Inexpensive and nonconventional fabrication of microfluidic devices in PMMA based on a soft‐embossing protocol

Abstract

This study describes an inexpensive and nonconventional soft-embossing protocol to produce microfluidic devices in poly(methyl methacrylate) (PMMA). The desirable microfluidic structure was photo-patterned in a poly(vinyl acetate) (PVAc) film deposited on glass substrate to produce a low-relief master. Then, this template was used to generate a highrelief pattern in stiffened PDMS by increasing of curing agent /monomer ratio (1:5) followed by thermal aging in a laboratory oven (200°C for 24 h). The stiffened PDMS masters were used to replicate microfluidic devices in PMMA based on soft embossing at 220-230°C and thermal sealing at 140°C. Both embossing and sealing stages were performed by using binder clips. The proposed protocol has ensured the replication of microfluidic devices in PMMA with great fidelity (>94%). Examples of MCE devices, droplet generator devices and spot test array were successfully demonstrated. For testing MCE devices, a mixture containing inorganic cations was selected as model and the achieved analytical performance did not reveal significant difference from commercial PMMA devices. Water droplets were successfully generated in an oil phase at rate of ca. 60 droplets/min (fixing the continuous phase flow rate at 100 μL/h) with size of ca. 322 ± 6 μm. Glucose colorimetric assay was performed on spot test devices and good detectability level (5 μmol/L) was achieved. The obtained results for two artificial serum samples revealed good agreement with the certified concentrations. Based on the fabrication simplicity and great analytical performance, the proposed soft-embossing protocol may emerge as promising approach for manufacturing PMMA devices.

Microfluidic systems for the analysis of blood‐derived molecular biomarkers

“…Droplet‐based microfluidics has also shown to be an invaluable tool for the detection of metabolites from serum [129, 133, 154], plasma [131], or even from dried blood spots [130, 134]. Droplets, ranging from 50 nl to 3 µl, act as microreactors, wherein sample and reagents are mixed to perform enzymatic assays [129, 131, 133, 155], resulting in short reaction times. Amino acids have been extracted from dried blood spots in a digital microfluidics platform and conditioned for an MS instrument to measure the amino acids present in the sample [130, 134].…”

Microchip Electrophoresis for Fluorescence-Based Measurement of Polynucleic Acids: Recent Developments

“…Reproduced from Inexpensive and nonconventional fabrication of microfluidic devices in PMMA based on a soft-embossing protocol, Lobo-Júnior, E. O.; Chagas, C. L. S.; Duarte, L. C.; Cardoso, T. M. G.; de Souza, F. R.; Lima, R. S.; Coltro, W. K. T. Electrophoresis , Vol. 41 , Issue 18 (ref ). Copyright 2020 Wiley.…”

“…The surface of the microchannel was smoothed by applying a chemical surface treatment procedure that exposed the channels to chloroform vapor. In addition, Coltro and co-workers developed an elegant, inexpensive fabrication method for PMMA that is based on a soft-embossing protocol (Figure G) . This method uses photocurable poly­(vinyl acetate) resin to create low-relief molds that are then used to create high-relief molds in stiffened PDMS.…”

“…In addition, Coltro and co-workers developed an elegant, inexpensive fabrication method for PMMA that is based on a softembossing protocol (Figure 1G). 45 This method uses photocurable poly(vinyl acetate) resin to create low-relief molds that are then used to create high-relief molds in stiffened PDMS. The PMMA microdevice is later embossed using the high-relief PDMS mold via binder clips and a laboratory oven (instead of a thermal press), making the overall fabrication process relatively inexpensive and simple.…”

An integrated plastic microchip for enhancing electrophoretic separation using tunable pressure‐driven backflows

“…Therefore, it has been a widespread concern by researchers [4,5]. Compared with glass microchip, plastic microchip has attracted much attention because of good light penetration, low cost, and easy fabricating option for executing MCE [6–8]. So far, plastic microchip has been successfully applied to the electrophoretic separation of amino acids [9,10], proteins [11,12], peptides [13,14], nucleic acids [15,16], and illegal addition in food [17,18].…”