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Osteoarticular implants are designed to facilitate full recovery of lost function and ensure effective fixation of the implant. However, challenges may arise, resulting in implant failure, primarily attributed to infections at the implantation site and aseptic loosening. Thus, the surface of an implant must be altered to simultaneously offer osteoinductive and antibacterial properties. Synthetic hydroxyapatite (HAP) is frequently employed to modify metallic implant surfaces or serve as a bone filler material. To enhance its biocompatibility, HAP-based polymer composites were developed. Among most popular synthetic polymers, poly(vinyl alcohol) (PVA), is widely used because of its similar structure to the native extracellular matrix, along with chitosan (CS), a natural cationic polysaccharide, that shows biocompatibility, biodegradability and antimicrobial action, and could act as a carrier of antibacterial agents. The antibiotic of choice was Gentamicin (Gent), a water-soluble aminoglycoside, with very potent antibacterial activity for the treatment of wide range of infections, caused by Gram-negative and Gram-positive bacteria. The original approach of the presented research is the single-step electrophoretic deposition (EPD) on Ti plates of thus prepared biocomposite that would allow for on-site release of the drug. Obtained hydroxyapatite/chitosan/poly(vinyl alcohol/gentamicin (HAP/PVA/CS/Gent) biocomposite coating exhibited strong antibacterial effect against E. coli and S. aureus. Gentamicin release study indicated “burst” release in the first 48 h, with ~ 30% of total gentamicin released from the HAP/PVA/CS/Gent coating which is beneficial for the blockage of biofilm formation, followed by slow and steady release in the later period. Cytotoxic effect of HAP/PVA/CS/Gent coating was not pronounced in investigated MRC-5 and L929 cell lines. Also, in MRC-5 fibroblast cells, alkaline phosphatase levels doubled when in contact with HAP/PVA/CS/Gent, indicating good o

Following orthopedic surgery, bacterial infection may lead to significant complications related to inflammation in the peri-implant region, including the potential for implant loosening. To address this concern, the surface of metallic implants was modified through the application of bioactive and antibacterial coatings, aiming to mitigate these issues.

Electrochemical methods were employed for synthesizing composites intended for applications in medicine as antibacterial coatings on titanium bone implants or as highly efficient antibacterial hydrogels for accelerated wound healing.

Sladoled je omiljena poslastica u kojoj uživaju potrošači svih starosnih grupa, zbog jedinstvenih teksturalnih svojstava. On nema značajnu nutritivnu vrednost a doprinosi prekomernom unosu masti i "praznih" kalorija, jer obiluje šećerima i mastima. 12 Poboljšanje nutritivnog profila sladoleda funkcionalnim sastojcima moglo bi imati dubok uticaj i na poboljšanje ishrane celokupne populacije. Nutritivna i senzorska svojstva sladoleda obogaćenog funkcionalnim sastojcima treba da zadovolje očekivanja potrošača. Iako je tržište funkcionalnog sladoleda u svetu u ranoj fazi razvoja, očekuje se njegov brzi rast u narednih 5 godina. S obzirom na široku potrošnju ovog proizvoda, brojne grupe potrošača, poput dijabetičara, osoba sa kardiovaskularnim oboljenjima i onih sa prekomernom težinom, novi funkcionalni proizvod bi mogle sa sigurnošću da uključe u svoju ishranu bez ugrožavanja zdravlja. Suština predloženog tehničkog rešenja je proizvodnja funkcionalnog sladoleda u prahu uz smanjenje energetske vrednosti, uz dodatak hidrolizata proteina surutke poboljšanih funkcionalnih svojstava, pre svega antioksidativnog kapaciteta u odnosu na nehidrolizovane proteine surutke. Kontrolisana enzimska hidroliza proteina je metoda koja se koristi za “oslobađanje” bioaktivnih peptida iz dugih lanaca proteina. Ovom metodom moguće je značajno povećati bioaktivna svojstva proteina. U okviru tehničkog rešenja izvršeno je ispitivanje mogućnosti kombinovanja tradicionalnih komponenti sladoleda u prahu sa hidrolizatom proteina surutke i određenom količinom vlakana (inulina), uz mogućnost primene nutritivnih i zdravstvenih izjava za ovaj proizvod. U cilju dobijanja takvog proizvoda najpre je ispitivan uticaj uslova hidrolize proteina surutke na antioksidativni kapacitet i tehnološka svojstva (stvaranje pene i emulgovanje). Korišćenje komponenti koje nisu deo standardne recepture sladoleda, može izazvati pogoršanja osetljivih reoloških, odnosno teksturalnih svojstva sladoleda. Zbog toga su u uzorcim

