1. ABSTRACT
Toward the Control of Partial Covalent Modification of Glassy Carbon
Surfaces.
The patterning of surfaces with control over the relative ratios of different components
represents one of the goals in the creation of devices for biosensing and energy storage, since
it could improve the stability and sensitivity of the response. Considering this, a general
methodology for the creation of controlled mixed monolayers on glassy carbon (GC) surfaces
was developed, using osmium bipyridyl complexes and anthraquinone as model redox
probes, but potentially applicable to more complex systems.
The work consisted in the electrochemical grafting on GC of a mixture of diamine linkers in
different ratios and characterised by protecting groups which allowed orthogonal
deprotection. After optimisation of the deprotection conditions, it was possible to selectively
remove one of the protecting groups, couple a suitable osmium complex and cap the residual
free amines. The removal of the second protecting group allowed the coupling of
anthraquinone. The characterisation of the surfaces by cyclic voltammetry showed the
variation of the surface coverage of the two redox centres in relation to the initial ratio of the
linking amine in solution. It was then possible to build patterned surfaces where the osmium
complex acted as mediator for Glucose dehydrogenase (GDH), covalently bonded to GC
through an exposed cysteine residue to a maleimide moiety.