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The development of new approaches in the treatment of Parkinson's disease presents a challenge due to the presence of the blood-brain barrier, which hinders effective drug delivery to the brain. Due to their unique physicochemical properties, nanoparticles have the potential to improve conventional therapeutic approaches and enable targeted drug delivery across the blood-brain barrier. The main goal of this doctoral thesis was to synthesize and characterize differently functionalized gold and selenium nanoparticles and to examine their interaction with catechols (levodopa and dopamine) in order to design more effective and safer therapeutic systems for Parkinson's disease. The process of drug binding to the nano-surface was investigated using various spectroscopic, laser and microscopic methods, while the bloodbrain barrier permeability of prepared nano-systems was tested under in vitro settings. The obtained results have provided a better understanding of the processes that occur during the binding of catechol drugs to gold and selenium nanoparticles. This will potentially enable the development of a nano-formulation with targeted drug delivery to the brain with the aim of improving the therapy of Parkinson's disease. Razvoj novih pristupa u liječenju Parkinsonove bolesti predstavlja izazov zbog prisutnosti krvno-moždane barijere koja otežava učinkovitu dostavu lijekova u mozak. Zahvaljujući jedinstvenim fizikalno-kemijskim svojstvima, nanočestice imaju potencijal poboljšati konvencionalne terapijske pristupe i omogućiti ciljanu isporuku lijekova preko krvnomoždane barijere. Glavni cilj ovog doktorskog rada bio je sintetizirati i karakterizirati različito funkcionalizirane nanočestice zlata i selena te ispitati njihovo međudjelovanje s kateholima (levodopa i dopamin) u svrhu dizajniranja učinkovitijih i sigurnijih terapijskih sustava za liječenje Parkinsonove bolesti. Proces vezanja lijekova na nano-površinu ispitivao se pomoću različitih spektroskopskih, laserskih i mikroskopskih metoda, a zatim su se provela istraživanja propusnosti krvno-moždane barijere za novopripravljene nanosustave u in vitro uvjetima. Dobiveni rezultati omogućili su bolje razumijevanje procesa koji se događaju prilikom vezanja lijekova kateholne strukture i novih nanočestica zlata i selena. Na taj način potiče se razvoj nano-formulacija s ciljanom isporukom lijekova u mozak s ciljem poboljšanja terapije za Parkinsonovu bolest.

LAT-1, the large neutral amino acid transporter-1, plays a crucial role in cancer growth and proliferation, making it a promising biomarker for imaging and treating human malignancies such as brain cancers. Thus, growing attention is being paid to the development of LAT-targeted drug delivery systems with blood-brain penetration ability [1, 2]. For this purpose, gold nanoparticles (AuNPs) functionalized with L-DOPA have been developed [1]. The great potential of such systems to be used in brain cancer therapy prompts the need for evaluation of the processes occurring at the nano-bio interface [3]. In the presence of gold salts, L-DOPA can undergo various transformations such as oxidation, cyclization, and polymerization [4]. To avoid binding structurally altered molecules to the nanosurface and prevent any negative impact on human health, it is important to consider these transformation patterns. This study aimed to investigate the behavior of L-DOPA upon interaction with a gold nanosurface by using a combination of nuclear magnetic resonance (NMR) spectroscopy and computational methods. Experimental results showed that the final form of L-DOPA on the AuNPs surface is dependent on the molar ratio of reactants used during synthesis. When there was an excess of L-DOPA compared to Au, no alterations in the structure of L-DOPA were observed. However, an excess of Au was found to promote the oxidation of L-DOPA, which could result in various oxidation products being bound to the gold nanosurface. NMR spectra revealed that L-DOPA underwent intramolecular cyclization but could not differentiate oxidation products. On the other hand, computational simulations using density functional theory (DFT) and molecular dynamics (MD) techniques identified the most probable oxidation products for binding to the AuNP surface. The highest affinity to gold nanosurface was obtained for dopachrome compared to its tautomer and leukodopachrome. The obtained results represent valuable mechanistic data about the binding events at the surface of AuNPs to encourage their application as a drug-delivery systems in cancer therapy

