In the diagnosis of disease, proteins are common biomarkers. These are typically detecting using antibodies which specifically target protein sequences, such as those used in lateral flow devices (LFDs). However, there is a challenge in that any given protein sequence can have many different post-translational modifications - phosphorylation, lipidation and many more including glycosylation - the addition of glycans. The presence of a particular protein (detected by antibodies) does not always indicate disease and the exact glycoform is an important parameter not detected by current biosensing strategies, requiring complicated methods or technologies such as mass spectrometry. In this work, we show a hybrid detection based on antibodies and lectins - glycan 'reading' proteins. We use the antibody on the surface of a biolayer interferometry sensor to first capture 'all proteins which match' the antibody, but they use lectin-coated gold nanoparticles as the signal generators, so that we only detect a single glycoform. We demonstrate this with prostate specific antigen (PSA), where the different glycoforms, not just protein concentration, are important markers of disease.

Read the paper here, published in Nanoscale Horizons

Discrimination between protein glycoforms using lectin-functionalised gold nanoparticles as signal enhancersLink opens in a new window