Hybrid Photopatterned Enzymatic Reaction (HyPER) for in Situ Cell Manipulation

Abstract

The ability to design artificial extracellular matrices as cell instructive scaffolds has opened the door to technologies capable of studying cell fate in vitro and to guide tissue repair in vivo. One main component of the design of artificial extracellular matrices is the incorporation of biochemical cues to guide cell phenotype and multicellular organization. The extracellular matrix is composed of a heterogeneous mixture of proteins that present a variety of spatially discrete signals to residing cell populations. In contrast, most engineered ECMs do not mimic this heterogeneity. In recent years the use of photodeprotection has been used to achieve spatial immobilization of signals. However, these approaches have been limited mostly to small peptides. Here we combine photodeprotection with enzymatic reaction to achieve spatially controlled immobilization of active bioactive signals that range from small molecules to large proteins. A peptide substrate for transglutaminase factor XIII (FXIIIa) is caged with a photodeprotectable group, which is then immobilized to the bulk of a cell compatible hydrogel. With the use of focused light the substrate can be deprotected and used to immobilize patterned bioactive signals. This approach offers an innovative strategy to immobilize delicate bioactive signals, such as growth factors, without loss of activity and enables In situ cell manipulation of encapsulated cells.

Accelerated wound healing by injectable microporous gel scaffolds assembled from annealed building blocks

“…The resultant μgel building blocks were composed of a completely synthetic hydrogel mesh of multi-armed poly(ethylene)glycol-vinyl sulfone (PEG-VS) backbones decorated with cell-adhesive peptide (RGD) and two previously utilized transglutaminase peptide substrates 29–31 (K and Q). The μgels were crosslinked via Michael type addition with cysteine-terminated matrix metalloprotease-sensitive peptide sequences that allowed for cell-controlled material degradation and subsequent resorption.…”

Spatiotemporal hydrogel biomaterials for regenerative medicine

“…This has been employed to immobilize peptides and proteins in three dimensional hydrogels. 77,78 In particular, cellular adhesion or directed 3D migration could be achieved by patterning a peptide (RGD), a fibronectin fragment, or a full length protein (platelet-derived growth factor) (Figure 14). 77 Such site specific-modifications may prove particularly useful for the immobilization of fragile biomolecules.…”

Spatially and temporally controlled hydrogels for tissue engineering

“…This method could ligated a myriad of proteins with the PEG network under mild conditions, which suggested that it could represent a powerful method to fabricate complex hydrogel matrices with spatiotemporal control over protein distribution [239]. A similar approach was reported by Griffin et al to prepare hydrogels with 3D protein patterns in the presence of cells [240]. …”