Dual Molecular Recognition Leading to a Protein-Polymer Conjugate and Further Self-Assembly.

Supramolecular conjugation between native protein concanavalin A (ConA) and synthetic polymer PEG (polyethylene glycol) was achieved by dual molecular recognition interactions via a linker, βCD-Man, of which β-cyclodextrin (βCD) and α-mannopyranoside (Man) recognized the adamantane (Ada) end of PEG and lectin ConA orthogonally. Further self-assembly of the resultant supra-conjugates of ConA-PEG was induced by the addition of αCD, which was selectively threaded by PEG chains, leading to nanoparticles in dilute solution or hydrogel at a higher concentration. The moduli of the obtained hydrogel were three magnitudes higher than those of the control sample without ConA, showing the dramatic cross-linking effect of ConA achieved by its rather weak interaction with α-d-mannopyranoside.