Interface engineering of microelectrodes toward ultrasensitive monitoring of β-amyloid peptides in cerebrospinal fluid in Alzheimer’s disease
Ultrasensitive detection of monomeric β-amyloid peptides (Aβ) is of fundamental significance for studying the pathological progression of Alzheimer’s disease (AD). In this article, by facilely engineering gold microelectrode interface, we developed a novel electrochemical biosensor for sensitive and selective monitoring of Aβ monomers in cerebrospinal fluid (CSF). Through the specific Cu2+-Aβ-hemin coordination, Aβ directed the assembly of Cu2+-PEI/AuNPs-hemin nanoprobes into network aggregates on microelectrode interface, which promoted the enrichment of Aβ monomers on microelectrode. Furthermore, the AuNP aggregate promote the deposition of silver nanoparticles, which were utilized for electrochemical stripping analysis of Aβ monomer. The proposed method displayed ultra-sensitivity for Aβ monomers with the detection limit down to 0.2 pM. Besides, high selectivity toward Aβ monomers was observed. Theses remarkable analytical performance made the electrochemical biosensor available for evaluating the dynamic change of Aβ monomers level in CSF of live mice with AD, promoting the investigation of the role that Aβ monomers play in brain events.