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Polyurethane (PU) nanocomposite materials, offer very desirable advantages over pure PU materials,as the nanocomposites have enhanced thermal, surface, mechanical and biological properties. The main goal of this study was to develop a new kind of novel nanocomposites consisting of crosslinked PUs (based on poly(dimetylsiloxane) and hyperbranched polyester) and ferrite nanoparticles (based on copper and zinc) for possible application as coatings on biomedical devices and implants. A series of PU/ferrite nanocomposites was prepared by in situ polymerization in solution. Characterization of prepared nanocomposites nanocomposites was conducted by Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Copper and zinc releases were investigated by microwave plasma atomic emission spectrometry (MP-AES). Characteristics of the prepared nanocomposites when in contact with a biological environment were examined through testing their biocompatibility, and adhesion of fibroblast cells. The presence of the nanoferrite nanoparticles influenced on surface and biological properties of PU nanocomposites. The prepared PU nanocomposites with noncytotoxic chemistry could be used as promising materials for vascular implants development.

Polyurethane (PU) and PU nanocomposites with good biocompatibility and mechanical properties can be used as the biomedical matrix and tissue engineering biomaterials. Magnetic nanoparticles, especially ferrite nanoparticles have attracted much interest due to their specific physicochemical properties in various areas including magnetic recording, biosensing, catalyst, drug delivery systems, magnetic resonance imaging (MRI) and cancer therapy. Despite all these advantages, the nanoparticle agglomeration reduces the efficiency of the nanoparticles, so the nanoparticle incorporation into an appropriate polymeric matrix to prepare organic-inorganic nanocomposites is a right direction in the current scenario of biomedical nanotechnology. In this study, organic-inorganic PU nanocomposites based on zinc and copper ferrites and with the same composition of PU were prepared. The properties of PU nanocomposites were evaluated by nanoindentation, water contact angle and water absorption measurements. The presence of the nanoferrite nanoparticles affects properties of PU nanocomposites such as bulk morphology, mechanical, and biological properties. The biocompatibility of PU nanocomposites was investigated by MTT assay and cell attachment using endothelial cells. According to the results, the prepared PU nanocomposites with noncytotoxic chemistry could be a potential choice for vascular implants development.

Introduction: We examined the molecular mechanisms of graphene quantum dot (GQD)- mediated protection of SH-SY5Y human neuroblastoma cells from oxidative/nitrosative stress induced by iron-nitrosyl complex sodium nitroprusside (SNP). Methods: GQD was produced by electrochemical oxidation of graphite and characterized by AFM, UVVIS and FTIR spectroscopy. The antioxidant activity of GQD in cell-free conditions was assessed by DPPH, NBT and EPR analysis. The neuroprotective potential of GQD was determined by cell viability assays MTT, CV. Flow cytometry was used to assess markers of apoptosis and GQD scavenging of intracellular ROS/RNS as well. Cellular internalization of GQD was determined using TEM. Results: GQD prevented SNP-induced apoptosis, caspase activation and mitochondrial depolarization in neuroblastoma cells. Although GQD diminished the NO levels in SNP-treated cells, NO scavengers displayed only a slight protection. GQD significantly protected SH-SY5Y cells from neurotoxicity of lightexhausted SNP, incapable of producing NO, implying that protective mechanism is independent of NO-scavenging. GQD reduced SNP-triggered increase in intracellular levels of ROS, particularly •OH, O2•− in cells and cell-free condition. Nonselective antioxidants, •OH scavengers and iron chelators, mimicked GQD cytoprotection, indicating that GQD protect cells by neutralizing •OH generated in the Fenton reaction. Cellular GQD internalization was required for optimal protection since the removal of extracellular GQD by extensive washing partly diminished their protective effect, suggesting that GQD exerted neuroprotective effect intra- and extracellularly. Conclusion: By demonstrating that GQD protect neuroblastoma cells from SNP-induced apoptosis by •OH/NO scavenging, our results suggest that GQD could be valuable candidates for treatment of neurodegenerative diseases associated with oxidative/nitrosative stress.

