Abstract
Hydrogel-based microfluidics offer an in vivo -relevant
micro-environments for construction of organs-on-chips. However, the
fabrication of heterogeneous microchannels using hydrogels is
challenging and fails to mimic the complex structures of organs in
vivo . Here we present a new methodology called “layer-by-layer
adhesion” for the construction of complex microfluidic chips. A
hydrosoluble and photo-crosslinkable adhesive, chitosan methacryloyl
(CS-MA), was used to stitch various hydrogels together layer-by-layer to
form perfusable microchannels. Our results show that CS-MA can bond
different types of hydrogels with adhesion energy ranging from 1.2-140
N/m. Using the layer-by-layer adhesion approach, we constructed
heterogeneous hydrogel-based microchannels with various morphologies of
snail, spiral, vascular-like, and bilayer. Based on this methodology,
liver-on-a-chip was established by entrapping hepatic cells inside a
biocompatible Gel-MA layer and covering it with the perfusable
microchannels in tough F127-DA layer. The “layer-by-layer adhesion”
provides a facile and cytocompatible approach for engineering
user-defined hydrogel-based chips potentially for organs-on-chips.
Keywords: Hydrogel microfluidic; layer-by-layer; adhesion;
sacrificial template; organ-on-a-chip