Proteini glutena spadaju u visokonutritivno vredne proteine koji čine osnovnu hemijsku građu zrna žitarica, kao što su pšenica, raž i ječam. Međutim, ovi proteini odlikuju se visokim sadržajem glutamina i prolamina što ih čini otporne na enzime (Pepsin, Tripsin i Himotripsin) prisutne u digestivnom traktu ljudi. Kao posledica toga, konzumiranjem proizvoda bogatih glutenom obrazuju se velike peptidne frakcije koje iniciraju imunogenu reakciju, čineći tako ovaj protein jednim od najznačajnih prehrambenih alergena. Upravo naveden problem poslužio je kao polazna osnova za kreiranje cilja ove doktorske disertacije, u kojoj su istraživanja bazirana na primeni enzima kao biokatalizatora prirodnog porekla i nekonvencionalnih termičkih tretmana, poput mikrotalasnog zračenja, zarad proizvodnje i modifikacije nealergenih proteina glutena. Generalno, u okviru ove disertacije pristupilo se definisanju parametara netermičkih postupaka za modifikaciju proteina glutena iz pšenice kakav je mikrotalasno zračenje pod kontrolisanim uslovima u odgovarajućem reaktoru, a sve u cilju smanjenja alergenosti, odnosno sadržaja alergenih epitopa glutena. Osim toga, u cilju smanjenja alergenosti pšeničnog glutena pristupilo se i razvoju biotehnološkog postupka zasnovanog na primeni proteolitičkih enzima velike specifičnosti. Ovaj postupak je optimizovan uz pažljivo definisanje svih važnih procesnih parametara, ali je i upotpunjen i/ili dopunjen kombinovanjem sa mikrotalanim zračenjem. Kao izvor pšeničnog glutena, u okviru eksperimenata, korišćena su dva supstrata: • prvi, model protein glutena poreklom iz pšenice (bogat frakcijama glutenina i gliadina), i • drugi, komercijalno dostupna sirovina koja se koristi u svakodnevnoj ishrani ljudi, pšenično belo brašno. U svakoj fazi eksperimentalnog rada vršena je detaljna karakterizacija modifikovanog pšeničnog glutena, kako model proteina, tako i pšeničnog brašna. Karaktertizacija je podrazumevala ispitivanje alergenih svojstava modifikovanih proteina, Gluten proteins belong to highly nutritionally valuable proteins that make up the basic chemical structure of cereal grains, such as wheat, rye and barley. However, these proteins are characterized by a high content of glutamine and prolamin, which makes them resistant to enzymes (Pepsin, Trypsin and Chymotrypsin) present in the human digestive tract. As a consequence, by consuming products rich in gluten proteins, large peptide fractions are formed that initiate an immunogenic reaction, thus making gluten proteins one of the most important food allergens. The problem just mentioned served as the starting point for creating the goal of this doctoral dissertation, in which research is based on the application of enzymes as biocatalysts of natural origin and unconventional thermal treatments, such as microwave radiation, for the production and modification of non-allergenic gluten proteins. In general, within the framework of this dissertation, the parameters of non-thermal procedures for the modification of wheat gluten protein, such as microwave radiation under controlled conditions in a suitable reactor, were defined, all with the aim of reducing allergenicity, i.e. the content of allergenic gluten epitopes. In addition, in order to reduce the allergenicity of wheat gluten, the development of a biotechnological procedure based on the application of highly specific proteolytic enzymes was also undertaken. This procedure was optimized with careful definition of all important process parameters, but it was also completed and/or supplemented by combining it with microwave radiation. As a source of wheat gluten, two substrates were used in the experiments: • the first, a model of gluten protein originating from wheat (rich in glutenin and gliadin fractions), and • the second, a commercially available raw material used in the daily diet of people, wheat white flour. In each phase of the experimental work, a detailed characterization of the modified wheat gluten, both the

