Photoactivatable Adhesive Ligands for Light‐Guided Neuronal Growth

Abstract

Neuro-regeneration after trauma requires growth and reconnection of neurons to reestablish information flow in particular directions across the damaged tissue. To support this process, biomaterials for nerve tissue regeneration need to provide spatial information to adhesion receptors on the cell membrane and to provide directionality to growing neurites. Here, photoactivatable adhesive peptides based on the CASIKVAVSADR laminin peptidomimetic are presented and applied to spatiotemporal control of neuronal growth to biomaterials in vitro. The introduction of a photoremovable group [6-nitroveratryl (NVOC), 3-(4,5-dimethoxy-2-nitrophenyl)butan-2-yl (DMNPB), or 2,2'-((3'-(1-hydroxypropan-2-yl)-4'-nitro-[1,1'-biphenyl]-4-yl)azanediyl)bis(ethan-1-ol) (HANBP)] at the amino terminal group of the K residue temporally inhibited the activity of the peptide. The bioactivity was regained through controlled light exposure. When used in neuronal culture substrates, the peptides allowed light-based control of the attachment and differentiation of neuronal cells. Site-selective irradiation activated adhesion and differentiation cues and guided seeded neurons to grow in predefined patterns. This is the first demonstration of ligand-based light-controlled interaction between neuronal cells and biomaterials.

Turning Cell Adhesions ON or OFF with High Spatiotemporal Precision Using the Green Light Responsive Protein CarH

“…Controlling cell adhesions with light is particularly attractive as it provides regulation with a subcellular spatial and high temporal resolution, unmatched by other stimuli. Studies using photocontrolled cell‐ECM interactions with high spatiotemporal control have provided new insight into the role of adhesions in intracellular signal transduction, dynamics of cell adhesions, mechanosensing, collective cell migration, vascularization of biomaterials, guiding neuronal growth and stem cell differentiation…”

Towards systems tissue engineering: Elucidating the dynamics, spatial coordination, and individual cells driving emergent behaviors

“…Cells across multiple material platforms respond with dramatic changes in behavior after altering the mechanical stiffness of the underlying substrate [29][30][31][32]. Similarly, material systems that allow for dynamic control of ECM ligands can guide diverse emergent behaviors [33][34][35][36]. These systems for modulating the signals on demand are enabling for analysis of dynamic cellular responses.…”

“…Continuing advances in biomaterial microsystems uniquely allow for spatial control of cells to interrogate the role of spatial organization on tissue function. Synthetic hydrogel chemistries for 3D cell culture allow for high-resolution patterning of degradation [29], mechanical stiffness/crosslinking (Figure 6A) [206], and protein ligands(Figure 6B) [33,207,230] using photolithography methods. Just as materials can be patterned with light, optogenetic technology, where light and photosensitive proteins are used to control gene expression [231,232], can be used to photo-pattern gene expression within inhabitant cells of a microtissue(Figure 6C) [208].…”

Optoregulated Biointerfaces to Trigger Cellular Responses

“…This peptide allowed α5β1-mediated adhesion of human umbilical vein endothelial cells (HUVECs) to surfaces after light exposure. Photoactivatable variants of laminin peptidomimetic CAS­IKV­AVS­ADR have also been designed and applied to trigger neuronal growth on biomaterials in vitro . In this case, the PPG is introduced at the amine rest of the Lys, which is relevant for binding and allows facile coupling of the PPG.…”