Glucose and Maltose Surface-Functionalized Thermoresponsive Poly(<i>N</i>-Vinylcaprolactam) Nanogels
Joonas Siirilä, Sami Hietala, Filip S. Ekholm, Heikki Tenhu
Abstract
-vinylcaprolactam), PNVCL, were surface-functionalized with different glucose and maltose ligands, and the colloidal properties of the gels were analyzed. The PNVCL nanogels were first prepared via semibatch precipitation polymerization, where a comonomer, propargyl acrylate (PA), was added after preparticle formation. The aim was to synthesize "clickable" nanogels with alkyne groups on their surfaces. The nanogels were then functionalized with two separate azido-glucosides and azido-maltosides (containing different linkers) through a copper-catalyzed azide-alkyne cycloaddition (CuAAc) click reaction. The glucose and maltose bearing nanogels were thermoresponsive and shrank upon heating. Compared to the PNVCL-PA nanogel, the carbohydrate bearing ones were larger, more hydrophilic, had volume phase transitions at higher temperatures, and were more stable against salt-induced precipitation. In addition to investigating the colloidal properties of the nanogels, the carbohydrate recognition was addressed by studying the interactions with a model lectin, concanavalin A (Con A). The binding efficiency was not affected by the temperature, which indicates that the carbohydrate moieties are located on the gel surfaces, and are capable of interacting with other biomolecules independent of temperature. Thus, the synthesis produces nanogels, which have surface functions capable of biorelevant interactions and a thermoresponsive structure. These types of particles can be used for drug delivery.