Layer‐by‐layer adhesion of hydrogels for constructing heterogeneous microfluidic chips

Abstract

AbstractHydrogel‐based microfluidics have emerged as a promising platform for constructing organs‐on‐chips, offering in vivo‐relevant micro‐environments. However, the fabrication of complex microchannels using hydrogels remains challenging and often fails to replicate the intricate organ structures. Here, we introduce a novel methodology called “layer‐by‐layer adhesion” for the construction of complex microfluidic chips. Leveraging a hydrosoluble and photo‐crosslinkable adhesive, chitosan methacryloyl (CS‐MA), we successfully stitched various hydrogels together in a layer‐by‐layer fashion to form perfusable microchannels. Our results demonstrate the versatility of CS‐MA in bonding different hydrogels, with adhesion energies ranging from 1.2 to 140 N m−1. By implementing the layer‐by‐layer adhesion approach, heterogeneous hydrogel‐based microchannels were fabricated with diverse morphologies. We applied this technique to establish liver‐on‐a‐chip by entrapping hepatic cells within a biocompatible gelatin methacryloyl layer and overlaying it with perfusable microchannels in a robust F127‐DA layer. The “layer‐by‐layer adhesion” technique offers a facile, efficient, and cytocompatible approach for engineering user‐defined hydrogel‐based chips.