Boronic acid-functionalized oligoamine colorimetric heparin receptor

Abstract

Here we developed a synthetic colorimetric heparin receptor (denoted as OHR) bearing phenylboronic acid (PBA) and intermediary cationic ammonium groups on a geometrically flat biocompatible oligoamine framework. OHR showed remarkable affinity for heparin (at physiological conditions) with a binding constant comparable to the best such values reported previously. The high affinity of OHR for heparin was ascribed primarily to the flat molecular geometry of the receptor, which apparently allowed for effective interactions of the cationic ammonium and PBA groups of OHR with the functional groups along the bulky polymer chain of heparin. Moreover, this high affinity of OHR for heparin under physiological conditions as well as the high biocompatibility of OHR are features that make OHR a promising candidate for use in potential biomedical applications including the bedside detection of heparin levels in human blood during surgery, and the use of heparin reversal agents.