Synthesis, characterization and application of macroporous nanocomposites of glycidyl methacrylate and magnetite

Makroporozni umreženi kopolimeri i nanokompoziti glicidil-metakrilata (GMA) sa etilen glikol dimetakrilatom (EGDMA) ili trimetilolpropan trimetakrilatom (TMPTMA) sintetisani su metodom suspenzione kopolimerizacije. Makroporozni nanokompoziti dobijeni su in-situ suspenzionom kopolimerizacijom tako što su nanočestice magnetita dodate u početnu reakcionu smešu za sintezu nemagnetičnih uzoraka makroporoznih kopolimera. Modifikacija uzoraka nanokompozita izvršena je u reakciji nanokompozita sa dietilentriaminom pri čemu su dobijeni amino-funkcionalizovani nanokompoziti. Dobijeni uzorci kopolimera i nanokompozita detaljno su analizirani infracrvenom spektroskopijom sa Furijevom transformacijom (FTIR), rendgenskom difrakcionom analizom (XRD), živinom porozimetrijom, skenirajućom elektronskom mikroskopijom sa energetski disperzivnom spektroskopijom X-zraka (SEM-EDX), transmisionom elektronskom mikroskopijom (TEM), mikroskopijom atomskih sila (AFM), termogravimetrijskom analizom (TGA) i elementarnom analizom (CHN). Magnetna svojstva nefunkcionalizovanih i amino-funkcionalizovanih makroporoznih nanokompozita analizirana su pomoću SQUID magnetometra. Na uzorcima amino-funkcionalizovanih makroporoznih nanokompozita vršena je sorpcija i razdvajanje oksianjona Mo(VI) i Re(VII) iz vodenih rastvora. Ispitan je uticaj pH vrednosti rastvora, vremena kontakta, temperature i početne koncentracije jona metala na efikasnost i kapacitet sorpcije, kao i uticaj jonske jačine rastvora i koncentracije koegzistirajućih anjona i katjona na kapacitet sorpcije oksianjona Mo(VI) i Re(VII). Eksperimentalni rezultati korišćeni su za izučavanje mehanizma sorpcije primenom četiri kinetička modela: modeli pseudo-prvog reda i pseudo-drugog reda, model unutar-čestične difuzije i Bojdov model. Ravnotežni podaci su analizirani primenom Lengmirovog i Frojndlihovog adsorpcionog modela izoterme. Na osnovu eksperimentalnih rezultata može se zaključiti da su amino-funkcionalizovani makroporoyni nanokompoziti pogodni kao sorbenti za selektivno razdvajanje oksianjona Mo(VI) i Re(VII) iz vodenih rastvora. Pokazalo se da Lengmirov model adsorpcione izoterme najbolje opisuje sorpciju jona metala na amino-funkcionalizovanim nanokompozitima i da na ukupnu brzinu sorpcije utiče unutar-čestična difuzija uz izvestan uticaj difuzije kroz film.Macroporous crosslinked copolymers and nanocomposites of glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA) or trimethylolpropane trimethacrylate (TMPTMA) were prepared by suspension copolymerization. The nanocomposites were synthesized with addition of magnetite nanoparticles in the reaction mixture used for synthesis of non-magnetic copolymer samples. The samples of amino-functionalized nanocomposites were prepared by modification of nanocomposite samples in reaction with diethylenetriamine. The obtained samples were characterized in detail by elemental analysis, Fourier transform infrared spectroscopy analysis (ATR-FTIR), X-ray diffractometry (XRD), mercury porosimetry, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and SQUID magnetometry. The chosen amino-functionalized nanocomposite samples were tested as a potential sorbents for sorption and separation of Mo(VI) and Re(VII) oxyanions from aqueos solutions. The effects of pH, contact time, temperature and initial concentration of the metal ions on the sorption capacity and the sorption efficiency were investigated. Also, the influence of ionic strength and possible interfering of cations and anions on the sorption capacity was investigated. The sorption behavior and rate controlling mechanisms were analysed using four kinetic models: pseudo-first order, pseudo-second order, intraparticle diffusion and Boyd models. Equilibrium data were analysed with Langmuir and Freundlich adorption isotherm models. All results indicate that the amino-functionalized nanocomposites could be used as promising sorbents for sorption and separation of Mo(VI) and Re(VII) oxyanions from aqueos solutions. The isotherm data were best fitted Langmuir model for both amino-functionalized nanocomposites. The sorption kinetics was determined to be governed by both the intraparticle diffusion and the external film diffusion to a lesser extent

