Page 8 - PERIODIC Magazine Issue 5

N ew Research

Lorna Softley and Christian van Engers report on Carbon is the most common anode material used in energy
some of the exciting and innovative research from storage devices. The graphene SFB thus allows for the
the Department of Chemistry study of processes occurring in every day materials, such as
Perkin Group mobile phone batteries.

The graphene Surface Force Balance - measurement
of graphene surface energy and application as model Read more:
2D carbon pore. Direct measurement of the surface energy of graphene,
van Engers et al., Nano Letters 2017, DOI: 10.1021/acs.
nanolett.7b01181
http://perkin.chem.ox.ac.uk/graphene-surface-
interactions.aspx

Bayley Group
A New Synthetic Retina

Graphene, an atomic layer of sp hybridized carbon, has
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received significant interest from the scientific community
due to its potential to impact a wide range of technologies.
While graphene is slowly entering the market, its surface
energy has received little attention.
Access to accurate surface energy values of graphene is
thus not only of fundamental interest, but provides a useful
reference for anyone involved in research on graphene
properties, (surface) modifications, and the implementation Researchers in the Bayley group* have developed the
of graphene in devices. first artificial retina made of soft materials, which could
transform the way degenerative eye conditions are treated.
By implementing graphene in a Surface Force Balance The biological materials from which the artificial retina is
(SFB), Christian van Engers – a DPhil in Susan Perkin’s constructed are more compatible with the body compared
group, was able to directly measure the surface energy of with existing, hard material technologies.
graphene.
The current device consists of a 4x4 array of bio-pixels
However, the graphene SFB allows for more than just the –aqueous droplets in lipid-containing oil, interfaced with
study of graphene properties. It serves as 2-dimensional a hydrogel scaffold, to form 16 individual bilayers. The
carbon pore and is thus ideally suited for the measurement presence of a light activated protein (bacteriorhodopsin)
of forces across electrolytes between graphene electrodes.
in the lipid bilayers drives a flow of ions across the bilayers
when illuminated by green light. This flow of ions produces
electrical signals that mimic the function of the natural
retina.
Photomasks were used to selectively illuminate individual
bio-pixels to show that each one could produce an
electrical signal independently of the others. This
‘controllable patterned current generation’ behaviour
has not previously been achieved with soft materials and
could allow for targeted stimulation of specific neurons.

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Periodic The Magazine of the Department of Chemistry