The precipitation of calcium phosphates (CaPs) in the presence of more than one type of additive is of interest both from a fundamental point of view and as a possible biomimetic route for the preparation of multicomponent composites in which the activity of the components is preserved. In this study, the effect of bovine serum albumin (BSA) and chitosan (Chi) on the precipitation of CaPs in the presence of silver nanoparticles (AgNPs) stabilized with sodium bis(2- ethylhexyl)sulfosuccinate (AOT-AgNPs), poly(vinylpyrrolidone) (PVP-AgNPs), and citrate (cit-AgNPs) was investigated. In the control system, the precipitation of CaPs occurred in two steps. Amorphous calcium phosphate (ACP) was the first precipitated solid, which transformed into a mixture of calcium-deficient hydroxyapatite (CaDHA) and a smaller amount of octacalcium phosphate (OCP) after 60 min of ageing. Both biomacromolecules inhibited ACP transformation, with Chi being a stronger inhibitor due to its flexible molecular structure. As the concentration of the biomacromolecules increased, the amount of OCP decreased both in the absence and presence of AgNPs. In the presence of cit-AgNPs and two highest BSA concentrations, a change in the composition of the crystalline phase was observed. Calcium hydrogen phosphate dihydrate was formed in the mixture with CaDHA. An effect on the morphology of both the amorphous and crystalline phases was observed. The effect depended on the specific combination of biomacromolecules and differently stabilized AgNP. The results obtained suggest a simple method for fine-tuning the properties of precipitates using different classes of additives. This could be of interest for the biomimetic preparation of multifunctional composites for bone tissue engineering.

The incidence of neurodegenerative diseases, including Parkinson’s disease (PD), is increasing with the aging of the population. PD is characterized by massive depletion of dopamine as a result of the degeneration of dopaminergic neurons, leading to motor symptoms and other neuropsychiatric and cognitive symptoms.1 Dopamine precursor levodopa (L-dopa) still represents the gold therapeutic standard for PD but long-term treatment can lead to serious side effects. Increased efficacy and better safety of PD treatment may be reached by novel formulation using nanotechnological tools and methods. Here, we present the design and efficacy of nanoformulation based on selenium nanoparticles (SeNPs), which exhibit antioxidant properties and neuroprotective effects.2 SeNPs stabilized with polyvinylpyrrolidone (PVP) were developed as a nanodelivery system for L-dopa. PVP-coated SeNPs were characterized by a hydrodynamic diameter of 82.9 ± 0.5 nm and a zeta potential of -28.0 ± 1.9 mV. The efficacy of such a system was tested using a hemiparkinsonian rat model, achieved by injection of 6-hydroxydopamine into the right hemisphere according to the stereotaxic atlas.3 Four weeks after injections, rats were treated orally with conventional L-dopa and L-dopa loaded on SeNPs for 28 days. Different behavioral assays were used to evaluate the efficacy of the treatments. The motor coordination was tested on the Rotarod apparatus, the neurological severity score (NSS) tests were used for estimating balance, motor coordination, and sensorimotor reflexes, while gait analysis was used to assess the changes in motor impairments in rats before and after surgery.4 Obtained results on improved motor dysfunction and coordination clearly showed beneficial effects of L-dopa loaded on SeNPs in comparison to L-dopa treatment.

Parkinson`s disease is the second most common neurodegenerative disorder (1). It is characterized by early prominent death of dopaminergic neurons in substantia nigra which results in classical motor symptoms of the disease: rigidity, rest tremor, bradykinesia, and postural instability (2). Although initially described more than 200 years ago (3), not a single drug is able to alter the natural history of the disease. Mainstay therapy is levodopa - a precursor in the synthesis of the dopamine - that can cross the blood brain barrier. Since introduction to the therapy, 50 years ago, many improvements have been made to enhance its efficiency and reduce side effects. However, passage of the blood brain barrier is still relatively poor, side effects can pose significant burden and long- term therapy is associated with motor complications. Motor complications are, at least in part, due to the fluctuations of levodopa concentrations in the plasma. In many cases these complications can be so intense that the only options is to discontinue the drug which inevitably leads to rapid decline in the quality of the life. Therefore, new formulations of levodopa, that can increase delivery of the drug to the brain and reduce plasma fluctuations are needed. This study tested the safety of phosphoglucomutase (PGM) functionalized gold nanoparticles (AuNP) as levodopa carrier using differentiated neuroblastoma (SH-SY5Y) cells as in vitro model of Parkinson`s disease. AuNPs shape, size, and surface charge were determined with transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential measurements, respectively. Cell viability and apoptosis induction test were performed using flow cytometry, while oxidative stress was determined by measuring the concentration of reactive oxygen species, glutathione (GSH) and mitochondrial membrane potential. In all experiments levodopa loaded AuNPs were compared with AuNPs and levodopa alone.

