Copper(II) ions-immobilized virus-like hollow covalent organic frameworks for highly efficient capture and sensitive analysis of amyloid beta-peptide 1–42 by MALDI-MS

Amyloid beta-peptide 1–42 (A β 1–42) is one of the biomarkers of Alzheimer's disease, and its selective capture and quantitative detection are important for diagnosis and treatment of Alzheimer's disease. Herein, copper(II) ions-immobilized virus-like hollow covalent organic frameworks (V-HCOFs@Cu 2+ ) were synthesized by a facile approach. The as-prepared V-HCOFs@Cu 2+ showed unique morphology, ultra-high specific surface (2552 m 2 /g), uniform mesoporous structure (3.2 nm), superior chemical stability and abundant binding sites. Based on these excellent properties, the V-HCOFs@Cu 2+ could be adopted as an ideal enrichment probe for highly efficient capture of A β 1–42, exhibiting high adsorption capacity (320 mg/g), and fast adsorption equilibration time (3 min). In addition, an attractive approach of the V-HCOFs@Cu 2+ -based matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was developed for the rapid screening and quantitative analysis of A β 1–42 in human serum by using C-peptide as an internal standard, which exhibited low limit of detection (LOD, 0.2 fmol/µL), and satisfactory recovery. This work provides an alternative solution for enrichment of biomarkers and also offers the potential applications of COFs in clinical analysis