4 research outputs found
ThiolāEne Alginate Hydrogels as Versatile Bioinks for Bioprinting
Bioprinting
is a powerful technique that allows precise and controlled
3D deposition of biomaterials in a predesigned, customizable, and
reproducible manner. Cell-laden hydrogel (ābioinkā)
bioprinting is especially advantageous for tissue engineering applications
as multiple cells and biomaterial compositions can be selectively
dispensed to create spatially well-defined architectures. Despite
this promise, few hydrogel systems are easily available and suitable
as bioinks, with even fewer systems allowing for molecular design
of mechanical and biological properties. In this study, we report
the development of a norbornene functionalized alginate system as
a cell-laden bioink for extrusion-based bioprinting, with a rapid
UV-induced thiolāene cross-linking mechanism that avoids acrylate
kinetic chain formation. The mechanical and swelling properties of
the hydrogels are tunable by varying the concentration, length, and
structure of dithiol PEG cross-linkers and can be further modified
by postprinting secondary cross-linking with divalent ions such as
calcium. The low concentrations of alginate needed (<2 wt %), coupled
with their rapid <i>in situ</i> gelation, allow both the
maintenance of high cell viability and the ability to fabricate large
multilayer or multibioink constructs with identical bioprinting conditions.
The modularity of this bioink platform design enables not only the
rational design of materials properties but also the gelās
biofunctionality (as shown via RGD attachment) for the expected tissue-engineering
application. This modularity enables the creation of multizonal and
multicellular constructs utilizing a chemically similar bioink platform.
Such tailorable bioink platforms will enable increased complexity
in 3D bioprinted constructs
ThiolāEne Alginate Hydrogels as Versatile Bioinks for Bioprinting
Bioprinting
is a powerful technique that allows precise and controlled
3D deposition of biomaterials in a predesigned, customizable, and
reproducible manner. Cell-laden hydrogel (ābioinkā)
bioprinting is especially advantageous for tissue engineering applications
as multiple cells and biomaterial compositions can be selectively
dispensed to create spatially well-defined architectures. Despite
this promise, few hydrogel systems are easily available and suitable
as bioinks, with even fewer systems allowing for molecular design
of mechanical and biological properties. In this study, we report
the development of a norbornene functionalized alginate system as
a cell-laden bioink for extrusion-based bioprinting, with a rapid
UV-induced thiolāene cross-linking mechanism that avoids acrylate
kinetic chain formation. The mechanical and swelling properties of
the hydrogels are tunable by varying the concentration, length, and
structure of dithiol PEG cross-linkers and can be further modified
by postprinting secondary cross-linking with divalent ions such as
calcium. The low concentrations of alginate needed (<2 wt %), coupled
with their rapid <i>in situ</i> gelation, allow both the
maintenance of high cell viability and the ability to fabricate large
multilayer or multibioink constructs with identical bioprinting conditions.
The modularity of this bioink platform design enables not only the
rational design of materials properties but also the gelās
biofunctionality (as shown via RGD attachment) for the expected tissue-engineering
application. This modularity enables the creation of multizonal and
multicellular constructs utilizing a chemically similar bioink platform.
Such tailorable bioink platforms will enable increased complexity
in 3D bioprinted constructs
Optimization of Media Change Intervals through Hydrogels Using Mathematical Models
Three-dimensional cell culture in engineered hydrogels
is increasingly
used in tissue engineering and regenerative medicine. The transfer
of nutrients, gases, and waste materials through these hydrogels is
of utmost importance for cell viability and response, yet the translation
of diffusion coefficients into practical guidelines is not well established.
Here, we combined mathematical modeling, fluorescent recovery after
photobleaching, and hydrogel diffusion experiments on cell culture
inserts to provide a multiscale practical approach for diffusion.
We observed a dampening effect of the hydrogel that slowed the response
to concentration changes and the creation of a diffusion gradient
in the hydrogel by media refreshment. Our designed model combined
with measurements provides a practical point of reference for diffusion
coefficients in real-world culture conditions, enabling more informed
choices on hydrogel culture conditions. This model can be improved
in the future to simulate more complicated intrinsic hydrogel properties
and study the effects of secondary interactions on the diffusion of
analytes through the hydrogel
Optimization of Media Change Intervals through Hydrogels Using Mathematical Models
Three-dimensional cell culture in engineered hydrogels
is increasingly
used in tissue engineering and regenerative medicine. The transfer
of nutrients, gases, and waste materials through these hydrogels is
of utmost importance for cell viability and response, yet the translation
of diffusion coefficients into practical guidelines is not well established.
Here, we combined mathematical modeling, fluorescent recovery after
photobleaching, and hydrogel diffusion experiments on cell culture
inserts to provide a multiscale practical approach for diffusion.
We observed a dampening effect of the hydrogel that slowed the response
to concentration changes and the creation of a diffusion gradient
in the hydrogel by media refreshment. Our designed model combined
with measurements provides a practical point of reference for diffusion
coefficients in real-world culture conditions, enabling more informed
choices on hydrogel culture conditions. This model can be improved
in the future to simulate more complicated intrinsic hydrogel properties
and study the effects of secondary interactions on the diffusion of
analytes through the hydrogel