Microfabricated valveless devices for thermal bioreactions based on diffusion-limited evaporation

Wang, Fang; Yang, Ming; Burns, Mark A.

doi:10.1039/b711770a

Cited by 12 publications

(18 citation statements)

References 46 publications

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“…However, the possible evaporation-induced liquid loss may result in insufficient PCR product for the detection. To avoid it, integrated chips reported so far have used mineral oils (Anderson et al 2000;Khandurina et al 2000;Lagally et al 2000;Lagally et al 2001;Lee et al 2004;Waters et al 1998), tape (Zhao et al 2003), Bostik's Blu-Tacksilicone (Yeung et al 2008), rubber gaskets (Yoon et al 2002), microvalves (Lagally et al 2001;Lagelly et al 2004;Ramalingam et al 2009), and long narrow diffusion channels (Wang et al 2008). All of them need extra materials to provide physical confinement or extra channel structure.…”

Section: Introductionmentioning

confidence: 99%

Fast detection of genetic information by an optimized PCR in an interchangeable chip

Kodzius

Xiao

et al. 2011

Biomed Microdevices

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In this paper, we report the construction of a polymerase chain reaction (PCR) device for fast amplification and detection of DNA. This device consists of an interchangeable PCR chamber, a temperature control component as well as an optical detection system. The DNA amplification happens on an interchangeable chip with the volumes as low as 1.25 μl, while the heating and cooling rate was as fast as 12.7°C/second ensuring that the total time needed of only 25 min to complete the 35 cycle PCR amplification. An optimized PCR with two-temperature approach for denaturing and annealing (Td and Ta) of DNA was also formulated with the PCR chip, with which the amplification of male-specific sex determining region Y (SRY) gene marker by utilizing raw saliva was successfully achieved and the genetic identification was in-situ detected right after PCR by the optical detection system.

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Section: Introductionmentioning

confidence: 99%

Fast detection of genetic information by an optimized PCR in an interchangeable chip

Kodzius

Xiao

et al. 2011

Biomed Microdevices

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“…For example, Lynn et al have shown that the evaporation rate is higher for an expanding reservoir than a contracting reservoir for a given volume of liquid (Lynn et al 2009). Wang et al (2008) also showed that the cross-sectional area of the channel affected the V loss /V ini ratio. In this work, a simple reservoir design consisting of a straight channel with uniform cross-section area is first used to evaluate the effects of different cross-section areas on the V loss /V ini and evaporation rate (Fig.…”

Section: Effect Of Hmdl and Tr's Channel Geometries On The Relative Ementioning

confidence: 92%

“…, the unit vector normal to the interface, the evaporation rate, E, is given by (Berthier et al 2008a). For a three-step PCR thermocycling reaction, Wang et al (2008) have recently proposed a relation expression for the total evaporative volume loss during a DL evaporation process (V loss ) :…”

Section: Principle Of Design For the Hmdl Methodsmentioning

confidence: 99%

“…Although the proposed approaches can limit the evaporation loss to approximately 1% of the reaction content, both thermal isolation and vapor replenishment techniques are complicated in design, and high in the chip fabrication and operation cost. When compared to the work of Wang et al (2008), the HMDL method proposed in this article does not require complicated thermal isolation to reduce the interfacial temperature, or external pure water to be heated synchronously with the reaction chamber to increase the vapor concentration in the diffusion channel and therefore decrease the concentration gradient. Using the HMDL method, the evaporation loss is only 15% within a comparatively long time (i.e., 240 min) in the case of T TR = 95°C.…”

Section: Comparison Of Different Methods To Decrease/ Prevent Liquid mentioning

confidence: 99%

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Decreasing microfluidic evaporation loss using the HMDL method: open systems for nucleic acid amplification and analysis

Zhang

Xing

2009

Microfluid Nanofluid

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Evaporation is of great importance when dealing with microfluidic devices with open air/liquid interfaces due to the large surface-to-volume ratio. For devices utilizing a thermal reaction (TR) reservoir to perform a series of biological and chemical reactions, excessive heatinduced microfluidic evaporation can quickly lead to reaction reservoir dry out and failure of the overall device. In this study, we present a simple, novel method to decrease heat-induced fluid evaporation within microfluidic systems, which is termed as heat-mediated diffusion-limited (HMDL) method. This method does not need complicated thermal isolation to reduce the interfacial temperature, or external pure water to be added continuously to the TR chamber to compensate for evaporation loss. The principle of the HMDL method is to make use of the evaporated reaction content to increase the vapor concentration in the diffusion channel. The experimental results have shown that the relative evaporation loss (V loss /V ini ) based on the HMDL method is not only dependent on the HMDL and TR region's temperatures (T HMDL and T TR ), but also on the HMDL and TR's channel geometries. Using the U-shaped uniform channel with a diameter of 200 lm, the V loss /V ini within 60 min is low to 5% (T HMDL = 105°C, T TR = 95°C). The HMDL method can be used to design open microfluidic systems for nucleic acid amplification and analysis such as isothermal amplification and PCR thermocycling amplification, and a PCR process has been demonstrated by amplifying a 135-bp fragment from Listeria monocytogenes genomic DNA.

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“…Recently, Burns et al reported an unsealed reactor for end-point PCR, in which optimized design geometry, thermal isolation and vapor replenishment were employed as methods to reduce evaporative loss (Wang et al 2008). Concerns about PCR failure due to evaporation have been addressed by Burns et al They found that for reactors having bridge channel volumes of less than 10% of the total reaction volume, the overall PCR efficiency in unsealed reactors, was not significantly affected (Wang et al 2008). For our array chip, we controlled evaporative loss of amplification mixture by implementing optimized reactor design geometry, smooth internal reactor surfaces, external heater, selective heating zone, suitable chip substrate based on thermal conductivity and reaction volume.…”

Section: Evaporative Loss Studies In Unsealed Reactorsmentioning

confidence: 99%

Microfluidic devices harboring unsealed reactors for real-time isothermal helicase-dependent amplification

Ramalingam

San

Kai

et al. 2009

Microfluid Nanofluid

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High-throughput microchip devices used for nucleic-acid amplification require sealed reactors. This is to prevent evaporative loss of the amplification mixture and cross-contamination, which may occur among fluidically connected reactors. In most high-throughput nucleic-acid amplification devices, reactor sealing is achieved by microvalves. Additionally, these devices require micropumps to distribute amplification mixture into an array of reactors, thereby increasing the device cost, and adding complexity to the chip fabrication and operation processes. To overcome these limitations, we report microfluidic devices harboring open (unsealed) reactors in conjunction with a single-step capillary based flow scheme for sequential distribution of amplification mixture into an array of reactors. Concern about evaporative loss in unsealed reactors have been addressed by optimized reactor design, smooth internal reactor surfaces, and incorporation of a localized heating scheme for the reactors, in which isothermal, real-time helicase-dependent amplification (HDA) was performed.

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Microfabricated valveless devices for thermal bioreactions based on diffusion-limited evaporation

Cited by 12 publications

References 46 publications

Fast detection of genetic information by an optimized PCR in an interchangeable chip

Fast detection of genetic information by an optimized PCR in an interchangeable chip

Decreasing microfluidic evaporation loss using the HMDL method: open systems for nucleic acid amplification and analysis

Microfluidic devices harboring unsealed reactors for real-time isothermal helicase-dependent amplification

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