Glucose-grafted gum arabic modified magnetic nanoparticles: Preparation and specific interaction with concanavalin A

Novel magnetic nanoparticles bearing glucose-grafted gum arabic were successfully synthesized by coupling maltose via reductive amination on gum arabic modified magnetic nanoparticles (GAMNP). By the analyses of FTIR and Raman spectra, the grafting of glucose on GAMNP was recognized. From the concentration change of maltose in solution, the amount of maltose coupled to GAMNP was estimated as 0.13 mmol/g. In comparison to GAMNP, the glucose-grafted GAMNP (G-GAMNP) significantly showed specific interaction with concanavalin A (Con A) with an association constant of about 1.26 x 10(9) M(-1). Less particle aggregation was observed when the particle/Con A ratio was high, whereas a particle might be bound by more Con A molecules and hence led to the aggregation when the particle/Con A ratio was low. The amount of Con A adsorbed was significantly dependent on pH, and the maximum adsorption capacity appeared around pH 7. The decrease in adsorption amount in lower and higher pH regions might be due to the release of ions from Con A and to the denaturation of Con A, respectively. In addition, it was shown that Con A molecules were bound onto G-GAMNP via the hydrogen bonds between the -OH groups of glucose and the -NH groups or oxygen atoms of asparagine in Con A.