Ferrocene-Encapsulated Zn Zeolitic Imidazole Framework (ZIF-8) for Optical and Electrochemical Sensing of Amyloid-β Oligomers and for the Early Diagnosis of Alzheimer's Disease

In this work, the ferrocene-encapsulated Zn zeolitic imidazole framework (ZIF-8) was prepared by the self-assembly of Zn ions and 2-methylimidazole and used for the dual detection of amyloid-beta oligomers (A beta O), which is the main neuropathological hallmark of Alzheimer's disease. Ferrocene is an optically and electrochemically active signal which was successfully encapsulated inside of the ZIF-8 and released by the competitive coordination between Zn ions and A beta O after being treated with A beta O. The released ferrocene content was monitored by ultraviolet/visible spectrophotometry and cyclic voltammetry. The dual determination of A beta O played a synergetic role in the quick qualitative and precise quantitative analyses in a wide detection range of 10(-5) to 10(2) mu M and good feasibility in artificial cerebrospinal fluid.