Characterization of four functional biocompatible pressure-sensitive adhesives for rapid prototyping of cell-based lab-on-a-chip and organ-on-a-chip systems

Abstract

In the advent of affordable photo- and soft-lithography using polydimethylsiloxane (PDMS), low cost multi-step microfabrication methods have become available to a broad scientific community today. Although these methods are frequently applied for microfluidic prototype production in academic and industrial settings, fast design iterations and rapid prototyping within a few minutes with a high degree of flexibility are nearly impossible. To reduce microfluidic concept-to-chip time and costs, a number of alternative rapid prototyping techniques have recently been introduced including CNC micromachining, 3D printing and plotting out of numeric CAD designs as well as micro-structuring of thin PDMS sheets and pressure sensitive adhesives. Although micro-structuring of pressure sensitive adhesives promises high design flexibility, rapid fabrication and simple biochip assembly, most adhesives are toxic for living biological systems. Since an appropriate bio-interface and proper biology-material interaction is key for any cell chip and organ-on-a-chip system, only a limited number of medical-grade materials are available for microfluidic prototyping. In this study, we have characterized four functional biomedical-grade pressure sensitive adhesives for rapid prototyping (e.g. less than 1 hour) applications including structuring precision, physical and optical properties as well as biocompatibilities. While similar biocompatibility was found for all four adhesives, significant differences in cutting behavior, bonding strength to glass and polymers as well as gas permeability was observed. Practical applications included stability testing of multilayered, membrane-integrated organ-on-a-chip devices under standard cell culture conditions (e.g. 2–3 weeks at 37 °C and 100% humidity) and a shear-impact up to 5 dynes/cm 2 . Additionally, time- and shear-dependent uptake of non-toxic fluorescently labelled nanoparticles on human endothelial cells are demonstrated using micro-structured adhesive-bonded devices. Our results show that (a) both simple and complex microdevices can be designed, fabricated and tested in less than 1 hour, (b) these microdevices are stable for weeks even under physiological shear force conditions and (c) can be used to maintain cell monolayers as well as 3D cell culture systems.

Deformation Response of Polydimethylsiloxane Substrates Subjected to Uniaxial Quasi-Static Loading

“…From uniaxial mechanical test deformation behaviour and elastic properties was derived. Reliability of the instrumentation and measurement procedure for hyperelastic materials with Young's modulus from single kilopascal corresponding to desired values for further organ-ona-chip systems application [7] was successfully tested . For further analysis focused on dynamic testing simulating physiological processes new voice coil based loading device will be developed for cyclic loading of proposed materials with frequency up to 5 Hz.…”

Low-cost microphysiological systems: feasibility study of a tape-based barrier-on-chip for small intestine modeling

“…It offers a key advantage over e.g. Kratz et al's use of manually drilled glass slides, 11 however, with a simple chip-to-world interface for elastic tubing (one of the most critical, but also most often overlooked considerations in academic microfluidics). The microscopy slide format also affords simple imaging with existing equipment.…”

“…Kratz et al only recently presented an excellent characterization of tapes for organ-on-chip use, and demonstrated HUVEC culture in a single-compartment chip. 11 Yet no study to dateincluding theirshas implemented a tape-based multi-compartment system, or barrier-on-chip specifically, and demonstrated its biological functionality.…”

A compression transmission device for the evaluation of bonding strength of biocompatible microfluidic and biochip materials and systems

“…Firstly, commercially available biocompatible pressure sensitive adhesive tapes offer an easy and fast way to bond different functional material such as flexible membranes, glass, silicone and polymers to assemble multi-material/hybrid devices to build up multiplicity set-ups 25 . Results in Fig.…”