Nanomaterials for in situ cell delivery and tissue regeneration

Nanomaterials can be defined as materials that possess clearly defined features of less than 100 nm, and whose nanostructured features confer characteristics crucial to the material's bulk property. The nanostructured features can be an intermediate or final state of the material in its synthesis process. The field of nanomaterials as applied to in situ cell delivery and tissue engineering is rapidly expanding. Nanomaterials that include peptide amphiphiles, self-assembling peptides, electrospun scaffolds, layer-by-layer complexes, nanotubes and nanocomposites have been applied to cell culture, encapsulation and delivery with promising results. As compared to scaffold-free cell delivery, nanomaterials are advantageous in terms of providing a means to control the biochemical and mechanical microenvironment of the cells. Nanomaterials are amenable to a bottom-up approach in functionalization and mechanical tuning, as illustrated in the examples presented in this review. Furthermore, nanomaterials such as DNA polyplexes and carbon nanotubes can also be incorporated into the cell delivery vehicle to improve the regenerative outcome. Lastly, while nanomaterials harbor much potential for cell delivery and tissue regeneration, further characterization is required in terms of clinical safety before these materials can be employed towards therapeutic applications.