BIO16: Toward a Blood-Compatible, 3D Printing Resin For Microfluidic Artificial Organs

Abstract

Purpose: Thrombogenic events are a limitation of artificial lung technologies for device longevity and patient safety. Currently, hollow fiber lungs and microfluidic artificial lungs (µALs) rely on surface modifications to improve hemocompatibility. Our goal to 3D print µALs inspired the development of a blood-compatible 3D printing resin to streamline fabrication of devices and remove the need for surface coatings. We aim to improve the blood compatibility of 3D-printed µALs via the inclusion of hydrophilic molecules directly into a high-resolution, polydimethylsiloxane 3D-printing resin formula. Methods: Hydrophilic molecules, dimethylsiloxane-[60-70% ethylene oxide] block copolymer (PEG-PDMS) and 2-Methacryloyloxyethyl phosphorylcholine (MPC) were directly integrated into our high-resolution 3D printing resin. Following resin work and printing characterization, thin films were made on the Asiga MAX X27 UV printer for subsequent testing. Wettability of the cured resin was determined with contact angle measurements over time. Blood compatibility was measured by exposing cured films to whole ovine blood, then running fluorescent assays and imaging for clot formation. Results: Incorporation of hydrophilic molecules induced a surface change from hydrophobic to hydrophilic when cured resin is exposed to water (Fig 1a). Printed surfaces containing hydrophilic additives reduced blood protein and cell adhesion after exposure to whole blood, as illustrated by reduced fluorescence intensity of FITC Fibrinogen and Membrite cell membrane stains (Fig 1b). Conclusion: The inclusion of hydrophilic molecules in the resin reduces the formation of blood clots thereby improving blood compatibility and potentially removing the need for subsequent surface modifications of printed parts. Fig. 1. (A) Contact angle measurements of commercially available PDMS, Sylgard 184, high-resolution resin alone referred to as “baseline resin”, the baseline resin with 1%MPC, and the baseline resin with 2%PEG (B) Protein (FITC Fibrinogen) and cell adhesion (Membrite) to cured films of resins (n=3 each) with and without hydrophilic additives. Images of representative films after testing with freshly drawn sheep blood are shown for (C) Sylgard 184, (D) Baseline resin, (E) 1% MPC, and (F) 2% PEG. The addition of hydrophilic molecules PEG and MPC to the resin decrease protein and cell adhesion compared to both the baseline resin and Sylgard 184.