02.09.2026 10:30 | Hörsaal III, Greinstraße 4-6, 50939 Köln

Membrane fusion between SARS-CoV-2 and host cells is mediated by the spike protein and involves the membrane-proximal external region (MPER), a trypto…

Mesoporous silica nanoparticles (mSiO2–NPs) are efficient drug delivery vehicles, yet their surface chemistry critically dictates payload uptake, therapeutic efficiency, and biocompatibility. Conventional organic coatings on the surface, such as polyethylenimine (PEI), improve drug loading capacity but substantiate cytotoxicity, while inorganic coatings/surface functionalization (e.g., (3-aminopropyl)trimethoxysilane (APTMS)) grafting reduces toxicity but offers uncontrolled drug release. Here, we present the first systematic comparison of APTMS- and PEI-functionalized mSiO2, with and without mannose conjugation, to establish how sequential surface modification governs nicotinic acid (NA) loading, release kinetics, and cellular response. Using NA as a model drug, PEI-coated carriers achieved the highest loading (DEE = 83%) and sustained, pH-responsive release (41% in 24 h at pH 5.5) but displayed pronounced cytotoxicity in breast cancer cells (MCF-7) and peripheral blood mononuclear cells (PBMCs). Mannose conjugation substantially reduced this toxicity, while maintaining drug loading efficiency and enhancing cellular uptake in both epithelial and immune cell cultures. Notably, mannose-functionalized PEI carriers exhibited targeted, stimulus-sensitive release and selective enrichment in monocyte subsets without inducing immune activation, consistent with uptake mediated by carbohydrate-binding receptors confirmed via confocal colocalization analysis. These findings establish mannose coating as an effective strategy to reconcile efficiency and safety in amine-functionalized silica nanocarriers, providing a practical design principle for targeted and biocompatible drug delivery systems.

Membrane fusion between SARS-CoV-2 and host cells is mediated by the spike protein and involves the membrane-proximal external region (MPER), a tryptophan-rich sequence implicated in viral entry. Here, we investigated the feasibility of MPER-derived ...

A research team at the University of Cologne has developed an artificial DNA base pair that works according to a new chemical principle. In contrast to natural bases, the novel artificial base pairs u...

The past decades have seen significant expansion of the nucleic acid space with the development of modified artificial base pairs based on natural nucleic acid analogues and even entirely new designed base pairs. This expansion has led to tremendous potential for applications such as site-specific labeling and structural investigations. However, natural nucleic acids rely strongly on hydrogen bonding as the attraction force, which has driven the development of artificial base pairs that adapt this mechanism. To achieve orthogonality with natural bases, unnatural base pairs with alternative attraction forces, such as hydrophobic interactions, have been developed which however can perturb duplex structures. Our work introduces a completely newly designed artificial base pair that leverages halogen bonding (R–Hal···) as a directional hydrogen bonding-like interaction. We report computational studies that led to the development of this novel unnatural base pair and its synthesis. Our results demonstrate the successful acceptance of a bulky iodinated nucleoside triphosphate by KlenTaq DNA polymerase, enabling the selective enzymatic synthesis of a DNA strand containing the dIIPO–doIPP base pair. Our work presents the first demonstration of a novel base pair with halogen bonding potential that is enzymatically incorporated into DNA.

The reaction of the radioactive pertechnetate (99TcO4)− with the oxidizer SO3 leads to blue crystals of (NH4)2[Tc2O2(S2O7)4]. The complex dimeric [Tc2O2(S2O7)4]2− anion exhibits the technetium in the...

99mTc is the most widely used radionuclide in medical diagnostics and typically obtained from high-specific-activity (HSA) 99Mo produced in nuclear reactors. However, recent reactor shutdowns have led to supply shortages and prompted efforts to implement alternative production methods. One promising approach is neutron activation of 98Mo, which yields low-specific-activity (LSA) 99Mo. Since conventional Al2O3-based 99Mo/99mTc generators are designed for HSA 99Mo, adaptations are required for LSA 99Mo usage. In this study, we evaluated the feasibility of modifying existing Al2O3-based 99Mo/99mTc generators for use with LSA 99Mo, anticipating production at the planned high brilliance neutron source (HBS) at Forschungszentrum Jülich. Key modifications included adjustments to the amount of Al2O3 on the column and the elution volume of 99mTc to enhance 99Mo adsorption and 99mTc elution efficiency. The performance of the modified “mock-up” system was compared with a standard clinical generator. The results demonstrated that only minor modifications are required for LSA 99Mo to be effectively utilized in a future generator, with elution efficiencies remaining comparable to conventional generators, while maintaining parameters like size, form, number, activity of the individual generator comparable. However, 99Mo breakthrough levels exceeded regulatory limits, highlighting the need for further optimization. Nevertheless, these findings support the feasibility of using LSA 99Mo in clinical applications with minimal changes to existing infrastructure.

The synthesis, crystal structures, and characterization of potassium 18 crown 6 complexes with tetrahedral oxoanions, [K(18 crown 6)][XO4] (X = Tc, Re), are reported. X-ray diffraction analysis, Rama...

YouTube video by Simons Chemiebaukasten

The increase in antibacterial resistance is one of the greatest challenges in modern medicine, driving an urgent need to develop new drugs to combat resistant pathogens. Peptides represent a promising...