Large-ring cyclodextrins (CD) are cyclic glucans composed of 9o rm ore a-1,4-linked glucose units.T hey are minor side products of bacterial glucanotransferases (CGTases,E C2.4.1.19) and have previously been available only in very small amounts for studies of their properties in supramolecular complex formation reactions.W ee ngineered aCGTase to synthesizemainly large-ring CD facilitating their preparation in larger amounts.B yr eversed phase chromatography,w eo btained single CD samples composed of 10 to 12 glucose units (CD10, CD11, and CD12) with ap urity of > 90 %. Their identity was confirmed by high resolution mass spectrometry and fragmentation analysis.Wedemonstrated the non-toxicity of CD10-CD12 for human cell lines by ac ell proliferation assaya nd impedimetric monitoring.W et hen showed that CD10 and CD11 are efficient chiral selectors for the capillary electrophoretic separation of the enantiomeric pharmaceuticals fluvastatin, mefloquine,c arvedilol, and primaquine.CDa re a-1,4-linked cyclic glucans with ad egree of polymerization (DP) between 6t o> 100. Branched a-1,6-CD have also been described. [1] In contrast to larger CD,CD6, CD7, and CD8 (a-, b-, g-CD) have been studied extensively and are produced commercially. [2] They form cone-shaped structures with ahydrophobic cavity and an outer hydrophilic area, enabling the reversible binding of hydrophobic mole-Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Understanding of cell migration and spreading out of tumor tissue is of great interest concerning the mechanism and causes of tumor malignancy and metastases. Although there are methods available for studying cell migration on monolayer cell cultures like transwell assays, novel techniques for monitoring cell spreading out of 3D organoids or tumor tissue samples are highly required. In this context, we developed an innovative high-dense microelectrode array for impedimetric monitoring of cell migration from 3D tumor cultures. For a proof of concept, a strongly migrating breast cancer cell line (MDA-MB-231) and two malignant melanoma cell lines (T30.6.9, T12.8.10ZII) were used for generating viable micro-tumor models. The migration propensity was determined by impedimetric monitoring over 144 hours, correlated by microscopy and validated by transwell assays. The impedimetric analysis of covered electrodes and the relative impedance maximum values revealed extended information regarding the contribution of proliferative effects. More strikingly, using reference populations of mitomycin C treated spheroids where proliferation was suppressed, distinction of proliferation and migration was possible. Therefore, our high-dense microelectrode array based impedimetric migration monitoring has the capability for an automated quantitative analysis system that can be easily scaled up as well as integrated in lab on chip devices.

The analysis of receptor activity, especially in its native cellular environment, has always been of great interest to evaluate its intrinsic but also downstream biological activity. An important group of cellular receptors are ion channels. Since they are involved in a broad range of crucial cell functions, they represent important therapeutic targets. Thus, novel analytical techniques for the quantitative monitoring and screening of biological receptor activity are of great interest. In this context, we developed an impedance spectroscopy-based label-free and non-invasive monitoring system that enabled us to analyze the activation of the transient receptor potential channel Vanilloid 1 (TRPV1) in detail. TRPV1 channel activation by capsaicin resulted in a reproducible impedance decrease. Moreover, concentration response curves with an EC value of 0.9 μM could be determined. Control experiments with non TRPV1 channel expressing HEK cells as well as experiments with the TRPV1 channel blocker ruthenium red validated the specificity of the observed impedance decrease. More strikingly, through correlative studies with a cytoskeleton restructuring inhibitor mixture and equivalent circuit analysis of the acquired impedance spectra, we could quantitatively discriminate between the direct TRPV1 channel activation and downstream-induced biological effects. In summary, we developed a quantitative impedimetric monitoring system for the analysis of TRPV1 channel activity as well as downstream-induced biological activity in living cells. It has the capabilities to identify novel ion channel activators as well as inhibitors for the TRPV1 channel but could also easily be applied to other ion channel-based receptors.

Mussel-derived surface coatings present integrin- and heparin-binding peptides for cell adhesion and modulator protein delivery to improve the endothelialization of biodegradable cardiovascular implants.

For miniaturization and integration of chemical synthesis and analytics on small length scales, the development of complex lab-on-chip (LOC) systems is in the focus of many current research projects. While application specific synthesis and analytic modules and LOC devices are widely described, the combination and integration of different modules is intensively investigated. Problems for in-line processes such as solvent incompatibilities, e.g., for a multistep synthesis or the combination of an organic drug synthesis with a cell-based biological activity testing system, require a solvent exchange between serialized modules. Here, we present a continuously operating microfluidic solvent exchanger based on the principle of free-flow electrophoresis for miscible organic/aqueous fluids. We highlight a proof-of-principle and describe the working principle for the model compound fluorescein, where the organic solvent DMSO is exchanged against an aqueous buffer. The DMSO removal performance could be significantly increased to 95% by optimization of the microfluidic layout. Moreover, the optimization of the inlet flow ratio resulted in a minimized dilution factor of 5, and we were able to demonstrate that a reduction of the supporting instrumentation is possible without a significant decrease of the DMSO removal performance. Finally, the compatibility of the developed solvent exchanger for cell based downstream applications was proven. The impedimetric monitoring of HEK293A cells in a continuously operating microfluidic setup revealed no adverse effects of the residual DMSO after the solvent replacement. Our solvent exchanger device demonstrates the power of micro-free-flow electrophoresis not only as a powerful technique for separation and purification of compound mixtures but also for solvent replacement.