BACKGROUND OF THE INVENTION

Tissue formation, wound repair, and many disease processes depend on expression and cell-mediated assembly of the appropriate extracellular matrix (ECM) proteins. In particular, oriented ECM fibers are essential for normal tissue development and homeostasis. The organization of the ECM can, however, go awry in many diseases and at sites of injury producing the unaligned collagen fibers that form in scar tissue.

A goal of regenerative medicine is to promote formation of new tissue that closely resembles the normal tissue in organization and function. Controlling cell growth in a spatially defined way enables regeneration of damaged or diseased tissues having the proper alignment of constituent cells and/or alignment of molecular complexes that the cells produce. In particular, cells direct the arrangement of ECM fibrils to correspond to their actin filaments by using cell surface receptors that are indirectly connected to the actin cytoskeleton. Therefore, a major challenge in regenerative medicine is to promote cells to assemble ECM fibrils, such as collagen, into particular orientations or alignments on a scaffold device in order to generate tissues with the required functional properties.

Many methods for controlling cell growth rely on physical patterning procedures that are not compatible with tissue scaffold device utilization. For example, grooved patterns that physically restrain cells may affect cell functions, and stamping of biologics is size and thickness limited.

SUMMARY OF THE INVENTION

The present invention is based, at least in part, on the discovery of methods for generating cell-adhesive chemical (i.e., non-biologic) patterns in nano- and micro-scale dimensions using a technique for surface-modifying solids or polymers to generate devices that have utility as bio-scaffold materials and other devices including electrodes and sensors.

The devices of the present invention can be used in, for example, regenerative medicine, wound repair, and transplant biology, as well as in screening assays to determine the effects of a test compound on living tissue by examining the effect of the test compound on various biological responses, such as for example, cell viability, cell growth, migration, differentiation and maintenance of cell phenotype.

Accordingly, in one aspect, the present invention provides patterned scaffolds for tissue. In one embodiment, the tissue scaffold comprises a base layer comprising a pattern of stripes, and an oxide layer comprising the pattern of stripes. In one embodiment the base layer and the oxide layer comprise a pattern of oxide layer stripes on the base layer.

In another embodiment, the present invention provides a tissue scaffold comprising a base layer comprising a pattern of stripes; an oxide layer comprising the pattern of stripes; and an extracellular matrix component aligned in parallel on the stripes.

In another embodiment, the tissue scaffold comprises a base layer comprising a pattern of stripes, an oxide layer comprising the pattern of stripes, and a non-biologic cell adhesive layer disposed on the oxide layer.

In another embodiment, the present invention provides a tissue scaffold comprising a base layer comprising a pattern of stripes; an oxide layer comprising the pattern of stripes; a non-biologic cell adhesive layer disposed on the oxide layer; and an extracellular matrix component aligned in parallel with the stripes.

In another embodiment, the present invention provides an artificial tissue comprising living cells attached to a tissue scaffold comprising a base layer comprising a pattern of stripes, and an oxide layer comprising the pattern of stripes.

In another embodiment, the present invention provides an artificial tissue comprising living cells attached to a tissue scaffold comprising a base layer comprising a pattern of stripes; an oxide layer comprising the pattern of stripes; and a non-biologic cell adhesive layer disposed on the oxide layer.

In another embodiment, the present invention provides an artificial tissue comprising living cells attached to a tissue scaffold comprising a base layer comprising a pattern of stripes; an oxide layer comprising the pattern of stripes; and an extracellular matrix component aligned in parallel with the stripes.

In another embodiment, the present invention provides an artificial tissue comprising living cells attached to a tissue scaffold comprising a base layer comprising a pattern of stripes; an oxide layer comprising the pattern of stripes; a non-biologic cell adhesive layer disposed on the oxide layer; and an extracellular matrix component aligned in parallel with the stripes.

In another embodiment, the present invention provides a method for making a tissue scaffold comprising: generating a pattern of stripes on a base layer by photolithography to form a substrate having a patterned base layer; and depositing an oxide layer onto the patterned base layer to form a patterned oxide layer. In another embodiment, the method for making a tissue scaffold further comprises contacting the patterned oxide layer with a non-biologic cell adhesive compound to generate a patterned cell adhesive layer.

In another embodiment, the present invention provides a method for making a tissue scaffold comprising: generating a pattern of stripes on a base layer by photolithography to form a substrate having a patterned base layer; depositing an oxide layer onto the patterned base layer to form a substrate having a patterned oxide layer; contact the substrate having the patterned oxide layer with cells and culturing under conditions suitable for the production of extracellular matrix components; and removing the cells from the substrate to provide a tissue scaffold comprising an extracellular matrix component aligned in parallel with the stripes.

In another embodiment, the present invention provides a method for making a tissue scaffold comprising: generating a pattern of stripes on a base layer by photolithography to form a substrate having a patterned base layer; depositing an oxide layer onto the patterned base layer to form a substrate having a patterned oxide layer; contacting the patterned oxide layer with a non-biologic cell adhesive compound to generate a substrate having a patterned cell adhesive layer; contacting the substrate having the patterned cell adhesive layer with cells and culturing under conditions suitable for the production of extracellular matrix components; and removing the cells from the substrate to provide a tissue scaffold comprising an extracellular matrix component aligned in parallel with the stripes.

In another embodiment, the present invention provides a method for making an artificial tissue comprising living cells attached to a tissue scaffold comprising contacting a tissue scaffold of the present invention with cells and culturing under conditions suitable for cell growth and/or differentiation.

In other embodiments, the present invention provides medical devices comprising the artificial tissues or tissue scaffolds of the invention.

In other embodiments, the present invention provides methods of tissue repair and regeneration comprising implanting the artificial tissues of the present invention in a subject in need of such tissue repair or regeneration.

In another embodiment, the present invention provides methods for identifying a compound that modulates a tissue function. The methods include providing a patterned scaffold for tissue as described herein, contacting the tissue with a test compound, and measuring the effect of the test compound on a tissue function in the presence and absence of the test compound, wherein a modulation of the tissue function in the presence of the test compound as compared to the tissue function in the absence of the test compound indicates that the test compound modulates a tissue function, thereby identifying a compound that modulates a tissue function.

In another embodiment, the present invention provides methods for identifying a compound useful for treating or preventing a tissue disease. The methods include providing a patterned scaffold for tissue as described herein, contacting the tissue with a test compound, and measuring the effect of the test compound on a tissue function in the presence and absence of the test compound, wherein a modulation of the tissue function in the presence of the test compound as compared to the tissue function in the absence of the test compound indicates that the test compound modulates a tissue function, thereby identifying a compound useful for treating or preventing a tissue disease.

In another embodiment, scaffolds for nerve tissue regeneration and methods of use thereof are provided that overcome the limitations of previous systems and methods for controlling cell alignment on polymer substrates by using cell-assembled, aligned ECM patterned polymer scaffolding that controls neurite outgrowth as opposed to the unpatterned scaffolding systems of previous inventions. The presence of aligned ECM patterns in the scaffolding systems of the present invention helps promote and coordinate neurite growth in the directions of the aligned ECM patterns. In specific embodiments of the tissue scaffold the cells are neural cells. The neural cells can be selected from the group consisting of neural stem cells, oligopotent stem cells, differentiated neurons, differentiated glial cells and neural crest cells. In some embodiments the tissue scaffold containing neural cells is co-cultured with glial support cells.