The great potential of gold nanoparticles (AuNPs) functionalized with catechols, dopamine and L-DOPA, in biomedical applications prompts the need for evaluation of their interaction at the nano-bio interface.[1] In the presence of gold slats, catechols are known to transform by various pathways including oxidation, cyclization and polymerization.[2] Thus, different transformation patterns should be considered in order to avoid binding the structurally changed molecule to the nanosurface while preventing unpredictable consequences for the health status of an organism. In this study, the fate of functionalization agents upon interaction with gold nanosurface was investigated by combining nuclear magnetic resonance (NMR) spectroscopy and a computational approach. Experimental results revealed that the final form of catechol on the AuNPs nanosurface depends on the molar ratio of reactant used in synthesis. The oxidation of both L-DOPA and dopamine was promoted in the case of molar excess of Au. However, their final products differ as L-DOPA underwent intramolecular cyclization. Computational simulations using density functional theory (DFT) and molecular dynamics (MD) methods revealed the mechanism that stays behind this difference and clarified the most likely candidates, among different oxidation products, for binding to the AuNPs surface. The obtained results represent valuable mechanistic data about the binding events at the surface of AuNPs to encourage their application in biomedicine.

In recent years, gold nanoparticles (AuNPs) have attracted vast interest in biosensing applications. Their unique functional and surface plasmon resonance properties, coupled with possibility to bound various biomolecules (e.g., antibodies, DNA, and RNA aptamers) may significantly enhance diagnostic features. Therefore, functionalizing AuNPs with antibodies could be a new approach for detecting COVID-19 caused by SARS-CoV-2 virus (1, 2). Here we present three conjugation strategies in order to assure efficient binding of monoclonal anti-SARS-CoV-2 antibodies to AuNPs in the oriented way: a) direct conjugation of antibodies by electrostatic interactions or physical adsorption on AuNPs, b) conjugation mediated by glycopeptide-functionalized AuNPs using peptidoglycan monomer, GlcNAc- MurNAc-L-Ala-D-isoGln- mesoDAP(NH2)-D-Ala-D-Ala (PGM)) and c) covalent conjugation using EDC/NHS method. The AuNPsantibodies conjugates were characterized by various spectroscopic and electrophoretic techniques. Additionally, gold nanoparticles labelled with secondary antibodies (Immunogold) were used to determine the amount of available epitopes of the primary monoclonal antibodies on the metal surface. Preliminary results showed that binding efficiency of antibody-AuNPs conjugate can be improved using the covalent binding strategy with their high potential for use in SARS-CoV-2 virus detection.

Parkinson’s disease (PD) is neurological disorder characterized by the loss of dopaminergic neurons. Because of that, dopamine levels are reduced and main consequences are bradykinesia, rigidity, tremor and depression (1). Levodopa is the most common therapy for PD but long-term treatment can have a lot of side effects. In order to that, drug delivery system needs to be designed for improving targeting ability. Selenium nanoparticles (SeNPs) constitute an attractive carrier platform because of their antioxidant properties and neuroprotective effects (2). This study aimed to develop drug delivery system consisted of selenium nanoparticles coated with polyvinylpyrrolidone (PVP) and polysorbate 20 (Tween 20). Differently coated SeNPs were prepared via reduction of sodium selenite by L-ascorbic acid. Synthesized nanoparticles were characterized with dynamic light scattering (DLS) and transmission electron microscopy (TEM) for determining their shape and size. In vitro model of blood-brain barrier (BBB), hBEC-5i cell line, was used in all experiments. Cell viability testing, oxidative stress response and permeability evaluation of BBB for SeNPs were used in biocompatibility assessment. For oxidative stress response experiments 3 different assays were used: dichlorodihydrofluorescein diacetate (DCFH- DA), dihydroethidium (DHE) and rhodamine 123 (Rh123). In transwell experiments cells were treated with SeNPs alone and in combination with L-dopa. Concentration of Se in all compartments (donor well, acceptor well, cells, gelatin) was analyzed by Graphite Furnace Atomic Absorption Spectroscopy (GFAAS) while L-dopa concentration was determined by commercial ELISA kit. Results showed that SeNPs in concentration of 1 mg Se/L did not reduce the cell viability significantly and that SeTween NPs have lower level of ROS production than SePVP. Transwell experiments resulted in low permeability for both SeNPs type but in vitro assays that were used in this study were not suitable for evaluating the BBB permeability of SeNPs because of their sticky properties.

The blood-brain barrier (BBB) protects the brain from toxic substances but also blocks the entry of many drugs into brain. Thus, brain specific drug delivery is one of the most challenging areas of research, such as therapy for Parkinson's disease. This research aimed to develop more efficient drug delivery system for Parkinson's disease based on selenium nanoparticles (SeNPs). SeNPs display lot of features that make them suitable for drug delivery system as simple preparation, antioxidant activity and neuroprotective effects. We prepared SeNPs functionalized with polyvinylpyrrolidone (PVP) and polysorbate 20 (Tween 20) and tested their delivery efficacy using L-3, 4- diydroxyphenylalanine (L-dopa) as model drug.

