Fluorescent Mannose-Functionalized Hyperbranched Poly(amido amine)s: Synthesis and Interaction with E. coli

A water-soluble, biodegradable and fluorescent hyperbranched poly(amidoamine) with mannose groups on their surface (M-HPAMAM) has been successfully prepared, and the synthetic strategy includes Michael addition polymerization of diacrylamide with 1-(2-aminoethyl)piperazine and, subsequently, surface modification with mannosamine. The photoluminescence of M-HPAMAM was enhanced significantly due to the surface mannose groups. Incubation of E. coli with M-HPAMAMs yielded brightly fluorescent bacteria clusters, but the fluorescent intensity of the aqueous solution lowered. This indicates that the M-HPAMAMs have strong affinity with bacteria due to their polyvalent interactions. Based on the size and the amount of bacteria clusters formed, the bacteria with the concentrations higher than 102 cfu/mL can be detected.