Silk film biomaterials for cornea tissue engineering

Abstract

Biomaterials for corneal tissue engineering must demonstrate several critical features for potential utility in vivo, including transparency, mechanical integrity, biocompatibility and slow biodegradation. Silk film biomaterials were designed and characterized to meet these functional requirements. Silk protein films were used in a biomimetic approach to replicate corneal stromal tissue architecture. The films were 2 μm thick to emulate corneal collagen lamellae dimensions, and were surface patterned to guide cell alignment. To enhance trans-lamellar diffusion of nutrients and to promote cell-cell interaction, pores with 0.5 to 5.0 μm diameters were introduced into the silk films. Human and rabbit corneal fibroblast proliferation, alignment and corneal extracellular matrix expression on these films in both 2D and 3D cultures was demonstrated. The mechanical properties, optical clarity and surface patterned features of these films, combined with their ability to support corneal cell functions suggest this new biomaterial system offers important potential benefits for corneal tissue regeneration.

Imaging Strategies for Tissue Engineering Applications

“…Therefore, in numerous tissue engineering studies, fluorescence microscopy has been used to distinguish matrix and matrix-embedded cells and examine their functionality. [79][80][81] In comparison to conventional optical microscopy, two-or multiphoton fluorescence microscopy can reduce optical attenuation and background signals by multiphoton absorption so that depth-resolved validation of the FIG. 7.…”

Silk Film Culture System for <em>in vitro</em> Analysis and Biomaterial Design

“…The culture system methodology presented here represents a scalable approach for rapid assessments of cell-silk film surface interactions. Of particular interest is the use of surface patterned silk films to study differences in cell proliferation and responses of cells for alignment 12,14 . The seeded cultures were cultured on both micro-patterned and flat silk film substrates, and then assessed through time-lapse phase-contrast imaging, scanning electron microscopy, and biochemical assessment of metabolic activity and nucleic acid content.…”

Corneal Tissue Engineering: Recent Advances and Future Perspectives

“…Therefore, engineering corneal stroma has been actively investigated by developing functional corneal stroma substrates through chemical, morphological, and mechanical cues. [50][51][52][53][54][55][56][57] In particular, synthetic polymers have been explored for stromal corneal substrates because of their tunable mechanical properties. They have also been processed in micron-nanosized fiber forms to direct stromal cell organization and differentiation in vitro, resulting in stratified collagen fibril lamellae in orthogonal orientations.…”

“…Primary human corneal fibroblast cells Torbet et al, 52 Crabb et al, 55 Wilson et al, 56 Gil et al, 65 Lawrence et al, 50 and Reichl et al…”