale of some 10 ms when transported to a different temperature zone. Hence, the thermal limitations on the cycle speed of the system are considerably reduced compared with conventional cyclers. The system was developed on a modular platform suitable for handling further microfluidic tasks such as DNA extraction and preparation of the PCR mix. Thus, the aspired chip-based platform represents not only a PCR system but a complete analysis system, from the injection of a patient's blood sample to its final appraisal.

Manipulating liquid plugs in microchannel with controllable air vents

“…One application example reported recently is the use of an air vent as a chip-integrated valve for positioning of a liquid plug. 12 We found that the air vents a) Author to whom correspondence should be addressed. Electronic mail: mhqgong@ntu.edu.sg.…”

Multichannel oscillatory-flow multiplex PCR microfluidics for high-throughput and fast detection of foodborne bacterial pathogens

“…The microchannel of the oscillatory-flow PCR can be constructed in such substrates as silicon (Bu et al 2003;Wang et al 2005), glass (Sugumar et al 2010), quartz (Baker et al 2003), and various polymers (for example SU-8 (Auroux et al 2003b, 2004a, poly(methylmethacrylate) (PMMA) (Hardt et al 2004;Münchow et al 2005;Cheng et al 2005), cycloolefin copolymer (COC) (Hardt et al 2004;Münchow et al 2005), polydimethylsiloxane (PDMS) (Hu et al 2006;Frey et al 2007;Ugsornrat et al 2008), polycarbonate (PC) (Ohashi et al 2007), and dry film resist (DFR) ). To form a chip with sealed channels, these chips are required to bond with another cover plate.…”

“…(2) The reactor' s heater and sensor elements. The heaters used for the oscillatoryflow PCR have changed from the metal/ceramic blocks with a certain heating cartridge (Chiou et al 2001(Chiou et al , 2002Auroux et al 2003a;Hardt et al 2004;Münchow et al 2005;Frey et al 2007;Sugumar et al 2010) to the Peltier heater (Chen et al 2007b;Paik et al 2007) and the film heaters integrated on the chips (for example indium tin oxide (ITO) (Cheng et al 2005), platinum (Bu et al 2003;Wang et al 2005;Polini et al 2010;Sciancalepore et al 2011), chromium/aurum (Ugsornrat et al 2008), and others (Baker et al 2003;Auroux et al 2003bAuroux et al , 2004aSista et al 2008)). And, the temperature sensor elements include the commercially available thermocouples (Chiou et al 2001(Chiou et al , 2002Auroux et al 2003a;Chen et al 2007b;Paik et al 2007), the thermistors (Sista et al 2008;Sugumar et al 2010), and the on-chip film sensors (Bu et al 2003;Wang et al 2005;Polini et al 2010;Sciancalepore et al 2011).…”

“…However, it is usually bulky and expensive, which adversely affects the development of an integrated and portable oscillatory-flow PCR device. To overcome some of these drawbacks, some micropumping components have been developed for the oscillatory-flow PCR chips, such as the piezoelectric peristaltic micropump (Bu et al 2003), the ferrofluidic magnetic micropump (Hardt et al 2004;Münchow et al 2005), the electrokinetic micropump (Hu et al 2006), the electrowetting micropump (Paik et al 2007;Ugsornrat et al 2008;Sista et al 2008), the pneumatic micropump with an external actuator (Frey et al 2007), and the droplet-based magnetic transportation (Ohashi et al 2007). (4) The detection sensitivity of the bidirectional flow reactor.…”

“…All existing nucleic acid detection methods can be used for offline detection of oscillatory-flow PCR products. Possibly due to cost-effectiveness, the use of intercalators in combination with agarose gel electrophoresis is still the most popular method for detection of oscillatory-flow PCR products (Münchow et al 2005;Wang et al 2005;Cheng et al 2005;Hu et al 2006;Ohashi et al 2007;Chen et al 2007b;Sista et al 2008;Sugumar et al 2010;Polini et al 2010;Sciancalepore et al 2011). Offline product detection is usually time-consuming and labor intensive.…”