In situ studies of transmembrane channels often require a model bioinspired artificial lipid bilayer (LB) decoupled from its underlaying support. Obtaining free-standing lipid membranes is still a challenge. In this study, we suggest an electrochemical approach for LB separation from its solid support via hydroquinone oxidation. Layer-by-layer deposition of polyethylenimine (PEI) and polystyrene sulfonate (PSS) on the gold electrode was performed to obtain a polymeric nanocushion of [PEI/PSS] 3 /PEI. The LB was deposited on top of an underlaying polymer support from the dispersion of small unilamellar vesicles due to their electrostatic attraction to the polymer support. Since lipid zwitterions demonstrate pH-dependent charge shifting, the separation distance between the polyelectrolyte support and LB can be adjusted by changing the environmental pH, leading to lipid molecules recharge. The proton generation associated with hydroquinone oxidation was studied using scanning vibrating electrode and scanning ion-selective electrode techniques. Electrochemical impedance spectroscopy is suggested to be a powerful instrument for the in situ observation of processes associated with the LB -solid support interface. Electrochemical spectroscopy highlighted the reversible disappearance of the LB impact on impedance in acidic conditions set by dilute acid addition as well as by electrochemical proton release on the gold electrode due to hydroquinone oxidation.

This article summarizes more than 10 years of cooperation with Prof. Helmuth Möhwald. Here we describe how the research moved from light-regulated feedback sustainable systems and control biodevices to the current focus on infochemistry in aqueous solution. An important advanced characteristic of such materials and devices is the pH concentration gradient in aqueous solution. A major part of the article focuses on the use of localized illumination for proton generation as a reliable, minimal-reagent-consuming, stable light-promoted proton pump. The in situ scanning vibration electrode technique (SVET) and scanning ion-selective electrode technique (SIET) are efficient for the spatiotemporal evolution of ions on the surface. pH-sensitive polyelectrolyte (PEs) multilayers with different PE architectures are composed with a feedback loop for bionic devices. We show here that pH-regulated PE multilayers can change their propertiesfilm thickness and stiffness, permeability, hydrophilicity, and/or fluorescencein response to light or electrochemical or biological processes instead of classical acid/base titration.

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We report here the effect of the photoelectrochemical photocurrent switching (PEPS) observed on highly-ordered pristine anodized Ti/TiO2 for the first time.

consequences on human health [1,2] and industrial processes [3,4] as well as antibiotics resistance. [5] Various approaches to inhibition of biofilm formation and their eradication were developed. [6] Biofilm formation at an interface is determined by several pheno mena, e.g., the initial adhesion of single bacteria to the surface and the further biofilm growth and spreading due to cell proliferation and biopolymer production. [7] Therefore, surface energy and electrostatic interactions with the substrate are two key determinants of biofilm formation. On this basis, a common strategy to fight bacterial colonization is the functionalization of surfaces that are prone to biofilm fouling. [6,8] For instance, surface hydrophilization [9] and low surface energy strategies [10] were considered. Surface topology was also modified to influence bacterial colonization, as recently reviewed in detail. [11] Polyelectrolyte coatings allow changing the surface energy, charge, and mechanical characteristics of various substrates easily. [12,13] Therefore, polyelectrolyte assemblies are often considered for possible application as antibacterial coatings. However, understanding the fundamental principles of bacteria-surface interactions remains of high importance. [14][15][16] Due to the negative charges found on their external membrane, bacteria tend to tightly attach to positively charged surfaces. [17] It was demonstrated that biofilm spreading rate was decreasing with increasing strength of adhesion. [17] One possible explanation is that bacteria elongation preceding cell division is obstructed by strong electrostatic binding to the surface. [18] Besides this, it is also known that positively charged molecules (and poly cations to a greater extent) exhibit antibacterial properties due to their ability to disrupt membranes of bacterial cells. [19] In contrast, negatively charged surfaces provide less stable bacterial cell contact with the surface, [18] so that the initial adhesion step is difficult but further biofilm spreading meets less obstacle.In addition to help preventing healthcare and industryrelated issues, investigating biofilm formation is beneficial to understand the development of biological tissues, [20] cell adaptability, [21] and communication [22] since some morphogenesis principles are common with higher organisms' tissues. Furthermore, colonies and biofilms of non-pathogenic microorganisms are considered to be promising to design hybrid living materials [23][24][25][26][27] challenging to get synthetically. Revealing