Doxorubicin (DOX) is a chemotherapeutic agent successfully used for the treatment of various neoplasms, however its use entails risks of side- effects such as irreversible cardiomyopathy [1]. To enhance its pharmaceutic potential, novel nanoformulated poly(lactic-co-glycolic acid) DOX (PLGA) was prepared and their cardiotoxic effects were compared with commercially and clinically approved conventional (CNV) and liposomal (LPS) formulations. Formulations were administrated intraperitoneally to male and female Wistar rats four times, once per week. Then, serum levels of cardiac troponin T (cTnT) and N-terminal prohormone of brain natriuretic peptide (NT- proBNP) were quantified with ELISA assays, and expression of inflammation-related genes (IL-6, IL-8, TNFα and IL-1β) in heart tissue of treated and control rats was evaluated using Real-Time PCR. Heart cryosections of treated and control rats were analyzed by imaging mass spectrometry (IMS). CNV and LPS formulations significantly increased cTNT levels compared to control animals, while PLGA showed no such effect. NT-proBNP was decreased in animals treated with CNV and LPS, while no changes were observed for treatment with PLGA formulation. CNV significantly increased expression of IL-6 and IL-8 in heart tissue, which was not observed in PLGA-treated rats. Results of IMS analysis have shown reduced expression of inflammation markers in PLGA-treated rats compared to CNV- and LPS-treated animals. Therefore, novel PLGA formulation demonstrated lower inflammatory potential compared to clinically approved CNV and LPS, indicating the potential for novel nanoformulations for safer drug delivery in cancer therapy.

The aim of the present study was to synthesize gold nanoparticles (AuNPs-PGM) modified with peptidoglycan monomer (GlcNAc-MurNAc-L-Ala-D- isoGln-mesoDAP(εNH2)-D-Ala-D-Ala) and probe their interaction with model WGA lectin which specifically recognized N-acetylglucosamine (GlcNAc). Our previous study investigates the ability of novel gold nanoparticles to be used as delivery systems for L-DOPA or dopamine by considering the binding capabilities of L-DOPA to the AuNPs-PGM. The results indicate that AuNPs functionalized with PGM enables a significantly higher L-DOPA binding compared to citrate stabilized AuNPs vesicles.1 Now, AuNPs-PGM were treated with the WGA lectin in order to investigate the spatial arrangement of PGM on the AuNPs surface and find out how bound L-DOPA affects the availability of the peptidoglycan and the interaction with lectin. Agglutination is one of the early methods to monitor sugar-receptor interactions, so the WGA lectin is added to the AuNPs-PGM and the hydrodynamic volumes of the resulting aggregates were measured by DLS. Preliminary results demonstrated that WGA lectin successfully recognize and bind to AuNPs-PGM as well as that the particle size grew immediately after WGA lectin is added to the AuNPs-PGM. The increase of size of AuNPs-PGM-L-DOPA was lower in comparison with AuNPs-PGM themselves, but still it is significant. The interaction of lectin and AuNPs-PGM confirmed availability of glycan part of PGM molecule to recognize the lectin receptors on the cell surface and promising potential of prepared nanoparticles to become efficient drug delivery system for Parkinson's disease.

Efficient and safe treatment of patients suffering from Parkinson’s disease possess many challenges. Common therapy that includes external administration of L-dopa to Parkinson’s disease patients is limited due to poor blood-brain barrier (BBB) penetration and lack of targeting ability [1-2]. To overcome these issues, gold nanoparticles (AuNPs) represent an attractive platform for targeted drug delivery into the brain, as they enter the central nervous system (CNS) by penetration through the BBB [3-4]. For this purpose, AuNPs functionalized with polyethylene glycol (PEG), adamantane derivatives, and peptidoglycan monomer (PGM) were prepared[5].In this study, the ability of novel AuNPs to be used as delivery systems for dopamine and L-dopa was evaluated considering their binding capabilities. Steady-state fluorescence spectroscopy was employed to investigate the binding interaction of dopamine and L-dopa on differently coated AuNPs. The strongest interaction was observed between L-dopa/dopamine and AuNPs functionalized with PGM. The intermolecular forces between L-dopa or dopamine and differently coated AuNPs were estimated by thermodynamic analysis. The binding predominantly occurred through Van der Waals interactions or hydrogen bonds, while positive entropy change that is indicative for electrostatic interactions was seen only in a few instances. In all cases, interactions were exothermic and spontaneous since enthalpy change and Gibbs free energy were negative, respectively.

