SPR imaging as a tool for detecting mucin – anti-mucin interaction. Outline of the development of a sensor for near-patient testing for mucin

Sensors able to provide ‘yes’/‘no’ answers have become of interest in recent years, especially in the fields of environmental research and healthcare. We describe a procedure based on surface plasmon resonance imaging (SPRI) to investigate the interaction between mucin and anti-mucin antibody, and we outline the development of an alarm sensor for the protein mucin, whose high concentration in saliva, blood or tissue is related to illnesses such as gingivitis, peridontitis or even cancer. Anti-mucin gastric antibodies are immobilised onto a gold surface. The immobilisation is evaluated for neat gold chips and for polymer-modified gold surfaces. We found that two different pHs are required, one for the immobilisation of the antibodies on gold (pH 5.5) and a different one for optimal interaction between the sample and the antibody layer (pH 7.0). Finally, we briefly demonstrate the application of the sensor to real saliva samples, both mucin-less and mucin-containing, evaluating the potential of the sensor to discriminate between healthy and ill.