Synthesis, surface modification and physicochemical characteristics of multifunctional, luminescent nanomaterials containing rare earth ions

Wydział Chemii: Zakład Ziem RzadkichCelem naukowym rozprawy doktorskiej było otrzymanie, modyfikacją powierzchni oraz zbadanie właściwości fizykochemicznych wielofunkcyjnych nanomateriałów luminescencyjnych opartych o jony pierwiastków ziem rzadkich. Pierwszym etapem badań była synteza nanokrystalicznych fluorków, fosforanów i wanadanów pierwiastków ziem rzadkich, domieszkowanych odpowiednimi jonami lantanowców. Otrzymane produkty wykazywały intensywną, wielokolorową luminescencję, zależną od użytego jonu aktywatora. Część zsyntetyzowanych produktów poddawano po syntezie obróbce hydrotermalnej lub organicznej modyfikacji powierzchni. W kolejnym etapie wyselekcjonowane nanocząstki poddano modyfikacji powierzchni na drodze hydrolizy i ko-kondensacji odpowiednich pochodnych silanowych. W wyniku tego otrzymano nanostruktury typu rdzeń/powłoka (core/shell), sfunkcjonalizowane powierzchniowo grupami aminowymi lub karboksylowymi. Modyfikacja powierzchni wpłynęła znacząco na zmianę właściwości fizykochemicznych i biologicznych otrzymanych produktów. Wybrane nanoluminofory użyto do dalszej syntezy złożonych nanostruktur luminescencyjno-magnetycznych typu core/shell. Otrzymane wielofunkcyjne nanomateriały wykazywały jednocześnie intensywną zieloną lub czerwoną luminescencję pod wpływem promieniowania UV oraz odpowiedź na przyłożone pole magnetyczne.The scientific aim of the doctoral dissertation was preparation, surface modification and investigation of physicochemical properties of the multifunctional, luminescent nanomaterials, based on the rare earth ions. The first part of the research was the synthesis of nanocrystalline rare earths fluorides, phosphates and vanadates, doped with appropriate lanthanide ions. The products obtained exhibited intense, multicolour luminescence, dependent on the activator ion used. After the synthesis, part of the synthesized products was hydrothermally post-treated or organically surface modified. In the next step of the studies, the selected nanoparticles were surface modified by hydrolysis and co-condensation of appropriate silane derivatives. The performed modifications resulted in the formation of core/shell type nanostructures, whose surface was functionalized with amino or carboxyl groups. The performed surface modification influenced on physicochemical and biological properties of the products obtained. The selected nanoluminophores based on the doped lanthanide fluorides and vanadates, were used further in the synthesis of complex, core/shell type luminescent-magnetic nanostructures. The as-prepared multifunctional nanomaterials, simultaneously exhibited red or green luminescence under UV light irradiation and a response to the applied magnetic field

Structural, spectroscopic and cytotoxicity studies of TbF3@CeF3 and TbF3@CeF3@SiO2 nanocrystals

Terbium fluoride nanocrystals, covered by a shell, composed of cerium fluoride were synthesized by a co-precipitation method. Their complex structure was formed spontaneously during the synthesis. The surface of these core/shell nanocrystals was additionally modified by silica. The properties of TbF3@CeF3 and TbF3@CeF3@SiO2 nanocrystals, formed in this way, were investigated. Spectroscopic studies showed that the differences between these two groups of products resulted from the presence of the SiO2 shell. X-ray diffraction patterns confirmed the trigonal crystal structure of TbF3@CeF3 nanocrystals. High resolution transmission electron microscopy in connection with energy- dispersive X-ray spectroscopy showed a complex structure of the formed nanocrystals. Crystallized as small discs, ‘the products’, with an average diameter around 10 nm, showed an increase in the concentration of Tb3+ ions from surface to the core of nanocrystals. In addition to photo-physical analyses, cytotoxicity studies were performed on HSkMEC (Human Skin Microvascular Endothelial Cells) and B16F0 mouse melanoma cancer cells. The cytotoxicity of the nanomaterials was neutral for the investigated cells with no toxic or antiproliferative effect in the cell cultures, either for normal or for cancer cells. This fact makes the obtained nanocrystals good candidates for biological applications and further modifications of the SiO2 shell

Children with monosymptomatic primary nocturnal enuresis - the clinical profile of patients during the first nephrological consultation