The development of new strategies to treat Parkinson’s disease suffers from many deficiencies. Common therapy that includes external administration of L-dopa to Parkinson’s disease patients is limited due to the lack of targeting ability.[1, 2] As an alternative for conventional therapeutic drugs, selenium nanoparticles (SeNPs) constitute an attractive carrier platform for targeted drug delivery into the brain.[3, 4] In this study, two different SeNPs were designed using polyvinylpyrrolidone (PVP) and polysorbate 20 (Tween) as surface modifiers. Their binding ability for dopamine and L-dopa was evaluated by steady-state fluorescence spectroscopy. The strongest interaction was observed between L-dopa and PVP-SeNPs. Thermodynamic analysis revealed that binding between Tween-SeNPs and L-dopa or dopamine predominantly occurs through van der Waals interactions and hydrogen bonds, while electrostatic interactions govern the binding of L-dopa or dopamine to the PVP-SeNPs. In all cases, interactions were exothermic and spontaneous.

Selenium is one of the essential elements crucial for the normal functioning of the human body. Applied in nano form, it has better pharmacokinetic parameters compared to inorganic forms so the research on the possibilities of using nanoselenium as a dietary supplement is being intensified. However, nanoparticles must have appropriate characteristics in order to ensure satisfactory stability and bioavailability. For this purpose, biologically active natural compounds isolated from biomass or food waste are increasingly used, thus improving the functionality of the obtained nanoparticles and reducing the ecological footprint of the synthesis process. The main objective of this study was to investigate the possibilities of green synthesis of nanoselenium using raw and purified pectins (extracted from mandarin peel and tomato pomace) and olive pomace extract rich in polyphenols. The influence of different synthesis conditions on the size distribution, zeta potential and gastrointestinal stability of the obtained nanoparticles was investigated.

Introduction Efficient and safe treatment of patients suffering Parkinson’s disease faces many challenges such as poor blood brain barrier penetration and decreased response to therapy with time. Nano-drug delivery systems may overcome these problems and can be designed to penetrate through the blood-brain barrier and interact with the central nervous system without causing any unwanted side effects. However, their efficiency largely depend on their stability in biological fluids like human plasma. This study evaluated impact of serum albumin on ability of novel gold nanoparticles (AuNPs) to be used as delivery system for dopamine or L-dopa and evaluated on their binding abilities. For this purpose, AuNPs functionalized with polyethylene glycol (PEG) and adamantane derivatives were prepared. Binding affinity of dopamine and L-dopa for these AuNPs was evaluated in the presence or absence of serum albumin using steady-state fluorescence spectroscopy. Results Differences in binding constants were observed for L-dopa/dopamine on differently functionalized AuNPs. The observed quenching mechanism was static in nature for all novel AuNPs. The presence of serum albumin interfered with L-dopa/dopamine binding on AuNPs. Conclusions Binding constants depend not only on the different functionalization of AuNPs, but also on the presence of serum protein.

Nano-drug delivery systems for treatment of Parkinson's disease are being designed to overcome present therapeutical challenges. L-dopa and dopamine attached to the surface of gold nanoparticles (AuNPs) may be efficiently delivered through the blood-brain barrier. However, the preparation of L-dopa and dopamine coated AuNPs by the traditional reduction method may lead to the creation of oxidation products, which will exacerbate oxidative stress in the body. For the development of L-dopa and dopamine nanocarriers, it is important to ascertain whether toxic byproducts might be present on the AuNP surface. Here, the surface events and interaction of AuNPs with L-dopa, dopamine and their oxidised derivatives are studied by employing a computational approach. Quantum chemical study using the Gaussian software yielded the optimized complexes of studied species with Aun (n=2, 4, 6) clusters at the M06L/LANL2DZ level of theory. It was found that the complexes with oxidised derivatives were more stable compared to complexes with L-dopa and dopamine. The binding behaviour and free energies were calculated by classical molecular dynamics. Although all studied molecules bind to the Au surface spontaneously, the free binding energies of oxidised derivatives are lower, confirming their higher affinity to Au. Thus, under the conditions of carrier AuNP preparation (where L-dopa or dopamine are present together with oxidation products), the oxidised derivatives are expected to bind in significant proportion. This study highlights the need to carefully characterize the binding events at the surface of potential drug nanocarriers, and demonstrates the usefulness of the in silico approach in such endeavours.

Due to their unique physical and chemical properties, gold nanoparticles (AuNPs) have been extensively used in biomedical fields, including drug delivery into the brain as they can easily penetrate through the blood-brain barrier. The study employed combined NMR and computational approach to study events at the nano-bio interface during preparation of L-DOPA/dopamine-functionalized AuNPs. During synthesis, LDOPA/dopamine were used as both reducens and surface coating agents, but mechanisms of their interaction with gold clusters and nanosurface have been not yet elucidated. Both dopamine and DOPA are oxidized in the course of Au cluster preparation, resulting in dopaminequineone and dopaquinone, resp. The latter undergoes intramolecular cyclization forming cyclodopa. All these intermediates are included in interactions with the AuNP surface.

