Polylactic is a Sustainable, Low Absorption, Low Autofluorescence Alternative to Other Plastics for Microfluidic and Organ-on-Chip Applications

Abstract

Organ-on-chips are miniaturised devices aiming at replacing animal models for drug discovery, toxicology and studies of complex biological phenomena. The field of Organ-On-Chip has grown exponentially, and has led to the formation of companies providing commercial Organ-On-Chip devices. Yet, it may be surprising to learn that the majority of these commercial devices are made from Polydimethylsiloxane (PDMS), a silicone elastomer that is widely used in microfluidic prototyping, but which has been proven difficult to use in industrial settings and poses a number of challenges to experimentalists, including leaching of uncured oligomers and uncontrolled adsorption of small compounds. To alleviate these problems, we propose a new substrate for organ-on-chip devices: Polylactic Acid (PLA). PLA is a material derived from renewable resources, and compatible with high volume production technologies, such as microinjection moulding. PLA can be formed into sheets and prototyped into desired devices in the research lab. In this article we uncover the suitability of Polylactic acid as a substrate material for Microfluidic cell culture and Organ-on-a-chip applications. Surface properties, biocompatibility, small molecule adsorption and optical properties of PLA are investigated and compared with PDMS and other reference polymers.

Biomedical Application of Functional Materials in Organ-on-a-Chip

“…• Heart-on-a-chip • Skin model (Zhao et al, 2016) • Microvascular networks (Yang et al, 2016) • Spheroid-based liver model ( • Scaffolds containing living cells (Ning et al, 2016) • Liver spheroids, tumor spheroids (Chan et al, 2016;Kang et al, 2016) • Hydrogel fibers (Zhu et al, 2017 • Self-organizing cardiac microchambers (Ma et al, 2015) • Liver organoids generation (Ng et al, 2018) • Intestinal organoids generation (Cruz-Acuña et al, 2017) showing a promising potential for future routine clinical use (Mottet et al, 2014). And recently, polylactic acid (PLA) as a sustainable, low absorption, low autofluorescence alternative to other plastics for OOC applications has been demonstrated (Ongaro et al, 2020). Thermoplastics are suitable for thermo-processing, which is excellent for commercial production due to high productionrate and low cost, but not economical for prototypic use (Ren et al, 2013).…”

“…They are also FDA approved, showing a promising potential for future routine clinical use ( Mottet et al, 2014 ). And recently, polylactic acid (PLA) as a sustainable, low absorption, low autofluorescence alternative to other plastics for OOC applications has been demonstrated ( Ongaro et al, 2020 ).…”

Microfluidic Skin‐on‐a‐Chip Models: Toward Biomimetic Artificial Skin

“…[ 55–57 ] In comparison, thermoplastic polymers are not permeable and thus do not adsorb small molecules and can be engraved using various micromachining techniques. [ 54,58 ]…”

Translational Roadmap for the Organs-on-a-Chip Industry toward Broad Adoption

“…Other commonly used materials for microfluidic device manufacture, including glass [61], polyurethane [62], polymethyl methacrylate (PMMA), and other thermoplastics, are much less flexible but do not absorb hydrophobic molecules, perhaps leading to more reliable cytotoxicity drug testing data [63]. Research for sustainable alternative plastic for manufacturing (such as bioderived materials) and new manufacturing techniques obviously requires funding in order to limit and streamline disposable plastic waste management, improve accuracy and resolution of fabrication, and to support the creativity of the developers [64].…”