Biology subjects

Claxton, N. L.

Publications and source records attributed to Claxton, N. L..

2 recordsLinked to original sources

bioRxiv2025

Focused Ultrasound Crosslinkable Granular Hydrogels

Minimally invasive delivery of biomaterials for tissue regeneration can be achieved using biomaterials delivered by injection that rapidly stabilize at the delivery site. Tissue regeneration has been shown to be dependent on material properties, with porosity strongly supporting revascularization and tissue regrowth. Here, a highly porous granular hydrogel system was designed that is compatible with the unique strengths of highly penetrating, minimal invasive focused ultrasound (FUS), to address this challenge. FUS offers well-defined spatial and temporal control over hydrogel crosslinking. We developed a composite granular hydrogel scaffold composed of two polyethylene glycol (PEG)-based components, microgels and fibers with FUS-responsive chemistry, and a pore-defining gelatin microgel component. Upon applying FUS, the bulk granular hydrogel stabilized through the formation of crosslinks between PEG components, with porosity designed by gelatin microgel melting. FUS-crosslinking parameters were determined that resulted in crosslinking both in vitro and a mouse cadaver model of minimally invasive delivery. The resulting granular hydrogels stability depended on the presence of fibers and exhibited viscoelastic properties comparable to granular hydrogels that were photocrosslinked. Hydrogels were highly porous and cytocompatible. This work defines a FUS-responsive granular system and extends the potential of FUS as a novel, noninvasive method for crosslinking regenerative hydrogel systems.

bioengineering↗

bioRxiv2023

Engineering Particle-based Materials for Vasculogenesis

Vascular networks are critical to the survival of cells within materials designed for regenerative medicine. Developing approaches to vascularize three-dimensional (3D) in vitro models that recreate tissue physiology and 3D tissue constructs for regenerative medicine remain an important focus of tissue engineering. Granular hydrogels are emerging as a promising class of materials for the regeneration of damaged tissues and fabricating tissue constructs. While granular hydrogels have supported vasculature formed by angiogenesis and fabrication processes that establish channels, parameters for designing these materials to support formation of vasculature by vasculogenesis from cells contained within these materials are not fully understood and remain largely unexplored. In this study, vasculogenesis within 3D granular hydrogels formed from polyethylene glycol (PEG) microgels are studied for its potential to establish a microvascular network within this class of materials. Self-organization of endothelial cells into networks within hours is observed in the presence of fibroblasts, and the effects of cell adhesive ligands (RGD) and porosity are measured. Increasing porosity is observed to enhance vasculogenesis while the addition of RGD impairs microvessel network formation. This work establishes parameters that support robust microvasculature formation within granular hydrogels that might be broadly applicable to this class of materials, with implications for other morphogenetic processes in 3D systems.

bioengineering↗