The «omics » era has contributed vastly to the potentially revolutionary development of point of care and personalised medicine. Success in these fields demands rapid, precise diagnostics. Carrying out relevant early diagnostics of a condition, i.e. as soon as, or even better, prior to, the manifestation of early symptoms permits prescription of a suitable treatment with obvious benefits both to the patient and to society in general.

Early diagnostics requires the detection and quantification of very small concentrations, or even trickier, slight variations of concentrations of a biomarker directly in small volumes of corporeal fluids such as blood, serum, saliva, urine and so forth. The task of early diagnosis is being carried out more and more by biosensors. However, the enormous advances made in instrument design that provide increasingly sensitive biosensors have not solved the problem of selectivity. Biochip surfaces in biosensors must be able to discern the presence of a single type of molecule amongst thousands or even millions of different molecules. This task falls necessarily to the biochip surface, which must have a surface chemistry that allows it to interact specifically and exclusively, with the target molecule.

We have developed a surface chemistry technology that allows biosensors to work at the instrument designated limit of detection by suppression of the noise level due to non-specific binding and selection only of target molecules thus necessarily increasing the signal to noise ratio.

I will cite examples using biosensors based on surface plasmon resonance and nanoparticles to illustrate some of the numerous advantages conferred to gold surface-based biosensors by our surface chemistry.