Simultaneous In Situ Quantification of Two Cellular Lipid Pools Using Orthogonal Fluorescent Sensors

Programmed Control of Fluorescence Blinking Patterns based on Electron Transfer in DNA

Fluorescence imaging uses changes in the fluorescence intensity and emission wavelength to analyze multiple targets simultaneously. To increase the number of targets that can be identified simultaneously, fluorescence blinking can be used as an additional parameter. To understand and eventually control blinking, we used DNA as a platform to elucidate the processes of electron transfer (ET) leading to blinking, down to the rate constants. With a fixed ET distance, various blinking patterns were observed depending on the DNA sequence between the donor and acceptor units of the DNA platform. The blinking pattern was successfully described with a combination of ET rate constants. Therefore, molecules with various blinking patterns can be developed by tuning ET. It is expected that the number of targets that can be analyzed simultaneously will increase by the power of the number of blinking patterns.

Highly Functionalized β-Cyclodextrins by Solid-Supported Synthesis

Using covalent capture, a high yielding selective mono-functionalization of heptakis-[6-deoxy-6-(2-aminoethylsulfanyl)]-β-CD with a 5-mercaptopentyl functional group has been achieved. Here, we demonstrate the immobilization of the mono-thiol functionalized β-CD on PEGA resin via a disulfide bond, enabling solid-phase elaboration of the remaining six primary amines. To showcase the potential of this method, the amines were elaborated to tripeptides through standard Fmoc-peptide chemistry. A small library of CD-tripeptide conjugates was generated which, when reduced from the solid support, could be tagged at the released thiol with an environmentally sensitive fluorophore. The resulting library of sensors showed potential for the differential sensing of various bile salts. The described methodology provides a rapid and versatile route to synthesize highly functionalized libraries of CD derivatives that may be tailored towards applications in sensing, catalysis, and multivalent displays.