2 research outputs found
Patterning Three-Dimensional Hydrogel Microenvironments Using Hyperbranched Polyglycerols for Independent Control of Mesh Size and Stiffness
The
extracellular
matrix is an environment rich with structural,
mechanical, and molecular signals that can impact cell biology. Traditional
approaches in hydrogel biomaterial design often rely on modifying
the concentration of cross-linking groups to adjust mechanical properties.
However, this strategy provides limited capacity to control additional
important parameters in 3D cell culture such as microstructure and
molecular diffusivity. Here we describe the use of multifunctional
hyperbranched polyglycerols (HPGs) to manipulate the mechanical properties
of polyethylene glycol (PEG) hydrogels while not altering biomolecule
diffusion. This strategy also provides the ability to separately regulate
spatial and temporal distribution of biomolecules tethered within
the hydrogel. The functionalized HPGs used here can also react through
a copper-free click chemistry, allowing for the encapsulation of cells
and covalently tethered biomolecules within the hydrogel. Because
of the hyperbranched architecture and unique properties of HPGs, their
addition into PEG hydrogels affords opportunities to locally alter
hydrogel cross-linking density with minimal effects on global network
architecture. Additionally, photocoupling chemistry allows micropatterning
of bioactive cues within the three-dimensional gel structure. This
approach therefore enables us to tailor mechanical and diffusive properties
independently while further allowing for local modulation of biomolecular
cues to create increasingly complex cell culture microenvironments
Bottom-Up Strategy To Prepare Nanoparticles with a Single DNA Strand
We
describe the preparation of cross-linked, polymeric organic
nanoparticles (ONPs) with a single, covalently linked DNA strand.
The structure and functionalities of the ONPs are controlled by the
synthesis of their parent linear block copolymers that provide monovalency,
fluorescence and narrow size distribution. The ONP can also guide
the deposition of chloroaurate ions allowing gold nanoparticles (AuNPs)
to be prepared using the ONPs as templates. The DNA strand on AuNPs
is shown to preserve its functions