Preparation of fluorapatite-based nanophosphorus doped with Pr3+ ions for bio-medical applications

    Luminescentni nanokristali (nanofosfori) na bazi fluorapatita (FAP-a) dopirani elementima retkih zemalja idealni su kontrastni agenti za bio-medicinske primene, kao što su detekcije, snimanja, praćenja i terapije ćelija kancera. Kancer je jedna od najčešćih bolesti modernog doba čiji uspeh lečenja zavisi od rane dijagnostike i neinvazivnog tretmana. Luminescentne nanočestice mogu uneti inovativnu paradigmu u lečenje kancera kombinovanjem biosnimanja, dijagnostike i tretmana. Za studije fluorescentnih biosnimanja nanokristali fluorapatita dopirani retkim zemljama kao kontrastni agenti pružaju značajne prednosti u vidu velikih kontrasta i dugotrajnosti luminescencije, i što je još važnije visoke biokompatibilnosti, netoksičnosti i bioaktivnosti. Glavni ciljevi ove doktorske disertacije su sinteza novih luminescentnih multifotonskih bionanomaterijala na bazi fluorapatita dopiranih jonima prazeodimijuma (Pr3+), njihova karakterizacija i evaluacija  primene za fluorescentna biosnimanja kancera. Sintezom nanoprahova u umerenim uslovima metodom ko-precipitacije, a potom sušenjem na 110 oC i kalcinacijom na temperaturama od 700 i 1000 oC očekuje se pronalaženje najboljih uslova za dobijanje novih nanofosfora koji bi našli i različite bio-medicinske primene u oblasti fluorescentnih biosnimanja. Proučavane su tri vrste PrFAP nanokristala, sa 0,1%, 0,5% i 1% atomskih procenta Pr3+, zajedno sa nedopiranim FAP kontrolnim uzorkom. Nivoi energije aktivator jona Pr3+ sadrže metastabilna multipletna stanja koja nude mogućnosti efikasnih emisionih linija u više boja u FAP nanokristalima, kao i u infracrvenoj i ultravioletnoj oblasti spektra. Metodom ko-precipitacije na sobnoj temperaturi (25 oC), a potom sušenjem na 110 oC, sintetisani su monofazni heksagonalni nanokristali PrFAPs nepravilnog sfernog oblika. Termičkom analizom sintetisanih uzoraka, na osnovu detektovanih temperaturnih opsega procesa dekarbonacije i dehidroksilacije, utvrđene su temperature kalcinacije od 700 i 1000 oC. Termička analiza i karakterizacija uzoraka su pokazale da Pr3+ joni dovode do stabilizacije FAP strukture na višim temperaturama, što je pripisano unosu lantanoidnih jona sa specifičnim magnetnim osobinama u sistem i stvaranju jačih privlačnih sila sa O2- anjonima. Nanokristali sušeni na 100 oC i kalcinisani na 1000 oC, zbog prisustva defekata kristalne rešetke koji zadržavaju emisiju Pr3+ jona, nisu pokazali luminescentne karakteristike od značaja za primene u medicinskim fluorescentnim biosnimanjima. Kalcinacijom uzoraka na 700 oC izrađen je novi tip aktiviranih fluorapatitnih nanokristala dopiranih prazeodimijumom (PrFAPa) sa ekscitaciono-emisionim profilima u vidljivom delu spektra. Fizičko-hemijska karakterizacija potvrdila je sferne kristale heksagonalne strukture do nanometrske veličine od oko 20 nm. Kvantno-hemijske kalkulacije predvidele su da se joni Pr3+ ugrađuju u kristalnu rešetku FAP nanokristala na položaju Ca2 (6h), što je praćeno deformacijama pozicije F- jona. Pretpostavljeni mehanizam supstitucije je jedan jon Pr3+ za jedan Ca2+, s delimičnom supstitucijom anjona F– sa O2– i OH– i stvaranjem vakansi usled postizanja neutralnosti sistema. Rezultati in vitro biokompatibilnosti i hemokompatibilnosti pokazali su da nanokristali PrFAPa nisu toksični za žive ćelije. Pored toga, internalizacija PrFAPa nanokristala od strane ćelija kancera kože (A431) i pluća (A549) je proučavana korišćenjem konfokalne mikroskopije i mikroskopije širokog polja zasnovane na fluorescenciji. Nanokristali pokazuju karakterističnu zelenu emisiju na 545 nm (3P0→3H5 tranzicija Pr3+ jona) i narandžastu emisiju na 600 nm (1D2→3H4), koje su korišćene za razlikovanje od pozadinske autofluorescencije ćelije. Studije dobijenih slika konfokalnom mikroskopijom u plavom, zelenom i crvenom kanalu su otkrile da nanokristali mogu da prepoznaju ćelijsku površinu i da se lepe za nju, ali nisu potvrdile ulazak nanokristala u ćelije. Mikroskopija širokog polja je detektovala emisione prelaze u zelenoj i narandžastoj boji i potvrdila da luminescentni signal dolazi iz unutrašnjosti ćelija. Korišćenjem rezonantne ekscitacije od 488 nm i emisije od 600 nm PrFAPa nanokristala, konfokalnom mikroskopijom ekstrahovan je signal fluorescencije iz unutrašnjosti ćelija kancera. Ortogonalne projekcije u 3D konfokalnim ravnima pokazuju da su nanokristali u stanju da uđu u ćelije kancera i da se raspoređuju po citoplazmi. Sveukupno, ovako dobijeni nanokristali PrFAPa su biokompatibilni i od testiranih uzoraka, aktivirani nanokristali dopirani sa 0,5% Pr3+ pokazuju najviše potencijala za primenu u medicinskim fluorescentnim biosnimanjima kao kontrastni agenti.    