Cost-efficient fabrication techniques for microchips and interconnects enabled by polycaprolactone

Abstract

In this paper we present a novel fabrication technique that utilizes polycaprolactone (PCL) as bonding media due to its low melting temperature property. PCL is biodegradable polyester with a melting point of 60°C, and a glass transition temperature of -60°C [1-10]. It is employed as a rapid bonding technique in the fabrication process that readily produces complete microfluidic chips. The microchannels are produced via laser ablation micromachining and thermal embossing, followed by bonding with PCL. The PCL is uniformly coated on a piece of polymer sheet to produce a thin film on its surface. A complete microfluidic channel is formed by enclosing the open channel with the PCL-coated polymer piece. This fabrication technique lends itself readily to various polymers, such as (poly)methylmethacrylate (PMMA), polycarbonate (PC), polyetherimide (PEI), and poly(ethylene terephthalate) (PETE), facilitating device production for a variety of application, even permitting hybrid polymer chips. The bonding was performed rapidly at 60°C. This approach provides a more direct method to generate hard polymer microfluidic chips than classical techniques and is therefore highly amendable to rapid prototyping. This work also explores the use of PCL as an alternative approach to making simple, costeffective universal adhesive for bonding interconnects. Bonding is performed at 60°C, by placing the adhesive layer in between an interconnect port and a microchip. This method allows for connections to be made easily and quickly.

Lab-on-a-chip devices: How to close and plug the lab?

“…Gutierrez-Rivera et al formed a 15 nm thick ''conformal adsorbate layer'' on KMPR Ò photoresist and used this thin layer to fabricate multilayer microfluidics by adhesive bonding [116]. Polycaprolactone, a biodegradable polyester, was used by Koesdjojo et al as an intermediate bonding medium for the bonding of polymer-based layers [117]. They reported compatibility with working pressures up to 10 MPa for chips sealed at 60°C.…”

“…For applications that require higher pressures of liquids, IDEX Health and Science (formerly Upchurch Scientific) provides pre-formed epoxy adhesive rings for high-quality (pressures up to 6.9 MPa) bonding of their NanoPort™ connectors to rigid chip surfaces [187]. Alternatively, Koesdjojo et al used a polycaprolactone film to bond NanoPorts to plastic chips at a lower temperature (around 60°C) [117].…”

Oxygen radical‐driven surface modification of polycaprolactone‐filled glass microfiber media: Probing the surface chemistry of wicking microfluidic devices

“…In our previous work, we have demonstrated the use of selective oxygen radical exposure as a tool for the fabrication of highly adaptable complex multidimensional (2D and 3D) microfluidic pathways on polycaprolactone (PCL)‐filled glass microfiber (GMF) membranes . PCL is a biocompatible and biodegradable polyester, which is hydrophobic in nature . Combining hydrophobic PCL as a patterning agent with the hydrophilic borosilicate GMF as a substrate yields an excellent platform for fabrication of wicking microfluidic devices.…”

“…10,11 PCL is a biocompatible and biodegradable polyester, which is hydrophobic in nature. [12][13][14][15] Combining hydrophobic PCL as a patterning agent with the hydrophilic borosilicate GMF 16 as a substrate yields an excellent platform for fabrication of wicking microfluidic devices. To the best of our knowledge, this is the only wicking microfluidic device fabrication technology that is capable of generating both 2D and 3D microfluidic pathways in a single membrane.…”

An easy-to-use microfluidic interconnection system to create quick and reversibly interfaced simple microfluidic devices

“…The individual commercially available connectors such as Luer and Nanoport, on the other hand, need to be irreversibly glued or bonded to the devices. While there are solutions to overcome some problems associated with epoxy glues [10], the additional material can lead to chemical or thermal incompatibilities. As an alternative, the required protruding structures can be molded as part of the device, which avoids the adhesive but complicates fabrication and bonding procedures [11].…”