Solvent free synthesis and structural evaluation of polyurethane films based on poly(ethylene glycol) and poly(caprolactone)

Biodegradable amphiphilic polyurethane films (bio-PUs) were synthesized by solvent free polyaddition reaction of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(caprolactone) (PCL) as macrodiols with hexamethylene diisocyanate. Samples were subsequently heat cured in order to obtain 3D crosslinked structure. Different PCL/PEG ratios allowed controlling the toughness of the resulting bio-PUs. Significant enhancement of Young’s modulus, strength and elongation at break was observed at a PCL/PEG molar ratio above 3. The change in the bio-PU mechanical behavior was ascribed to the formation of crystalline PCL domains in the bio-PU network. The presence of PEG increased both the ability to absorb water and the rate of hydrolytic degradation, while PCL increased the cell viability. Prepared solvent free bio-PUs may advantageously be used in medicine as elastic resorbable material applicable against post-surgical adhesions

Transfection by polyethyleneimine-coated magnetic nanoparticles: Fine-tuning the condition for electrophysiological experiments

A non-viral tool for the delivery of nucleic acids termed magnetofection was recently developed as a promising transgenic technique with high transfection efficiency for gene delivery into mammalian cells. Despite the fact that transfection efficiency was the objective in the past, the post-transfection cell morphology and the essential gigaseal formation between cells and patch clamp glass electrodes have not been studied in detail. The cell viability and fluorescent response of Accelerated Sensor of Action Potentials (ASAP1) were studied in somatic HEK293 cells with respect to preserving physiological cell behavior and morphology. The DNA vector (pcDNA3.1/Puro-CAG-ASAP1) was intracellularly delivered by DNA/polyethyleneimine/magnetic nanoparticles and the transfection protocols varied in complex formations were optimized with respect to transfection rate, cytotoxicity of modified nanoparticles and essential gigaseal formation needed for patch clamp technique. A patch clamp study of transfected cells was carried out 72 hours post-transfection. Our results showed the best complex formation in order DNA/magnetic nanoparticle/polyethyleneimine that provides 51.82% transfection efficiency, 83.45% of patch clamp applicable cells, and 90.15% of gigasealed patch clamp applicable cells. A significant difference in fluorescent response of transfected cells was not found compared to control. Thus, these observations suggested that a large amount of the cells were able to create a gigaseal with a glass electrode 72 hours from transfection despite the lower transfection efficiencies. © 2018 American Scientific Publishers

Transfection by polyethyleneimine-coated magnetic nanoparticles: Fine-tuning the condition for electrophysiological experiments

A non-viral tool for the delivery of nucleic acids termed magnetofection was recently developed as a promising transgenic technique with high transfection efficiency for gene delivery into mammalian cells. Despite the fact that transfection efficiency was the objective in the past, the post-transfection cell morphology and the essential gigaseal formation between cells and patch clamp glass electrodes have not been studied in detail. The cell viability and fluorescent response of Accelerated Sensor of Action Potentials (ASAP1) were studied in somatic HEK293 cells with respect to preserving physiological cell behavior and morphology. The DNA vector (pcDNA3.1/Puro-CAG-ASAP1) was intracellularly delivered by DNA/polyethyleneimine/magnetic nanoparticles and the transfection protocols varied in complex formations were optimized with respect to transfection rate, cytotoxicity of modified nanoparticles and essential gigaseal formation needed for patch clamp technique. A patch clamp study of transfected cells was carried out 72 hours post-transfection. Our results showed the best complex formation in order DNA/magnetic nanoparticle/polyethyleneimine that provides 51.82% transfection efficiency, 83.45% of patch clamp applicable cells, and 90.15% of gigasealed patch clamp applicable cells. A significant difference in fluorescent response of transfected cells was not found compared to control. Thus, these observations suggested that a large amount of the cells were able to create a gigaseal with a glass electrode 72 hours from transfection despite the lower transfection efficiencies. © 2018 American Scientific Publishers