Neural cell alignment by patterning gradients of the extracellular matrix protein laminin

Abstract

Anisotropic orientation and accurate positioning of neural cells is achieved by patterning stripes of the extracellular matrix protein laminin on the surface of polystyrene tissue culture dishes by micromoulding in capillaries (MIMICs). Laminin concentration decreases from the entrance of the channels in contact with the reservoir towards the end. Immunofluorescence analysis of laminin shows a decreasing gradient of concentration along the longitudinal direction of the stripes. The explanation is the superposition of diffusion and convection of the solute, the former dominating at length scales near the entrance (characteristic length around 50 μm), the latter further away (length scale in excess of 900 μm). These length scales are independent of the channel width explored from about 15 to 45 μm. Neural cells are randomly seeded and selectively adhere to the pattern, leaving the unpatterned areas depleted even upon 6 days of incubation. Cell alignment was assessed by the orientation of the long axis of the 4′,6-diamidino-2-phenylindole-stained nuclei. Samples on patterned the laminin area exhibit a large orientational order parameter. As control, cells on the unpatterned laminin film exhibit no preferential orientation. This implies that the anisotropy of laminin stripes is an effective chemical stimulus for cell recruiting and alignment.

Surface Modification of Polymer Substrates for Biomedical Applications

“…Cells adhered to samples irradiated perpendicularly (ripple width of 200 nm) exhibit random orientation akin to those adhered to a pristine sample while those adhered to samples irradiated under the 15° angle (270 nm) exhibit preferential orientation in about 50% of cases and the cells proliferated on samples irradiated under the angles of 30° and 45° (340 nm and 430 nm, respectively) are fully aligned along the main axis of the ripples [37]. The degree of the preferential orientation of the cells along the surface structures is affected not only by the dimension of said structures, but also by the type of the seeded cells [41,42]. The Chinese hamster ovary cell line, CHO-K1, for example, while showing results similar to the HEK-293 cell line, seems to prefer structures of larger dimensions.…”

Nano-engineered bioactive interfaces

“…The potential to pattern these material properties with micro-and nano-metric precision paves the way for the design of a novel class of materials-referred to as cell-instructive materialswith extended functionality and bioactivity. Chelli et al [1] demonstrate that patterning molecular adhesive islands of laminin on substrate by a novel technology called MIMICs proves to be very effective in guiding the formation of adhesive plaques, and therefore affecting neural cell adhesion, shape and migration. The effect of gradients of adhesive signal is demonstrated to have a profound effect on cell alignment and stretching along the longitudinal direction of the molecular adhesive stripes.…”

Coextruded, Aligned, and Gradient-Modified Poly(ε-caprolactone) Fibers as Platforms for Neural Growth

“…14 Laminin and laminin-derived peptides, such as IKVAV, are known to promote cell adhesion and induce neurite outgrowth of neural progenitor cells. 15–17 Additionally, neural cells are known to respond to haptotactic gradients of surface-immobilized peptides or proteins, allowing directional growth of neurites along the gradient. 15,18–21 Neural cells can also respond to topographical cues, such as lithographically patterned substrates, or more relevant to this work, aligned fibers.…”

“…15–17 Additionally, neural cells are known to respond to haptotactic gradients of surface-immobilized peptides or proteins, allowing directional growth of neurites along the gradient. 15,18–21 Neural cells can also respond to topographical cues, such as lithographically patterned substrates, or more relevant to this work, aligned fibers. 22,23 When neural cells are grown on aligned fibers, neurite outgrowth is typically seen along the direction of the polymeric fiber.…”