The carbohydrates present on the cells surface can act as a receptor for many pathogens to facilitate cell-cell adhesion through which humans can be infected, for example, mannose binds pathogenic bacteria E. coli and sialic acid binds influenza virus. Therefore, cell surface can be mimicked by preparing SAMs of carbohydrates to study and understand different types of binding and inhibition studies in vitro. SAMs of carbohydrates are also used for detecting disease biomarkers and carrying drugs.
1.1. Carbohydrate-lectin interactions
The diverse arrangement of carbohydrate in biological molecules makes their study challenging. However, the ubiquitous presence of ten common monosaccharaides namely D-glucose (D-Glc), D-mannose (D-Man), D-galactose …show more content…
coli was through the multiple binding to lipopolysaccharides (O-antigen) exposed on cell wall of E. coli. LOD for mannose/Con A sensor was improved down to 7.5 × 102 cells/mL from 3.0 × 107 cells/mL for mannose-alone sensor. Similarly, four decades wider linear range (7.5 × 102 –7.5 × 107 cells/mL) was found for the mannose/Con A based sensor compared to mannose-alone QCM sensor (107). In detecting E. coli on mannose terminated SAMs, it is always preferred to have minimum nonspecific interaction for better selectivity and specificity of the detector. Grabosch et. al. introduced a dual click chemistry strategy for creating a biorepulsive background with the exposed mannose terminal SAMs (23). A polyethylene glycol linker having azide and amine terminal groups was used to support dual click reactions. Azides react with alkynes to form triazole ligation products and amines react with isothiocyanate to form thiourea bridges where the other ends of alkyne and isothiocyanate consist of thiol head group and terminal mannose, respectively. The SAMs of mannose prepared by this dual click strategy was found to be very effective in reducing the nonspecific interactions while specifically and selectively capturing green fluorescent protein (GFP)-tagged E. coli strain (pPKL1162) evident by epifluorescence micrographs with and without terminal mannose, Figure XYZ. The same strand of E. coli was also successfully detected on self-assembled dendritic monolayer (SADM) having disulfide cores using SPR and resonance-enhanced surface impedance (RESI) (22). Generation 1 dendrimer having four terminal mannoses was found to have binding efficiency of approximately 3600 cells·(pmol of Man)−1 whereas generation 3 dendrimer having 16 terminal mannose have binding efficiency of 4200 cells·(pmol of Man)−1. In this work, binding efficiency of generation three dendrimer having terminal mannoses and hydroxides groups to E. coli was also compared showing that mannose
1.1. Carbohydrate-lectin interactions
The diverse arrangement of carbohydrate in biological molecules makes their study challenging. However, the ubiquitous presence of ten common monosaccharaides namely D-glucose (D-Glc), D-mannose (D-Man), D-galactose …show more content…
coli was through the multiple binding to lipopolysaccharides (O-antigen) exposed on cell wall of E. coli. LOD for mannose/Con A sensor was improved down to 7.5 × 102 cells/mL from 3.0 × 107 cells/mL for mannose-alone sensor. Similarly, four decades wider linear range (7.5 × 102 –7.5 × 107 cells/mL) was found for the mannose/Con A based sensor compared to mannose-alone QCM sensor (107). In detecting E. coli on mannose terminated SAMs, it is always preferred to have minimum nonspecific interaction for better selectivity and specificity of the detector. Grabosch et. al. introduced a dual click chemistry strategy for creating a biorepulsive background with the exposed mannose terminal SAMs (23). A polyethylene glycol linker having azide and amine terminal groups was used to support dual click reactions. Azides react with alkynes to form triazole ligation products and amines react with isothiocyanate to form thiourea bridges where the other ends of alkyne and isothiocyanate consist of thiol head group and terminal mannose, respectively. The SAMs of mannose prepared by this dual click strategy was found to be very effective in reducing the nonspecific interactions while specifically and selectively capturing green fluorescent protein (GFP)-tagged E. coli strain (pPKL1162) evident by epifluorescence micrographs with and without terminal mannose, Figure XYZ. The same strand of E. coli was also successfully detected on self-assembled dendritic monolayer (SADM) having disulfide cores using SPR and resonance-enhanced surface impedance (RESI) (22). Generation 1 dendrimer having four terminal mannoses was found to have binding efficiency of approximately 3600 cells·(pmol of Man)−1 whereas generation 3 dendrimer having 16 terminal mannose have binding efficiency of 4200 cells·(pmol of Man)−1. In this work, binding efficiency of generation three dendrimer having terminal mannoses and hydroxides groups to E. coli was also compared showing that mannose