Characterization of glycidyl methacrylate based magnetic nanocomposites

Magnetic and non-magnetic macroporous crosslinked copolymers of glycidyl methacrylate and trimethylolpropane trimethacrylate were prepared by suspension copolymerization and functionalized with diethylenetriamine. The samples were characterized by mercury porosimetry, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy analysis (FTIR-ATR), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM) and SQUID magnetometry. The FTIR-ATR analysis of synthesized magnetic nanocomposites confirmed the presence of magnetite and successful aminofunctionalization. Non-functionalized and amino-functionalized nanocomposites exhibited superparamagnetic behavior at 300 K, with a saturation magnetization of 5.0 emu/g and 2.9 emu/g, respectively. TEM analysis of the magnetic nanocomposite has shown that magnetic nanoparticles were homogeneously dispersed in the polymer matrix. It was demonstrated that incorporation of magnetic nanoparticles enhanced the thermal stability of the magnetic nanocomposite in comparison to the initial non-magnetic macroporous copolymer

Synthesis and characterization of quercetin-conjugated gold nanoparticles

Gold nanoparticles and quercetin-conjugated gold nanoparticles complex were synthesized using trisodium citrate as reducing agent. Both kinds of nanoparticles were characterized using spectrophotometry, dynamic light scattering and zeta potential measurements. Comparison of the results confirmed successful synthesis of quercetin-conjugated gold nanoparticles complex.Physical chemistry 2018 : 14th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 2018

Thermodynamcis of molybdenum adsorption onto porous copolymer

Macroporous glycidyl methacrylate and ethylene glycol dimethacrylate copolymer functionalized with diethylene triamine, PGME-deta, was tested as molybdate ion adsorbent from aqueous solutions. Kinetics of Mo(VI) sorption was investigated in batch static experiments, in the temperature range 298-343 K. The temperature rise promotes Mo(VI) removal, with the maximum experimental adsorption capacity of 585 mg g-1 at 343 K. Thermodynamic parameters revealed spontaneous and endothermic nature of Mo(VI) adsorption onto PGME-deta.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Hydrogels based on poly(methacrylic acid) for controlled release of anti-inflammatory drugs

Everyday struggle of humanity with novel diseases and present once, urge researchers to find novel and improve existing therapies to enhance their efficiency and safety. One of the promising approaches to overcome these challenges is controlled release of drugs. Biomaterials based on poly(methacrylic acid) (PMAA) are excellent drug delivery systems because they can control release rate and released amount of drug. Also, due to their pH sensitivity the PMAA hydrogels can release drug at the site of action. Namely, these nontoxic and biocompatible hydrogels swell in the environment with pH value higher than pKa of PMAA (4.6) and release encapsulated drug during the process. In present study, PMAA hydrogels are synthetized under ambient conditions by simple, cost effective and eco-friendly synthesis. Novel initiation system based on hydrogen peroxide, potato peel peroxidase and vitamin C (VC) is used for the first time for free radical polymerization of PMAA hydrogel. In accordance with the principles of circular economy, peroxidase was isolated from potato peel waste by water extraction for 12 h at 4 ℃. Four PMAA hydrogels were prepared by using potato peel peroxidase with various enzyme activity (0.4; 0.8; 1.2 and 1.8 IU), whereas the amounts of H2O2 (30 mL) and VC (10 mg) have been kept constant. The composition of the PMAA hydrogels was confirmed by FTIR analysis, whereas their porous structure was revealed by SEM. The swelling of the PMAA hydrogels was monitored in two media: 0.1M HCl (as simulation of human stomach) and phosphate buffer with pH 7.4 (as simulation of human intestines). In order to encapsulate anti-inflammatory drug – dexamethasone into the PMAA hydrogels, the hydrogels were immersed into the dexamethasone aqueous solution (5 mg/ml) and left to swell to the equilibrium, after which they were dried at room temperature. Dexamethasone release from the PMAA hydrogels was monitored in the same environments as was the PMAA swelling. The results showed that around seven times higher amount of dexamethasone was released in the medium with pH 7.4 than in the medium with pH 1. Present study has showed that the PMAA hydrogels, prepared through green and eco-friendly method, have huge potential for encapsulation and controlled release of anti-inflammatory drugs and therefore, for the treatment of rheumatoid arthritis

