Microfluidic channels laser-cut in thin double-sided tapes: Cost-effective biocompatible fluidics in minutes from design to final integration with optical biochips

Abstract

A simple, reliable and cost-effective fluidic channel, fabricated by using double-sided pressure-sensitive tapes, is demonstrated here. A laser-cutting method is applied to engrave structures in sheets of the tapes. After peeling off the tape liners, the structures could be easily integrated at room temperature with label-free optical waveguide biochips without further modifications or additional processing steps. It is shown that the well-defined and controllable height of the channels is advantageous for stopped-flow measurements of analyte binding.The easy fabrication of a fully transparent integrated sensor unit -tape cuvette system is also demonstrated for parallel microscopic investigations. The transparent unit was used to on-line monitor the surface adhesion of Salmonella cells on poly-L-lysine-coated biochip surfaces, followed by the straightforward microscopic visualization of the adhered bacterial cells. The material of the double sided tape is stable in aqueous solutions. Furthermore, its material is biocompatible, making it ideal for biological applications. Excellent, stable and reversible bonding of the microstructured tapes to biocompatible plastic and glass is also demonstrated.The simplicity of the fabrication at ambient temperatures makes the developed processes appealing for lab-on-a-chip applications, particularly if the bonded biochips are precious. / 12

Sample handling in surface sensitive chemical and biological sensing: A practical review of basic fluidics and analyte transport

“…Using this notation, the amount of glycerol in the cuvette at the instant of stopping the flow is and the total amount of glycerol following the equilibration of local concentration differences is . Building on the fact that the amount of glycerol present in does not change after the flow is stopped, the two qauntities can be equated, yielding (12) Our experimental findings were qualitatively confirmed by computational simulations of the flow in one of our flow-through cuvettes (Fig. 4a).…”

“…Biosensing technologies enabling label-free detection at a solid-liquid interface include surface plasmon resonance (SPR) (and SPR imaging, SPRi) [3,4,5], quartz crystal microbalance (QCM) [6], dual polarization interferometry (DPI) [7,8], grating-coupled interferometry (GCI) [9,10,11,12], the high-throughput compatible resonant waveguide grating biosensing [13,14,15], and optical waveguide lightmode spectroscopy (OWLS) [8,16,17,18]. OWLS instruments are currently among the most sensitive commercial label-free biosensors which enable the monitoring of various processes accompanied by refractive index changes 100-200 nm above a sensor surface .…”

“…However, diminishing the flow rate will ultimately result in transport-limited adsorption of analyte, during which the surface adsorption step in the sensing area is fast compared to the rate the analyte is supplied by the flow system and, therefore, the true surface process will not dominate the kinetics of the obtained signal (see §2.3), which is presumably what one wishes to quantify. Moreover, during data evaluation it is a common assumption that by the time the presence of the sample first appears in the recorded data, the cuvette has already been perfectly flushed 12 through by the sample solution (e.g., the liquids have been perfectly exchanged). The lower the flow rate, the more carefully this assumption needs scrutiny ( §2.3).…”

Adhesion kinetics of human primary monocytes, dendritic cells, and macrophages: Dynamic cell adhesion measurements with a label-free optical biosensor and their comparison with end-point assays

“…Evanescent field-based optical biosensors, including surface plasmon resonance (SPR), 36,37 optical waveguide lightmode spectroscopy (OWLS), 28,[38][39][40] photonic crystal biosensors, 41 grating coupling interferometry, 42,43 and resonant waveguide grating (commonly recognized as Epic) 44,45 biosensors, are considered to be especially straightforward means to monitor surface adhesion. First, they are sensitive only in a $150 nm thick layer closest to the substratum, exactly where establishment and maturation of anchorage and spreading occurs.…”

Microfluidic assembly kit based on laser-cut building blocks for education and fast prototyping

“…18 Laser cut tape has been used for replica-molding 19 and to fabricate cost-effective optical biochips. 20 Also, advanced tape bonding techniques 21 and low-cost prototyping methods with micro-milling, 22 robotic cutter, 23 or simple personal craft cutter (e.g., Silhouette) have been developed. 18,24,25 Laser cutting also has been used to direct-write channels into polymethyl-methacrylate substrates.…”