This study presents comparison of our recently formulated two compartmental model with General fractional derivative (GFD) and Korsmeyer-Peppas, Makoid-Banakar and Kopcha diffusion models. We have used our GFD model to study the release of gentamicin in poly (vinylalcohol)/chitosan/gentamicin (PVA/CHI/Gent) hydrogel aimed for wound dressing in medical treatment of deep chronical wounds. The PVA/CHI/Gent hydrogel was prepared by physical cross linking of poly(vinyl alcohol)/chitosan dispersion using freezing-thawing method, and then was swollen for 48 h in gentamicin solution, at 37 °C. Different physico-chemical (FTIR, SEM), mechanical and biological (cytotoxicity, antibacterial activity) properties have been determined. The concentration of released gentamicin was determined using a high-performance liquid chromatography (HPLC) coupled with mass spectrometry (MS). The ratio between concentration of released gentamicin and initial concentration of gentamicin in the hydrogel was monitored for the prolonged time period in order to obtain gentamicin release profile. It was proven that our novel diffusion GFD model better fitted with experimental data, and enabled the determination of diffusion coefficient precisely for the entire time period.

INTRODUCTION: Tissue engineering strives for innovative solutions in addressing challenges associated with contemporary bone tissue implants. This study focuses on the electrophoretic deposition (EPD) of hydroxyapatite-based bioceramic composites containing antibacterial agents onto titanium surfaces. Two composite coatings, hydroxyapatite/ chitosan (HAP/CS) and hydroxyapatite/chitosan/gentamicin (HAP/CS/Gent) were developed to combat issues such as poor adhesion, limited antibacterial potential, limited bioactivity, and potential toxicity of implant materials [1]. EXPERIMENTAL: EPD was performed at constant voltage (5 V, 12 min) on pure Ti plates from aqueous (HAP/CS and HAP/CS/Gent) suspensions. The uniformity and functionality of the deposited coatings were assessed through comprehensive physico-chemical characterization using X-ray diffraction (XRD) (Philips PW 1710, Netherlands) and scanning electron microscopy (SEM, Hitachi S-4700, J) equipped with energy dispersive X-Ray spectroscopy (EDS, X-Max, Oxford Instruments, UK). Antibacterial activity was evaluated against Staphylococcus aureus TL and Escherichia coli ATCC 25922 by quantitatively monitoring changes in the viable number of bacterial cells in suspension. Cytotoxicity against MRC-5 and L929 cell lines was investigated using trypan blue dye-exclusion test (DET) and MTT assay for assessing cell metabolic activity. Statistical significance was determined for antibacterial and cytotoxicity results by one-way analysis of variance (ANOVA), followed by multiple comparisons post-hoc test. RESULTS AND DISCUSSION: XRD revealed broadened diffraction maximums corresponding to fine HAP crystallites. Porous surface with homogeneously distributed spherical HAP agglomerates embedded in wax-like polymers' matrix of CS was observed for both coatings by SEM. The addition of gentamicin significantly enhanced the antibacterial activity of the HAP/CS/Gent coating – complete reduction of S. aureus bacterial cells was achieved

Hidrogel poli(vinil alkohol)/hitozan/gentamicin (PVA/CHI/Gent) pripremljen je fizičkim umrežavanjem disperzije poli(vinil alkohola)/hitozana i namenjen je za upotrebu kao materijal za medicinske obloge dubokih nekrotičnih rana kao što su dekubitusi. Ispitivane su fizičko-hemijske (FTIR, SEM), mehaničke i biološke (citotoksičnost, antibakterijska aktivnost) osobine. Mehanizam difuzije gentamicina iz hidrogela PVA/CHI/Gent proučavan je upoređivanjem novog dvo-kompartmentskog modela sa opštim frakcionim izvodima (GFD) i Korsmajer-Pepas, Makoid-Banakar i Kopča difuzionih modela. GFD model bolje se poklapao sa eksperimentalnim podacima od drugih modela i takođe je omogućio određivanje koeficijenta difuzije gentamicina tokom celog proučavanog vremenskog perioda.

