Fabrication of microfluidic hydrogels using molded gelatin as a sacrificial element

TLDR

The paper presents a general method for creating hydrogels with integrated microfluidic networks. The method uses micromolded gelatin meshes as sacrificial templates, which are encapsulated in a hydrogel and then melted and flushed to leave behind interconnected channels. The resulting microfluidic hydrogels feature channels as narrow as ~6 µm, faithfully replicate the gelatin mesh geometry, allow delivery and transport of macromolecules and particles in 50‑µm‑wide collagen and fibrin networks, and support endothelial cell seeding to form rudimentary vascular networks for tissue engineering.

Abstract

This paper describes a general procedure for the formation of hydrogels that contain microfluidic networks. In this procedure, micromolded meshes of gelatin served as sacrificial materials. Encapsulation of gelatin meshes in a hydrogel and subsequent melting and flushing of the gelatin left behind interconnected channels in the hydrogel. The channels were as narrow as ∼6 µm, and faithfully replicated the features in the original gelatin mesh. Fifty micrometre wide microfluidic networks in collagen and fibrin readily enabled delivery of macromolecules and particles into the channels and transport of macromolecules from channels into the bulk of the gels. Microfluidic gels were also suitable as scaffolds for cell culture, and could be seeded by human microvascular endothelial cells to form rudimentary endothelial networks for potential use in tissue engineering.