Brilliant glyconanocapsules for trapping of bacteria

Abstract

Sugar moieties play a prominent role in a myriad of biological processes, which explains the latest development of glycomimetics to simulate the attributes of naturally occurring oligo-or polysaccharides.1 Monosaccharides generally weakly interact with their receptors, whereas several epitopes grafted on a common scaffold (multivalent molecules, dendrimers, polymer chains) show enhanced activities -thanks to the cluster glycoside effect -for targeting specific glycan-binding proteins. Recently, we demonstrated that a careful establishment and reading of both oil and polymer phase diagrams allows for setting conditions ensuring the rapid preparation of nanocapsules in a simple batch mixing. 7 This concomitant nanoprecipitation/polymer crosslinking procedure (called ''Shift'N'Go process'') also permits simultaneous functionalization of the shell and filling of the core with molecules of biological interest. In this communication, we substantiate this proof of concept by preparing biocompatible functional capsules of utility for bio-applications. Particularly, we report on the one-pot synthesis of precisely defined, miglyol-filled, epoxide-functionalized glyconanocapsules and on subsequent post-modifications of the polymer shell via ring opening reactions. We show that the nanocapsules can be easily loaded with actives and that the presence of numerous pendent epoxides within the walls permits an efficient incorporation of relevant molecules such as ligands, probes or metal nanoparticles. Furthermore, the multiple n-heptyl a-D-mannose motifs present at the capsule surface strongly interact with the lectin sugarbinding sites (adhesin FimH) of adhesive proteinaceous hair-like organelles (type 1 fimbrae) expressed by Escherichia coli (E. coli) to promote adhesion and infection of tissues. 8 The construction of tag-labelled nanocapsules, with bright fluorophores and/or coated magnetic nanoparticles, is exploited here to monitor aggregation kinetics between the mannosylated nano-objects and AdherentInvasive E. coli bacteria (AIEC) and promote bacterial removal. A water-soluble random copolymer of N-[7-(a-D-mannopyranosyloxy)heptyl] methacrylamide (HMM) and glycidyl methacrylate (GMA) was prepared by 4-cyano-4-(phenylcarbonothioylthio) pentanoic acid-mediated RAFT polymerization (P(HMM 206 -stat-GMA 17 ), M n NMR = 77.1 kg mol À1, Ð = 1.10, details in ESI †). In order to account for the disparity between the relative reactivity ratios of the two monomers (r GMA = 2.82/2.77 and r HMM = 0.14/0.13 using Jaacks and Kelen-Tüdös methods, respectively, see ESI †) and the hydrophobicity of GMA, polymerizations were carried out in a semi-batch process using a low molar fraction of GMA (see Experimental part

Affinity of Glycan‐Modified Nanodiamonds towards Lectins and Uropathogenic Escherichia Coli

“…To scrutinize the potential of the photochemically formed mannose‐NDs, we investigated if such particles display enhanced agglutination effects towards E. coli UTI89 when compared to free mannose in solution. A fluorescence‐based agglutination assay was used for this purpose . It is based on mixing different concentrations of mannose and mannose‐NDs with fluorescently labeled E. coli UTI89 formed through genetic modification to express turboFP635 (Katushka) fluorescent proteins, emitting at 635 nm (upon excitation at 580 nm) .…”

“…Af luorescence-based agglutination assay was used for this purpose. [33] It is based on mixing different concentrationso fm annosea nd mannose-NDs with fluorescently labeled E. coli UTI89 formed through genetic modification to express turboFP635 (Katushka)f luorescentp roteins,e mitting at 635 nm (upon excitation at 580 nm). [34] Figure 5d epicts diverse fluorescencei mages of Katushka expressing E. coli after interaction for 4h at 4 8Cw ith different concentrations of mannose-NDs (1-300 mgmL À1 ).…”

“…The coupling strategy used for the fabrication of these particles was based on the Cu I ‐catalyzed Huisgen cycloaddition reaction (“click” reaction) between NDs decorated with surface azidophenyl or propargyl functions and the corresponding synthetic sugar analogue. Herein, we investigate the potential of photochemically grafted native mannose versus mannan to interact with E. coli UTI89 using a fluorescence‐based agglutination assay …”

“…Herein,w ei nvestigate the potentialo fp hotochemically grafted native mannose versus mannant oi nteract with E. coli UTI89 using af luorescencebased agglutination assay. [33] 2. Results and Discussion…”

Functional Hybrid Glyconanocapsules by a One-Pot Nanoprecipitation Process

“…symbolizes miglyol droplets, symbolizes monocomponent polymeric nanocapsules, the red dot indicates the nanoprecipitation conditions chosen here for preparing monocomponent polymeric nanocapsules (59 wt % of acetone, 0.05 wt % of miglyol and 0.05 wt % of polymer). Reprinted with permission from ref [18]. Copyright [2015] [Royal Society of Chemistry] and ref [19].…”