Structural hybridization of bimetallic zeolitic imidazolate framework (ZIF) nanosheets and carbon nanofibers for efficiently sensing α-synuclein oligomers

Abstract

A high-efficiency sensing system for α-synuclein (α-Syn) oligomers was designed based on a novel one dimensional (1D)/2D structural nanohybrid (denoted as CoMnZIF@CNF) of CoMn-based zeolitic imidazolate framework nanosheets (CoMnZIF NSs) vertically grown around carbon nanofibers (CNFs). CNFs were prepared by calcining electrospun polyacrylonitrile under Ar/H2 atmosphere and used as the template for CoMnZIF synthesis, which can remarkably enlarge the electrochemical signal of the CoMnZIF@CNF nanohybrid. The series of CoMnZIF@CNF nanohybrids were modulated by changing the ratios of precursors Co(NO3)2 and Mn(NO3)2 (i.e. 3:1, 1:1, and 1:3), leading to optimized sensing performances of α-Syn oligomers. Owing to the hierarchical nanostructure, good biocompatibility, and strong bioaffinity, the α-Syn oligomer aptamer can be strongly anchored over the CoMnZIF@CNF nanohybrid. Although the three CoMnZIF@CNF nanohybrids show comparable electrochemical activity, the CoMnZIF@CNF(1–3)-based aptasensor exhibits the superior sensing performance to other CoMnZIF@CNF nanohybrids and reported MOFs, giving a low detection limit of 0.87 fg mL−1 (45.7 fM) within the concentration of α-Syn oligomers rangefrom 1 fg mL−1 (52.6 fM) to 0.2 ng mL−1 (0.1 nM). The aptasensor based on CoMnZIF@CNF also has excellent selectivity, stability, reproducibility, and usability for the detection of α-Syn oligomersin human serum. The efficient strategy of structural hybridization can be used in designing different aptasensors and further extend the application range of ZIFs materials.