Nanoporous PEGDA ink for High-Resolution Additive Manufacturing of Scaffolds for Organ-on-a-Chip

Abstract

Polydimethylsiloxane (PDMS), commonly used in organ-on-a-chip (OoC) systems, faces limitations in replicating complex geometries, hindering its effectiveness in creating 3D OoC models. In contrast, poly(ethylene glycol)diacrylate (PEGDA-250), favored for its fabrication ease and resistance to small molecule absorption, is increasingly used for 3D printing microfluidic devices. However, its application in cell culture has been limited due to poor cell adhesion. Here, we introduce a nanoporous PEGDA ink (P-PEGDA) designed to enhance cell adhesion. P-PEGDA is formulated with a porogen, photopolymerized, followed by the removal of the porogen. Utilizing P-PEGDA, complex microstructures and membranes as thin as 27 µm were 3D-printed. Porogen concentrations from 10% to 30% were tested yielding constructs with increasing porosity, and without compromising printing resolution. Our tests across four cell lines showed over 80% cell viability, with a notable 52-fold increase in MDA-MB-231 cell coverage compared to non-porous PEGDA. Finally, we introduce an OoC model comprising a gyroid scaffold with a central opening filled with a cancer spheroid. This setup, after a 14-day co-culture, demonstrated significant endothelial sprouting and integration within the spheroid. The P-PEGDA is suitable for high-resolution 3D printing of constructs for 3D cell culture and OoC owing to its printability, biocompatibility, and cell adhesion.

In Vitro Investigation of Vocal Fold Cellular Response to Variations in Hydrogel Porosity and Elasticity

“…These hydrogels’ adjustable mechanical properties make them suitable for engineering a broad spectrum of tissues, which ranges from ∼1 kPa for the brain and ∼10 kPa for muscle to ∼100 kPa for bones, expanding their use in various biomedical and tissue engineering applications. Additionally, their rapid solidification upon UV light exposure renders them as optimal inks for vat photopolymerization-based 3D printing, facilitating the creation of intricate, high-resolution structures. − Overall, the hydrogels’ inherent biocompatibility, microporosity, adjustability, and UV responsiveness position them as promising materials for cutting-edge therapeutic applications, including mechanotransduction research, tissue engineering, and the construction of complex 3D-printed biomedical devices.…”

High-resolution low-cost LCD 3D printing for microfluidics and organ-on-a-chip devices

“…The design of PLInk was based on our prior ink formulations for 385 nm DLP 3D printing, 7,16 and adapted for LCD-based photopolymerization by considering the light heterogeneity, low irradiance, and 405 nm illumination wavelength. Based on our prior inks, PEGDA-250 was selected as the monomer due to its low viscosity, low protein adsorption, inherent cytocompatibility, and compatibility with solvents such isopropyl alcohol for efficient removal of uncured ink in embedded microchannels.…”

“…47 Recently, DLP 3D printed OoC and cell culture devices have been introduced with complex 3D architectures not feasible by replica molding. 16,48 However, the biocompatibility of photoinks including the photopolymer and additives such as the photoinitiator and photoabsorber must be validated, and in some case poorly cytocompatible phototoxins can be leached out for applications requiring cell seeding, cell reorganization and migration. 11,15,29 In the case of PLInk, biocompatibility was assessed after washing and sterilizing the 3D printed devices in 70% ethanol and PBS for 5 days before cell seeding (see PLInk performance metrics above and Materials and methods for more details).…”

“…The development of open-source inks such as those based on poly(ethylene glycol) diacrylate (PEGDA) for DLP 3D printing benefit from known compositions, which could help evaluate the impact of leachable and washable cytotoxic photosensitive components, and can be tailored and optimized for highresolution embedded 3D printing, enhanced mechanical properties, low viscosity for fast printing, as well as for low protein adsorption and cytocompatibility. 7,15,16 Altogether, high-precision 3D printers, custom inks, and direct 3D printable designs enables digital manufacturing, i.e., the seamless and automated fabrication from digital file to final product with minimal post-processing. Digital manufacturing of microfluidic components has been possible early on, and now extended to the fabrication of fully functional systems based on capillary flow.…”