Silicon‐Based Sensing Surface for Alzheimer's Disease Diagnosis by Phages Probes

Alzheimer's disease (AD) is a diffused neurodegenerative disorder affecting people in advanced age causing loss of memory and dementia. Nowadays, diagnosis and treatment of AD are still challenging due to the lack of diagnostic systems that allow for an early and reliable diagnosis and therapy monitoring. Moreover, conventional strategies for AD diagnosis are based on brain imaging techniques that are invasive and expensive for early and massive screening. Phage display approach, using engineered phage probe for direct amyloid-beta (A beta)-autoantibodies detection, overcome these limitations leading to the possibility of safe and low-cost screening. Moreover, the combination with silicon technology further improves the easiness of diagnosis due to the portability of devices and the integration of sensitive transduction signals. In this work, an innovative silicon-based sensing technology is reported detecting A beta-autoantibodies, specifically Immunoglobulin G (IgG), in human sera by engineered M13-phage probes (ADPP). The strategy hinges on a bio-surface that is integrated on top of a silicon biosensor. Thanks to phages probes exposing A beta-mimic peptides, this chip can capture and reveal A beta-autoantibodies, discriminating between healthy and AD conditions. The surface chemistry is morphologically and chemically characterized and the phage-based biosensor ability to recognise A beta-autoantibodies is proved by transduction with enzyme-linked anti-M13 antibodies.