The aim of this study is to compare the antimicrobial activity of clove essential oil against probiotic strains isolated from different pharmaceutical preparations currently available on the local market (Lacticaseibacillus rhamnosus GG, Lactiplantibacillus plantarum 299v, Lactobacillus acidophilus, Saccharomyces boulardii).

The search for waste minimization possibilities and the valorization of by-products are key to good management and improved sustainability in the food industry. Although dairy products still remain at the forefront of probiotic food development, in recent years non-dairy food products have increased in popularity owing to their unique characteristics and advantages. Due to its beneficial properties, caused by the presence of various bioactive compounds, the almond parts that remain after almond milk production can be considered promising sources of ingredients for the development of non-dairy food products. The aim of this study was to examine the potential and possibility of using a surplus product that remains after almond milk production. The antioxidant properties of the remained surplus product were characterized based on the polyphenol, flavonoid, and anthocyanin content as well as FRAP, DPPH, and ABTS antioxidant activity. The fermented beverage that combines the properties of almonds and probiotic bacteria, formulated using inulin, lyophilized fruit and aroma, was evaluated for physicochemical, microbiological, and sensory properties during cold storage (4 °C, 21 day). The surplus product that remains after the almond milk production contains 61.4 mg GAE/100g DW, 16.11 mg QE/100g DW, and 0.993 mg CYE/100g DW of polyphenols, flavonoids, and anthocyanins (respectively), and expresses DPPH, FRAP and ABTS antioxidant activity of 71.56 mg DW/mL, 50.47 mg DW/mL and 53.11 mg DW/mL (respectively). The fermentation of surplus product that remains after almond milk production leads to the production of the beverage with satisfactory values of quality parameters as follows: pH value of 4,75, titratable acidity 28,8 °SH, syneresis 7,5%, viable cell count of 7.77 log (CFU mL-1), and sensory characteristics value of 10, that is stable during 21 day of cold storage. A new probiotic almond-based beverage that combines the properties of both almonds and probiotics can be con

Biocomposite hydroxyapatite/poly(vinyl alcohol)/chitosan/gentamicin coatings were fabricated on titanium by an electrophoretic deposition process (EPD) from an aqueous suspension using the constant voltage method. Characterization of the deposited coatings was performed by scanning electron micros-copy with field emission (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) after immersion in simulated body fluid (SBF) at 37 °C. The concentration of the released gentamicin was determined using high-performance liquid chromatography (HPLC) coupled with a mass spectrometer (MS). The release profile confirmed an initial “burst-release effect” with ~ 30 % of the gen-tamicin released in the first 48 h, which could be of assistance in the prevention of biofilm formation. An-tibacterial activity was proven by the agar diffusion method on Staphylococcus aureus TL and Escherich-ia coli ATCC 25922 bacterial strains. Cytotoxicity was tested by the dye exclusion test (DET) on MRC-5 and L929 fibroblast cell lines, with both coatings expressing nontoxicity. The results showed the high ap-plicability potential of a poly(vinyl alcohol)-based biocomposite coating for medical purposes.

Bioactive peptides are promising cosmetic active ingredients that can improve skin healthand appearance. They exhibit a broad spectrum of activity, including anti-aging, antioxidant, an-timicrobial, and anti-inflammatory effects. The aim of this study was to develop a safe, stable, andefficacious environmentally friendly (“green”) emulsion using a milk protein hydrolysate as a modelactive ingredient. Potential emulsions were formulated with biodegradable emollients, stabilizedwith naturally derived mixed emulsifier, and prepared by cold process. They were evaluated forrheological behavior (continuous rotation and oscillation tests), physical stability (dynamic me-chanical thermal analysis—DMTA test), and texture profiles, as well as cytotoxic, antioxidant, andantimicrobial effects. Rheological characterization revealed shear-thinning flow behavior with yieldpoint from continuous rotation tests and predominantly elastic character from oscillation (amplitudeand frequency sweep) tests, with small structural change detected in the DMTA test. These resultsimplied satisfactory rheological properties and good stability. Texture analysis revealed acceptablespreadability and substantivity of the emulsions. The protein hydrolysate showed antioxidant activity.The developed emulsions showed low antibacterial activity against selected microorganisms, butthis was due to the action of preservatives, not peptides. All potential emulsions showed a desirablesafety profile. The results obtained provide the basis for the next stage of formulation development,i.e., in vivo efficacy tests.

