WELPCR: Low-cost polymerase chain reaction (PCR) thermal cycler for nucleic acid amplification and sensing

The COVID-19 pandemic highlighted the need for sensitive and cost-effective diagnostics. The gold standard test to diagnose infectious diseases such as COVID-19 is quantitative polymerase chain reaction (qPCR). Although there have been multiple advances in nucleic acid testing, PCR thermocyclers are expensive and typically not affordable for offering hands-on training to PCR in instructional laboratory courses in undergraduate colleges. We introduce a low-cost, portable, and automated real-time PCR device designed at the Wadhwani Electronics Lab (WEL) at IIT Bombay, christened WELPCR. WELPCR is an open-source design, and capable of reverse transcription PCR (RT-PCR) for complementary DNA synthesis, as well as end-point PCR of small amount of DNA in a test sample. The WELPCR design enables ramp rate up to 2 °C/s, weighs less than 2 kg, and is easy to assemble. The built-in LED display and keypad provides an intuitive and seamless user interface to configure and set up WELPCR. With bill of materials (BOM) cost less than INR Rs. 10000, WELPCR is an attractive solution for bringing PCR technology to instructional and research laboratories in a cost-effective manner.