Supramolecular Kandinsky circles with high antibacterial activity

Abstract

Nested concentric structures widely exist in nature and designed systems with circles, polygons, polyhedra, and spheres sharing the same center or axis. It still remains challenging to construct discrete nested architecture at (supra)molecular level. Herein, three generations (G2−G4) of giant nested supramolecules, or Kandinsky circles, have been designed and assembled with molecular weight 17,964, 27,713 and 38,352 Da, respectively. In the ligand preparation, consecutive condensation between precursors with primary amines and pyrylium salts is applied to modularize the synthesis. These discrete nested supramolecules are prone to assemble into tubular nanostructures through hierarchical self-assembly. Furthermore, nested supramolecules display high antimicrobial activity against Gram-positive pathogen methicillin-resistant Staphylococcus aureus (MRSA), and negligible toxicity to eukaryotic cells, while the corresponding ligands do not show potent antimicrobial activity.

Anticancer Activity and Cisplatin Binding Ability of Bis-Quinoline and Bis-Isoquinoline Derived [Pd2L4]4+ Metallosupramolecular Cages

“…Several groups have examined MSAs as drug delivery vectors (Therrien et al, 2008 ; Schmitt et al, 2012 ; Yi et al, 2012 ; Zheng et al, 2015 ; Samanta et al, 2016 , 2017 ; Bhat et al, 2017 ; Xu et al, 2017 ; Wang J.-F. et al, 2018 ; Yue et al, 2018 ). Additionally, MSAs have been shown to bind DNA (Oleksy et al, 2006 ; Garci et al, 2017 ; Zhao et al, 2017 ) and RNA (Phongtongpasuk et al, 2013 ; Malina et al, 2015 ), interact with proteins (Li et al, 2014 ; Mitchell et al, 2017 ) and have anticancer (Hotze et al, 2008 ; Faulkner et al, 2014 ; Grishagin et al, 2014 ; Dubey et al, 2015 ; Zheng et al, 2016 ; Allison et al, 2018 ) and antibacterial (Richards et al, 2009 ; Howson et al, 2012 ; Wang H. et al, 2018 ) properties.…”

Supramolecular Antibacterial Materials for Combatting Antibiotic Resistance

“…In another effort inspired by natural nested structures, Wang et al developed three generations of antibacterial molecules that have hierarchical self‐assembly properties . They found that these 2D‐nested hexagons form channels through a supramolecular self‐assembly process (Figure b) and the assembled channels composed of concentric rings (Kandinsky circles) interact with MRSA cell walls to form transmembrane channels and kill pathogens because of their hexagonal shapes and nanosizes.…”

Over one century after discovery: pyrylium salt chemistry emerging as a powerful approach for the construction of complex macrocycles and metallo-supramolecules

“…As such, a modular synthetic strategy was further developed by Li et al to prepare the target ligands in high efficiency 28 . Instead of performing coupling reaction on pyridinium salts, tpy units were introduced on to the Ph B phenyl groups of pyrylium salts by Suzuki coupling reaction before the condensation (Figure 13).…”

“…Also, feasible separation and characterization were developed for the building blocks with multiple positive charges. Moreover, modularized synthetic strategy 28 and in-situ one-pot approach 29 were further explored to simplify the synthesis of multitopic ligands using pyrylium salts chemistry.…”