Photoresponsive Cucurbit[8]uril‐Mediated Adhesion of Bacteria on Supported Lipid Bilayers

Abstract

In this work, the development of a photoresponsive platform for the presentation of bioactive ligands to study receptor-ligand interactions has been described. For this purpose, supramolecular host-guest chemistry and supported lipid bilayers (SLBs) have been combined in a microfluidic device. Quartz crystal microbalance with dissipation monitoring (QCM-D) studies on methyl viologen (MV)-functionalized oligo ethylene glycol-based self-assembled monolayers, gel and liquid-state SLBs have been compared for their nonfouling properties in the case of ConA and bacteria. In combination with bacterial adhesion test, negligible nonspecific bacterial adhesion is observed only in the case of methyl-viologen-modified liquid-state SLBs. Therefore, liquid-state SLBs have been identified as most suitable for studying specific cell interactions when MV is incorporated as a guest on the surface. The photoswitchable supramolecular ternary complex is formed by assembling cucurbit[8]uril (CB[8]) and an azobenzene-mannose conjugate (Azo-Man) onto MV-functionalized liquid-state SLBs and the assembly process has been characterized using QCM-D and fluorescence techniques. Mannose has been found to enable binding of E. coli via cell-surface receptors on the nonfouling supramolecular SLBs. Optical switching of the azobenzene moiety allows us to "erase" the bioactive surface after bacterial binding, providing the potential to develop reusable sensors. Localized photorelease of bacterial cells has also been shown indicating the possibility of optically guiding cellular growth, migration, and intercellular interactions.

Photo‐responsive Bioactive Surfaces Based on Cucurbit[8]uril‐Mediated Host–Guest Interactions of Arylazopyrazoles

“…Cucurbit[8]uril‐mediated host–guest heteroternary complexes including photoactive azobenzenes have been used in photomodulation of the assembly of (bio)molecules on surfaces . For example, Scherman et al.…”

“…reported the photoinduced disassembly of raspberry‐shaped colloids, representing these systems as useful tools for cargo delivery . We have recently assembled these photoresponsive azobenzene‐containing heteroternary complexes onto chips and employed them to attract and release proteins, viruses and bacteria by photoisomerization . Interestingly, when these heteroternary complexes have been constructed with both redox‐ and light‐responsive elements multi stimuli‐responsivity becomes available …”

Stimuli‐Responsive Cucurbit[n]uril‐Mediated Host‐Guest Complexes on Surfaces

“…This surface consisted of a supported lipid bilayer with improved nonfouling properties onto which the pseudorotaxane system MV 2 + /CB [8] was installed (Figure 12a, b). [102] The E. coli bacteria strain ORN178 bearing a carbohydrate binding receptor was found to bind mannose, which could be shown by QCMÀD measurements. [102] In contrast, the control strain ORN208, which lacks the mannose binding receptor, was not able to bind to the mannose bearing surface.…”

“…[102] The E. coli bacteria strain ORN178 bearing a carbohydrate binding receptor was found to bind mannose, which could be shown by QCMÀD measurements. [102] In contrast, the control strain ORN208, which lacks the mannose binding receptor, was not able to bind to the mannose bearing surface. [99] Local photo-switching from the trans-to cis-azobenzene mannose leads to dissociation of the ligand from the surface.…”

“…As a consequence nearly 80 % of the bacteria were removed from the surface. [102] Ravoo and coworkers reported heterocomplexation of arylazopyrazole-modified integrin-binding peptides onto pseudorotaxane-based CB [8] SAMs (Figure 13). [103] Arylazopyrozoles are of interest to improve the photoswitching characteristics of the CB [8] SAMs.…”