Introduction Silver nanoparticles are one of the most commercialized types of nanoparticles, with a wide range of applications owing to their antimicrobial activity. However, there is a lack of data on cumulative toxicity of silver nanoparticles used with polymeric materials, especially polymer nanoparticles. In this study, toxicity of PVP-coated silver nanoparticles (AgNP) combined with polystyrene nanoparticles (PSNP) was tested on Jurkat cells. Results Silver and polystyrene nanoparticles reduced cell viability through generation of reactive oxygen species (ROS), depletion of cellular GSH, and damage to cellular structures and mitochondria. Nanoparticle treatment also reduced cell stiffness, measured by Atomic Force Microscope (AFM), which is indicative of changes in cytoskeletal structure. Cellular treatment with combinations of non-toxic AgNP and PSNP concentrations resulted in significant induction of oxidative stress and reduction of cell viability. Conclusions AgNP share the mechanism of toxicity with PSNP and results for combined AgNP/PSNP treatments can be understood as compounded effect of overloading cellular mechanisms for managing oxidative stress. These results have important implications for use of these materials in medical contexts, particularly for long-term medical implants.

Doxorubicin (DOX) is one of the most effective cytotoxic drugs against solid tumors and hematologic malignant diseases. However, the clinical application of DOX is limited due to dose-related toxicity and inflammatory response. In order to reduce toxic side-effects of antitumor agents, nanoformulation were developed as novel drug delivery systems as they may favor accumulation of the drug at tumor sites and consequently reduce its toxicity. The aim of this study was to determine inflammatory effects of DOX administered in three different forms – DOX as free compound solution, a novel delivery system of nanoformulated poly(lactic-co-glycolic acid) (PLGA-DOX), and commercially available DOX encapsulated in liposomal nanoparticles (nanoDOX). These formulations were administrated to male and female Wistar rats four times, once per week, by intraperitoneal application. Expression of inflammation-related genes (IL-6, IL-8, TNFα and IL-1β) in heart, liver and kidney tissue of treated and control rats was evaluated using Real-Time PCR. Free DOX compound significantly increased expression of IL-6 and IL-8 in heart and liver tissue, which supports previously obtained results on DOX cardiotoxicity and liver toxicity. PLGA-DOX increased production of only IL-8 in liver tissue, but did not significantly elevate expression of other inflammation-related genes in heart or kidney tissue, which was similar to results obtained for nanoDOX. Additionally, significant reduction of IL-1 expression in kidney tissue as potential attenuation of inflammatory response was noticed after administration of PLGA-DOX. Therefore, novel PLGA-DOX formulation demonstrated lower inflammatory potential compared to clinically approved nanoDOX and DOX.

Excess of catechols compared to HAuCl4 did not induce change in proton signals of L-DOPA or dopamine Original signals disappeared and different oxidation products were observed when HAuCl4 was in excess compared to catechols New signals correspond to dopamine-o-quinone in the case of dopamine, in contrast to L-DOPA where oxidation went one more step further via cyclization to dopachrome.

U novije vrijeme sve se više promovira konzumacija divljih srodnika povrća i samoniklih biljaka. U ovom istraživanju je po prvi puta istražena mogućnost biofortifikacije štira (Amaranthus caudatus L.) s različitim kemijskim oblicima selena u uvjetima plutajućeg hidropona. Selen je primijenjen u tri oblika i to kao selenat i selen nanočestice stabilizirane huminskom kiselinom (HA-SeNP) ili polisorbatom (PS-SeNP) te u dvije koncentracije (200 μM m-3 i 400 μM m-3 hranjive otopine). Pokus je proveden u plasteniku u zasebnim bazenima ovisno o obliku selena. Vegetacija je trajala ukupno 27 dana (12 dana u hidroponu). Nakon uzorkovanja, izmjereni su svježa i suha masa lista, stabljike i korijena te visina biljke i broj listova. U prosjeku, najveće vrijednosti visine, dužine korijena te broja listova su zabilježene u slučaju biofortifikacije s HA-SeNP. Značajno najmanja vrijednost je zabilježena kod varijante PS-SeNP 400 gdje se očitovala pojava fitotoksičnosti jer je došlo do propadanja korijena i venuća biljaka. Značajno povećanje svježe mase lista, korijena i stabljike je uočeno kod varijanata SEL 200 i PS-SeNP 200. Općenito, kontrolne biljke su bile slabijeg rasta u usporedbi s biofortificiranim uz iznimku varijante PS-SeNP 400. Očekivano, slični trend je zabilježen kod suhe mase lista, korijena i stabljike. Prema ovim rezultatima je očito da selen utječe na rast i razvoj štira te u ovisnosti o obliku i koncentraciji može doći do pojave fitotoksičnosti kao u slučaju primjene PS-SeNP. Ovo istraživanje je financirano od strane Hrvatske zaklade za znanost u sklopu projekata HRZZ-IP-2018-01-8119 i HRZZ-PZS-2019- 02-4323.

