A Glass–Ultra-Thin PDMS Film–Glass Microfluidic Device for Digital PCR Application Based on Flexible Mold Peel-Off Process

Abstract

The microfluidic device (MFD) with a glass–PDMS–glass (G-P-G) structure is of interest for a wide range of applications. However, G-P-G MFD fabrication with an ultra-thin PDMS film (especially thickness less than 200 μm) is still a big challenge because the ultra-thin PDMS film is easily deformed, curled, and damaged during demolding and transferring. This study aimed to report a thickness-controllable and low-cost fabrication process of the G-P-G MFD with an ultra-thin PDMS film based on a flexible mold peel-off process. A patterned photoresist layer was deposited on a polyethylene terephthalate (PET) film to fabricate a flexible mold that could be demolded softly to achieve a rigid structure of the glass–PDMS film. The thickness of ultra-thin patterned PDMS could reach less than 50 μm without damage to the PDMS film. The MFD showcased the excellent property of water evaporation inhibition (water loss < 10%) during PCR thermal cycling because of the ultra-thin PDMS film. Its low-cost fabrication process and excellent water evaporation inhibition present extremely high prospects for digital PCR application.

Breaking the clean room barrier: exploring low-cost alternatives for microfluidic devices

“…Additionally, PDMS has adsorptive properties for certain molecules that can affect the accuracy of experiments or their analyses ( Akther et al, 2020 ; Grant et al, 2021 ). Water evaporation through the channel walls is a concern because it can lead to alterations in solution concentration, negatively affecting experimental results ( Schneider et al, 2021b ; Xia et al, 2022 ). The hydrophobicity of PDMS can make it difficult to fill microfluidic channels with aqueous solutions, resulting in fluid flow and analyte detection difficulties ( Akther et al, 2020 ; Hu H et al, 2020 ).…”

Advances in Simple, Rapid, and Contamination-Free Instantaneous Nucleic Acid Devices for Pathogen Detection

“…Time-domain thermal cycling involves keeping the sample stationary during temperature changes. It includes contact heating [135][136][137][138][139][140][141], as well as noncontact heating methods such as infrared heating [142], laser heating [143] and microwave heating [144].…”