Abstract

Solvatochromic isocyanonaphthalene dyes as ligands for Silver(I) complexes, their applicability in silver(I) detection and background reduction in biolabelling, Sensors

The optical and biolabeling properties of a novel molecule 1-(2-acryloyloxy-3-chloro-prop-1-yl)-amino-5-isocyanonaphthalene (ACAIN) is reported. In addition to being a real solvatochromic fluorophore it reacts quantitatively and rapidly with simple thiols in a thiol-ene click reaction. DFT calculations revealed a dark nonfluorescent state of ACAIN due to a close energy triplet state where electron transition can happen between the acrylic double bond and the aromatic core through an intramolecular hydrogen bond between the NH and C]O moieties. The hydrothiolation reaction is accompanied by a 1.5e19 fold increase in fluorescence intensity depending on the solvent used owing to the saturation of the acrylic group. The quantum yield and reactivity of the molecules were found to be largely dependent on the substituent of the acryl moiety. The biolabeling properties were investigated in detail by fluorometry and electrospray ionization (ESI) mass spectrometry using cysteine, KAC as a simple tripeptide and BSA as a model protein.

No abstract

Multiple drug resistant fungi pose a serious threat to human health, therefore the development of completely new antimycotics is of paramount importance. The in vitro antifungal activity of the original, 1-amino-5-isocyanonaphthalenes (ICANs) was evaluated against reference strains of clinically important Candida species. Structure-activity studies revealed that the naphthalene core and the isocyano- together with the amino moieties are all necessary to exert antifungal activity. 1,1-N-dimethylamino-5-isocyanonaphthalene (DIMICAN), the most promising candidate, was tested further in vitro against clinical isolates of Candida species, yielding a minimum inhibitory concentration (MIC) of 0.04–1.25 µg/mL. DIMICAN was found to be effective against intrinsically fluconazole resistant Candida krusei isolates, too. In vivo experiments were performed in a severly neutropenic murine model inoculated with a clinical strain of Candida albicans. Daily administration of 5 mg/kg DIMICAN intraperitoneally resulted in 80% survival even at day 13, whereas 100% of the control group died within six days. Based on these results, ICANs may become an effective clinical lead compound family against fungal pathogens.