Effect of peptides' binding on the antimicrobial activity and biocompatibility of ‎protein-based substrates ‎Kaisersberger Vincek, Maja (Avtor) Kokol, Vanja (Mentor) woolgelatineantimicrobial peptidesε-poly-L-lysineoligo-acyl-lysylgrafting chemistry‎grafting approachpeptide orientationantibacterial activitycytotoxicity‎This work reveals the effect of coupling approach (chemical by using carbodiimide chemistry ‎and grafting-to vs. grafting-from synthesis routes, and enzymatic by using transglutaminase) ‎of a hydrophilic ε-poly-L-lysine (εPL) and an amphiphilic oligo-acyl-lysyl (OAK) derivative (K-7α12-OH) to wool fibers and gelatine (GEL) macromolecules, respectively, and substrates ‎antibacterial activity against Gram-negative E. coli and Gram-positive S. aureus bacteria ‎after 1–24 h of exposure, as well as their cytotoxicity. Different spectroscopic (ultraviolet-‎visible, infrared, fluorescence and electron paramagnetic resonance) and separation ‎techniques (size-exclusion chromatography and capillary zone electrophoresis) as well as ‎zeta potential and potentiometric titration analysis, were performed to confirm the covalent ‎coupling of εPL/OAK, and to determine the amount and orientation of its immobilisation.‎ The highest and kinetically the fastest level of bacterial reduction was achieved with ‎wool/GEL functionalised with εPL/OAK by chemical grafting-to approach. This effect ‎correlated with both the highest grafting yield and conformationally the highly-flexible ‎(brush-like) orientation linkage of εPL/OAK, implicating on the highest amount of accessible ‎amino groups interacting with bacterial membrane. However, OAK`s amphipathic structure, ‎the cationic charge and the hydrophobic moieties, resulted to relatively high reduction of S. ‎aureus for grafting-from and the enzymatic coupling approaches using OAK-functionalised ‎GEL. ‎ The εPL/OAK-functionalised GEL did not induce toxicity in human osteoblast cells, even at ‎‎~25-fold higher concentration than bacterial minimum inhibitory (MIC) concentration of ‎εPL/OAK, supporting their potential usage in biomedical applications.‎ It was also shown that non-ionic surfactant adsorbs strongly onto the wool surface during ‎the process of washing, thereby blocking the functional sites of immobilized εPL and ‎decreases its antibacterial efficiency. ‎ ‎[M. Kaisersberger Vincek]20172017-04-05 20:16:33Doktorska disertacija65459sl