Freeform 3D printing affords novel opportunities for using sacrificial materials within versatile hydrogels to reconstruct complex and sparse architectures. Carbohydrate glasses are a versatile tool for rapid and controlled freeform 3D printing, while offering exceptional potential as a biocompatible scaffold. Applications to tissue engineering, however, require protective coatings to utilize carbohydrate glasses due to the materials’ rapid dissolution kinetics in aqueous environments. Conformal coatings on intricate 3D structures cannot be easily achieved via conventional dip or spray coating methods. Therefore, we developed a method and report the application of protective coatings via surface-initiated polymerization (SIP) in this study. Photoinitiators (PI) were incorporated into isomalt and simple freeform 3D structures were printed. Structures were dipped into a photo-curable prepolymer bath and exposed to light for reaction initiation. Surface polymerization for isomalt presents several challenges: 1) the photoinitiator incorporated requires miscibility with isomalt, and 2) stability at 150°C and vacuum pressure during the pre-process isomalt dehydration, 3) the system has to be an anhydrous environment to prevent isomalt dissolution, 4) the temperature of the polymerization reaction needs to be under the glass transition temperature of isomalt (~61°C) for the printed scaffolds to maintain structural fidelity. Miscibility between commercial type-one photoinitiators and isomalt was modeled and predicted by solubility parameters using the group contribution method. A dye-based, type-two photoinitiator, Eosin Y, was selected for its miscibility with isomalt and stability under high temperature. A previously described Eosin Y (EY) / triethanolamine (TEA) radical polymerization system was used to polymerize poly (ethylene glycol) diacrylate (PEGDA). This method can be applied to coat dense, highly complex architectures and has the potential for organ modeling and high throughput analyses. This should facilitate the application of 3D sacrificial molding in a variety of hydrogels towards building biomimetic structures such as vascular constructs.

Surface-initiated photopolymerization enabling 3D sacrificial molding of biomimetic vascular constructs

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.