PL
 |
EN
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 13

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  dextran
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available Hydrogel microspheres containing dextran-based nanoparticles as novel anticancer drug delivery system
Kulikowska-Darłak Aleksandra, Stefanek Agata, Wasiak-Wojasińska Iga, Wiechecka-Ożdżyńska Paulina, Ciach Tomasz
Chemical and Process Engineering
|
2022
|
Vol. 43, nr 3
405-–417
EN
Developing an effective and safe cancer therapy could significantly reduce the number of deaths and improve the quality of life of treated patients. Nowadays medicine has developed a wide range of anticancer chemotherapeutics but at the same time there is a lack of effective drug delivery methods. Therefore, the development of the targeted drug delivery system which will selectively release drug into the cancer cells is a key challenge of modern medicine. The main aim of the presented research was to investigate the targeting effect of a drug delivery system based on the controlled release of dextran nanoparticles containing the anticancer drug – doxorubicin from the alginate microspheres coated with chitosan multilayers. During the research the physicochemical properties of the alginate microspheres and its stability in the physiological environment were investigated. Moreover, the kinetics of the nanoparticles with doxorubicin release from the alginate microspheres covered with chitosan multilayers was characterized, depending on the thickness of the chitosan layer. Further, the cytotoxicity study of the alginate microspheres covered with chitosan multilayer and containing nanoparticles was performed to determine the therapeutic effect of the released nanoparticles with doxorubicin on the HeLa cells during the in vitro cell culture.
2
Content available Engineering of dextran-based matrices for soft tissue regeneration
Szafulera K. J., Wach R. A., Ulański P.
Engineering of Biomaterials
|
2018
|
Vol. 21, no. 148
77
3
Content available Egzopolisacharydy bakteryjne : budowa i funkcje
Samaszko-Fiertek J., Kuźma M., Dmochowska B., Ślusarz R., Madaj J.
Wiadomości Chemiczne
|
2016
|
[Z] 70, 7-8
473--496
EN
Exopolysaccharides fulfil protective functions and allow bacteria live in the communities, single or mixed, by facilitating adhesion to surfaces and to each other. Microbes prefer to exist in the form of a biofilm. The term biofilm was introduced in 1978 and is the group of microorganisms surrounded by extracellular, highly hydrated mucus, which allows adhesion on various surfaces and adhesion of cells to each other [1]. The extracellular slime owes its character mainly due to the presence of exopolysaccharides. Bacteria living in biofilms, have a high resistance to external factors, such as changes in temperature, pH, humidity, oxygenation, presence of bacteriocins, antibodies or antibiotics. They may be up to 1,000 times more resistant to antibiotics than planktonic forms. They can be synthesized inside and outside bacteria cell. The structure of the bacterial exopolysaccharide is very diverse, but very often, due to the presence of uronic acid residues, or non-sugar organic acids as pyruvic acid, succinic acid, as well as residues of inorganic acids such as phosphoric acid or sulfuric acid, they are negatively charged particles. In addition, a characteristic of most of the exopolysaccharides (EPS) is their enormous molecular mass of up to several million g/mol [11]. Thanks to its rheological properties, ease of isolation, and often biodegradable antioxidant activity extracellular polysaccharides are increasingly used in industry as a gelling agents, hardening and thickening agents, emulsifiers, food coatings and pharmaceutical products. In addition, they can be used as bandages, anti-cancer agents, cholesterol-lowering, antiulcer or immunomodulators [20–27]. This article discusses in details the selected exopolysaccharides such as xanthan, gellan, exopolysaccharides of lactic acid bacteria, dextran, bacterial cellulose, alginic acid, hyaluronic acid, mannans.
4
Content available remote Dekstran i jego pochodne w inżynierii tkanek miękkich - opatrunki do leczenia ran trudno gojących się
Szafulera K.
Eliksir
|
2016
|
nr 1
32--37
5
Content available Nanocząstki magnetytu pokryte polimerami do zastosowań biomedycznych. Cz. I. Otrzymywanie nanocząstek Fe304 z powłokami z polisacharydów
Chełminiak D., Ziegler-Borowska M., Kaczmarek H.
