Design of a New Type of Compact Chemical Heater for Isothermal Nucleic Acid Amplification

Abstract

Previous chemical heater designs for isothermal nucleic acid amplification have been based on solid-liquid phase transition, but using this approach, developers have identified design challenges en route to developing a low-cost, disposable device. Here, we demonstrate the feasibility of a new heater configuration suitable for isothermal amplification in which one reactant of an exothermic reaction is a liquid-gas phase-change material, thereby eliminating the need for a separate phase-change compartment. This design offers potentially enhanced performance and energy density compared to other chemical and electric heaters.

Single-use paper-based hydrogen fuel cells for point-of-care diagnostic applications

“…This temperature profile agrees with observations in previous chemical heaters studies using this reaction. [37][38][39] The average peak temperature for all tested combinations is 30.0 ± 2.8 °C. Higher NaCl concentrations result in higher peak temperatures.…”

“…the corrosion of magnesium iron particles. [36][37][38][39][40][41][42] This chemistry is very convenient, as it , requires only the addition of water to achieve 100°C (a reason why it has also been widely used to heat portable meals). During the course of the chemical reaction the magnesium is oxidized, releasing hydrogen gas as a byproduct, which previously was simply vented off to the atmosphere.…”

Versatile printed microheaters to enable low-power thermal control in paper diagnostics

“…15 Although chemical heaters do not require batteries or external power supplies, they typically rely on highly variable exothermic reactions such as magnesium iron alloy (MgFe) and saline cartridges which are single-use and are difficult to control without a phase change material (PCM) chamber to buffer the sample temperatures. 10,[16][17][18] Current PCB-based heaters, while effective, require long copper traces which result in slow rampups to the target temperature and excess heat and power consumption. 7 In Hwang et al, sample overheating and control of the working voltage for each heating stage of a polymerase chain reaction (PCR) to detect Chlamydia trachomatis remained problematic even after reducing the size of the heating pattern and utilizing a complex electronics system to perform the thermocycling.…”

Direct colorimetric LAMP assay for in-field detection of African swine fever virus: a validation study during an outbreak in Vietnam

“…All those advantages make LAMP an excellent isothermal nucleic acid amplification technique which has been broadly utilized currently. Besides, to supply stable heat for amplification reactions, numerous electricity-free and portable devices were developed, allowing the simpler application of LAMP at field usage (Buser et al, 2015; Shah et al, 2015; Singleton et al, 2014; Singleton et al, 2013). In this study, we developed a rapid test kit based on colorimetric LAMP assay for the detection of ASFV utilizing a pH-sensitive dye for readout visualization.…”