Deoxyestrone-based lipofection agents with solution- and solid-state emission properties.

In this contribution, three deoxyestrone-based emissive lipofection agents are reported. Because of a centrally incorporated terephthalonitrile motif, these ligands can be classified as solution and solid-state emitters (SSSEs). With the attachment of tobramycin, these amphiphilic structures are able to form lipoplexes, mediating gene transfection of HeLa and HEK 293T cells.

Phosphorescence Induction by Host-Guest Complexation with Cyclodextrins - The Role of Regioisomerism and Affinity.

We present an in-depth investigation of cyclodextrin complexes with guest compounds featuring complexation-induced room temperature phosphorescence (RTP) in aqueous solution. Very interestingly, only the complexed regioisomers bearing lateral substituents on meta-position show RTP, whereas the stronger host-guest systems with para-substituted dyes show no RTP features. The reported systems were investigated regarding their complexation behavior in water using isothermal titration calorimetry and mass spectrometry. In the case of γ-CD very strong 1 : 1 inclusion complexes (Ka up to 5.13×105  M-1 ) were unexpectedly observed. It was found that not only a strong binding to the cyclodextrin cavity is needed to restrict motion, inducing the emission, but also the conformation inside the cavity plays a pivotal role - as supported by an extensive NMR study and MD simulations.

Evolution of Artificial Arginine Analogues-Fluorescent Guanidiniocarbonyl-Indoles as Efficient Oxo-Anion Binders.

In this article, we present fluorescent guanidiniocarbonyl-indoles as versatile oxo-anion binders. Herein, the guanidiniocarbonyl-indole (GCI) and methoxy-guanidiniocarbonyl-indole (MGCI) were investigated as ethylamides and compared with the well-known guanidiniocarbonyl-pyrrole (GCP) concerning their photophysical properties as well as their binding behavior towards oxo-anions. Hence, a variety of anionic species, such as carboxylates, phosphonates and sulfonates, have been studied regarding their binding properties with GCP, GCI and MGCI using UV-Vis titrations, in combination with the determination of the complex stoichiometry using the Job method. The emission properties were studied in relation to the pH value using fluorescence spectroscopy as well as the determination of the photoluminescence quantum yields (PLQY). Density functional theory (DFT) calculations were undertaken to obtain a better understanding of the ground-lying electronic properties of the investigated oxo-anion binders. Additionally, X-ray diffraction of GCP and GCI was conducted. We found that GCI and MGCI efficiently bind carboxylates, phosphonates and sulfonates in buffered aqueous solution and in a similar range as GCP (Kass ≈ 1000-18,000 M-1, in bis-tris buffer, pH = 6); thus, they could be regarded as promising emissive oxo-anion binders. They also exhibit a visible fluorescence with a sufficient PLQY. Additionally, the excitation and emission wavelength of MGCI was successfully shifted closer to the visible region of the electromagnetic spectrum by introducing a methoxy-group into the core structure, which makes them interesting for biological applications.

Reversible Self-Assembly of Gold Nanoparticles Based on Co-Functionalization with Zwitterionic and Cationic Binding Motifs*.

We report a pH- and temperature-controlled reversible self-assembly of Au-nanoparticles (AuNPs) in water, based on their surface modification with cationic guanidiniocarbonyl pyrrole (GCP) and zwitterionic guanidiniocarbonyl pyrrole carboxylate (GCPZ) binding motifs. When both binding motifs are installed in a carefully balanced ratio, the resulting functionalized AuNPs self-assemble at pH 1, pH 7 and pH 13, whereas they disassemble at pH 3 and pH 11. Further disassembly can be achieved at elevated temperatures at pH 1 and pH 13. Thus, we were able to prepare functionalized nanoparticles that can be assembled/disassembled in seven alternating regimes, simply controlled by pH and temperature.

Body donation as a grateful gift for a long and active life with a Björk-Shiley valve.

An 87-year-old patient donated his body to the Institute of Anatomy and Cell Biology in gratefulness for the longevity of a Björk-Shiley convexo-concave (BSCC) prosthetic aortic valve, implanted 34 years ago. The dissection of the enlarged heart showed no major signs of thrombosis, malignant fibrosis, or any other relevant issue that could potentially lead to valve failure as in other patients. Despite the reported high mortality rate of the earlier designs, especially of the BSCC valves, some patients survived for longer than expected. In more than 34 years after the BSCC valve implantation, the patient was a very active and lively man, working both as full-time and volunteer firefighter. The lifespan of this BSCC valve is among the longest reported.