Luminescent nanocrystals (nanophosphorus) based on fluorapatite (FAP) doped with rare earth elements are ideal contrast agents for biomedical applications such as cancer cell detection, imaging, tracking and therapy. Cancer is one of the most common diseases of the modern times whose success of the cure depends on early diagnosis and non-invasive treatment. Luminescent nanoparticles can bring an innovative paradigm into the treatment of cancer by combining bioimaging, diagnostics and treatment. Rare earth doped fluorapatite nanocrystals as contrast agents for studies of fluorescence bioimaging, offer significant advantages in terms of high contrasts and long-term luminescence, and more importantly high biocompatibility, non-toxicity and bioactivity. The main objectives of this doctoral dissertation are the synthesis of novel luminescent multiphoton bionanomaterials based on fluorapatites doped with praseodymium ions (Pr3+), their characterization and evaluation of their application for cancer fluorescence bioimaging. Synthesis of nanopowders under moderate conditions by the co-precipitation method, followed by dried at 110 °C and calcination at 700 and 1000 °C, is expected to find the best conditions for obtaining new nanophosphors that would find different bio- medical applications in the field of fluorescence bioimaging. Three types of PrFAP nanocrystals were studied, with 0,1%, 0,5%, and 1% atomic percentages of Pr3+, together with an undoped FAP control sample. Energy levels of the Pr3+ ion activator contain metastable multiplet states that offer the possibility of efficient multi-color emission lines in FAP nanocrystals as well as in the infrared and ultraviolet regions of the spectrum. Single-phase hexagonal nanocrystals PrFAPs of irregular spherical shape were synthesized by the method of co-precipitation at room temperature (25 oC) and then drying at 110 oC. Thermal analysis of the synthesized samples, based on the detected temperature ranges of the decarbonation and dehydroxylation processes, determined calcination temperatures of 700 and 1000 oC. Thermal analysis with characterization showed that Pr3+ ions lead to stabilization of the FAP structure at higher temperatures, which was attributed to the entry of lanthanoid ions with specific magnetic properties into the system and the creation of stronger attractive forces with O2- anions. Nanocrystals dried at 100 oC and calcined at 1000 oC, due to the presence of crystal lattice defects that quench the emission of Pr3+ ions, did not show luminescent characteristics of significance for applications in medical fluorescence imaging. Calcination of the samples at 700 oC produced a new type of activated praseodymium doped fluorapatite nanocrystals (PrFAPa) with excitation-emission profiles in the visible part of the spectrum. Physicochemical characterization confirmed spherical crystals of hexagonal structure up to a nanometer size of about 20 nm. Quantum-chemical calculations predicted that Pr3+ ions would be embedded in the crystal lattice of FAP nanocrystals at the Ca2 position (6h), which was followed by deformations of the F- ion position. The assumed substitution mechanism is one Pr3+ ion for one Ca2+, with partial substitution of F– anions with O2– and OH– and creation of vacancies due to achieving system neutrality. The results of in vitro biocompatibility and hemocompatibility showed that PrFAP nanocrystals were not toxic to living cells. In addition, the internalization of PrFAPa nanocrystals by skin (A431) and lung (A549) cancer cells was studied using fluorescence-based confocal microscopy and wide-field microscopy. The nanocrystals show characteristic green emission at 545 nm (3P0→3H5 transition of Pr3+ ion) and orange emission at 600 nm (1D2→3H4), which we use to discriminate from cell autofluorescence. Studies of the images obtained by confocal microscopy in the blue, green, and red channels revealed that nanocrystals could recognize the cell surface and adhere to it, but they did not confirm the entry of nanocrystals into the cells. The wide-field microscopy detected emission transitions in green and orange color, and confirmed that the luminescent signal was coming from inside the cells. Using resonant excitation of PrFAP nanocrystals at 488 nm and emission of 600 nm, confocal microscopy extracted the fluorescence signal from inside the cancer cells. Orthogonal projections across 3D confocal stacks show that the nanocrystals are able to enter the cells positioning themselves within the cytoplasm. Overall, the obtained PrFAPa nanocrystals are biocompatible and of the tested types, the 0,5% Pr3+ doped nanocrystals show the highest promise as a tracking nanoparticle probe for bioimaging applications

