Protein arrays are used in a wide range of applications, including diagnostic biosensors. Diagnostic biosensors detect diseases in the human body. When diagnosing infectious diseases, biosensors must be sensitive and quick enough to distinguish between viral and bacterial infections. For example meningitis (a bacterial or viral infection) can be fatal if not diagnosed correctly and attended to quickly.

Diagnostic biosensors need a high performance protein surface array, an invisible engineered biological film that detects virus proteins in a sample. Orla Protein Technologies, a spinout of Newcastle University, design custom protein surfaces for some of the most advanced biosensor manufacturers. Orla wanted to show how proteins bind to its biological film to give clear and accurate results [Le Brun et al., Eur Biophys (2008) 37 639]. These results were necessary to ensure Orla's protein surfaces were reliable for manufacturing

Orla researchers used neutron scattering at ISIS to confirm the structure of its protein surfaces. ISIS enabled Orla to view its layers in action under water, binding to specific molecules and rejecting others. Optimisation of molecular orientation is critical to device miniaturisation allowing more clinical tests per square millimetre.

The ISIS experiments provided the physical and structural information required, in this case the antibody orientation and antigen binding sites onto an engineered surface of fully folded outer-membrane protein A (OmpA).

“Neutron scattering at ISIS is the only method capable of looking into the structure of these protein surfaces at scales 10 000 times thinner than a human hair,” said Orla Co-founder Professor Jeremy Lakey. “Neutrons can differentiate between isotopes of hydrogen. Therefore we can introduce isotopically labelled molecules into the reactions to help us tell where each component part is.”

Following the success of these experiments, Orla are planning further research at the new ISIS Second Target Station.