Feasibility study on bonding quality inspection of microfluidic devices by optical coherence tomography

Abstract

This paper reports the feasibility of optical coherence tomography (OCT) technology for inspection of bonding quality of microfluidic devices in manufacturing environments. A compact optical-fiber-based OCT is developed and its measurement performance is characterized. A series of microfluidic devices respectively bonded by adhesive tape, thermal method, and oxygen plasma, are inspected. The defects of geometry deformation and sealing completeness are emphasized during measurements. Based on the inspection results, some discoveries related to the production of microfluidic devices are discussed.

Assessment of the flow velocity of blood cells in a microfluidic device using joint spectral and time domain optical coherence tomography

“…To the best of our knowledge, this is the first report of imaging the flow of whole blood, and red blood cells in shallow microchannels using OCT. Previously described, by the other authors, use of OCT related to microfluidic devices has been limited to the measurement of the Intralipid flow in 100 μm deep channels [38] and the electro-osmotic flow seeded with polystyrene beads in Polydimethylsiloxane-glass (PDMS-glass) microchannels [33], inspection of the bonding quality of microfludics devices in manufacturing environments [39] and the characterization of two-fluid mixing in microfludics devices [40,41].…”

Dimensional metrology of lab‐on‐a‐chip internal structures: a comparison of optical coherence tomography with confocal fluorescence microscopy

“…). The use of OCT to examine microfluidic devices has been limited to qualitatively inspecting several bonding methods of polycarbonate and polydimethylsiloxane devices (Li et al ., ). Despite this initial demonstration, the OCT technique has not been broadly used in microfluidic applications mainly because promises and challenges of OCT in microfluidic devices have not been assessed.…”

“…Optical Coherence Tomography (OCT) is a technique that could provide the imaging capabilities required for the analysis of deep subsurface internal structures within completely sealed (final products) polymeric devices with poor optical transparency or thicknesses of up to a few millimetres (Choma et al 2003;de Boer et al 2003;Drexler and Fujimoto 2008;Frohman et al 2008;Leitgeb et al 2003). The use of OCT to examine microfluidic devices has been limited to qualitatively inspecting several bonding methods of polycarbonate and polydimethylsiloxane devices (Li et al, 2011). Despite this initial demonstration, the OCT technique has not been broadly used in microfluidic applications mainly because promises and challenges of OCT in microfluidic devices have not been assessed.…”

Laser confocal feedback tomography and nano-step height measurement

“…Thus, a lot of attention has been paid to optical techniques in noninvasive imaging of biological tissues, such as scanning confocal microscopy16, diffusion photon density-wave propagation17, spectral fluorescence imaging1819, photoacoustic tomography2021. Especially, in recent years, optical coherence tomography (OCT)222324 has made a great progress in resolution, penetration depth, and scanning speed, and thereby has been widely used in the cross-sectional imaging of retina and teeth. However, due to the rapid decrease of the backscattering intensity when the depth increases, these methods are usually confined to measurements of a few millimeters in biological samples.…”