Novel polyurethane nanocomposite (PUN) materials containing different surface-functionalized mesoporous silica nanoparticles (MSNs) were prepared by in situ polymerization methodology. Polyurethane network was formed from poly(dimethylsiloxane)-based macrodiol (PDMS), 4,4′-methylenediphenyldiisocyanate (MDI), and hyperbranched polyester of the second pseudo-generation (BH-20; used as crosslinking agent). PU and PU/MSN nanocomposites contained equal ratios of soft PDMS and hard MDI-BH-20 segments. Non-functionalized and surface-functionalized (with 3-(trihydroxysilyl)propyl methylphosphonate (FOMSN) and 2-[methoxy(polyethyleneoxy)6−9propyl]trimethoxysilane (PEGMSN)) MSNs were used as the nanofillers at a concentration of 1 wt%. Prepared materials were characterized by Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analyses (DMTA), nanoindentation, equilibrium swelling and water absorption measurements. Characteristics of the prepared PUNs when in contact with a biological environment were assessed through testing their biocompatibility, protein adsorption and adhesion of endothelial cells. The favourable influence of MSNs on the physico-chemical and biological characteristics of these novel PUN materials was identified, which evidences their vast applicability potential as coatings for medical devices and implants.

We investigated the ability of graphene quantum dot (GQD) nanoparticles to protect SH-SY5Y human neuroblastoma cells from oxidative/nitrosative stress induced by iron-nitrosyl complex sodium nitroprusside (SNP).GQD reduced SNP cytotoxicity by preventing mitochondrial depolarization, caspase-2 activation, and subsequent apoptotic death. Although GQD diminished the levels of nitric oxide (NO) in SNP-exposed cells, NO scavengers displayed only a slight protective effect, suggesting that NO quenching was not the main protective mechanism of GQD. GQD also reduced SNP-triggered increase in the intracellular levels of hydroxyl radical (•OH), superoxide anion (O2•- ), and lipid peroxidation. Nonselective antioxidants, •OH scavenging, and iron chelators, but not superoxide dismutase, mimicked GQD cytoprotective activity, indicating that GQD protect cells by neutralizing •OH generated in the presence of SNP-released iron. Cellular internalization of GQD was required for optimal protection, since a removal of extracellular GQD by extensive washing only partly diminished their protective effect. Moreover, GQD cooperated with SNP to induce autophagy, as confirmed by the inhibition of autophagylimiting Akt/PRAS40/mTOR signaling and increase in autophagy gene transcription, protein levels of proautophagic beclin-1 and LC3-II, formation of autophagic vesicles, and degradation of autophagic target p62. The antioxidant activity of GQD was not involved in autophagy induction, as antioxidants N-acetylcysteine and dimethyl sulfoxide failed to stimulate autophagy in SNP-exposed cells. Pharmacological inhibitors of early (wortmannin, 3-methyladenine) or late stages of autophagy (NH4Cl) efficiently reduced the protective effect of GQD. Therefore, the ability of GQD to prevent the in vitro neurotoxicity of SNP depends on both •OH/NO scavenging and induction of cytoprotective autophagy.

Novel polyurethane nanocomposite (PUN) materials containing different surface-functionalized mesoporous silica nanoparticles (MSNs) were prepared by in situ polymerization methodology. Polyurethane network was formed from poly(dimethylsiloxane)-based macrodiol (PDMS), 4,4′-methylenediphenyldiisocyanate (MDI), and hyperbranched polyester of the second pseudo-generation (BH-20; used as crosslinking agent). PU and PU/MSN nanocomposites contained equal ratios of soft PDMS and hard MDI-BH-20 segments. Non-functionalized and surface-functionalized (with 3-(trihydroxysilyl)propyl methylphosphonate (FOMSN) and 2-[methoxy(polyethyleneoxy)6−9propyl]trimethoxysilane (PEGMSN)) MSNs were used as the nanofillers at a concentration of 1 wt%. Prepared materials were characterized by Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analyses (DMTA), nanoindentation, equilibrium swelling and water absorption measurements. Characteristics of the prepared PUNs when in contact with a biological environment were assessed through testing their biocompatibility, protein adsorption and adhesion of endothelial cells. The favourable influence of MSNs on the physico-chemical and biological characteristics of these novel PUN materials was identified, which evidences their vast applicability potential as coatings for medical devices and implants.

