Modulation of surface stiffness and cell patterning on polymer films using micropatterns

Abstract

Here, a new technology was developed to selectively produce areas of high and low surface Young's modulus on biomedical polymer films using micropatterns. First, an elastic polymer film was adhered to a striped micropattern to fabricate a micropattern-supported film. Next, the topography and Young's modulus of the film surface were mapped using atomic force microscopy. Contrasts between the concave and convex locations of the stripe pattern were obvious in the Young's modulus map, although the topographical map of the film surface appeared almost flat. The concave and convex locations of a polymer film supported by a different micropattern also contrasted clearly. The resulting Young's modulus map showed that the Young's modulus was higher at convex locations than at concave locations. Hence, regions of high and low stiffness can be locally generated based on the shape of the micropattern supporting the film. When cells were cultured on the micropattern-supported films, NIH3T3 fibroblasts preferentially accumulated in convex regions with high Young's moduli. These findings demonstrate that this new technology can regulate regions of high and low surface Young's modulus on a cellular scaffold with high planar resolution, as well as providing a method for directing cellular patterning. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 976-985, 2018.

Programmable microscale stiffness pattern of flat polymeric substrates by temperature-memory technology

“…Polymeric substrates comprising local mechanical stiffness pattern or nanostructural features are intensively investigated in the context of applications such as haptic displays (touchpads), stretchable electronics, mechanical and optical data storage devices, [1][2][3][4][5][6][7][8] or as instructive cell substrates guiding mechanosensitive (stem) cells. [9][10][11][12][13][14][15] While individual cells can react to structural features of few nanometers in size and mechanical differences in the Pascal (Pa) range, [9,14] the tactile sensitivity of a human finger is only capable of detecting structural features above 10 nm and local mechanics in the kPa regime. [16][17][18][19][20] Mechanically patterned surfaces can be realized by variation of the polymer's chemical composition (e.g., phase separated blends) [2] or crosslinking density (e.g., hydrogels).…”

Atomic force acoustic microscopy reveals the influence of substrate stiffness and topography on cell behavior

“…Yet, the stiffness of the substrate also regulates the cell morphology and movement. It has been observed that the fibroblasts cultured on the micropatterned film move towards stiffer surfaces in the stripe pattern, particularly at the boundaries between a stiff area and a soft area [46]. However, there are only few studies on the spreading of fibrotic cells on nanopatterned stiffness substrates.…”

A 3D Microfabricated Scaffold System for Unidirectional Cell Migration

“…These micropatterns were fabricated on silicon substrate using photolithography, as has been reported previously. [15,16,19] The silicon substrate was a square of 10 mm × 10 mm with a thickness of 725 µm. Twenty-five types of micropatterns with different shapes were fabricated on the silicon substrate of a single sheet.…”

“…B) Frequencies of cell protrusion directions toward either the right or left of each micropattern (1-20). The cell numbers used for counting cell protrusion directions on micropatterns 1-20 were19,19,14,18, 25, 22,15,12, 22, 20,17, 22, 22, 24, 20, 24,16, 25,12, and 17, respectively. C) The frequencies of cell protrusion directions toward either the right or left for all cells on all micropatterns (1-20).…”