Mannose-Decorated Stimuli-Responsive Fluorescent Poly(aminoamide) Microgels for Lectin Binding and Sensing

Development of suitable carbohydrate-decorated, biocompatible, and stimuli-responsive fluorescent microgels that can selectively bind and detect proteins (such as lectins) is an important research topic. Herein, we report the development of mannose-decorated, dual-stimuli (temperature and pH)-responsive fluorescent poly(aminoamide) microgels, which can selectively bind to and thereby detect the presence of concanavalin A (Con A). The resultant stimuli-responsive microgels have a lower critical solution temperature (VPTT) of 37.4 °C and exhibit pH responsiveness over a wide range. The microgels exhibited robust multivalent interactions with Con A. Binding kinetics, as shown by fluorescence quenching, demonstrated a rapid response within 8 min, with a detection limit of 15 nM and a binding constant (<i>K_d</i>) of 3.77 × 10⁶ M^-1.