Introduction: Nocturnal enuresis can be diagnosed in a child older than 5 years of age who involuntarily discharges urine in the wrong time, i.e. at night, and in the wrong place, i.e. in bed. Aim: The aim of the study was to analyse the profile of patients who consult the specialist physician with monosymptomatic primary nocturnal enuresis. Material and methods: The data were collected from a questionnaire completed by guardians of children during the first nephrological consultation. The questions concerned the following: family history of nocturnal enuresis, bedwetting intensity, other urinary tract symptoms, a voiding chart and fluid intake record, number of nocturnal enuresis incidents in 14 days, episodes of nocturia, nocturnal diuresis volume, urinary urgency volume and constipation. Moreover, basic anthropometric measurements were taken. The data were analysed and the following values were calculated: average voided volumes, maximum voided volumes, voided volumes before 5 p.m. and 24-hour diuresis. An analogous analysis was conducted with respect to fluid intake. Results: Most patients were males. The family history of nocturnal enuresis was positive in ⅓ of patients. Approximately ⅓ of patients tended to drink fluids directly before bedtime. The number of patients with sporadic nocturnal enuresis (23–45%) was comparable to the number of patients with frequent nocturnal enuresis (28–55%). Nocturnal diuresis suggested nocturnal polyuria in 11 patients (21.6%). Decreased functional bladder capacity was found in almost ¼ of patients (12–23.5%). Conclusions: Monosymptomatic nocturnal enuresis is more common in boys. The family history was positive in ⅓ of patients. Patients and their guardians are not aware of fluid intake restrictions at bedtime. The frequency of nocturnal polyuria and decreased functional bladder capacity is comparable in the investigated patients

Hypertension treatment preferences in long-term dialysed children in Poland - a survey of pediatric nephrologists

Wstęp Przewlekła choroba nerek prowadzi do rozwoju nadciśnienia tętniczego u większości chorych. Leczenie nadciśnienia towarzyszącego niewydolności nerek jest utrudnione przez ograniczenia w stosowaniu wielu preparatów i brak wystarczających doświadczeń klinicznych, a ponadto istniejące obecnie rekomendacje nie obejmują w ogóle chorych ze schyłkową niewydolnością nerek. Wybór terapii hipotensyjnej ogranicza też młody wiek chorych, gdyż wielu leków nie można stosować u dzieci. Celem badania była analiza jakości leczenia przeciwnadciśnieniowego u dzieci ze schyłkową niewydolnością nerek poddawanych przewlekłej dializoterapii. Materiał i metody Analizą objęto wszystkie dzieci dializowane w Polsce w dniu 30 listopada 2004 roku (n = 134). Uzyskano informacje dotyczące grup stosowanych leków oraz dawek preparatów, a także opinie lekarzy na temat doboru leków stosowanych przy nagłym wzroście ciśnienia tętniczego oraz tych, których dzieciom dializowanym nie powinno się podawać. Wyniki Nadciśnienie tętnicze stwierdzono u 74 (55%) dzieci (47 chłopców, 27 dziewczynek). Najczęstszą przyczyną niewydolności nerek w grupie dzieci z nadciśnieniem było kłębuszkowe zapalenie nerek (27/74). W badanej grupie 65% dzieci leczono za pomocą kilku leków hipotensyjnych, 32% za pomocą jednego leku, a 3% jedynie metodami niefarmakologicznymi. Mimo aktywnego leczenia, zaledwie u 58% dializowanych dzieci prowadziło ono do obniżenia wartości ciśnienia tętniczego poniżej 95 percentyla dla wzrostu i wieku. Najmniejszą skuteczność kontroli ciśnienia tętniczego obserwowano w przypadku leczenia skojarzonego, zwłaszcza wielolekowego. Najczęściej stosowanymi lekami byli antagoniści wapnia, które podawano u ogółem 73% dzieci, w tym u 43/48 w politerapii, a 11/24 w monoterapii. Inhibitory konwertazy angiotensyny były najczęściej stosowane w monoterapii (50%). Mimo znanych kontrowersji, przy nagłym wzroście ciśnienia tętniczego stosowano najczęściej nifedipinę. Wnioski Badanie wykazało, że w Polsce odsetek dializowanych dzieci wymagających leczenia nadciśnieniowego sięga 55%, w tym większość z nich wymaga podawania kilku leków. Pomimo że zasady leczenia są podobne we wszystkich ośrodkach, skuteczność leczenia pozostaje niezadowalająca (58%).Background Chronic kidney disease is associated with the development of arterial hypertension in a vast majority of patients. The treatment of hypertension in these subjects is difficult and challenging due to a limited clinical experience with most drugs and no widely recognised recommendations for patients with end-stage renal disease. A choice of antihypertensive drugs is further narrowed by the young age of the patients since almost all drugs are not recommended in children with renal failure. The aim of this nationwide retrospective analysis was to assess the hypertension treatment patterns in the population of children with chronic kidney diseases (CKD) undergoing hemodialysis or peritoneal dialysis in Poland. Material and methods Among all 134 children dialysed on 30th November 2004 in 13 pediatric dialysis centres in Poland seventy four (55%; 47M, 27F) children were hypertensive. For each patients the treating physicians filled a questionnaire that allowed to collect the following data: the primary kidney disease, chronic dialysis treatment, diagnostic criteria of hypertension and present antihypertensive medication if any. Additionally we asked of the doctors’ preference for a therapy for the acute rise in blood pressure and suggestions which drugs, in their opinion, should not be used in dialysed children. Results In the hypertensive dialysed patients the most frequent causes of chronic kidney disease were chronic glomerulopathies (27/74). Thirty two percent of children were on monotherapy whereas 65% required combined treatment. The therapy was adequate only in 58% of subjects. The lowest rate of efficacy was detected in patients requiring a combined antihypertensive therapy. Among antihypertensive drug classes calcium channel blockers were administered most frequently (in 73% of children, in 11/24 cases in monotherapy and in 43/48 patients in combination). Angiotensin converting enzyme inhibitors were most frequently administered in monotheraphy (50%). Nifedipine was preferred in acute blood pressure rise in children. Conclusion We conclude that incidence of hypertension in dialysed children in Poland is relatively high. The pattern of the treatment was quite uniform, although the efficacy was relatively low (58%)