Polimery
|
2015
|
T. 60, nr 1
12—17
PL
Artykuł stanowi przegląd literatury z ostatnich lat dotyczącej nanocząstek magnetycznych powlekanych różnymi polimerami, wykorzystywanych w wielu dziedzinach, głównie w biologii i medycynie. Przedstawiono metody otrzymywania Fe3O4 w postaci nanocząstek, modyfikacje ich powierzchni za pomocą polisacharydów (chitozan, dekstran), właściwości oraz różne zastosowania takich układów.
EN
This article is a review of the literature from the last years concerning magnetic nanoparticles coated with various polymers, which are widely used in many reseach fields, mainly in biology and medicine. The methods of preparation and surface modification of Fe3O4 nanoparticles as well as the properties and applications of magnetic nanoparticles coated by polysaccharides (chitosan, dextran) are described.
6
Content available Rozpuszczalne w wodzie kopolimery dekstran-poliakryloamid i ich pochodne anionowe jako matryce w syntezie in situ nanocząstek metali
Bezugly M., Kutsevol N., Rawiso M., Bezugla T.
Chemik
|
2012
|
Vol. 66, nr 8
862-867
PL
Przeprowadzono syntezę nanocząstek metali w matrycach wodorozpuszczalnych polimerów o różnej wewnętrznej budowie makromolekularnej. Liniowy poliakryloamid (PAA) i rozgałęzione gwiaździste kopolimery dekstran-szczepiony poliakryloamid (D-g-PAA) i ich pochodne anionowe zastosowano do syntezy in-situ nanoukładów Ag i Pd. Zbadano wpływ charakteru matrycy i budowy wewnętrznej makrocząsteczek w roztworze na tworzenie nanocząstek.
EN
Metal nanoparticles were synthesized in water-soluble polymer matrices with different internal macromolecule structures. Linear Polyacrylamide (PAA) and branched star-like copolymers Dextrangraft- Polyacrylamide (D-g-PAA) and their anionic derivatives were used for in situ synthesis of Ag and Pd nanosystems. The influence of the matrix nature and internal structure of macromolecules in solution on the nanoparticles formation was studied.
7
Content available Preparation of silver core nanoparticles with polysaccharide shell
Wasiak I., Ciach T.
Challenges of Modern Technology
|
2012
|
Vol. 3, no. 2
15--17
EN
The objective of the present study was to obtain silver core nanoparticles coated with dextran shell. In the described method dextran plays role of reductive and protective agent and also functionalisation ligand. Our research was aimed at nanoparticles synthesis at 37°C. It is the human body temperature, which is safe for temperature-sensitive drugs (proteins). In the presented work the time of reaction, dextran molecular weight and its chemical functionalisation was investigated. Particles were characterized by Nanosight and SEM, their UV–Vis spectroscopic absorption properties were also determined. Nanoparticles with diameter less than 95 nm with relatively narrow size distribution were obtained. Our work demonstrated that it was possible to obtain nanoparticles in 37°C without using any harmful reagents.
8
Content available Improvement of enzyme stability via non-covalent complex formation with dextran against temperature and storage lifetime
Altikatoglu M., Kuzu H.
Polish Journal of Chemical Technology
|
2010
|
Vol. 12, nr 1
12-16
EN
The optimal methodology to prepare the novel modified enzyme, polymer-enzyme complex, was developed to give a high catalytic activity in aqueous solution. The non-covalent complexes of two different enzymes (horseradish peroxidase and glucose oxidase) were prepared with various molar ratios (nD/nE 0,05; 0,1; 1; 5; 10; 15; 20) by using 75kDa dextran. The thermal stabilities of the obtained complexes were evaluated with the activities determined at different temperatures (25, 30, 35, 40, 50, 60, 70, 80°C) applying 60 minutes incubation time for pH 7. The complexes with the molar ratio nD/nHRP: 10 and nD/nGOD: 5 showed the highest thermal stability. Its activity was very high (ca. 1,5-fold higher activity than pure enzyme for HRP-dextran complexes) and almost the same between applying one hour incubation time and without incubation, and could also be measured at high temperatures (70, 80 °C). We finally succeeded in preparing dextran-enzyme complexes which showed higher activity than pure enzyme in aqueos solution at all temperatures for pH 7. In addition, the mentioned complexes at pH 7 had very long storage lifetime compared to purified enzyme at +4 °C; which is considered as a good feature for the usage in practice.