Preparation of fluorapatite-based nanophosphorus doped with Pr3+ ions for bio-medical applications

    Luminescentni nanokristali (nanofosfori) na bazi fluorapatita (FAP-a) dopirani elementima retkih zemalja idealni su kontrastni agenti za bio-medicinske primene, kao što su detekcije, snimanja, praćenja i terapije ćelija kancera. Kancer je jedna od najčešćih bolesti modernog doba čiji uspeh lečenja zavisi od rane dijagnostike i neinvazivnog tretmana. Luminescentne nanočestice mogu uneti inovativnu paradigmu u lečenje kancera kombinovanjem biosnimanja, dijagnostike i tretmana. Za studije fluorescentnih biosnimanja nanokristali fluorapatita dopirani retkim zemljama kao kontrastni agenti pružaju značajne prednosti u vidu velikih kontrasta i dugotrajnosti luminescencije, i što je još važnije visoke biokompatibilnosti, netoksičnosti i bioaktivnosti. Glavni ciljevi ove doktorske disertacije su sinteza novih luminescentnih multifotonskih bionanomaterijala na bazi fluorapatita dopiranih jonima prazeodimijuma (Pr3+), njihova karakterizacija i evaluacija  primene za fluorescentna biosnimanja kancera. Sintezom nanoprahova u umerenim uslovima metodom ko-precipitacije, a potom sušenjem na 110 oC i kalcinacijom na temperaturama od 700 i 1000 oC očekuje se pronalaženje najboljih uslova za dobijanje novih nanofosfora koji bi našli i različite bio-medicinske primene u oblasti fluorescentnih biosnimanja. Proučavane su tri vrste PrFAP nanokristala, sa 0,1%, 0,5% i 1% atomskih procenta Pr3+, zajedno sa nedopiranim FAP kontrolnim uzorkom. Nivoi energije aktivator jona Pr3+ sadrže metastabilna multipletna stanja koja nude mogućnosti efikasnih emisionih linija u više boja u FAP nanokristalima, kao i u infracrvenoj i ultravioletnoj oblasti spektra. Metodom ko-precipitacije na sobnoj temperaturi (25 oC), a potom sušenjem na 110 oC, sintetisani su monofazni heksagonalni nanokristali PrFAPs nepravilnog sfernog oblika. Termičkom analizom sintetisanih uzoraka, na osnovu detektovanih temperaturnih opsega procesa dekarbonacije i dehidroksilacije, utvrđene su temperature kalcinacije od 700 i 1000 oC. Termička analiza i karakterizacija uzoraka su pokazale da Pr3+ joni dovode do stabilizacije FAP strukture na višim temperaturama, što je pripisano unosu lantanoidnih jona sa specifičnim magnetnim osobinama u sistem i stvaranju jačih privlačnih sila sa O2- anjonima. Nanokristali sušeni na 100 oC i kalcinisani na 1000 oC, zbog prisustva defekata kristalne rešetke koji zadržavaju emisiju Pr3+ jona, nisu pokazali luminescentne karakteristike od značaja za primene u medicinskim fluorescentnim biosnimanjima. Kalcinacijom uzoraka na 700 oC izrađen je novi tip aktiviranih fluorapatitnih nanokristala dopiranih prazeodimijumom (PrFAPa) sa ekscitaciono-emisionim profilima u vidljivom delu spektra. Fizičko-hemijska karakterizacija potvrdila je sferne kristale heksagonalne strukture do nanometrske veličine od oko 20 nm. Kvantno-hemijske kalkulacije predvidele su da se joni Pr3+ ugrađuju u kristalnu rešetku FAP nanokristala na položaju Ca2 (6h), što je praćeno deformacijama pozicije F- jona. Pretpostavljeni mehanizam supstitucije je jedan jon Pr3+ za jedan Ca2+, s delimičnom supstitucijom anjona F– sa O2– i OH– i stvaranjem vakansi usled postizanja neutralnosti sistema. Rezultati in vitro biokompatibilnosti i hemokompatibilnosti pokazali su da nanokristali PrFAPa nisu toksični za žive ćelije. Pored toga, internalizacija PrFAPa nanokristala od strane ćelija kancera kože (A431) i pluća (A549) je proučavana korišćenjem konfokalne mikroskopije i mikroskopije širokog polja zasnovane na fluorescenciji. Nanokristali pokazuju karakterističnu zelenu emisiju na 545 nm (3P0→3H5 tranzicija Pr3+ jona) i narandžastu emisiju na 600 nm (1D2→3H4), koje su korišćene za razlikovanje od pozadinske autofluorescencije ćelije. Studije dobijenih slika konfokalnom mikroskopijom u plavom, zelenom i crvenom kanalu su otkrile da nanokristali mogu da prepoznaju ćelijsku površinu i da se lepe za nju, ali nisu potvrdile ulazak nanokristala u ćelije. Mikroskopija širokog polja je detektovala emisione prelaze u zelenoj i narandžastoj boji i potvrdila da luminescentni signal dolazi iz unutrašnjosti ćelija. Korišćenjem rezonantne ekscitacije od 488 nm i emisije od 600 nm PrFAPa nanokristala, konfokalnom mikroskopijom ekstrahovan je signal fluorescencije iz unutrašnjosti ćelija kancera. Ortogonalne projekcije u 3D konfokalnim ravnima pokazuju da su nanokristali u stanju da uđu u ćelije kancera i da se raspoređuju po citoplazmi. Sveukupno, ovako dobijeni nanokristali PrFAPa su biokompatibilni i od testiranih uzoraka, aktivirani nanokristali dopirani sa 0,5% Pr3+ pokazuju najviše potencijala za primenu u medicinskim fluorescentnim biosnimanjima kao kontrastni agenti.    