Hypertension treatment preferences in long-term dialysed children in Poland : a survey of pediatric nephrologists

Wstęp Przewlekła choroba nerek prowadzi do rozwoju nadciśnienia tętniczego u większości chorych. Leczenie nadciśnienia towarzyszącego niewydolności nerek jest utrudnione przez ograniczenia w stosowaniu wielu preparatów i brak wystarczających doświadczeń klinicznych, a ponadto istniejące obecnie rekomendacje nie obejmują w ogóle chorych ze schyłkową niewydolnością nerek. Wybór terapii hipotensyjnej ogranicza też młody wiek chorych, gdyż wielu leków nie można stosować u dzieci. Celem badania była analiza jakości leczenia przeciwnadciśnieniowego u dzieci ze schyłkową niewydolnością nerek poddawanych przewlekłej dializoterapii. Materiał i metody Analizą objęto wszystkie dzieci dializowane w Polsce w dniu 30 listopada 2004 roku (n = 134). Uzyskano informacje dotyczące grup stosowanych leków oraz dawek preparatów, a także opinie lekarzy na temat doboru leków stosowanych przy nagłym wzroście ciśnienia tętniczego oraz tych, których dzieciom dializowanym nie powinno się podawać. Wyniki Nadciśnienie tętnicze stwierdzono u 74 (55%) dzieci (47 chłopców, 27 dziewczynek). Najczęstszą przyczyną niewydolności nerek w grupie dzieci z nadciśnieniem było kłębuszkowe zapalenie nerek (27/74). W badanej grupie 65% dzieci leczono za pomocą kilku leków hipotensyjnych, 32% za pomocą jednego leku, a 3% jedynie metodami niefarmakologicznymi. Mimo aktywnego leczenia, zaledwie u 58% dializowanych dzieci prowadziło ono do obniżenia wartości ciśnienia tętniczego poniżej 95 percentyla dla wzrostu i wieku. Najmniejszą skuteczność kontroli ciśnienia tętniczego obserwowano w przypadku leczenia skojarzonego, zwłaszcza wielolekowego. Najczęściej stosowanymi lekami byli antagoniści wapnia, które podawano u ogółem 73% dzieci, w tym u 43/48 w politerapii, a 11/24 w monoterapii. Inhibitory konwertazy angiotensyny były najczęściej stosowane w monoterapii (50%). Mimo znanych kontrowersji, przy nagłym wzroście ciśnienia tętniczego stosowano najczęściej nifedipinę. Wnioski Badanie wykazało, że w Polsce odsetek dializowanych dzieci wymagających leczenia nadciśnieniowego sięga 55%, w tym większość z nich wymaga podawania kilku leków. Pomimo że zasady leczenia są podobne we wszystkich ośrodkach, skuteczność leczenia pozostaje niezadowalająca (58%).Background Chronic kidney disease is associated with the development of arterial hypertension in a vast majority of patients. The treatment of hypertension in these subjects is difficult and challenging due to a limited clinical experience with most drugs and no widely recognised recommendations for patients with end-stage renal disease. A choice of antihypertensive drugs is further narrowed by the young age of the patients since almost all drugs are not recommended in children with renal failure. The aim of this nationwide retrospective analysis was to assess the hypertension treatment patterns in the population of children with chronic kidney diseases (CKD) undergoing hemodialysis or peritoneal dialysis in Poland. Material and methods Among all 134 children dialysed on 30th November 2004 in 13 pediatric dialysis centres in Poland seventy four (55%; 47M, 27F) children were hypertensive. For each patients the treating physicians filled a questionnaire that allowed to collect the following data: the primary kidney disease, chronic dialysis treatment, diagnostic criteria of hypertension and present antihypertensive medication if any. Additionally we asked of the doctors’ preference for a therapy for the acute rise in blood pressure and suggestions which drugs, in their opinion, should not be used in dialysed children. Results In the hypertensive dialysed patients the most frequent causes of chronic kidney disease were chronic glomerulopathies (27/74). Thirty two percent of children were on monotherapy whereas 65% required combined treatment. The therapy was adequate only in 58% of subjects. The lowest rate of efficacy was detected in patients requiring a combined antihypertensive therapy. Among antihypertensive drug classes calcium channel blockers were administered most frequently (in 73% of children, in 11/24 cases in monotherapy and in 43/48 patients in combination). Angiotensin converting enzyme inhibitors were most frequently administered in monotheraphy (50%). Nifedipine was preferred in acute blood pressure rise in children. Conclusion We conclude that incidence of hypertension in dialysed children in Poland is relatively high. The pattern of the treatment was quite uniform, although the efficacy was relatively low (58%)