Autofagija, proces programirane ćelijske razgradnje unutarćelijskog sadržaja, je uključena u regulaciju preživljavanja i smrti ćelija kancera. U ovoj doktorskoj disertaciji je po prvi put ispitivana sposobnost antileukemijskih lekova citarabina i idarubicina da indukuju autofagiju u različitim humanim leukemijskim ćelijskim linijama i mononuklearnim ćelijama periferne krvi (MNPK) pacijenata obolelih od leukemije in vitro. Takođe, ispitivani su unutarćelijski mehanizmi odgovorni za indukciju autofagije, kao i uloga autofagije u citotoksičnosti ovih lekova. Vijabilitet REH, HL-60, K562 leukemijskih ćelijskih linija, MNPK pacijenata obolelih od leukemije i MNPK zdravih kontrola je određivan merenjem aktivnosti kisele fosfataze i mitohondrijalnih dehidrogenaza. Protočna citofluorimetrija je korišćena za detekciju apoptoze i zakišeljavanja citoplazme. Indukcija autofagije je ispitivana fluorescentnom mikroskopijom (detekcija unutarćelijskih kiselih vezikula obojenih akridin oranžom), transmisionom elektronskom mikroskopijom (posmatranje autofagnih vezikula) i imunoblot analizom (konverzija LC3-I u LC3-II, degradacija SQSTM1/p62). Aktivacija signalnih puteva koji učestvuju u regulaciji autofagije je analizirana imunoblot metodom. Uloga autofagije u citotoksičnosti citarabina i idarubicina je ispitivana primenom farmakološke inhibicije bafilomicinom A1, hlorokinom, vortmaninom i amonijum hloridom, kao i genetske inaktivacije ekspresije beklina-1, LC3β i SQSTM1 transfekcijom odgovarajućim malim interferirajućim RNK. Citarabin i idarubicin su izazvali povećanje unutarćelijske kiselosti i pojavu autofagnih vezikula sa delimično razgrađenim ćelijskim sadržajem u leukemijskim ćelijskim linijama. Antileukemijski lekovi su stimulisali razgradnju supstrata autofagije SQSTM1 i povećali konverziju LC3-I u LC3-II formu asociranu autofagozomima u odsustvu ili prisustvu inhibitora proteolize, ukazujući tako na povećanje autofagnog fluksa. Oba leka su smanjila fosforilaciju mTOR kinaze, Autophagy, a process of programmed cellular self-digestion, has been implicated in regulation of cancer cell survival and death. The present study investigated for the first time the ability of antileukemic drugs cytarabine and idarubicin to induce autophagy in different human leukemic cell lines and peripheral blood mononuclear cells (PBMC) from leukemia patients in vitro. Intracellular mechanisms responsible for the induction of autophagy, as well as the role of autophagy in cytotoxicity of these drugs were also investigated. Cell viability of REH, HL-60, K562 leukemic cell lines, and PBMC from leukemic patients and healthy controls was determined by measuring the acid phosphatase and mitochondrial succinate dehydrogenase activity. Flow cytometry was used for the detection of apoptosis and intracellular acidification. Autophagy induction was assessed by fluorescent microscopy (detection of acridine orange stained intracellular acidic vesicles), by transmission electron microscopy (observation of autophagic vacuoles), as well as by immunoblot analysis of LC3 conversion and SQSTM1/p62 proteolysis. Activation of autophagy-regulating signaling pathways was analyzed by immunoblotting. Pharmacological inhibition of autophagy with bafilomycin A1, chloroquine, wortmannin, and NH4Cl or RNA interference-mediated knockdown of beclin-1, LC3β and SQSTM1 were used to determine the role of the autophagy in cytotoxicity of antileukemic drugs. Cytarabine and idarubicin induced an increase in intracellular acidification and appearance of autophagic vesicles with partially digested cellular components in leukemic cell lines. Antileukemic drugs stimulated the degradation of autophagic target SQSTM1 and enhanced the conversion of LC3-I to autophagosome-associated LC3-II in the absence or presence of proteolysis inhibitors, thus indicating the increase in autophagic flux...