Silver nanoparticles are one of the most commercialized types of nanoparticles, with a wide range of applications owing to their antimicrobial activity.[1] However, there is a lack of data on cumulative toxicity of silver nanoparticles used with polymeric materials, especially polymer nanoparticles. In this study, toxicity of PVP-coated silver nanoparticles (AgNP) combined with polystyrene nanoparticles (PSNP) was tested on Jurkat cells. Silver and polystyrene nanoparticles reduced cell viability through generation of reactive oxygen species (ROS), depletion of cellular GSH, and damage to cellular structures and mitochondria. Cellular treatment with combinations of non-toxic AgNP and PSNP concentrations resulted in significant induction of oxidative stress and reduction of cell viability. Results for combined AgNP/PSNP treatments can be understood as compounded effect of overloading cellular mechanisms for managing oxidative stress. These results have important implications for use of tested nanomaterials in medical contexts.

The application of olive pomace extract (OPE) was investigated for biogenic synthesis of selenium nanoparticles (SeNPs). The OPE was used at different amounts ranging from 0.3 % to 0.6 %. Obtained SeNPs were characterised in terms of size distribution by dynamic light scattering (DLS), surface charge as measured by  potential, antioxidant activity as determined by ORAC and TEAC method, and reductive capacity using Folin- Ciocalteu method. Characteristics of biogenically produced SeNPs were compared to those obtained by standard chemical synthesis using polyvinylpyrrolidone (PVP) as coating agent. The application of 0.3 % OPE resulted in stable SeNPs dispersion of 100 nm particle size similar to PVP- coated SeNPs, while the increase in OPE amount in reaction mixture increased the mean particle size and led to polydisperse system. Surface charge of biologically synthesized SeNPs was more negative (-34 mV) compared to PVP-SeNPs (-17.2 mV) indicating better stability. Antioxidant and reductive efficacy of biologenically synthesized SeNPs was significantly higher than for SeNPs prepared by chemical synthesis. Obtained results demonstrated advantages of using natural polyphenol rich plant extracts in preparation of stable SeNPs in terms of development of green synthesis processes and improved functional properties of obtained nanomaterials.

Mandarin peel has been recognized as the valuable source of functional ingredients such as polyphenols (hesperidin, tangeretin and nobiletin) and dietary fibres (pectin). In this study, we optimized the procedure of extraction and purification of pectin from mandarin peel extract for using raw pectin fraction (RP) and purified pectin fraction (PP) in biogenic synthesis of selenium nanoparticles (bnSeNPs). Obtained SeNPs were compared to chemically synthesised particles (cnSeNPs) in terms of size distribution, zeta potential, stability and functional properties (antiradical and reductive ability). The bnSeNPs stabilized with 0.7 % RP and PP showed particle size distribution comparable to cnSeNPs with average diameter of 230 nm and 290 nm, respectively. Surface charge of bnSeNPs showed more negative values than for cnSeNPs (-35 mV in relation to -10 mV) indicating better stability of obtained colloidal system. Also, in comparison to cnSe, bnSe coated with 0.7 % RP and PP showed significantly higher antioxidant activity (24.5 and 46.3 gTE molSe-1, respectively) in comparison to cnSeNPs (1.91 gTE molSe-1) that were probably associated to polyphenols remaining in pectin fractions. Obtained results revealed the potential of mandarin peel as a source of natural coating materials for development of green synthesis processes of SeNPs achieving improved functional properties.

