Paper-based microfluidic chips for wide time range fluid control based on knife crafting and laser cutting

In recent years, paper-based microfluidic chips have emerged as a promising microfluidic platform due to their simplicity, low cost, portability, and ease of fabrication. They have been applied in various fields such as biological analysis, environmental monitoring, and medical diagnostics. However, the current paper-based chips made of nitrocellulose membrane still can be improved in liquid flow rate control. To address these issues, a novel paper-based microfluidic chip is designed to control liquid in a wide time range, and the liquid delay and acceleration control are realized by laser cutting and knife crafting respectively. Microfluidic chip's hydrophobic boundaries can be manufactured in a one-step process using laser cutting, taking less than 10 seconds. Additionally, the structural parameters of microgrooves, which have a significant impact on flow rate, can be precisely controlled using a scalpel-based cutting platform. This enables efficient and consistent microgroove processing. Furthermore, experimental optimization of laser cutting and knife crafting parameters is performed, along with an exploration of factors influencing the delay and acceleration effects in the chip structures. The effectiveness of these processing methods is validated through practical applications. In summary, this study realizes a wide time range fluid control in paper-based microfluidic chips, which can achieve delay and acceleration in the range of −55.6% to +828.3%, thus expanding the application range of paper-based microfluidic chips.