Fabrication of Cost-Effective Microchip-Based Device Using Sandblasting Technique for Real-Time Multiplex PCR Detection.

The combination of multiplex polymerase chain reaction (mPCR) and microfluidic technologies demonstrates great significance in biomedical applications. However, current microfluidics-based molecular diagnostics face challenges in multi-target detection due to their limited fluorescence channels, complicated fabrication process, and high cost. In this research, we proposed a cost-effective sandblasting method for manufacturing silicon microchips and a chip-based microdevice for field mPCR detection. The atomic force microscopy (AFM) images showed a rough surface of the sandblasted microchips, leading to poor biocompatibility. To relieve the inhibitory effect, we dip-coated a layer of bovine serum albumin (BSA) on the irregular substrate. The optimized coating condition was determined by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) (65 °C for 60 min). After sufficient coating, we performed on-chip PCR tests with 500 copies/mL Coronavirus Disease 2019 (COVID-19) standard sample within 20 min, and the sandblasted microchip displayed a higher amplification rate compared to dry etching chips. Finally, we achieved a 50 min mPCR for screening five resistance genes of the endophthalmitis pathogens on our microdevices, with strong specificity and reliability. Thus, this sandblasted microchip-based platform not only provides a rapid, accessible, and effective solution for multiplex molecular detection but also enables large-scale microfabrication in a low-cost and convenient way.