Browsing by Author "Philipova N."

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    Novel Fluorescent Benzimidazole-Hydrazone-Loaded Micellar Carriers for Controlled Release: Impact on Cell Toxicity, Nuclear and Microtubule Alterations in Breast Cancer Cells
    (2023-06-01) Bryaskova R.; Georgiev N.; Philipova N.; Bakov V.; Anichina K.; Argirova M.; Apostolova S.; Georgieva I.; Tzoneva R.
    Fluorescent micellar carriers with controlled release of a novel anticancer drug were developed to enable intracellular imaging and cancer treatment simultaneously. The nanosized fluorescent micellar systems were embedded with a novel anticancer drug via the self-assembling behavior of well-defined block copolymers based on amphiphilic poly(acrylic acid)-block-poly(n-butyl acrylate) (PAA-b-PnBA) copolymer obtained by Atom Transfer Radical Polymerization (ATRP) and hydrophobic anticancer benzimidazole-hydrazone drug (BzH). Through this method, well-defined nanosized fluorescent micelles were obtained consisting of a hydrophilic PAA shell and a hydrophobic PnBA core embedded with the BzH drug due to the hydrophobic interactions, thus reaching very high encapsulation efficiency. The size, morphology, and fluorescent properties of blank and drug-loaded micelles were investigated using dynamic light scattering (DLS), transmission electron microscopy (TEM), and fluorescent spectroscopy, respectively. Additionally, after 72 h of incubation, drug-loaded micelles released 3.25 μM of BzH, which was spectrophotometrically determined. The BzH drug-loaded micelles were found to exhibit enhanced antiproliferative and cytotoxic effects on MDA-MB-231 cells, with long-lasting effects on microtubule organization, with apoptotic alterations and preferential localization in the perinuclear space of cancer cells. In contrast, the antitumor effect of BzH alone or incorporated in micelles on non-cancerous cells MCF-10A was relatively weak.
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    PORPHYRINE/SILVER NANOPARTICLES BASED PHOTOACTIVE ANTIBACTERIAL COATINGS
    (2023-01-01) Philipova N.; Georgiev N.; Ganchev D.; Lalov I.; Bryaskova R.
    A novel amino-modified protoporphyrin IX with included silver nanoparticles (PPIX-ED/AgNPs) complex was synthesized and used as a last layer for preparation of photoactive antibacterial coatings. The obtained PPIX-ED/ AgNPs complex was appropriately analyzed using various spectroscopic methods such as fluorescence analysis and infrared spectroscopy (ATR-FTIR). The size and morphology of the synthesized PPIX-ED/AgNPs complex were analyzed by Transmission electron microscopy (TEM) and dynamic light scattering (DLS). Then, the photoactive antibacterial coatings were obtained by deep coating procedure as the last layer consists of PPIX-ED/AgNPs complex, which is expected to possess strong antibacterial activity. The EDX-SEM analysis was employed to prove the deposition of the layers and nanoindentation analysis was used to determine their mechanical properties. The antibacterial properties of the photoactive coatings against G. negative E. coli and G. positive B. Subtilis were determined using disk diffusion method (DDM).
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    SURFACE AND MECHANICAL PROPERTIES OF BIO-INSPIRED COATINGS
    (2021-01-01) Philipova N.; Mineva N.; Bryaskova R.
    In this article we report on the surface and mechanical properties of bio-inspired polymer coatings, obtained by the deposition of two consequent polymer layers on stainless steel (SS) substrate. As a first layer was employed 3,4-dihydroxy-phenylalanine (DOPA) functionalized P(mDOPA)-co-P(DMAEMA+) polycation which anchor to the surface by DOPA/metal interaction. The second layer consists in nanogels on the basis of Pox(mDOPA)/PAH. The deposition of the layers was confirmed by Quartz crystal microbalance coupled with dissipation (QCM-D) and proved by ATR-FTIR spectroscopy. The surface properties were demonstrated by AFM and contact angle measurements. The adhesion of the coating to the substrate was evaluated using scratch test and SEM analysis was applied to visualize the scratch tracks.