Ionic Conductivity as a Tool To Study Biocidal Activity of Sulfobetaine Micelles against Saccharomyces cerevisiae Model Cells

Abstract

Zwitterionic sulfobetaine surfactants are used in pharmaceutical or biomedical applications for the solubilization and delivery of hydrophobic molecules in aqueous medium or in biological environments. In a screening on the biocidal activity of synthetic surfactants on microbial cells, remarkable results have emerged with sulfobetaine amphiphiles. The interaction between eight zwitterionic sulfobetaine amphiphiles and Saccharomyces cerevisiae model cells was therefore analyzed. S. cerevisiae yeast cells were chosen, as they are a widely used unicellular eukaryotic model organism in cell biology. Conductivity measurements were used to investigate the interaction between surfactant solution and cells. Viable counts measurements were performed, and the mortality data correlated with the conductivity profiles very well, in terms of the inflection points (IPs) observed in the curves and in terms of supramolecular properties of the aggregates. A Fourier transform infrared (FTIR)-based bioassay was then performed to determine the metabolomic stress-response of the cells subjected to the action of zwitterionic surfactants. The surfactants showed nodal concentration (IPs) with all the techniques in their activities, corresponding to the critical micellar concentrations of the amphiphiles. This is due to the pseudocationic behavior of sulfobetaine micelles, because of their charge distribution and charge densities. This behavior permits the interaction of the micellar aggregates with the cells, and the structure of the surfactant monomers has impact on the mortality and the metabolomic response data observed. On the other hand, the concentrations that are necessary to provoke a biocidal activity do not promote these amphiphiles as potential antimicrobial agents. In fact, they are much higher than the ones of cationic surfactants.

Positively Charged Nanoaggregates Based on Zwitterionic Pillar[5]arene that Combat Planktonic Bacteria and Disrupt Biofilms

“…To overcome these challenges,w ee ngineered ap illar- [5]arene-based zwitterionic molecule that possess antibacterial activity and can disrupt biofilms.Z witterionic molecules bearing an equimolar number of homogenously distributed anionic and cationic groups have attracted growing attention as potential antimicrobial agents. [12,13] While previous reports have established that pillar [5]arene derivatives functionalized with different groups on the framework can be used as antibacterial or anti-biofilm formation agents.T herefore,the combination of zwitterionic groups and pillar [5]arene scaffold would endow the new molecule with new biological applications.H erein, we report az witterionic pillar [5]arene,w hich not only shows antibacterial activity against Gram-negative Escherichia coli [E. coli (DH5a)] and Gram-positive Staphylococcus aureus [S. aureus (SH1000)] bacterial strains,b ut also can disrupt established E. coli (DH5a)b iofilms and kill the biofilm-enclosed bacteria without rapid generation of resistance.…”

Sulfobetaine N‐Chloramines: Chemical Synthesis and Antibacterial Application

“…As a result, the biocidal activity declined consequently caused by the interaction between surfactant micelles and microbial cells . By means of 13 C NMR analysis, Chevalier and coworkers found that the measured intercharge distance in betaine structure is shorter than the real ‐(CH 2 ) n ‐ linker length (from ‐(CH 2 ) 2 ‐ to ‐(CH 2 ) 7 ‐), indicating the spacer linker coiling occurred which well corresponded with Tiecco's research work . However, Weers et al .…”

Positiv geladene Nanoaggregate auf Basis eines zwitterionischen Pillar[5]arens zur Bekämpfung von planktonischen Bakterien und zum Abbau von Biofilmen

“…Zum anderen kçnnen diese Nanoaggregate mit der Bakterienzellmembran durch elektrostatische [15] und hydrophobe Wechselwirkungen interagieren, was zur Verformung der Bakterienzellmembran und letztendlich zum Zelltod führt. [13,16] Ermutigt durch die Wirksamkeit von ZW-PAg egenüber planktonischen Bakterienzellen, untersuchten wir als nächstes dessen Potential bakterielle Biofilme zu zerstçren. Verschiedene Stadien von E. coli (DH5a)B iofilmen (1 Tag, 3T age und 5T age) wurden zunächst vorkultiviert [17] und anschließend fürw eitere 24 hm it ZW-PA-Nanoaggregaten inkubiert.…”

“…Je länger die Nanoaggregate mit der E. coli Suspension inkubiert wurden, desto stärker war die Fluoreszenz. [13,16] Ermutigt durch die Wirksamkeit von ZW-PAg egenüber planktonischen Bakterienzellen, untersuchten wir als nächstes dessen Potential bakterielle Biofilme zu zerstçren. Darüber hinaus wurden Cryo-TEM-Messungen durchgeführt, um die Wirkung der ZW-PA-Behandlung auf die Zellmorphologie von E. coli (DH5a)z uv isualisieren (Abbildung 2d-i).…”

“…Zwitterionische Moleküle mit einer äquimolaren Anzahl von homogen verteilten anionischen und kationischen Gruppen haben als potentielle antimikrobielle Wirkstoffe zunehmend an Bedeutung gewonnen. [12,13] Frühere Berichte haben gezeigt, dass Pillar [5]arenderivate,d ie mit verschiedenen Gruppen funktionalisiert sind, entweder als antibakterielle Wirkstoffe oder zur Vermeidung der Biofilmbildung eingesetzt werden kçnnen. Daher würde eine Kombination aus zwitterionischen Gruppen und Pillar [5]arenen ein neuartiges Moleküle rgeben, das beide Eigenschaften fürd ie gewünschten biologischen Anwendungen vereint.…”