Dual-pore size covalent organic frameworks shelled magnetic particles for anti-microbial peptide and microprotein enrichment with simultaneous exclusion of large proteins.

Antimicrobial peptides (AMPs) are critical effectors of innate immunity and promising alternatives to conventional antibiotics. However, their low abundance and interference from high-molecular-weight proteins in biological matrices hinder their selective enrichment and detection. Here, we report the design and synthesis of dual-pore covalent organic framework (COF)-shelled magnetic particles (M-Si@COF12) for efficient AMP and microprotein enrichment. The particles consist of magnetic core coated with silica (M-Si), followed by room-temperature, silanol-initiated growth of hair-like COF structures. This unique design provides precise control over hydrophobicity and dual pore sizes (2.7 and 3.2 nm), facilitating both size-selective and affinity-driven capture of low-molecular-weight bioactive peptides. M-Si@COF12 exhibits a high surface area (1014.95 m²/g), strong adsorption capacity (39.36 mg/g), and excellent selectivity toward AMPs. The material was validated using human serum and K-562 cell lysate, demonstrating effective enrichment of AMPs and AMP-like hydrophobic peptides (microprotein mimics). The particles are also reusable without significant loss of performance. This work presents a facile, scalable, and reusable material platform for targeted enrichment of bioactive microproteins, establishing a potential foundation for future applications in clinical proteomics and biomarker discovery.