2 research outputs found
Injectable Shear-Thinning Fluorescent Hydrogel Formed by Cellulose Nanocrystals and Graphene Quantum Dots
In
the search for new building blocks of nanofibrillar hydrogels,
cellulose nanocrystals (CNCs) have attracted great interest because
of their sustainability, biocompatibility, ease of surface functionalization,
and mechanical strength. Making these hydrogels fluorescent extends
the range of their applications in tissue engineering, bioimaging,
and biosensing. We report the preparation and properties of a multifunctional
hydrogel formed by CNCs and graphene quantum dots (GQDs). We show
that although CNCs and GQDs are both negatively charged, hydrogen
bonding and hydrophobic interactions overcome the electrostatic repulsion
between these nanoparticles and yield a physically cross-linked hydrogel
with tunable mechanical properties. Owing to their shear-thinning
behavior, the CNC-GQD hydrogels were used as an injectable material
in 3D printing. The hydrogels were fluorescent and had an anisotropic
nanofibrillar structure. The combination of these advantageous properties
makes this hybrid hydrogel a promising material and fosters the development
of new manufacturing methods such as 3D printing
Patterning of Structurally Anisotropic Composite Hydrogel Sheets
Compositional
and structural patterns play a crucial role in the
function of many biological tissues. In the present work, for nanofibrillar
hydrogels formed by chemically cross-linked cellulose nanocrystals
(CNC) and gelatin, we report a microextrusion-based 3D printing method
to generate structurally anisotropic hydrogel sheets with CNCs aligned
in the direction of extrusion. We prepared hydrogels with a uniform
composition, as well as hydrogels with two different types of compositional
gradients. In the first type of gradient hydrogel, the composition
of the sheet varied parallel to the direction of CNC alignment. In
the second hydrogel type, the composition of the sheet changed orthogonally
to the direction of CNC alignment. The hydrogels exhibited gradients
in structure, mechanical properties, and permeability, all governed
by the compositional patterns, as well as cytocompatibility. These
hydrogels have promising applications for both fundamental research
and for tissue engineering and regenerative medicine