Histidine-Triggered GO Hybrid Hydrogels for Microfluidic 3D Printing

Area of Science:

• Materials Science
• Biotechnology
• Additive Manufacturing

Background:

• Graphene oxide (GO) hydrogels offer potential for complex construct fabrication.
• 3D printing of GO hydrogels is hindered by low viscosity, poor gelation, and weak interfacial tension, especially without photocuring.

Purpose of the Study:

• To develop a novel strategy for 3D printing graphene oxide hybrid hydrogels.
• To overcome the limitations of traditional 3D printing methods for GO-based materials.

Main Methods:

• A microfluidic 3D printing technique was employed.
• A histidine-assisted strategy was developed to control gelation of GO-polymer solutions.
• The Knoevenagel condensation reaction was utilized for hydrogel formation.

Main Results:

• Graphene oxide addition inhibited the Knoevenagel condensation reaction, but histidine addition rapidly induced hydrogel formation.
• Low-viscosity GO-polymer solutions were printable as inks, forming hydrogel microfibers.
• The resulting GO hybrid hydrogel microfibers supported cell viability and enabled the construction of complex 3D structures.
• The microfibers demonstrated excellent electrical conductivity, sensing motion changes and converting them into electrical resistance signals.

Conclusions:

• The histidine-assisted printing strategy successfully enabled the microfluidic 3D printing of GO hybrid hydrogels.
• This method provides a new avenue for fabricating complex, conductive, and cell-compatible 3D structures using aqueous GO inks.
• The developed technique expands the applications of 3D printable GO-based materials in various fields.