Highly Specific Molecular Recognition by a Roughly Defined Supramolecular Nanocapsule: A Fuzzy Recognition Mechanism

Can a supramolecular host conduct fuzzy recognition like a man? Currently, molecular recognition in supramolecular chemistry is generally promoted by specific interaction formed between a guest and a well-defined but usually costly synthesized complementary host. Here we show that a roughly defined macromolecular nanocapsule derived from hyperbranched polyethylenimine (HPEI) can act as a highly selective host for the recognition of featureless guests. The recognition is not promoted by specific molecular interaction but by a fuzzy recognition mechanism, i.e., the statistical accumulation of elementary host−guest interactions, where a guest can be regarded as a multivalent entity for supramolecular interactions. It is found that core engineering of the macromolecular nanocapsule will influence its guest affinity; the difference of the competitive guest species can be amplified, and highly specific recognition is thus possible. Because the macromolecular nanocapsule derived from HPEI is structurally feature...