Chemistry Reference
In-Depth Information
outcome of this experiment established the potential of a self-assembling
peptide molecular gel as a tool for the synthesis and accumulation of a
cartilage-like extracellular matrix for tissue regeneration. The versatility of
molecular gels in medical applications is neatly demonstrated in their com-
bination with a traditional prosthetic material for regenerative medicine. The
regeneration or replacement of hard tissue in the body has proven to be a
challenge due to its mechanical properties.
One solution is the use of metal prostheses to replace the hard tissue. As an
example of how molecular gels could serve to assist the regeneration of hard
tissue, Sargeant and coworkers took a biologically inert Ti-6Al-4V prosthesis
and incorporated a peptide amphiphile 6.29 (Chart 6.6) based molecular gel
into the bone implant. This hybrid material was shown to be able to mineralise
with calcium phosphate over time and cells could be encapsulated in these
hybrids in a controlled manner. In vivo experiments showed that de novo bone is
formed adjacent to and inside the PA 6.29:Ti hybrid by four weeks, thus
offering strong evidence of osteoconduction, the growth of bone on the surface
and into the pores of the implant.
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In order for the successful application of hydrogels in tissue engineering there
is clearly a need to be able to fabricate scaffolds with controlled and intricate
precision. This will allow scientists to engineer tissues with the architectures
needed for their application.
Molecular gels have been used to control the 3D structure of polymeric gels
in tissue engineering. Komatsu et al. have demonstrated this using a molecular
hydrogel 6.30 with the ability to degrade in response to pH and UV irradiation,
which allows for the controlled fabrication of intricate 3D structures.
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The
technique utilises precise photofabrication, using focused UV laser light
(266 nm), which causes the hydrogel to transition to a liquid state and results in
the formation of fine channels in the hydrogel scaffold. Subsequent casting of
alternative gelators within the hydrogel mould results in the formation of the
desired structure. The cast material, in this example collagen, can be infused
with various cultures to create interweaving structures with differing cell lines.
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Chart 6.6
