A Two-Dimensional Metallacycle Cross-Linked Switchable Polymer for Fast and Highly Efficient Phosphorylated Peptide Enrichment

Abstract

The selective and efficient capture of phosphopeptides is critical for comprehensive and in-depth phosphoproteome analysis. Reported here is a new switchable two-dimensional (2D) supramolecular polymer that can serve as an ideal platform for the enrichment of phos-phopeptides. A well-defined, positively charged metallacycle incorporated into the polymer endows the resultant polymer with a high affinity for phosphopeptides. Importantly, the stimuli-responsive nature of the polymer facilitates switchable binding affinity of phos-phopeptides, thus resulting in excellent performance in phosphopeptide enrichment and separation from model proteins. The polymer has a high enrichment capacity (165 mg/g) and detection sensitivity (2 fmol), high enrichment recovery (88%), excellent specificity, and rapid enrichment and separation properties. Additionally, we have demonstrated the capture of phosphopeptides from the tryptic digest of real bio-samples, thus illustrating the potential of this polymeric material in phosphoproteomic studies.