Lilia Clima

Novel cyclodextrin-based pH-sensitive supramolecular host–guest assembly for staining acidic cellular organelles

The preparation and characterization of a supramolecular host–guest inclusion complex between a fluorescent indolizinyl-pyridinium salt and β-cyclodextrin is reported. The formation of the inclusion complex was investigated by ESI-MS experiments, transmission electron microscopy, Jobs plot investigations and molecular docking studies, proving the formation of 1 : 1 and 1 : 2 species. Several interesting features of the investigated fluorescent indolizinyl-pyridinium salt/β-cyclodextrin inclusion complexes like the absence of cytotoxicity, cellular permeability, long-lived intracellular fluorescence and selective accumulation within acidic organelles made them remarkable candidates for the intracellular labelling of acidic organelles (lysosomes or mitochondria). Taking into account that a number of reported or commercially available cell staining dyes with low toxicity and solubility have already been used in cyclodextrin formulations with good results regarding the improvement of their properties, our results showed that this approach may also work with new and interesting toxic dyes capable of forming host–guest inclusion complexes with cyclodextrins.

Squalene/polyethylenimine based non-viral vectors: synthesis and use in systems for sustained gene release

The design of new non-viral gene vectors and their integration into a biomaterial scaffold are intensively explored nowadays, aimed at developing more efficient gene delivery systems capable of clinical translation. Herein, a series of squalene/branched polyethylenimine (Sq/BPEI) based conjugates were synthesized and their potential in gene delivery, as such or included in a three-dimensional hybrid scaffold (atelocollagen-glycosaminoglycan-polycaprolactone/nano-hydroxyapatite), was investigated. The developed materials were characterized through spectral (1H-NMR, 13C-NMR, FT-IR) and optical (STEM) techniques. The extent and duration of gene expression for the developed systems were monitored using luciferase assays and fluorescence microscopy. All the investigated systems exhibited a high transfection efficiency without or with moderate cytotoxic side effects (MTS assay data). The best results were obtained with the guanidinylated compound Sq-BPEI-G for both simple and combined polyplex/matrix systems. The polyplex delivery from the hybrid matrix was assessed through kinetic studies using a labeled Sq/BPEI conjugate. For the polyplex (Sq/BPEI – DNA plasmid)/3D matrix system, the expression of the delivered plasmids was observed over a 26 day- period. The reported preliminary data recommend the studied biomaterials as possible candidates for the development of a new gene-activated matrix (GAM) platform.

Synthesis, structure, computational modeling, and biological activity of two novel bimesitylene derivatives

Tetrazole- and nitrile-containing bimesitylene derivatives with potential use in coordination chemistry were synthesized and characterized, and their structural particularities are discussed. For the bimesitylene bistetrazole derivative, geometry optimization was carried out by quantum-chemical calculations using density functional theory together with vibrational frequencies, natural bond orbitals, and highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) calculations. The newly synthesized bimesitylene derivatives were also evaluated for their antimicrobial activity against three different reference strains, namely Escherichia coli, Staphylococcus aureus, and Candida albicans.

Optimization of Polyplex Formation between DNA Oligonucleotide and Poly(ʟ-Lysine): Experimental Study and Modeling Approach

The polyplexes formed by nucleic acids and polycations have received a great attention owing to their potential application in gene therapy. In our study, we report experimental results and modeling outcomes regarding the optimization of polyplex formation between the double-stranded DNA (dsDNA) and poly(l-Lysine) (PLL). The quantification of the binding efficiency during polyplex formation was performed by processing of the images captured from the gel electrophoresis assays. The design of experiments (DoE) and response surface methodology (RSM) were employed to investigate the coupling effect of key factors (pH and N/P ratio) affecting the binding efficiency. According to the experimental observations and response surface analysis, the N/P ratio showed a major influence on binding efficiency compared to pH. Model-based optimization calculations along with the experimental confirmation runs unveiled the maximal binding efficiency (99.4%) achieved at pH 5.4 and N/P ratio 125. To support the experimental data and reveal insights of molecular mechanism responsible for the polyplex formation between dsDNA and PLL, molecular dynamics simulations were performed at pH 5.4 and 7.4.