Fluorescent dyes are applied in various fields of research, including solar cells and light-emitting devices,and as reporters for assays and bioimaging studies.F luorescent dyes with an added high dipole moment pave the way to nonlinear optics and polarity sensitivity.Redox activity makes it possible to switch the moleculesp hotophysical properties.D iaminodicyanoquinone derivatives possess high dipole moments,y et only low fluorescence quantum yields,and have therefore been neglected as fluorescent dyes.H ere we investigate the fluorescence properties of diaminodicyanoquinones using acombined theoretical and experimental approach and derive molecules with af luorescence quantum yield exceeding 90 %. The diaminodicyanoquinone core moiety provides chemical versatility and can be integrated into novel molecular architectures with unique photophysical features.

A synthetic route for oxidation-sensitive core− multishell (osCMS) nanocarriers was established, and their drug loading and release properties were analyzed based on their structural variations. The nanocarriers showed a drug loading of 0.3−3 wt % for the anti-inflammatory drugs rapamycin and dexamethasone and the photosensitizer meso-tetra-hydroxyphenylporphyrin (mTHPP). Oxidative processes of the nanocarriers were probed in vitro by hydrogen peroxide, and the degradation products were identified by infrared spectroscopy supported by ab initio calculations, yielding mechanistic details on the chemical changes occurring in redox-sensitive nanocarriers. Oxidationtriggered drug release of the model drug Nile Red measured and assessed by time-dependent fluorescence spectroscopy showed a release of up to 80% within 24 h. The drug delivery capacity of the new osCMS nanocarriers was tested in ex vivo human skin with and without pretreatments to induce local oxidative stress. It was found that the delivery of mTHPP was selectively enhanced in skin under oxidative stress. The number and position of the thioether groups influenced the physicochemical as well as drug delivery properties of the carriers.

A method is described to transfer and integrate transparent and polar 2D materials into heterostructures.

Drug penetration in human skin ex vivo following a modification of skin barrier permeability is systematically investigated by scanning transmission X-ray microscopy. Element-selective excitation is used in the O 1s regime for probing quantitatively the penetration of topically applied rapamycin in different formulations with a spatial resolution reaching <75 nm. The data were analyzed by a comparison of two methods: (i) two-photon energies employing the Beer–Lambert law and (ii) a singular value decomposition approach making use of the full spectral information in each pixel of the X-ray micrographs. The latter approach yields local drug concentrations more reliably and sensitively probed than the former. The present results from both approaches indicate that rapamycin is not observed within the stratum corneum of nontreated skin ex vivo, providing evidence for the observation that this high-molecular-weight drug inefficiently penetrates intact skin. However, rapamycin is observed to penetrate more efficiently the stratum corneum when modifications of the skin barrier are induced by the topical pretreatment with the serine protease trypsin for variable time periods ranging from 2 to 16 h. After the longest exposure time to serine protease, the drug is even found in the viable epidermis. High-resolution micrographs indicate that the lipophilic drug preferably associates with corneocytes, while signals found in the intercellular lipid compartment were less pronounced. This result is discussed in comparison to previous work obtained from low-molecular-weight lipophilic drugs as well as polymer nanocarriers, which were found to penetrate the intact stratum corneum exclusively via the lipid layers between the corneocytes. Also, the role of the tight junction barrier in the stratum granulosum is briefly discussed with respect to modifications of the skin barrier induced by enhanced serine protease activity, a phenomenon of clinical relevance in a range of inflammatory skin disorders.

Fluoreszenzfarbstoffe werden in verschiedenen Forschungsbereichen eingesetzt, darunter Solarzellen, lichtemittierende Dioden, Reporter fürA ssays oder Bioimaging-Studien. Ein zusätzliches hohes Dipolmoment ebnet den Weg zu nichtlinearer Optik und Polaritätsempfindlichkeit. Die Redoxaktivitäte rmçglicht es zudem, photophysikalische Eigenschaften der Moleküle zu verändern. Diaminodicyanochinon-Derivate besitzen hohe Dipolmomente,a ber nur geringe Fluoreszenzquantenausbeuten und galten daher bislang nicht als Fluoreszenzfarbstoffe.Wir untersuchen in dieser Arbeit die Fluoreszenzeigenschaften von Diaminodicyanochinonen mit einem kombiniert theoretisch-experimentellen Ansatz und leiten Moleküle mit einer Fluoreszenz-Quantenausbeute von über 90 %a b. Die Diaminodicyanochinon-Einheit bietet chemische Vielseitigkeit und kann in neuartige molekulare Architekturen mit einzigartigen photophysikalischen Eigenschaften integriert werden.