Glucosamine-functionalized silver glyconanoparticles: characterization and antibacterial activity.

We report the analytical and in vitro antibacterial activity of glucosamine-functionalized silver glyconanoparticles. Morphological characterization ensured the surface topography and particle size distribution of both silver and glucosamine-silver nanoparticles. Surface plasmon resonance of both types of nanoparticle was determined from UV-visible spectroscopy using four different sample concentrations (10-40 μL). The resulting functionalized glyconanoparticles show maximum absorbance with a red shift of 30 ± 5 nm (390-400 nm) from their initial absorbance (425-430 nm). FT-Raman and (1)H-NMR spectroscopic measurement confirmed the surface functionalization of glucosamine on the silver surface through the carbonyl group of a secondary amide linkage (-NH-CO-), elucidated by the conjugation of N-hydroxysuccinimide (NHS)-terminated silver nanoparticles and the amino group of glucosamine. Antimicrobial experiments with well-characterized silver nanoparticles (AgNPs) and glucosamine-functionalized silver nanoparticles (GlcN-AgNPs) demonstrate that GlcN-AgNPs have similar and enhanced minimum inhibitory concentration (MIC) against eight gram-negative and eight gram-positive bacteria compared with AgNPs. MIC data shows that Klebsiella pneumoniae (ATCC 700603) and Bacillus cereus isolate express high levels of inhibition, with the quantity and magnitude of inhibition being higher in the presence of GlcN-AgNPs.