A Thermocycler Using a Chip Resistor Heater and a Glass Microchip for a Portable and Rapid Microchip-Based PCR Device

Area of Science:

• Biotechnology
• Microfluidics
• Analytical Chemistry

Background:

• Conventional polymerase chain reaction (PCR) systems are limited by size, cost, and operational time, hindering on-site diagnostics.
• Existing microchip PCR devices often rely on expensive, complex thin-film heaters fabricated via semiconductor processes.
• There is a need for cost-effective and rapid microchip PCR solutions for point-of-care applications.

Purpose of the Study:

• To develop a rapid and inexpensive thermocycler for polymerase chain reaction (PCR) using a microchip and a chip resistor.
• To overcome the limitations of conventional and existing microchip PCR systems for on-site diagnostics.
• To demonstrate a significant reduction in PCR operating time and cost.

Main Methods:

• A compact glass microchip (12.5 mm × 12.5 mm × 2 mm) was designed to hold 2 μL PCR samples.
• A standard surface-mounted chip resistor (6432 size) was used as a low-cost alternative to thin-film heaters.
• Selective laser-induced etching was employed to create a 3D chip structure for improved heat transfer.
• The microchip was integrated with a thermistor sensor, blower fan, and microcontroller.

Main Results:

• The fabricated thermocycler achieved a rapid heating rate of 28.8 °C/s.
• The total PCR operating time for a DNA sample was reduced by approximately 20% compared to a commercial PCR apparatus.
• The use of a chip resistor proved to be a viable and cost-effective heating element.

Conclusions:

• The proposed thermocycler offers a rapid, inexpensive, and miniaturized solution for polymerase chain reaction (PCR).
• This technology has the potential to significantly improve the accessibility and efficiency of on-site diagnostics.
• The integration of a chip resistor and selective laser-induced etching presents a novel approach to microchip PCR device fabrication.