Pressure-Free Assembling of Poly(methyl methacrylate) Microdevices via Microwave-Assisted Solvent Bonding and Its Biomedical Applications.

Kieu The Loan Trinh,Woo Ri Chae,Nae Yoon Lee

doi:10.3390/bios11120526

Abstract

Poly(methyl methacrylate) (PMMA) has become an appealing material for manufacturing microfluidic chips, particularly for biomedical applications, because of its transparency and biocompatibility, making the development of an appropriate bonding strategy critical. In our research, we used acetic acid as a solvent to create a pressure-free assembly of PMMA microdevices. The acetic acid applied between the PMMA slabs was activated by microwave using a household microwave oven to tightly merge the substrates without external pressure such as clamps. The bonding performance was tested and a superior bond strength of 14.95 ± 0.77 MPa was achieved when 70% acetic acid was used. Over a long period, the assembled PMMA device with microchannels did not show any leakage. PMMA microdevices were also built as a serpentine 2D passive micromixer and cell culture platform to demonstrate their applicability. The results demonstrated that the bonding scheme allows for the easy assembly of PMMAs with a low risk of clogging and is highly biocompatible. This method provides for a simple but robust assembly of PMMA microdevices in a short time without requiring expensive instruments.

Highlights

The advancement of microfabrication techniques has resulted in the transition from batch analysis in laboratories to portable, cost-effective, and highly efficient miniaturized microfluidic systems
To compensate for the limitations associated with the use of silicon-based materials, thermoplastics such as poly(methyl methacrylate) (PMMA), polycarbonate (PC), and polyethylene terephthalate (PET) have been widely used
All of the PMMA substrates were treated with acetic acid solutions in varying concentrations before being microwave irradiated for 2 min 50 s

Summary

Introduction

The advancement of microfabrication techniques has resulted in the transition from batch analysis in laboratories to portable, cost-effective, and highly efficient miniaturized microfluidic systems. PMMAs can be assembled through thermal bonding by increasing the bonding temperature above the glass transition temperature to soften the chains and interlock the two surfaces [8,9]. This is an intuitively simple method that does not require any additional adhesive reagents, but it is typically only applicable between homogeneous plastics or plastics with similar glass transition temperatures, as the high heat and pressure can cause deformation of the microfluidic channels. The modified surfaces may not be suitable for the microdevices’

Methods

Results

Conclusion