Luminescent nanocrystals (nanophosphorus) based on fluorapatite (FAP) doped with rare earth elements are ideal contrast agents for biomedical applications such as cancer cell detection, imaging, tracking and therapy. Cancer is one of the most common diseases of the modern times whose success of the cure depends on early diagnosis and non-invasive treatment. Luminescent nanoparticles can bring an innovative paradigm into the treatment of cancer by combining bioimaging, diagnostics and treatment. Rare earth doped fluorapatite nanocrystals as contrast agents for studies of fluorescence bioimaging, offer significant advantages in terms of high contrasts and long-term luminescence, and more importantly high biocompatibility, non-toxicity and bioactivity. The main objectives of this doctoral dissertation are the synthesis of novel luminescent multiphoton bionanomaterials based on fluorapatites doped with praseodymium ions (Pr3+), their characterization and evaluation of their application for cancer fluorescence bioimaging. Synthesis of nanopowders under moderate conditions by the co-precipitation method, followed by dried at 110 °C and calcination at 700 and 1000 °C, is expected to find the best conditions for obtaining new nanophosphors that would find different bio- medical applications in the field of fluorescence bioimaging. Three types of PrFAP nanocrystals were studied, with 0,1%, 0,5%, and 1% atomic percentages of Pr3+, together with an undoped FAP control sample. Energy levels of the Pr3+ ion activator contain metastable multiplet states that offer the possibility of efficient multi-color emission lines in FAP nanocrystals as well as in the infrared and ultraviolet regions of the spectrum. Single-phase hexagonal nanocrystals PrFAPs of irregular spherical shape were synthesized by the method of co-precipitation at room temperature (25 oC) and then drying at 110 oC. Thermal analysis of the synthesized samples, based on the detected temperature ranges of the decarbonation and dehydroxylation processes, determined calcination temperatures of 700 and 1000 oC. Thermal analysis with characterization showed that Pr3+ ions lead to stabilization of the FAP structure at higher temperatures, which was attributed to the entry of lanthanoid ions with specific magnetic properties into the system and the creation of stronger attractive forces with O2- anions. Nanocrystals dried at 100 oC and calcined at 1000 oC, due to the presence of crystal lattice defects that quench the emission of Pr3+ ions, did not show luminescent characteristics of significance for applications in medical fluorescence imaging. Calcination of the samples at 700 oC produced a new type of activated praseodymium doped fluorapatite nanocrystals (PrFAPa) with excitation-emission profiles in the visible part of the spectrum. Physicochemical characterization confirmed spherical crystals of hexagonal structure up to a nanometer size of about 20 nm. Quantum-chemical calculations predicted that Pr3+ ions would be embedded in the crystal lattice of FAP nanocrystals at the Ca2 position (6h), which was followed by deformations of the F- ion position. The assumed substitution mechanism is one Pr3+ ion for one Ca2+, with partial substitution of F– anions with O2– and OH– and creation of vacancies due to achieving system neutrality. The results of in vitro biocompatibility and hemocompatibility showed that PrFAP nanocrystals were not toxic to living cells. In addition, the internalization of PrFAPa nanocrystals by skin (A431) and lung (A549) cancer cells was studied using fluorescence-based confocal microscopy and wide-field microscopy. The nanocrystals show characteristic green emission at 545 nm (3P0→3H5 transition of Pr3+ ion) and orange emission at 600 nm (1D2→3H4), which we use to discriminate from cell autofluorescence. Studies of the images obtained by confocal microscopy in the blue, green, and red channels revealed that nanocrystals could recognize the cell surface and adhere to it, but they did not confirm the entry of nanocrystals into the cells. The wide-field microscopy detected emission transitions in green and orange color, and confirmed that the luminescent signal was coming from inside the cells. Using resonant excitation of PrFAP nanocrystals at 488 nm and emission of 600 nm, confocal microscopy extracted the fluorescence signal from inside the cancer cells. Orthogonal projections across 3D confocal stacks show that the nanocrystals are able to enter the cells positioning themselves within the cytoplasm. Overall, the obtained PrFAPa nanocrystals are biocompatible and of the tested types, the 0,5% Pr3+ doped nanocrystals show the highest promise as a tracking nanoparticle probe for bioimaging applications

