Bio‐Origami Hydrogel Scaffolds Composed of Photocrosslinked PEG Bilayers

Abstract

We describe the self-folding of photopatterned poly (ethylene glycol) (PEG)-based hydrogel bilayers into curved and anatomically relevant micrometer-scale geometries. The PEG bilayers consist of two different molecular weights (MWs) and are photocrosslinked en masse using conventional photolithography. Self-folding is driven by differential swelling of the two PEG bilayers in aqueous solutions. We characterize the self-folding of PEG bilayers of varying composition and develop a finite element model which predicts radii of curvature that are in good agreement with empirical results. Since we envision the utility of bio-origami in tissue engineering, we photoencapsulate insulin secreting β-TC-6 cells within PEG bilayers and subsequently self-fold them into cylindrical hydrogels of different radii. Calcein AM staining and ELISA measurements are used to monitor cell proliferation and insulin production respectively, and the results indicate cell viability and robust insulin production for over eight weeks in culture.

Smart hydrogels for 3D bioprinting

“…It can self-fold or self-unfold in response to temperature change with the application of yeast cell encapsulation [105] . This group of materials have a potential in bioprinting with the possibility of creating 4D bioprinted structures or bio-origami hydrogel scaffolds [106] .…”

Biomimicry, Biofabrication, and Biohybrid Systems: The Emergence and Evolution of Biological Design

“…[7] Gracias and co-workers have utilized this principle of patterned differential swelling to drive self-folding of poly (ethylene glycol) (PEG)-based hydrogel bilayers. [8] Their approach, relying on conventional photolithography to pattern PEG-based hydrogels, has broad applicability toward the manufacturing of microscale and macroscale 3D geometries. Precise tuning of hydrogel molecular weight and thickness in each layer allowed for the patterned self-folding of a range of geometries, including spheres, helices, and cylinders.…”

“…[67] Gracias and co-workers have demonstrated that cells can also be embedded within self-folding PEG-based hydrogels prior to assembly into 3D structures, and that multicellular multilayered structures can be generated using this methodology. [8] Manufacturing techniques inspired by textile weaving have also been explored for their ability to generate complex 3D architectures. Guilak and co-workers drove early advances in this field by developing a weaving technique for generating cartilage tissue from a composite mixture of chondrocytes and hydrogels.…”

A Perspective on 3D Bioprinting Technology: Present and Future

“…It enables the user to design almost any arbitrary shape, transformable to another shape using wide variety of materials. The arena of 4D printing has opened up a new platform where different properties can be combined to add functionalities in existing systems and thus have dynamic microstructures that can have wide applications (Jamal et al, 2013). For bio-medical field, 4D printing can enable capabilities where objects constructed using bio-inks can fuse, fold and re-model to generate tissues and constructs in fourth dimension of time.…”