Chemical and topographical patterning of hydrogels for neural cell guidancein vitro

Abstract

This review focuses on hydrogels and their patterning techniques in relation to central nervous system applications, with emphasis on synthetic and natural materials and chemical and topographical patterning techniques. We describe the properties of hydrogel materials and various techniques used in hydrogel patterning methods. Also, the applicability and utilization of patterned hydrogels with neural cells is discussed. Surface chemistry and topography significantly affect cell behaviour, including cell attachment, migration and maturation. Although several patterning techniques are described in the literature, a review of techniques applicable to hydrogel materials is needed. Use of these patterned cell-hydrogel constructs might provide novel ways to treat central nervous system deficits in the future.

Extracellular matrix cues modulate Schwann cell morphology, proliferation, and protein expression

“…As mentioned, the high RhoA activity can inhibit cell spreading and thus inactivate Rac1, which is consistent with previous research establishing an antagonism between the two proteins (Etienne-manneville, 2002). Further, SC elongation was shown to enhance c-Jun expression, which has been demonstrated in other research using aligned electrospun fibers and topographical cues to enhance SC elongation and nerve regeneration (Hoffman-Kim, Mitchel, & Bellamkonda, 2010;Turunen, Haaparanta, Aanismaa, & Kellomaki, 2013) Identifying the specific phenotypes of SCs following injury has been shown to be reasonably quantified through c-Jun expression (Arthur-Farraj et al, 2012). As SCs undergo differentiation, or transition to a "repair cell" where proliferation rate and cell morphology are altered from myelinating SCs, c-Jun levels rise whereas myelination factors are suppressed.…”

“…As mentioned, the high RhoA activity can inhibit cell spreading and thus inactivate Rac1, which is consistent with previous research establishing an antagonism between the two proteins (Etienne‐manneville, ). Further, SC elongation was shown to enhance c‐Jun expression, which has been demonstrated in other research using aligned electrospun fibers and topographical cues to enhance SC elongation and nerve regeneration (Hoffman‐Kim, Mitchel, & Bellamkonda, ; Turunen, Haaparanta, Aanismaa, & Kellomaki, )…”

Microscale Architecture in Biomaterial Scaffolds for Spatial Control of Neural Cell Behavior

“…Soft lithography is a technique used in conjunction with photolithography. First a patterned stamp or mold is made from materials such as polydimethylsiloxane (PDMS) using photolithography (Turunen et al, 2013). The patterned stamp is then placed on the substrate and the voids created by the stamp's pattern are filled with a biomaterial of interest, called ink.…”

Bridging the Gap: From 2D Cell Culture to 3D Microengineered Extracellular Matrices

“…This approach has been harnessed to explore and direct diverse cellular functions including neural guidance [168], [169], promotion of myotubes [170], stem cell differentiation [171]–[173], and epigenetic changes[174]–[176]. In addition, topographic patterning enables approximation on a materials surface the patterned features observed within the in vivo environment.…”

“…Human mesenchymal stem cells (hMSCs) cultured on 350 nm gratings have an elongated morphology with an aligned actin cytoskeleton, while on unpatterned controls, spreading cells showed a random but denser actin cytoskeleton network with altered cytoskeletal and focal adhesion protein expression [179]. Neurite growth can also be influenced by topographic cues and will follow along surface topographies [168], [169], [180] while a closely spaced array of non-adhesive PEG nanohydrogels will promote directional axon growth while limiting the attachment of astrocytes [169]. Micropatterned PDMS channels can promote neurite alignment in adult human neural stem cells; however, smaller channels force cells to deform their cytoskeleton which is unfavorable to neurogenesis [181].…”