Food sterilization by ionizing radiation

In addition to the usual methods for food preservation, the use of radiation isincreasingly widespread. The beginnings of radiation use date from the endof the 19th century, but more intensive application is noticed only after theSecond World War [1]. Most of the research was carried out to determinethe stability and food safety.Compared to the thermal sterilization, the radiation technique wasdeveloped later, and found less or limited application in the conservation offoods [2]. It should be noted that electromagnetic radiation is used not onlyfor the destruction of microorganisms, but also for: destruction of insects, culinary food processing (microwave ovens), slowing down certain biochemical activities (preventinggermination) improving certain technological parameters of some foods(improving the rehydration of dried fruits and vegetables).The radiation of a short wavelength (approximately 30 nm) is characterizedby high energy, so it has a pronounced mutagenic and lethal effect. Thisradiation acts in two ways, either directly with nucleic acids or by formingthe very reactive radicals that can react easily with various organiccompounds, making them unavailable to microorganisms. Free radicals areionized molecules - most commonly water molecules.Besides electromagnetic radiation (X - rays, gamma rays and cosmic rays),alpha and beta - (corpuscular) radiation can also perform ionization ofmolecules. By using ionizing radiation, only a small part of the energy istransformed into heat. Compared to thermal sterilization, this amounts toless than 2%, i.e. the temperature of the food does not rise more than 2 ° C,which is why this treatment is called cold sterilization.6th Workshop Specific Methods for Food Safety and Quality : September 27th, 2018, Belgrade. Within 14th International Conference on Fundamental and Applied Aspects of Physical Chemistr

