Aromatic Dipeptide−Polymer-Derived Carboxylated Nanospheres for Hg2+ Binding

Abstract

Functionalized peptide−polymer conjugates have been used for applications such as drug delivery, catalysis, metal-ion binding, and gas separation due to their low toxicity. Reported herein is an acyclic aromatic dipeptide−polynorbornene conjugate decorated with carboxylate groups for cation binding. The peptide−polymer conjugate is prepared using an aromatic dipeptide scaffold functionalized with norbornene that readily self-assembles to form spherical aggregates. The self-assembly is covalently captured using ring-opening metathesis polymerization in the presence of a crosslinker to give robust nanospheres. Hydrolysis of the peptide C-terminus affords the carboxylated spheres with excellent thermal stability. These nanospheres can selectively remove 27.94 mg g⁻¹ of Hg(II) ions, which translates to an 86.5% removal efficiency. The nanospheres being insoluble can be readily isolated, regenerated, and reused for mercury removal without compromising the removal efficiency. Owing to their stability, selectivity, and reusability, the carboxylated spheres offer exciting prospects for environmental remediation applications.