Background: Dietary intake influence changes in fatty acids (FA) profiles in liver which plays a central role in fatty acid metabolism, triacylglycerol synthesis and energy homeostasis. We investigated the effects of 4-weeks treatment with milk-and fish-based diet, on plasma biochemical parameters and FA composition of liver phospholipids (PL) in rats of both sexes. Methods: Adult, 4 months old, Wistar rats of both sexes, were fed with different types of diets: standard, milk-based and fish-based, during 4 weeks. Analytical characterization of different foods was done. Biochemical parameters in plasma were determined. Fatty acid composition was analyzed by gas-chromatography. Statistical significance of FA levels was tested with two-way analysis of variance (ANOVA) using the sex of animals and treatment (type of diet) as factors on logarithmic or trigonometric transformed data. Results: Our results showed that both, milk-and fish-based diet, changed the composition and ratio of rat liver phospholipids FA, in gender-specific manner. Initially present sex differences appear to be dietary modulated. Although, applied diets changed the ratio of total saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), and effects were gender specific. Milk-based diet lowered SFA and elevated MUFA in males and increased PUFA in females vs. standard diet. The same diet decreased n-3, increased n-6 and n-6/n-3 ratio in males. Fish-based diet increased n-3, decreased n-6 and n-6/n-3 ratio vs. standard and milk-based diet in females. However, the ratio of individual FA in liver PL was also dietary-influenced, but with gender specific manner. While in females fish-based diet decreased AA (arachidonic acid) increased level of EPA (eicosapentaenoic acid), DPA (docosapentaenoic acid) and DHA (docosahexaenoic acid), the same diet elevated only DHA levels in males. Conclusion: Gender related variations in FA composition of rat liver PL were obser

The treatment of mood and anxiety disorders by nutraceuticals is gaining growing awareness. Berries of Aronia melanocarpa (Black chokeberry) and their extracts, exceptionally abundant in diverse phenolic compounds, have become famous for the highest in vitro antioxidant activity among fruits and notable health benefits (e.g. anti-diabetic, anti-inflammatory, cardioprotective). This study was designed to investigate the behavioral effects of month-long unlimited consumption of Aronia master juice (AJ) and/or juice reconstruct without polyphenols (RJ), in young male rats. AJ was initially evaluated for its content of phenolic compounds by spectrophotometric assays and HPLC-DAD. Rats that were supplied with three various water concentrations of AJ and RJ, respectively: 20% + 0% (ARO group), 5% + 15% (RAJ) and 0 + 20% (PLC), were compared with those which consumed only water (CTL). Daily drinking of AJ solution was significantly elevated from the second or third week onward, which was most expressed in the ARO group. Only this group displayed behavioral variations, manifested by certain hyperactivity in open field tests and prominent reductions of anxiety-like behaviors in the elevated plus maze. The ARO rats also expressed an alleviation of depression-like behavior in forced swimming tests. These findings demonstrate the beneficial behavioral effects of the one-month-long free drinking of phenolic-rich AJ in rats ( gt 20 ml per kg b. mass daily) that may be recognized as stimulating, anxiolytic-like and antidepressant-like. The in vitro assays suggested that MAO-A/MAO-B inhibitions by the phenolic compounds of AJ might be the possible in vivo mechanisms for such behavioral actions.

