In situ cell manipulation through enzymatic hydrogel photopatterning

Abstract

The physicochemical properties of hydrogels can be manipulated in both space and time through the controlled application of a light beam. However, methods for hydrogel photopatterning either fail to maintain the bioactivity of fragile proteins and are thus limited to short peptides, or have been used in hydrogels that often do not support three-dimensional (3D) cell growth. Here, we show that the 3D invasion of primary human mesenchymal stem cells can be spatiotemporally controlled by micropatterning the hydrogel with desired extracellular matrix (ECM) proteins and growth factors. A peptide substrate of activated transglutaminase factor XIII (FXIIIa)-a key ECM crosslinking enzyme-is rendered photosensitive by masking its active site with a photolabile cage group. Covalent incorporation of the caged FXIIIa substrate into poly(ethylene glycol) hydrogels and subsequent laser-scanning lithography affords highly localized biomolecule tethering. This approach for the 3D manipulation of cells within gels should open up avenues for the study and manipulation of cell signalling.

Harnessing developmental processes for vascular engineering and regeneration

“…polyethylene glycol (PEG) and its derivatives (Park et al, 2011;Koehler et al, 2013;Sandker et al, 2013;Stahl et al, 2014;Tokuda et al, 2014). In addition, hydrogels can be easily tailored with bioactive molecules (Mosiewicz et al, 2013), and their physicochemical properties are easily controlled (Tibbitt et al, 2013).…”

Design and Characterization of a Synthetically Accessible, Photodegradable Hydrogel for User-Directed Formation of Neural Networks

“…Such approaches have relied on advances of bio-orthogonal reactions and cytocompatible photochemical reactions to render advanced cell culture niches. (15)(16)(17)(18)(19)(20)(21)(22)(23) Specifically, photopatterned protein-ligand interactions have enabled the spatially controlled presentation of bioactive signaling proteins to drive stem cell migration, (12,24) orthogonal photocleavage reactions have been used to more efficiently differentiate cells by mimicking in vivo pathways, (15) and in situ photodegradation has been used to isolate the effect of cellular traction on stem cell differentiation. (25) For example, the Shoichet group developed a system exploiting strong protein-ligand interactions to immobilize gradients of sonic hedgehog protein to drive neural progenitor cell migration into an agarose gel.…”

“…(12) The Lutolf group used a photoactivated enzymatic ligation to pattern gradients of VEGF to demonstrate control over mesenchymal stem cell migration. (24) Previous work in the Anseth group identified orthogonal photodegradation reactions that allowed the sequential release of bone morphogenic proteins, which enabled more efficient differentiation of human mesenchymal stem cells. (15) While the above advances have demonstrated the power of controlled biological signaling to cells through regulation of material properties in space and time, complementary materials and simplified systems provide opportunities to expand the accessibility of the chemistry to a broader community of biomaterial researchers.…”

Dynamic bioengineered hydrogels as scaffolds for advanced stem cell and organoid culture

“…Spatial manipulation of biologically relevant molecules enables studies of cell adhesion, aggregation, spreading, and invasion within user-defined and intricate geometries. [70][71][72][73][74] Concentration gradients of bioactive molecules enable studies of cell migration, development, and growth. [75,76] Ultimately, simplified and adaptable systems will be required for widespread implementation whether for research or clinical application.…”