Electrophoretic deposition (EPD) was employed to fabricate composite coatings aimed for orthopedic implants. Hydroxyapatite (HAP), poly(vinyl alcohol) (PVA) and chitosan (CS) coatings, with or without antibiotic gentamicin (Gent) were deposited in a single-step process from aqueous suspension, using EPD. Polymer/mineral composite coatings were formed with the aim to mimic the natural composition of bone tissue, along with improved coatings antibacterial properties, at the same time serving as a drug carrier, allowing local administration of antibiotic. Structural and morphological characterization of HAP/PVA/CS and HAP/PVA/CS/Gent coatings was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), and scanning electron microscopy (SEM) proving carbonate-substituted HAP. The presence of gentamicin contributed to the bactericidal activity of composite HAP/PVA/CS/Gent coating against Staphylococcus aureus and Escherichia coli. Cytotoxicity studies were performed towards human MRC-5 and mice L929 fibroblast cell lines, and both investigated samples (HAP/PVA/CS and HAP/PVA/CS/Gent) expressed good biocompatibility, without causing toxic effect on tested cells. Biomineralization potential was investigated by measuring the alkaline phosphatase activity, demonstrating high potential of HAP/PVA/CS/Gent to induce the growth of new HAP layer. Therefore, the present investigation proposes the production of nents, along with antibiotic gentamicin, improving the antibacterial coatings’ properties.

Uvođenje antibiotika u polimer/mineralnu kompozitnu prevlaku poboljšava antibakterijska svojstva prevlaka. Kompozitna prevlaka (hidroksiapatit - HAP, poli(vinilalkohol), hitozan, gentamicin) dobijena je elektroforetskim taloženjem iz četvorokomponentne vodene suspenzije. Primenom termogravimetrijske i rendgenske difrakcione analize pokazano je prisustvo karbonatno-supstituisanog HAP. Antibakterijska aktivnost kompozitne prevlake sa gentamicinom potvrđena je protiv soja S. aureus i E. coli, čineći ovu prevlaku pogodnom za potencijalnu primenu u biomedicini., Antibiotic introduction in polymer/mineral coating can improve the antibacterial properties of coatings. Composite coating (hydroxyapatite, poly(vinyl alcohol), chitosan, gentamicin) was fabricated from a four-component aqueous suspension using electrophoretic deposition. Structural and morphological characterization of the coating was investigated by X-ray diffraction and thermogravimetric analysis proving carbonate-substituted HAP. The presence of gentamicin contributed to the antibacterial activity of composite coating against S. aureus and E. coli strains, representing a suitable material for possible application in biomedicine.