BiFeO3 fine powder controlled hydrothermal process synthesis and characterization

From the technological point of view, the mutual control of electric and magnetic properties is an attractive possibility, but the number of candidate multiferroic materials is limited. One of the most studied of them, BiFeO3 , has critical conditions for synthesizing single phase since the phase temperature stability range is very narrow. Bismuth ferrite (BFO) particles were synthesized by controlled hydrothermal process, where the particles of small sizes and high purity were obtained. A fitting refinement procedure using the Rietveld method was performed. Bismuth ferrite crystallizes in the perovskite type structure (α-BiFeO3 ) with rhombohedral space group R3c. The effects of thermal treatment through applied hydrothermal method on the obtained BFO grains morphology were evaluated by SEM and TEM analyses.SEM analysis showed that grains are very well crystallized, with non- fragmented crystal flats. Individual particles HRTEM analysis confirmed the evidence of ultra-fine single crystal particles, with characteristic (012) crystal planes. Furthermore, HRTEM confirmed the existence of twin stacking faults responsible for synthesized fine particles enhanced magnetic properties. The EPR results suggested the existence and participation of electrons trapped by vacancies or defects. It has been proposed that the existence of Fe 3+−OV defect complex could be generated at elevated temperatures followed by formation of Fe 3+ ions, which intensely provide the local 3d moments.IX Serbian Ceramic Society Conference - Advanced Ceramics and Application : new frontiers in multifunctional material science and processing : program and the book of abstracts; September 20-21, 2021; Belgrad

Synthesis, Characterization, and Cytotoxicity of a Novel Gold(III) Complex with O,O-Diethyl Ester of Ethylenediamine-N,N-Di-2-(4-Methyl)Pentanoic Acid

A novel gold(III) complex, [AuCl2{(S,S)-Et(2)eddl}]PF6, ((S,S)-Et(2)eddl = O,O-diethyl ester of ethylenediamine-N,N-di-2-(4-methyl)pentanoic acid) was synthesized and characterized by IR, 1D (H-1 and C-13), and 2D (H,H-COSY and H,H-NOESY) NMR spectroscopy, mass spectrometry, and elemental analysis. Density functional theory calculations confirmed that (R,R)-N,N diastereoisomer was energetically the most stable isomer. In vitro antitumor action of ligand precursor [(S,S)-H(2)Et(2)eddl]Cl-2 and corresponding gold(III) complex was determined against tumor cell lines: human adenocarcinoma (HeLa), human colon carcinoma (LS174), human breast cancer (MCF7), non-small cell lung carcinoma cell line (A549), and non-cancerous cell line human embryonic lung fibroblast (MRC-5) using microculture tetrazolium test (MTT) assay. The results indicate that both ligand precursor and gold(III) complex have showed very good to moderate cytotoxic activity against all tested malignant cell lines. The highest activity was expressed by [AuCl2{(S,S)-Et(2)eddl}]PF6 against the LS174 cells, with IC50 value of 7.4 +/- 1.2 mu M

