Observation Interface of PDMS Membrane in a Microfluidic Chip Based on One-Step Molding

Abstract

Nowadays, researchers are focusing on sorting, characterizing and detecting micron or submicron particles or bacteria in microfluidic chips. However, some contradictions hinder the applications of conventional microfluidic chips, including the low working distance of high resolving power microscopy and the low light transmittance of conventional microfluidic chips. In this paper, a rapid and readily accessible microfluidic fabrication method is presented to realize observation with high magnification microscopy. With the one-step molding process, the interconnections, the thin observation interface of polydimethylsiloxane (PDMS) membrane and microfluidic channels were integrated into an intact PDMS replica. Three kinds of PDMS replicas with different auxiliary beams were designed and optimized by leakage experiments and analytical software. The observation interfaces of a 170 μm thickness PDMS membrane enlarges the application domain of microfluidic chips. By adopting a solution of high magnification observation, microfluidic devices could be applied widely in medical science, biology and material science.

Mixing and jetting analysis using continuous flow microfluidic sample delivery devices

“…This is due to the low pressure resistance of PDMS combined with the comparatively weak oxygen plasma assisted bonding. 28,29 Recently, Koralek et al 30 analysed ultrathin (between 20 nm and 1 mm) free standing liquid sheets produced using a glass based microuidic injector. Characterization of the devices was performed using optical, infrared, and X-ray spectroscopies.…”

Demonstration of a Transparent and Adhesive Sealing Top for Microfluidic Lab-Chip Applications

“…Depending on the magnification of the objective lens, it could be less than 0.3 mm. The contradiction between the thickness of microfluidic chips and the recommendation for the working distance of high-resolution microscopy prevents microfluidic devices from being further exploited in many applications [ 56 ]. Since, in our test, the range of thickness for the four materials being tested was considerably low (140 µm to 200 µm), we expected that the observation of the fluorescence particles in our device with a thin observation interface via the object of high numerical aperture would be sufficient for any optical interrogation.…”

Application of Polymethylpentene, an Oxygen Permeable Thermoplastic, for Long-Term on-a-Chip Cell Culture and Organ-on-a-Chip Devices

“…A major challenge with common microfluidic cell culture devices fabricated in PDMS is that due to the high elasticity of the material, a device thickness in the millimetre range is necessary to obtain suitable rigidity for robust channel geometry. To perform high-resolution imaging a working distance of generally less than 0.3 mm is necessary [ 35 ], hence millimetre-thick PDMS devices are not practical. Most objective lenses are designed to work with glass coverslips of thickness 0.17 mm (coverslip #1.5) when the specimen is in direct contact with the coverslip [ 36 ].…”