Predmet istraţivanja ove doktorske teze je priprema biopolimernih emulzija i disperzija, kao i dobijanje tankih filmova i prevlaka od njih, koje se mogu koristiti u aktivnom pakovanju za zaštitu namirnica i kao biopesticid. Glavni koncept nauĉno-istraţivaĉkog rada zasniva se na ugradnji aktivnih komponenti (etarsko ulje limunove trave, Zn(CH3COO)2∙2H2O, nanoĉestice ZnO) u polimernu matricu pektina i hitozana, sa ciljem da se postigne njihovo sporo otpuštanje i produţena antimikrobna/insekticidna aktivnost. Emulzije i filmovi su ispitani razliĉitim metodama u cilju strukturne (Particle Analyzer, ATR-FTIR, TGA/DTG i DSC) i morfološke (AFM, SEM) karakterizacije. TakoĊe, odreĊena su mehaniĉka svojstava i rastvorljivost filmova. Antibakterijsko dejstvo emulzija i disperzija testirano je u in vitro uslovima na vrstama bakterija koje su ĉesti uzroĉnici kontaminacije i trovanja namirnicama (Escherichia coli, Bacillus subtilis i Staphylococcus aureus). Filmovi na bazi hitozana pokazali su bolja mehaniĉka svojstva i niţi stepen rastvorljivosti u poreĊenju sa filmovima na bazi pektina. Emulzije i disperzije na bazi hitozana su pokazale jaĉi antibakterijski efekat u in vitro uslovima, dok je kod emulzija na bazi pektina primećeno sinergistiĉko dejstvo izmeĊu aktivnih komponenti. Efikasnost prevlaka, koje bi se primenjivale u izradi aktivnog pakovanja, testirana je u in vivo uslovima na sveţim malinama (Rubus idaeus L.), pri ĉemu je ostvaren produţetak sveţine i roka trajanja maline sa ĉetiri na osam dana. Dejstvo emulzije na bazi pektina kao biopesticida ispitano je na krompirovom moljcu (Phthorimaea operculella L.), kada je efekat sporog otpuštanja doveo do produţenog dejstva bioaktivnih jedinjenja inkapsuliranog etarskog ulja u efikasnom suzbijanju krompirovog moljca., The research subject of this doctoral thesis is the preparation of biopolymer emulsions and dispersions, as well as obtaining thin films and coatings from them, which can be used in active packaging for food protection and as a biopesticide. The main concept of the scientific research is based on the incorporation of active components (lemongrass essential oil, Zn(CH3COO)2∙2H2O, ZnO nanoparticles) into the polymer matrix of pectin and chitosan, to achieve their slow-release and prolonged antimicrobial/insecticidal activity. The emulsions and films were investigated by various methods for structural (Particle Analyzer, ATR-FTIR, TGA/DTG, and DSC) and morphological (AFM, SEM) characterization. Also, the mechanical properties and solubility of the films were determined. The antibacterial effect of emulsions and dispersions was tested in vitro on the bacteria that are frequent causes of contamination and food poisoning (Escherichia coli, Bacillus subtilis, and Staphylococcus aureus). The chitosan-based films showed better mechanical properties and a lower degree of solubility compared to the pectin-based films. The chitosan-based emulsions and dispersions showed a stronger antibacterial effect in vitro, while a synergistic effect between the active components was observed in the pectin-based emulsions. The effectiveness of the coatings, which would be applied in the production of active packaging, was tested in vivo on fresh raspberries (Rubus idaeus L.), whereby the freshness and shelf life of raspberries were extended from four to eight days. The effect of the pectin-based emulsion as a biopesticide was tested on the potato tuber moth (Phthorimaea operculella L.) when the slow release effect led to the prolonged activity of the bioactive compounds of the encapsulated essential oil in the effective control of the potato tuber moth.

Recent advances in biomaterials science are increasingly focused on (re)search for next-generation soft tissue regeneration solutions. Hydrogel-based materials are becoming a focal point to address many tissue engineering requirements, possessing exceptional biocompatibility, with tailorable shape, structure and mechanical properties, as well as infinite possibilities drug delivery. The widespread antibiotics use has led to aggravated resistance issues in many bacterial strains, so the focus is increasingly shifted towards alternative antibacterial solutions such as silver nanoparticles (AgNPs). In this work, we have developed novel composite materials based on poly(vinyl alcohol)/chitosan (PVA/CHI) and poly(vinyl alcohol)/ chitosan/graphene (PVA/CHI/Gr) hydrogels with silver nanoparticles obtained through green in situ constant-voltage electrochemical synthesis. The obtained AgNPs’ properties, sizes and size distributions were examined using UV-visible spectroscopy, dynamic light scattering and transmission electron microscopy. In vitro swelling and silver release kinetics were monitored in the simulated physiological conditions (pH7.4, 37 C). The obtained release and swelling isotherms were fitted with several theoretical models that helped discern the mechanisms of these processes. Tensile testing was carried out to examine the composites’ mechanical behavior and elasticity – important properties for soft tissue engineering materials. Finally, the excellent antibacterial activity of the obtained silver/ poly(vinyl alcohol)/chitosan (Ag/PVA/CHI) and silver/poly(vinyl alcohol)/chitosan/graphene (Ag/PVA/CHI/Gr) hydrogels against Staphylococcus aureus and Escherichia coli was confirmed quantitatively by colony counting method, and their non-toxicity was verified towards two model fibroblast cell lines (MRC-5 and L929) utilizing the MTT assay. Through thorough characterization, the obtained nanocomposite hydrogel materials were identified as strong candidates for acti

