The relevance of buffer system ionic strength in immunoassay development

The best validated immunoassays for neurodegeneration have been developed for class III and IV intermediate filaments. There are a number of unique biochemical features of the intrinsically unstructured polyampholytic tail regions of these proteins which affect domain structure and thereby affinity and epitope recognition of antibodies used in immunoassays. Here one of these intermediate filaments, the neurofilament heavy chain, is chosen to demonstrate the effect of the ionic strength of a buffer system on the analytical signal to noise ratio. Higher ionic strengths gave better results. Next, a dose-dependent effect is demonstrated for barbitone to increase epitope recognition and protein quantification. The described effects of the buffer systems may be found helpful for future immunoassay developments.