Biointerfaces Between Cells and Substrates in Three Dimensions - Biointerfaces: Where Material Meets Biology - page 137

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Figure 6.3 Cell culture in the electrospun scaffolds. Top: SEM micrograph of an
electrospun scaffold. Bottom: breast cancer cells (blue) growing in an
electrospun scaffold (green).
Images taken from the Electrospinning Company, UK (www.
electrospinning.co.uk).

The technique is hugely versatile enabling a range of different fibrous
compositions and architectures with different diameters and porosities to be
formed. As a result the technique has attracted significant attention for 3D
cell growth applications, with cells being able to migrate into the mesh
structure and grow in a 3D manner. 11 Furthermore, electrospun materials
are now available as commercial scaffolds for 3D cell growth (Mimetix t ;
Electrospinning Company). Figure 6.3, taken from the Electrospinning
Company website (www.electrospinning.co.uk), illustrates how cells are able
to grow in a 3D manner within these materials. There are also exciting new
developments with aligned electrospun fibres, which may have important
applications for cells that require a specific orientation for function, such as
peripheral nerves and tendons. The materials are also inexpensive to pro-
duce, once the initial electrospinning equipment has been purchased.
However, the main limitation of electrospun materials is that 3D growth is
generally restricted to the nodes where fibres overlap, as large holes separ-
ating individual fibres can prevent extensive organisation. Consequently, 3D
growth tends to be as individual pockets dispersed throughout the material,
and very rarely will high cell densities be packed into the structure.
The mechanical properties of such materials are also quite poor, signifi-
cantly reducing their suitability for routine in vitro applications.

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6.2.4 Three-dimensional Printed Scaffolds
The development of 3D printing and selective laser sintering (SLS) has
opened up new opportunities for a range of versatile 3D interfaces which are
suitable for 3D cell growth, particularly for hard tissues such as bone. 12 Here
digital prototypes are used to construct 3D structures of a material one layer
at a time. As the materials are digitally designed, there is excellent control