Self-healing hydrogels

Fabrication

Pathology

Nanotechnology

Organic chemistry

Mathematics

Membrane

Microfluidics

Mathematics education

Physical chemistry

Microscale chemistry

Chemistry

Materials science

Alternative medicine

Lipid bilayer

Colloid

Soft materials

Soft matter

Biochemistry

Medicine

Nature Chemistry

Responsive hydrogels that undergo controlled shape changes in response to a range of stimuli are of interest for microscale soft robotic and biomedical devices. However, these applications require fabrication methods capable of preparing complex, heterogeneous materials. Here we report a new approach for making patterned, multi-material and multi-responsive hydrogels, on a micrometre to millimetre scale. Nanolitre aqueous pre-gel droplets were connected through lipid bilayers in predetermined architectures and photopolymerized to yield continuous hydrogel structures. By using this droplet network technology to pattern domains containing temperature-responsive or non-responsive hydrogels, structures that undergo reversible curling were produced. Through patterning of gold nanoparticle-containing domains into the hydrogels, light-activated shape change was achieved, while domains bearing magnetic particles allowed movement of the structures in a magnetic field. To highlight our technique, we generated a multi-responsive hydrogel that, at one temperature, could be moved through a constriction under a magnetic field and, at a second temperature, could grip and transport a cargo.                                                                                                        Responsive hydrogels are of interest for a range of potential applications, including microscale soft robotic and biomedical devices. Now, a versatile fabrication approach has been developed to prepare patterned, multi-material and multi-responsive hydrogels. Pre-gel droplets are connected through lipid bilayers in predetermined architectures and photopolymerized to yield continuous hydrogel structures that respond to a variety of stimuli.

Multi-responsive hydrogel structures from patterned droplet networks