Nanofabrication and characterisation of magnetic Fe3O4 nanostructures for potential environmental and biomedical applications

Magnetic iron oxide nanomaterials, which enable a multitude of uses, are given special focus in the fields of biomedicine and environmental protection. The detection, sorption, and/or degradation of inorganic (lead, chromium, arsenic, and cadmium), organic (dyes, pharmaceuticals, pesticides, phenols, and benzene), and biological (viruses and bacteria) pollutants can all be effectively accomplished with the use of magnetic nanoparticles. Magnetic iron oxide nanomaterials are in particular focus for use as hyperthermia media in cancer treatment and as magnetic resonance imaging (MRI) contrast agents. The possibility of magnetic separation of such materials, due to their essential properties under the influence of an external magnetic field, reduces production costs and also prevents the production and accumulation of toxic waste. Among the many metal oxide nanomaterials, magnetite (Fe3O4) and maghemite (γ-Fe2O3) are currently the only two magnetic materials approved by the US Food and Drug Administration (FDA) for human use as iron deficiency therapeutics and as contrast agents for MRI. Here, we synthesized nanoparticles of magnetite (Fe3O4) by the method of reduction-precipitation and characterized. Additionally, potential binding of brilliant green dye on Fe3O4 and construction of innovative magnetic composite was investigated. The physicochemical features were explored using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM). XRD analysis confirms formation of the crystal phase of magnetite. The presence of magnetite nanoparticles is shown by typical groups for the peaks of iron compounds at a lower wavelength (≤ 700 cm-1 ) that are characteristic of the Fe-O bond. Morphological analyzes with FESEM showed that magnetite is a composite of nanospheres and nanorods that provide a large surface area. Dye binding study was performed using UVvisible and FTIR spectrometer.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

Predicting the modulus of elasticity of biocompatible titanium alloys using machine learning

Titanium alloys are widely employed in various fields, particularly in biomedical engineering, due to their mechanical and corrosion resistance properties combined with good biocompatibility. The modulus of elasticity is a distinguishing feature of this group of materials compared to others used for similar purposes. A database of approximately 238 titanium alloys free of toxic elements was compiled for this study. The influence of different factors (such as alloy element proportions, density, and specific heat) on the modulus of elasticity was predicted using four methods: support vector machine, XGBoost, Neural Network, and Random Forest. The Random Forest mean absolute error (MAE) of 7.33 GPa, falls within the range of experimentally obtained absolute errors in the literature (up to about 11 GPa). A strong correlation (R2 = 0.72) was observed between experimental and predicted data. Lastly, specific alloying element regions were identified for the modulus of elasticity, which can be used to design new biocompatible titanium alloys in the future

Synthesis and characterization of fluorapatite/polyethylene composite

In the present study, fluorapatite/polyethylene composite was prepared and characterized by means of different techniques (XRD and TEM). The effects of fluorapatite on the composite properties were investigated. It is found that the fluorapatite–polyethylene composite has an immiscible intercalated structure.PHYSICAL CHEMISTRY 2016 : 13th International Conference on Fundamental and Applied Aspects of Physical Chemistry : 5th Workshop "Specific methods for food safety and quality" : September 27, 2016, Belgrade

Luminescence transitions of Pr3+ (4f2) in fluorapatite nanocrystals for potential biomedical application

Fluorapatite (FAP) crystals have drawn significant interest over the last few decades as important hosts matrix for optically active trivalent rare earth ions, due to the strong crystal field splitting and large transition cross-sections. Nano-sized FAP particles doped with rare earth ions have been extensively studied as luminescent materials for biomedical applications for cell labeling and bioimaging, as well as antimicrobial agents for therapeutics.Fluorapatite nanoparticles doped with praseodymium ions (Pr3+) were prepared by the co precipitation method and characterized. The different number of Pr3+ (4f2) transitions in the ultraviolet and visible parts of the spectrum was investigated by photoluminescence spectroscopy. Multivariate Curve Resolution–Alternating Least Squares (MCR-ALS) analyses of fluorescence spectra and ab initio calculation indicated that Pr3+ ions are preferentially substituted Ca2 (6h) sites in FAP lattice. In addition to the substitution of cations, there is also the substitution of anionic species such as OH-, CO32-, and NO3-, which are confirmed by the CHNS method. The obtained samples were tested as bioimaging and antibacterial agents and can potentially be used for further biomedical research

