A Thin-Wall Bonding Process for Reliable Microfluidic Device Fabrication

A novel Thin-Wall Bonding (TWB) process is presented to overcome the limitations of conventional thermoplastic bonding in microfluidic device fabrication. Traditional solvent and thermal bonding methods often generate interfacial bubbles and cause deformation, compromising biocompatibility and optical clarity. The proposed TWB approach reduces the bonding area to enhance localized pressure, achieving uniform, bubblefree, and leak-free sealing between PMMA layers. The process requires no surface treatment, or cleanroom facilities, maintaining low-cost and high reproducibility. Experimental results demonstrate complete optical transparency, strong adhesion, and stable fluidic performance under continuous flow. Cell culture tests further confirm the biocompatibility of the bonded chips. This simple and reliable bonding technique offers a scalable route for the fabrication of transparent thermoplastic microfluidic devices applicable to biomedical and diagnostic systems.