title: 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.
authors.affiliation: Department of Fibre and Polymer Technology, School of Chemical Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
authors.forename: Kim
authors.initials: K
authors.lastname: Öberg
authors.forename: Jarmo
authors.initials: J
authors.lastname: Ropponen
authors.forename: Jonathan
authors.initials: J
authors.lastname: Kelly
authors.forename: Peter
authors.initials: P
authors.lastname: Löwenhielm
authors.forename: Mattias
authors.initials: M
authors.lastname: Berglin
authors.forename: Michael
authors.initials: M
authors.lastname: Malkoch
mesh_terms: D001422:Bacterial Adhesion; D004925:Escherichia; D006046:Gold / Q000737:chemistry*; D006880:Hydroxy Acids / Q000737:chemistry; D015394:Molecular Structure; D011091:Polyesters / Q000737:chemistry*; D011422:Propionates / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D020349:Surface Plasmon Resonance; D013499:Surface Properties
chemical_list: D006880:Hydroxy Acids; D011091:Polyesters; D011422:Propionates; C110034:2,2-bis(hydroxymethyl)-propionic acid; D006046:Gold