Candida albicans is pathogenic yeast species present as a part of the normal microbiota mucosal surface oral and vaginal cavities and digestive tract of warm-blooded animals and humans, without causing any health problems. Intensive growth and infection can occur as a result of excessive use of broad-spectrum antibiotics, corticosteroids, in immunosuppressive individuals, so as under the influence of numerous external factors that weaken the body's defence system. Since antibiotics stimulate the growth of Candida albicans, treatment is based on the use of antimycotic drugs and dietary adjustments, when healing process can sometimes take several weeks. In addition, long-term use of antimycotic drugs causes side effects (nausea, vomiting, diarrhea) and their frequent use contributes development of resistant strains of Candida albicans, which further complicates curing. In order to alleviate treatment, recent years great interest is focused on finding and application of natural preparations, such as essential oils of spices and medicinal herbs, which possess numerous biological properties, including antifungal activity. The aim of this study was to evaluate the antifungal activity of essential oils of various spices and medicinal herbs against Candida albicans in order to find an alternative treatment for candidiasis. The antifungal activity of twenty essential oils and herbal tinctures was investigated by agar well diffusion and broth macrodilution methods, and the obtained results were compared with the effect of antimycotic drugs (nystatin) and commercial preparations present in the local marketplace. Based on the results obtained by the agar well diffusion method, undiluted essential oils and herbal tinctures can be divided into five groups, according to the diameter of inhibition zone they form. Very strong antifungal activity was observed with essential oils of oregano, basil, thyme and cinnamon, with a diameter of the inhibition zones greater than 40mm, while st

Titanium (Ti) is an implant material widely used in orthopedics due to its high corrosion resistance (naturally forms a passive oxide layer) and good mechanical properties. Although Ti has certain ability to osseointegrate, the biocompatibility and bioactivity of Ti can be significantly improved by modifying its surface. In order to improve antibacterial properties a broad spectrum antibiotic gentamicin was loaded in a composite coating of hydroxyapatite (HAP) with natural polymers chitosan (CS) and poly(vinyl alcohol (PVA) and was deposited on Ti using electrophoretic deposition (EPD) technique. EPD was carried out at the constant voltage on pure titanium plates from an aqueous suspension. Deposited HAP/CS/PVA and HAP/CS/PVA/Gent coating were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and field emission scanning electron microscopy (FE-SEM). The obtained results confirmed the formation of new composite coatings. Cytotoxicity against two types of cell lines (MRC-5 and L929) was investigated using trypan blue dye-exclusion test (DET) and MTT assay for assessing cell metabolic activity. The antibiotic loaded coating (HAP/CS/PVA/Gent) exhibited good antibacterial activity against Staphylococcus aureus and Escherichia coli, while preserving low cytotoxicity, indicating the high potential for biomedical applications. Excellent osteogenic properties, through the promotion of osteoblast differentiation were confirmed by ALP assay. Results were much more pronounced for HAP/CS/PVA/Gent coating. Therefore, HAP/CS/PVA/Gent coating can be considered as an excellent promising candidate for biomedical hard tissue implants.

Multifunkcionalni i višekomponentni biomaterijali se cesto primenjuju u rekonstruktivnoj hirurgiji zbog sposobnosti da pospešuju osteointegraciju, istovremeno omogucavajuci primenu antibakterijskih agenasa direktno na mestu intervencije. Primenom elektroforetskog taloženja, iz cetvorokomponentne vodene suspenzije (hidroksiapatit, poli(vinilalkohol), hitozan i gentamicin) dobijene su, u jednom koraku, bioaktivne i antibakterijske kompozitne prevlake na titanu. Karakterizacija prevlaka je izvršena primenom rendgenske difrakcione analize (XRD), infracrvene spektroskopije sa Furijeovom transformacijom (FTIR) i skenirajuce elektronske mikroskopije (SEM). Pracenjem kinetike antibakterijske aktivnosti u suspenziji potvr ena je antibakterijska efikasnost prevlake sa gentamicinom. Prema dobijenim rezultatima moguce je zakljuciti da dobijene kompozitne prevlake sa gentamicinom predstavljaju uspešan biomaterijal za potencijalnu primenu u biomedicini., Multifunctional and multicomponent biomaterials are very often the material of choice in reconstructive surgery, having the ability to promote osteointegration, allowing the antibacterial agents application directly at the site of intervention. Single-step electrophoretic deposition was employed to assemble bioactive and antibacterial composite coatings on titanium, from a four-component aqueous suspension (hydroxyapatite, poly(vinyl alcohol), chitosan and gentamicin). Physico-chemical characterization of the coatings was performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Antibacterial activity of gentamicin loaded coating was confirmed by antibacterial activity kinetics in suspension. According to the obtained results, it can be concluded that composite coating loaded with gentamicin represents a successful biomaterial for possible application in biomedicine.

