This study details the design, fabrication, and data analysis of SPEED, a smartphone-based digital polymerase chain reaction (dPCR) device. The dPCR chips use partitions (50 µm to 5 µm) organized into six blocks for image processing. Silicon's thermal conductivity and mass production potential led to its use as the substrate. A Peltier element and a preheating/cooling protocol optimize thermal cycling. The optical system uses four 470 nm LEDs, filters, and mirrors. An algorithm corrects illumination nonuniformity, identifies partitions, corrects skew, and generates an image mask. Validation using various DNA targets demonstrates its potential.

Haoqing Zhang, Xiaocheng Liu, Xinlu Wang, Zhiqiang Yan, Ying Xu, Martina Gaňová, Tomáš Řezníček, Marie Korabečná, Pavel Neuzil