Coumarin derivatives are important motifs, which can be widely found in many natural products, and many of them displaying diverse biological activities. Many molecules based on the coumarin have been synthesized utilizing innovative synthetic techniques. The diversity oriented synthesis has led to interesting derivatives including the iminocoumarins, furanocoumarins and pyranocoumarins, which have been found to be useful in photochemotherapy, antitumor and anti‐ HIV therapy, and as stimulants for central nervous system, antibacterials, anti‐inflammatory agents, anti‐coagulants, and dyes [1]. Benzofused derivatives of coumarin bridged with 1, 2, 3‐ triazole emerged as the class of compounds exhibiting the highest antiproliferative activity [2]. Furthermore, 1, 2, 3‐triazole ring has a great role as pharmacophore which is responsible for antitumor and antimicrobial activity. It is introduced in many drugs due to moderate dipole properties, rigid structure and stability in vivo. Besides, 1, 2, 3‐triazoles have attracted considerable attention in recent years because of their wide range of biological activities against various viruses, malignant cells, microorganisms and their inhibitory activities against several enzymes [3]. In order to evaluate cytostatic activity, the novel 1, 2, 3‐triazolyl‐tagged coumarin and iminocoumarin derivatives have been synthesized by click reaction of 3‐azidocoumarin or 6‐ azidoiminocoumarines with corresponding terminal acetylenes in the presence of copper as a catalyst. Of the all evaluated compounds against malignant human cell lines, 1, 2, 3‐ triazole‐ coumarin derivative with 3, 5‐ ditrifluoromethylphenyl substituent exhibited the most pronounced activity against HeLa cell lines.

U ovom radu prikazana je sinteza, strukturna i spektroskopska karakterizacija novih 7-hidroksi-4-metil derivata kumarina supstituiranih u položaju C-3 (hidroksi/metoksifenil) etinilnim supstituentom u svrhu ispitivanja njihovog antioksidativnog djelovanja. Sonogashira-inom reakcijom unakrsnog povezivanja 7-hidroksi-3-klor-4-metilkumarina i 2-metoksifeniletina ili 3-hidroksifeniletina uz tetrakistrifenilfosfin paladij kao katalizator, CuI kao kokatalizator i uz bazu Et3N pripravljeni su spojevi 1 i 2. Strukturna i spektroskopska karakterizacija novosintetiziranih spojeva 1 i 2 provedena je 1H- i 13C-NMR, UV/Vis i fluorimetrijskom spektroskopijom. Farmakološki učinci i moguće biološke mete novopripravljenih spojeva predviđene su in silico analizom (PASS). Antiosidativna aktivnost novosintetiziranih spojeva ispitat će se cikličkom voltametrijom. This work presents the synthesis, structural and spectroscopic characterization of novel 7-hidroxy-4-methylcoumarin derivatives substituted in position C-3 with (hydroxy/methoxyphenyl)ethynyl substituent in order to determine their antioxidant activity. Sonogashira cross-coupling reaction of 3-chloro-7-hydroxy-4-methylcoumarin and 2-methoxyphenylethyne or 3-methoxyphenylethyne with tetrakistriphenylphosphine palladium as a catalyst, CuI as a cocatalyst and Et3N as a base compounds 1 and 2 were obtained. The structural and spectroscopic characterization of new synthesized compounds 1 and 2 was conducted by 1H- and 13C-NMR, UV / Vis and fluorimetric spectroscopy. Pharmacological effects and possible biological targets of novel compounds are predicted by in silico analysis (PASS). The antioxidant activity of new synthesized compounds will be tested by cyclic voltammetry.

Gold nanoparticles (AuNPs) have found applications in biomedicine as diagnostic tools, but extensive research efforts have been also directed toward their development as more efficient drug delivery agents. The high specific surface area of AuNPs may provide dense loading of molecules like catechols (L-DOPA and dopamine) on nanosurfaces, enabling functionalization strategies for advancing conventional therapy and diagnostic approaches of neurodegenerative diseases. Despite numerous well-described procedures in the literature for preparation of different AuNPs, possible transformation and structural changes of surface functionalization agents have not been considered thoroughly. As a case in point, the catechols L-DOPA and dopamine were selected because of their susceptibility to oxidation, cyclization, and polymerization. To assess the fate of coating and functionalization agents during the preparation of AuNPs or interaction at the nano-bio interface, a combination of spectroscopy, light scattering, and microscopy techniques was used while structural information and reaction mechanism were obtained by NMR in combination with computational tools. The results revealed that the final form of catechol on the AuNP nanosurface depends on the molar ratio of Au used for AuNP preparation. A large molar excess of L-DOPA or dopamine is needed to prepare AuNPs funtionalized with fully reduced catechols. In the case of molar excess of Au, the oxidation of catechols to dopamine quinone and dopaquinone was promoted, and dopaquinone underwent intramolecular cyclization in which additional oxidation products, leukodopachrome, dopachrome, or its tautomer, were formed because of the larger intrinsic acidity of the more nucleophilic amino group in dopaquinone. MD simulations showed that, of the oxidation products, dopachrome had the highest affinity for binding to the AuNPs surface. The results highlight how a more versatile methodological approach, combining experimental and in silico techniques, allows more reliable characterization of binding events at the surface of AuNPs for possible applications in biomedicine.