Nanotechnology provides a new generation of biocompatible nanomaterials for repairing
and replacing human tissues.

Human tissue that is diseased or traumatically compromised may require synthetic
materials for its repair or replacement. While most types of tissues repair the interaction
of stem cells with chemical modulators, there are differences in the ways that various
tissues heal.

“Hard” tissues such as bone and teeth heal by reproducing tissues indistinguishable from
the original. However in cases where a dental or artificial bone implant is required, the
structural material used in the implant may trigger immune rejection, corrode in the body
fluids, or no longer bond to the host bone. This can require additional surgery or result in
the loss of the implant’s function. In many cases, the failure occurs at the tissue-implant
interface, which may be due to the implant material weakening its bond with the natural
material. To overcome this, implants are often coated with a biocompatible material to
increase their adherence properties and produce a greater surface area to volume ratio for
the highest possible contact area between the implant and natural tissue.
“Soft” tissues such as skin, muscle, nerves, blood vessels and ligaments repair damaged
areas with fibrous tissue. Damaged tissue from various sources such as burns and ulcers
can be self-repaired by the body, but can also result in scar formation. Graft material
using artificial sheets can replace skin and other tissue with reasonable graft stability and
cosmetic outcome.

In other types of tissue, notably “Ultrasoft” tissue such as cell membrane and organelles
that exhibit metabolic function, tissue replacement can best occur when living cells are
transplanted in a mesh-structured synthetic scaffold.

The scaffold incorporates signalling ligands or DNA fragments to elicit specific cellular
responses, and molecular sensors to accept feedback from the in vivo environment. The
scaffold is typically a temporary structure that is bioresorbable when the tissue is
regenerated. The scaffold material needs to be fabricated into a desired shape or threedimensional
structure, with specific surface properties to support the site where the
organized growth of multiple cell types will take place.