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Exploiting phase change materials in tunable passive heating system for low-resource point-of-care diagnostics

Tijdschriftbijdrage - Tijdschriftartikel

We present a passive heating system that allows controlled and localized on-chip heating, showing a huge potential for point-of-care (POC) diagnostic applications in low-resource settings. By coupling the thermal regulation properties of organic phase change materials (PCMs) to the exothermic crystallization reaction of supercooled sodium acetate trihydrate (SAT), on-chip temperature control is achieved without requiring external power supply. This enables the performance of sensitive and specific diagnostic tests in the field, which are currently restricted to laboratory environments. The presented system consists of 3 stacked microfluidic chambers (SAT, PCM, reagent), fabricated by means of a simple layer-by-layer manufacturing method using low-cost plastics. We showed that the SAT heat source was tunable between 35 and 55 °C by varying the salt fraction in the solution. A PCM was integrated between the SAT and reagent chamber to maintain temperature constant over time. Additionally, the introduction of this thermal buffer layer, increased the system its robustness to fluctuating ambient temperatures. Moreover, to facilitate the PCM and SAT chamber design optimization, a finite element model (FEM) was built to simulate the heat generation and transfer through the chip. With the optimized PCM-SAT system, a constant temperature between 37 and 42 °C was maintained for at least 15 min at different ambient temperatures (25 to 35 °C), typical conditions for a recombinase polymerase amplification assay. The ability to have simple control over both the heat release from the heat source and the regulation temperature of the PCM combined with the developed FEM, makes this system flexible to a variety of isothermal assay requirements. Moreover, the low-cost and simple fabrication method makes the system compatible with most passive microfluidic technologies (i.e., paper-based and capillary microfluidics), opening up many opportunities for integrated POC platforms.
Tijdschrift: Applied Thermal Engineering
ISSN: 1359-4311
Volume: 173
Jaar van publicatie:2020
BOF-keylabel:ja
IOF-keylabel:ja
BOF-publication weight:3
CSS-citation score:1
Authors from:Higher Education
Toegankelijkheid:Open