Cilj ove doktorske disertacije bila je sinteza novih biomaterijala, hidrogelova polivinil-alkohola i hitozana, sa i bez grafena, sa elektrohemijski inkorporisanim nanočesticama srebra i njihova detaljna karakterizacija u cilju ispitivanja mogućnosti primene u obliku antibakterijskih obloga za rane. Hidrogelovi srebro/polivinil-alkohol/hitozan i srebro/polivinil-alkohol/hitozan/grafen su dobijeni metodom zamrzavanja i odmrzavanja, praćenom elektrohemijskom in situ sintezom nanočestica srebra unutar polimernih matrica hidrogelova, nakon bubrenja u rastvoru Ag+ jona. Detaljna karakterizacija dobijenih hidrogelova je izvršena u cilju ispitivanja njihove strukture, morfologije, hemijskog sastava, mehaničkih i termičkih svojstava, kao i oblika, dimenzija i strukture sintetisanih nanočestica srebra. Ispitan je uticaj sadržaja hitozana na efikasnost elektrohemijske sinteze nanočestica, kao i na strukturu i svojstva samih hidrogelova. Karakterizacija u in vitro uslovima je obuhvatala ispitivanje sposobnosti bubrenja svih dobijenih hidrogelova i kinetike otpuštanja srebra u fiziološki relevantnim uslovima (pH 7,4, 37 ºC), kao i određivanje antibakterijskih svojstava i biokompatibilnosti dobijenih materijala. Rezultati ove disertacije su pokazali da dobijeni nanokompozitni hidrogelovi imaju visok potencijal za primenu kao aktivne obloge za rane sa jakim antibakterijskim efektom, koji se postiže kontrolisanim otpuštanjem elektrohemijski sintetisanih nanočestica srebra. Dobijeni rezultati su takođe pokazali povoljan efekat hitozana, kako na samu elektrohemijsku sintezu nanočestica srebra, tako i na fizičko-hemijska i antibakterijska svojstva dobijenih hidrogelova, tako da se ovi materijali mogu smatrati pogodnim kandidatima za dalja ispitivanja u oblasti biomedicinskih materijala. Ključne, The aim of this doctoral dissertation was the synthesis of new biomaterials, poly(vinyl alcohol) and chitosan hydrogels, with and without graphene, with electrochemically incorporated silver nanoparticles, and their detailed characterization in terms of potential applications as antibacterial wound dressing materials. Silver/poly(vinyl alcohol)/chitosan and silver/poly(vinyl alcohol)/chitosan/graphene hydrogels were obtained via the freezing-thawing method, followed by in situ electrochemical synthesis of silver nanoparticles inside hydrogel matrices, previously swollen in Ag+ ion solutions. Extensive characterization of the obtained hydrogels was carried out in order to examine their structure, morphology, chemical composition, mechanical and thermal properties, as well as the shape, size and structure of the synthesized silver nanoparticles. The effect of chitosan content on the electrochemical synthesis yield and on the structure and properties of the synthesized hydrogels was also investigated. In vitro characterizations included the investigation of the hydrogels’ swelling properties and silver release kinetics in physiologically-relevant environment (pH 7.4, 37 ºC), as well as the determination of antibacterial properties and biocompatibility. The results of this dissertation demonstrated that the synthesized nanocomposite hydrogels exhibited compelling potential for applications as active wound dressings with potent antibacterial effect, achieved through controlled release of the electrochemically embedded silver nanoparticles. The significant beneficial chitosan influence on both the electrochemical synthesis of silver nanoparticles, and the physicochemical and antibacterial properties of the hydrogels was proven. Therefore, these materials could be considered as apt candidates for further research in biomedical materials field.