Abstract
We synthesized and characterized the physicochemical properties of a dual stimuli-responsive receptor designed based on oligoamine incorporating four phenylboronic acid (PBA) groups. This receptor, denoted to OAB, showed excellent responsiveness to major endogenous metabolites, specifically carbon dioxide (CO2) and monosaccharides glucose and fructose. The reversible complexation of OAB with CO2 (i.e., association followed by dissociation) was confirmed by changes observed in the conductivity of an OAB solution over time during slow bubbling of CO2 and then nitrogen (N-2) into the solution. The PBA groups on OAB displayed strong binding to glucose and fructose at the physiological pH 7.4, unlike the majority of the related materials, which require a high pH ( > 9) for the formation of a boronic ester. The binding constant (K-eq) values of the synthetic OAB receptor for glucose and fructose were determined to be 5.8 M-1 and 73.4 M-1, respectively. The reversible binding of OAB to green triggers such as CO2 and monosaccharides at neutral pH makes OAB an ideal choice for designing stimuli-responsive nano- and micro assembles and capsules for drug delivery, and also glycoconjugate receptors for various biomedical applications.