Basic ISO standards related to the quality and safety/security in health care institutions

Health systems are under significant pressure in many countries. Every day, with the introduction of new methods/techniques, expensive equipment of high technological value, the latest very expensive drugs... the price of health care is growing much faster than the growth of the national product and the most developed countries, despite the fact that in many countries the percentage of health expenditures in the national product is growing. Funding constraints in health systems are evident even in wealthy countries. The cost of health care is significantly influenced by: the increase in the number of the population, changes in the age structure of the population, constant demands for increasing the level of quality of health services, as well as an increase in the demand for new services. The application of international management standards in healthcare institutions and in state institutions in charge of healthcare can significantly alleviate evident problems in healthcare

Biomaterijali

Početak XXI veka nesumnjivo je obeležen interdisciplinarnim i multidisciplinarnim naporima istraživača u različitim oblastima nauke. Jedna od najizrazitijih tendencija ovog tipa uočava se u biomedicinskim istraživanjima, gde se združuju napori lekara, biologa, genetičara i biohemičara, s jedne strane, i biofizičara i inženjera, s druge strane – sa ciljem dubljeg razumevanja zdravlja i bolesti, i primene ovih saznanja u biomedicinskoj praksi, tako važnoj u svakodnevnom životu ljudi.Kao rezultat ovih svetskih trendova, u Srbiji već više godina na nekoliko fakulteta postoji nastava iz oblasti biomedicinskog inženjerstva, sa ciljem da osposobi inženjere ovih usmerenja za multidisciplinarno povezivanje znanja iz oblasti tehnike sa biomedicinskim znanjima. Jedan od bazičnih predmeta ovih usmerenja jesu Biomaterijali, kojima je i posvećen naš udžbenik, čiji je cilj da predstavi pregled teorije i prakse biomaterijala u biomedicinskoj nauci.Nauka o biomaterijalima je nesumnjivo najmultidisciplinarnija od svih nauka, jer zahteva ovladavanje znanjima iz mnogih oblasti nauke i tehnologije, inženjerstva i medicine, kako bi naučnici iz oblasti biomaterijala mogli da se uhvate u koštac sa ovom profesijom. Zato posle uvodnog dela, udžbenik iz Biomaterijala sadrži četiri celine: (I) Osnovni biomedicinski koncepti i reakcije organizma na biomaterijale, (II) Struktura, fizičko-mehanička karakterizacija i modeliranje biomaterijala i tkiva, (III) Savremeni biomaterijali i tehnologije, (IV) Perspektive biomaterijala i tehnologija, iza kojih slede Zadaci sa rešenjima, Ispitna test pitanja i Ispitna teorijska pitanja, koji pomažu studentima da lakše savladaju veoma obimno i kompleksno gradivo. Na kraju svakog poglavlja data su pitanja za rekapitulaciju, kao i spisak dopunske literature za opcionu detaljniju obradu pojedinih oblasti.Grupa od dvadeset četiri profesionalca sa univerziteta i naučnih instituta, pod okriljem Instituta tehničkih nauka Srpske akademije nauka i umetnosti, Beograd, i Društva za istraživanje materijala Srbije (MRS Srbija) doprinela je pisanju ovog kapitalnog udžbenika o biomaterijalima, prvog do sada na srpskom jeziku. Mada uključivanje veće grupe autora nužno dovodi do stilske neujednačenosti, ipak je oblast biomaterijala toliko multidisciplinarna da je ovakav pristup bio neophodan, kako uostalom pokazuju slična svetska iskustva sa uključivanjem i preko pedeset autora. Ipak urednici su se potrudili da koliko je to moguće stilski i pedagoški ujednače udžbenik, kako bi bio korisna literatura za sve studente diplomskih, master i doktorskih studija iz biomedicinskog inženjerstva u Srbiji i okruženju