Templating Gold Surfaces with Function: A Self-Assembled Dendritic Monolayer Methodology Based on Monodisperse Polyester Scaffolds

Abstract

The antibiotic resistance developed among several pathogenic bacterial strains has spurred interest in understanding bacterial adhesion down to a molecular level. Consequently, analytical methods that rely on bioactive and multivalent sensor surfaces are sought to detect and suppress infections. To deliver functional sensor surfaces with an optimized degree of molecular packaging, we explore a library of compact and monodisperse dendritic scaffolds based on the nontoxic 2,2-bis(methylol)propionic acid (bis-MPA). A self-assembled dendritic monolayer (SADM) methodology to gold surfaces capitalizes on the design of aqueous soluble dendritic structures that bear sulfur-containing core functionalities. The nature of sulfur (either disulfide or thiol), the size of the dendritic framework (generation 1-3), the distance between the sulfur and the dendritic wedge (4 or 14 Å), and the type of functional end group (hydroxyl or mannose) were key structural elements that were identified to affect the packaging densities assembled on the surfaces. Both surface plasmon resonance (SPR) and resonance-enhanced surface impedance (RESI) experiments revealed rapid formation of homogenously covered SADMs on gold surfaces. The array of dendritic structures enabled the fabrication of functional gold surfaces displaying molecular covering densities of 0.33-2.2 molecules·nm(-2) and functional availability of 0.95-5.5 groups·nm(-2). The cell scavenging ability of these sensor surfaces for Escherichia coli MS7fim+ bacteria revealed 2.5 times enhanced recognition for G3-mannosylated surfaces when compared to G3-hydroxylated SADM surfaces. This promising methodology delivers functional gold sensor surfaces and represents a facile route for probing surface interactions between multivalently presented motifs and cells in a controlled surface setting.

Multifunctional Poly(ethylene glycol): Synthesis, Characterization, and Potential Applications of Dendritic–Linear–Dendritic Block Copolymer Hybrids

“…7,8 Dendrimers are the most studied dendritic structures due to their monodisperse nature that allows researchers to accurately correlate structure and final properties. 8 In comparison to linear polymers, dendrimers have a constrained globular geometry with multiple peripheral end-groups, which has resulted in a myriad of proposed applications, 9 such as drug delivery vehicles, 10,11 catalysis, 12 biosensors, 13,14 and tissue adhesives. 15 An elegant example of their promise was reported by Hawker et al describing a layer-by-layer (LbL) approach for the fabrication of ultrathin functional films.…”

Self-Assembled Monolayers of Carbohydrate Derivatives on Gold Surfaces

“…Carbohydrate cells/pmol of end groups, whereas generation three dendrimer detected 4170 cells/pmol of end groups [26].…”

“…To create a well-defined multivalency, SAMs of glycodendrimers of various generations were prepared using CuAAC reactions on a gold surface ( Figure 4) and characterized using XPS, ellipsometry, MALDI-ToF mass spectrometry, cyclic voltammetry, 1 Ha n d 13 CN M R , contact angle goniometry and FTIR [4,26]. The equilibrium association constants (K a )a n d kinetic association rate constants (k on ) and dissociation rate constants (k off )f o rt h ei n t e r a ctions of terminal monosaccharides (α-Man, β-GlcNAc, and β-Gal) to their corresponding lectins were determined using SPR [4].…”

The linker length of glucose–fipronil conjugates has a major effect on the rate of bioactivation by β‐glucosidase

“…Compounds 2a , 1b , 2c–2d , 3b , 8a , 8b , 8c , and 8d were prepared according to procedures found in the literature or with slight modifications. The reactions are shown in Schemes .…”