1. Bromelain and nisin: The natural antimicrobials with high potential in biomedicineUrška Jančič, Selestina Gorgieva, 2022, pregledni znanstveni članek Opis: Infectious diseases along with various cancer types are among the most significant public
health problems and the leading cause of death worldwide. The situation has become even more
complex with the rapid development of multidrug-resistant microorganisms. New drugs are urgently
needed to curb the increasing spread of diseases in humans and livestock. Promising candidates
are natural antimicrobial peptides produced by bacteria, and therapeutic enzymes, extracted from
medicinal plants. This review highlights the structure and properties of plant origin bromelain and
antimicrobial peptide nisin, along with their mechanism of action, the immobilization strategies, and
recent applications in the field of biomedicine. Future perspectives towards the commercialization of
new biomedical products, including these important bioactive compounds, have been highlighted.
Ključne besede: bromelain, nisin, bioactivity, antimicrobial agent, biomedicine, carrier
Objavljeno v DKUM: 27.03.2025; Ogledov: 0; Prenosov: 1
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2. Nisin-loaded gelatin microparticles for the enhanced bioactivity of bacterial nanocelluloseMaša Hren, Janja Trček, Aleksandra Šakanović, Hristina Obradović, Mateja Erdani-Kreft, Silvo Hribernik, Selestina Gorgieva, 2025, izvirni znanstveni članek Opis: Bacterial nanocellulose (BnC) is of immense importance in medicine, although its lack of bioactivity present intriguing issue. We propose a method to modify BnC with gelatin and nisin biomolecules, and explore their synergistic effect on the antimicrobial activity. Gelatin microparticles (without/with nisin loading) with a size ~0.5 μm and ~ 1.3 μm were prepared by spray drying and stabilised by dehydrothermal treatment. Modified BnC-based membranes supported the formation of biologically relevant minerals and were non-cytotoxic to human gingival fibroblast cells (HGF). The presence of gelatin microparticles improved the viability of HGF by approximately 20 %, due to the effect of gelatin alone, independent of the addition of nisin. BnC coated with a nisin/gelatin solution reduces the viability of HGF by about 20 %, but this negative effect is not observed by nisin coated gelatin microparticles. The cell viability of BnC membranes was above 90 % in both porcine and human urothelial cells. The antimicrobial activity study confirmed an inhibitory effect of membranes modified with nisin-coated microparticles or a gelatin/nisin solution against Staphylococcus aureus at a non-cytotoxic nisin dose (150 μg/mL). The study demonstrates the structural effects of gelatin and gelatin/nisin mixtures on the bioactivity of BnC and provides a rationale for the modification procedure.
Ključne besede: bacterial nanocellulose, gelatin, nisin, spray-drying, antimicrobial function, bioactivity
Objavljeno v DKUM: 10.03.2025; Ogledov: 0; Prenosov: 6
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3. Morphological, mechanical, and in-vitro bioactivity of gelatine/collagen/hydroxyapatite based scaffolds prepared by unidirectional freeze-castingYasir Beeran Potta Thara, Tomaž Vuherer, Uroš Maver, Vanja Kokol, 2021, izvirni znanstveni članek Opis: The fabrication of biomaterials to be used in segmental bone defects, mimicking the bone's organic-inorganic architecture and mechanical properties to induce osteogenesis, persists as a key challenge. The purpose of this study was to elucidate the effect of a lightweight, morphologically graded, and multiphase self-standing scaffold structure prepared from a combination of gelatine (Gel), collagen type 1 (Col) and/or hydroxyapatite (HAP) nanoparticles by a unidirectional freeze-casting process at different temperatures (−20, −40, −60 °C), followed by carbodiimide induced cross-linking, on their in-vitro mechanical stability and bioactive properties. In addition, the rheological study of differently formulated Gel solutions has been performed to determine the effect of Col and HAP content on their microstructural arrangement, which, together with the freezing kinetic, affects Gel/Col orientation and cross-linking, and, thus, the scaffold's mechanical strength and stability. A bone-like anisotropic, interconnected, and graded porosity (from 120 to a few μm) scaffold structure with up to 30% total porosity and ~61 μm average pores' diameter is obtained by using a higher Col content (Col: Gel = 2:5) and freezing temperature (−20 °C) while forming a few μm thick close-to-parallel lamellae, separated with a 10–100 μm space when prepared at −60 °C. Such a structure influenced in-vitro stability strongly (lower swelling without weight loss), being accompanied with a ~76% increase of compression strength (to 37 kPa) and ~67% decrease of elastic modulus (to 17 kPa) when prepared with HAP and incubated in HBSS for 7 days. On the other hand, a significant reduction of both strength (~78%, to 15 kPa) and elasticity (~95%, to 5 kPa) was noted for a scaffold prepared with HAP at −60 °C, being related to faster degradation and the formation of a highly opened structure on the bottom, required to stimulate the bone ingrowth, while a more closed network structure on the top to adhere with the surrounding soft tissue. None of the scaffolds induced cytotoxicity to human bone-derived osteoblasts, even after 19 days of incubation, but rather improved their viability while promoting cells' adhesions, proliferation, and differentiation, being supported with an increased alkaline phosphatase activity and rod-like CaP formation.
Ključne besede: biomimetic scaffolds, rheology, unidirectional freeze-casting, morphology, compression properties, bioactivity
Objavljeno v DKUM: 10.03.2025; Ogledov: 0; Prenosov: 3
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4. Exploring chitosan-plant extract bilayer coatings: Advancements in active food packaging via polypropylene modificationSaša Kaloper, Olivija Plohl, Sonja Smole Možina, Alenka Vesel, Vida Šimat, Lidija Fras Zemljič, 2024, izvirni znanstveni članek Opis: UV-ozone activated polypropylene (PP) food films were subjected to a novel bilayer coating process involving primary or quaternary chitosan (CH/QCH) as the first layer and natural extracts from juniper needles (Juniperus oxycedrus; JUN) or blackberry leaves (Rubus fruticosus; BBL) as the second layer. This innovative approach aims to redefine active packaging (AP) development. Through a detailed analysis by surface characterization and bioactivity assessments (i.e., antioxidant and antimicrobial functionalities), we evaluated different coating combinations. Furthermore, we investigated the stability and barrier characteristics inherent in these coatings. The confirmed deposition, coupled with a comprehensive characterization of their composition and morphology, underscored the efficacy of the coatings. Our investigation included wettability assessment via contact angle (CA) measurements, X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), which revealed substantial enhancements in surface concentrations of elements and functional groups of CH, QCH, JUN, and BBL. Scanning electron microscopy (SEM) unveiled the coatings' heterogeneity, while time-of-flight secondary ion mass spectrometry (ToF-SIMS) and CA profiling showed moderately compact bilayers on PP, providing active species on the hydrophilic surface, respectively. The coatings significantly reduced the oxygen permeability. Additionally, single-layer depositions of CH and QCH remained below the overall migration limit (OML). Remarkably, the coatings exhibited robust antioxidative properties due to plant extracts and exceptional antimicrobial activity against S. aureus, attributed to QCH. These findings underscore the pivotal role of film surface properties in governing bioactive characteristics and offer a promising pathway for enhancing food packaging functionality.
Ključne besede: chitosan, plant extracts, polypropylene, active packaging, surface characterization, bioactivity
Objavljeno v DKUM: 27.05.2024; Ogledov: 241; Prenosov: 21
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