Generation of Pure Green Up-Conversion Luminescence in Er³⁺ Doped and Yb³⁺-Er³⁺ Co-Doped YVO₄ Nanomaterials under 785 and 975 nm Excitation

Materials that generate pure, single-color emission are desirable in the development and manufacturing of modern optoelectronic devices. This work shows the possibility of generating pure, green up-conversion luminescence upon the excitation of Er3+-doped nanomaterials with a 785 nm NIR laser. The up-converting inorganic nanoluminophores YVO4: Er3+ and YVO4: Yb3+ and Er3+ were obtained using a hydrothermal method and subsequent calcination. The synthesized vanadate nanomaterials had a tetragonal structure and crystallized in the form of nearly spherical nanoparticles. Up-conversion emission spectra of the nanomaterials were measured using laser light sources with λex = 785 and 975 nm. Importantly, under the influence of the mentioned laser irradiation, the as-prepared samples exhibited bright green up-conversion luminescence that was visible to the naked eye. Depending on the dopant ions used and the selected excitation wavelengths, two (green) or three (green and red) bands originating from erbium ions appeared in the emission spectra. In this way, by changing the UC mechanisms, pure green luminescence of the material can be obtained. The proposed strategy, in combination with various single-doped UC nanomaterials activated with Er3+, might be beneficial for modern optoelectronics, such as light-emitting diodes with a rich color gamut for back-light display applications

Gold Nanorods as a High-Pressure Sensor of Phase Transitions and Refractive-Index Gauge

The absorption peaks of surface plasmon resonance (SPR) in Au NRs are highly sensitive to their surrounding medium and to its refractive index (RI) changes. However, no applications of NRs for detecting phase transitions have been reported. Here we show that Au NRs effectively detect phase transitions of compressed compounds, liquid and solid, by measuring their RI. Owing to the direct interaction of the NRs with their surrounding medium, its subtle RI changes can be observed by the use of high-pressure absorption Vis-NIR spectroscopy.</b

Eu3+ and Tb3+ doped LaPO4 nanorods, modified with a luminescent organic compound, exhibiting tunable multicolour emission

Co-precipitation reaction followed by hydrothermal treatment were used to synthesise Eu3+ or Tb3+ doped LaPO4 nanorods, of 5–10 nm in width and 50–100 nm in length. Surface modification of the as-prepared nanoparticles with a selected luminescent organic compound resulted in formation of hybrid inorganic–organic nanomaterials. The products obtained exhibited tunable multicolour luminescence, dependent on the surface modification and applied excitation wavelength. The colour of their emission can be altered from red- orange to yellow-green. Powder X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM) confirmed the structure and morphology of the products synthesized. Successful surface modification of the nanophosphors was evidenced by analytical and spectroscopic techniques such as dynamic light scattering (DLS) – providing size distribution histograms and zeta potentials of the nanoparticles; IR spectroscopy and elemental analysis which proved the presence of an organic phase in the structure; spectrofluorometry (excitation/emission spectra and luminescence decay curves) which confirmed the formation of hybrid, surface modified nanomaterials revealing tunable multicolour emission