Segmented polyurethanes based on poly(dimethylsiloxane), currently used for biomedical applications, have sub-optimal biocompatibility which reduces their efficacy. Improving the endothelial cell attachment and blood-contacting properties of PDMS-based copolymers would substantially improve their clinical applications. We have studied the surface properties and in vitro biocompatibility of two series of segmented poly(urethane-dimethylsiloxane)s (SPU-PDMS) based on hydroxypropyl- and hydroxyethoxypropyl-terminated PDMS with potential applications in blood-contacting medical devices. SPU-PDMS copolymers were characterized by contact angle measurements, surface free energy determination (calculated using the van Oss-Chaudhury-Good and Owens-Wendt methods), and atomic force microscopy. The biocompatibility of copolymers was evaluated using an endothelial EA.hy926 cell line by direct contact assay, before and after pre-treatment of copolymers with multicomponent protein mixture, as well as by a competitive blood-protein adsorption assay. The obtained results suggested good blood compatibility of synthesized copolymers. All copolymers exhibited good resistance to fibrinogen adsorption and all favored albumin adsorption. Copolymers based on hydroxyethoxypropyl-PDMS had lower hydrophobicity, higher surface free energy and better microphase separation in comparison with hydroxypropyl-PDMS-based copolymers, which promoted better endothelial cell attachment and growth on the surface of these polymers as compared to hydroxypropyl-PDMS-based copolymers. The results showed that SPU-PDMS copolymers display good surface properties, depending on the type of soft PDMS segments, which can be tailored for biomedical application requirements such as biomedical devices for short- and long-term uses., Segmentirani poliuretani na bazi poli(dimetilsiloksana), koji se trenutno koriste u biomedicini, imaju biokompatibilnost ispod optimalne što smanjuje njihovu efikasnost. Poboljšavajući vezivanje endotelnih ćelija i svojstva kopolimera na bazi PDMS u dodiru sa krvlju značajno bi se poboljšala i proširila njihova klinička primena. U ovom radu su proučavana površinska svojstva i in vitro biokompatibilnost dve serije segmentiranih poli(uretan-dimetilsiloksana) (SPU-PDMS) na bazi hidroksipropil- i hidroksietoksipropil- PDMS pretpolimera sa potencijalnim primenama u medicinskim uredjajima u kontaktu sa krvlju. SPU-PDMS kopolimeri su karakterisani merenjem kontaktnih uglova, određivanjem površinske energije (izračunate prema van Oss-Chaudhury-Good i Owens-Wendt metodama), i mikroskopijom atomskih sila. Biokompatibilnost kopolimera je ispitivana primenom endotelnih EA.hy926 ćelija u direktnom kontaktu, pre i nakon pretretiranja kopolimera sa višekomponentnom smešom proteina, kao i pomoću kompetitivne adsorpcije proteina. Dobijeni rezultati su potvrdili da sintetisani kopolimeri imaju dobru kompatibilnost prema krvi. Svi sintetisani kopolimeri pokazivali su dobru otpornost prema adsorpciji fibrinogena i svi kopolimeri su favorizovali adsorpciju albumina. Kopolimeri na bazi hidroksietoksipropil-PDMS imali su manju hidrofobnost, veću površinsku energiju, i bolju mikrofaznu separaciju u poređenju sa kopolimerima na bazi hidroksipropil-PDMS, što je dovelo do boljeg vezivanja i rasta endotelnih ćelija na površini ovih polimera u poređenju sa kopolimerima na bazi hidroksipropil-PDMS. Rezultati su pokazali da SPU-PDMS kopolimeri prikazuju dobra površinska svojstva, zavisno od vrste mekih PDMS segmenata, koja se mogu prilagođavati zahtevima u biomedicini, kao što su biomedicinski uređaji za kratkoročnu i dugoročnu upotrebu.