Multifunctional wax valves for liquid handling and incubation on a microfluidic CD

Kong, Ling X.; Parate, Kshama; Abi-Samra, Kameel; Madou, Marc

doi:10.1007/s10404-014-1492-x

Cited by 33 publications

(26 citation statements)

References 26 publications

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“…33, 34 One exception is the centrifugal type microfluidic platform, where the reagent can be preloaded and driven by centrifugal forces 35 . The preloaded reagents rely on passive valves to prevent mixing 36, 37 .…”

Section: Resultsmentioning

confidence: 99%

A field-deployable mobile molecular diagnostic system for malaria at the point of need

et al. 2016

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In response to the urgent need of a field-deployable and highly sensitive malaria diagnosis, we developed a standalone, “sample-in-answer-out” molecular diagnostic system (AnyMDx) to enable quantitative molecular analysis of blood-born malaria in low resource areas. The system consists of a durable battery-powered analyzer and a disposable microfluidic compact disc loaded with reagents ready for use. A low power thermal module and a novel fluorescence-sensing module are integrated into the analyzer for real-time monitoring of loop-mediated isothermal nucleic acid amplification (LAMP) of target parasite DNA. With 10 μL of raw blood sample, the AnyMDx system automates the nucleic acid sample preparation and subsequent LAMP and real-time detection. Under the laboratory conditions with whole-blood samples spiked with cultured Plasmodium falciparum, we achieved a detection limit of ∼0.6 parasites/μL, much lower than those for the conventional microscopy and rapid diagnostic tests (∼50-100 parasites/μL). The turnaround time from sample to answer is less than 40 minutes. The AnyMDx is user-friendly requiring minimal technological training. The analyzer and the disposable reagent compact discs are cost-effective, making AnyMDx a potential tool for malaria molecular diagnosis under field settings for malaria elimination.

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Section: Resultsmentioning

confidence: 99%

A field-deployable mobile molecular diagnostic system for malaria at the point of need

et al. 2016

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“…Techniques implemented while the platform is spinning are preferred, because sample evaporation is reduced as condensate is collected back into the reservoir. 95 More concentrated efforts to improve temperature control and to decrease the complexity and power requirements of hardware used in noncontact heating methods on CDs must be made.…”

Section: Future Outlook For Na Amplificationmentioning

confidence: 99%

Lab-on-a-CD: A Fully Integrated Molecular Diagnostic System

et al. 2016

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The field of centrifugal microfluidics has experienced tremendous growth during the past 15 years, especially in applications such as lab-on-a-disc (LoD) diagnostics. The strength of LoD systems lies in its potential for development into fully integrated sample-to-answer analysis systems. This review highlights the technologies necessary to develop the next generation of these systems. In addition to outlining valving and other fluid-handling operations, we discuss the recent advances and future outlook in four categories of LoD processes: reagent storage, sample preparation, nucleic acid amplification, and analyte detection strategies.

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“…18,60 On the other hand, aliquoting is popular for multiplexing of the heat-based assays, in which the integration of the gas-impermeable valves is considered a great advantage to prevent the evaporation of miniaturized reagents and the risk of cross-contamination. 24,26,50,61 To demonstrate the ability of the new valving system to overcome those challenges, an array of RTPVs is embedded in microfluidic Design C, which is created to automate the fluidic procedures commonly required for the multiplexing of heat-based assays. As a pilot study, Design C was used for the conversion of Dengue viral RNA to cDNA, and for the preparation of PCR reaction mixtures.…”

Section: Sequential Aliquotingmentioning

confidence: 99%

Reversible thermo-pneumatic valves on centrifugal microfluidic platforms

et al. 2015

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Centrifugal microfluidic systems utilize a conventional spindle motor to automate parallel biochemical assays on a single microfluidic disk. The integration of complex, sequential microfluidic procedures on these platforms relies on robust valving techniques that allow for the precise control and manipulation of fluid flow. The ability of valves to consistently return to their former conditions after each actuation plays a significant role in the real-time manipulation of fluidic operations. In this paper, we introduce an active valving technique that operates based on the deflection of a latex film with the potential for real-time flow manipulation in a wide range of operational spinning speeds. The reversible thermo-pneumatic valve (RTPV) seals or reopens an inlet when a trapped air volume is heated or cooled, respectively. The RTPV is a gas-impermeable valve composed of an air chamber enclosed by a latex membrane and a specially designed liquid transition chamber that enables the efficient usage of the applied thermal energy. Inputting thermo-pneumatic (TP) energy into the air chamber deflects the membrane into the liquid transition chamber against an inlet, sealing it and thus preventing fluid flow. From this point, a centrifugal pressure higher than the induced TP pressure in the air chamber reopens the fluid pathway. The behaviour of this newly introduced reversible valving system on a microfluidic disk is studied experimentally and theoretically over a range of rotational frequencies from 700 RPM to 2500 RPM. Furthermore, adding a physical component (e.g., a hemispherical rubber element) to induce initial flow resistance shifts the operational range of rotational frequencies of the RTPV to more than 6000 RPM. An analytical solution for the cooling of a heated RTPV on a spinning disk is also presented, which highlights the need for the future development of time-programmable RTPVs. Moreover, the reversibility and gas impermeability of the RTPV in the microfluidic networks are validated on a microfluidic disk designed for performing liquid circulation. Finally, an array of RTPVs is integrated into a microfluidic cartridge to enable sequential aliquoting for the conversion of dengue virus RNA to cDNA and the preparation of PCR reaction mixtures.

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Multifunctional wax valves for liquid handling and incubation on a microfluidic CD

Cited by 33 publications

References 26 publications

A field-deployable mobile molecular diagnostic system for malaria at the point of need

A field-deployable mobile molecular diagnostic system for malaria at the point of need

Lab-on-a-CD: A Fully Integrated Molecular Diagnostic System

Reversible thermo-pneumatic valves on centrifugal microfluidic platforms

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