Fig. 2: Sample-to-answer multiplex RT-qPCR assay.

A Total assay on the chip. B The built-in valve system. The rigid body of the valve was inserted into an empty space of the flexible top layer. The fluid was not allowed to pass at a normally closed status of the valve, wherein the channel in the valve core was not aligned with the main channel of the system. To allow fluid motion, the valve was pressed externally, creating a vertical displacement of the valve, hence aligning the valve channel with the system channel network. The rigid valve returns to its original position and closed status after removing the pressing force. C Structure of the integrated silica matrix. A top inlet enabled the extraction buffers and the RNA to pass through the silica matrix to capture, purify, and release the RNA. D The valve performance. Pressure burst (maximum pressure that the valve can hold before leaking) vs the chip operation pressure for different sizes of the rigid valve. E Evaluation of on-chip extracted RNA using a benchtop real-time PCR machine. The error bars represent the standard deviation calculated from 3 independent experiments.