Adsorption of selected pharmaceuticals on LDPE, PA, and PET microplastics

Unappropriated disposing of unused drugs leads to an increase in their concentration in the environment. Furthermore, wastewater treatment plants are not sufficient to prevent the transport of drugs. Microplastics (MPs), which are also recognized as important pollutants, can be divided into primary and secondary. The primary MPs are produced for commercial purposes, while the secondary MPs are formed by the decomposition of plastic residues. The hydrophobic nature and large specific surface area of MPs facilitate pollutants binding. Animals misunderstand MPs for food and consume it, which could have harmful health impacts because both MPs and adsorbed pollutants are ingested. In this paper, the adsorption of the selected drugs - azithromycin, carbamazepine, sulfamethoxazole, and diclofenac on low-density polyethylene (LDPE), polyamide (PA), and poly(ethylene terephthalate) (PET) microplastics are presented. The experiment showed that drugs bind best to PA and that azithromycin has the highest binding affinity.Neadekvatno odlaganje neiskorišcenih lekova dovodi do povecanja njihove koncentracije u životnoj sredini. Pored toga, postrojenja za precišcavanje otpadnih voda nisu dovoljna barijera za sprecavanje transporta lekova. Mikroplastika (MP), koja je tako e detektovana kao bitan polutant, može se podeliti na primarnu i sekundarnu. Primarna se proizvodi za komercijalne svrhe, a sekundarna nastaje razgradnjom plasticnih ostataka. Hidrofobna priroda i velika specificna površina MP olakšava adsorpciju polutanata na ove materijale. Životinje mešaju MP sa hranom i unose je u svoj organizam, što može imati negativni uticaj na njihovo zdravlje, jer se tako unose i MP i adsorbovani polutanti. U ovom radu je prikazana adsorpcija odabranih lekova - azitromicina, karbamazepina, sulfametoksazola i diklofenaka na sledecim vrstama mikroplastike - polietilenu niske gustine (LDPE), poliamidu (PA) i poli(etilen tereftalatu) (PET). Eksperiment je pokazao da se lekovi najbolje vezuju za PA, kao i da azitromicin ima najveci afinitet vezivanja

Preparation and antimicrobial activity of polyethylene composite with silver-doped fluorapatite

The high-density polyethylene/silver-doped fluorapatite composite (HDPE/AgFAP) with 1 wt% of AgFAP was produced using a twin screw extruder. Characterization studies of XRD and TEM results showed that AgFAP particles were drowned and partially dispersed in the polymer. Antimicrobial study has demonstrated that composite exhibits antimicrobial activity in vitro against the S. aureus.6th Workshop Specific Methods for Food Safety and Quality : September 27th, 2018, Belgrade. Within 14th International Conference on Fundamental and Applied Aspects of Physical Chemistr

Effects of Ag+ ion doping on UV radiation absorption and luminescence profiles of fluorapatite nanomaterials obtained by neutralization method

In the present study we have analyzed effects of Ag+ ions doping on energetic profiles of nanophosphors materials based on fluorapatite crystal system. The UV radiation absorption and luminescence properties of monophase fluorapatite (FAP) and Ag+ doped fluorapatite (AgFAP) nanomaterials obtained by neutralization method were investigated using the photoluminescence spectrophotometry. The excitation-emission profiles of nanomaterials were analyzed statistically by MCR-ALS method and number of fluorophores was extracted. FAP lattice absorbed light at 350 nm in the UVA part of spectrum, and with increasing concentration of Ag+ ions new absorption maximum appeared at 270 nm in the UVC part. Fluorescence of FAP nanoparticles was in violet region of visible part of the spectrum, with a red shift to the green region when Ag+ was doped in lattice. MCR-ALS analyses of fluorescence spectra confirm formation of two maxima, at 484 and 505 nm, as a consequence of Ag+ ions doping in FAP lattice at Ca1 (4f) sites. The results of quantum chemical calculations showed that an Ag+ ion is stronger bonded to the binding site 1 (-1352:6 kcal/mol) than to the binding site 2 (-1249:0 kcal/mol). Considering that AgFAP1 nanopowder absorbs photons over all part of UV radiation spectrum, this material might be used as potential radiation protective nanomaterial