9
Content available remote Optical properties of deposit of red blood cells suspended in dextran solutions
Strzelecka J., Bosek M., Grzegorzewski B.
Optica Applicata
|
2010
|
Vol. 40, nr 1
177--185
EN
The optical properties of the deposit of red blood cells (RBCs) formed during sedimentation have been investigated. The human blood was obtained from healthy donors. RBCs were suspended in isotonic saline containing Dextran 70 of concentrations 2, 4 and 6 g/dl. Hematocrit of the samples was adjusted to 40%. The intensity of the light scattered by the samples of the RBC suspensions as a function of time and altitude from the bottom of a sample was measured. The region occupied by forming and sedimenting aggregates and the region occupied by deposit of the cells can be found in the sample and the temporal dependence of position of the interface separating both regions, called the deposit formation curve, can be determined. This curve exhibits the growth phase and the packing phase. We have obtained the mean intensity of light scattered by the deposit as a function of time. This intensity exhibits a monotonous decay with time over the growth as well as the packing phase, what shows that packing of the deposit occurs in the same way in both phases. The dependence from time of the mean hematocrit of the deposit was determined. We have introduced an empirical expression describing this dependence. Finally, using this dependence, we have obtained the mean intensity of light scattered by the deposit as a function of hematocrit. We have shown that this intensity follows an exponential decay. The values of an optical parameter of the deposit were found from this dependence.
10
Content available Flocculation properties of Dextran-graft-Polyacrylamide of various internal structure
Kutsevol N., Bezuglyi M., Vysotska V.
Ecological Chemistry and Engineering. A
|
2009
|
Vol. 16, nr 1-2
127-133
EN
Two series of Dextran-graft-Polyacrylamide copolymers (D-g-PAA) with polysaccharide backbone having different molecular weights (Mw= 20 000 and Mw= 70 000) and willi 5, 10, 15 or 20 PAA-grafts per one Dextran macromolecule were tested as flocculation aids in the model kaolin suspensions. These copolymers have shown high flocculation efficiency significantly dependent upon their internal structure. The flocculation ability or D-g-P AA samples with the same number or P AA-grafts inversely relates to the spacing or the grafts (ie the length or back-bone between the grafts).
PL
Badano właściwości flokulacyjne kopolimerów dekstran-graft-poliakryloamidowych (DG-PAA) ze szkieletem dekstranowym o dwóch różnych masach molekularnych (Mw = 20 000 i Mw = 70 000) oraz z 5, 10, 15 lub 20 molekułami PAA dołączonymi (zaszczepionymi) do tego makromolekularnego szkieletu. Do pomiarów wykorzystywano zawiesinę kaolinu w wodzie. Kopolimery te miały dużą skuteczność flokulacyjną zależną od ich struktury molekularnej. Zdolność flokulacyjna próbek D-g-PAA, z taką samą liczbą zaszczepionych molekuł P AA, jest odwrotnie proporcjonalna do odległości między molekułami zaszczepionymi do szkieletu molekuły dekstranu.
11
Badania procesu mikrofiltracji roztworów substancji wielkocząsteczkowych z zastosowaniem membran nieorganicznych
Gabruś E., Szaniawska D.
Inżynieria i Aparatura Chemiczna
|
2006
|
Nr 5s
45-46
EN
Microfiltration data experimentally obtained for α-Al2O3TiO2 membrane and 0.05 wt% solutions of dextran 110 and 500 kD are reported. The experimental data are discussed in terms of concentration polarization models, i.e. resistance-in-series model, film theory model, modified film theory model and the Sherwood correlation.
12
Novel polymeric photosensitizer based on dextran
Sterzel M., Szczubiałka K., Nowakowska M.
Zeszyty Naukowe. Chemia / Politechnika Śląska
|
2001
|
z. 146
267-270
EN
A new polymeric photosensitizer, hydrophobically-modified dextran (DEX-ICN), was synthesized and studied. The hydroxyl groups in dextran have been substituted using 1-naphthyl isocyanate. The modified dextran was characterised by IR, UV - Vis and fluorescence spectroscopies , and by GPC chromatography. Photophysical and photochemical properties of DEX-ICN were investigated. The polymer was found as being able to solubilize hydrophobic compounds such as perylene. The DEX-ICN was then tested as the photosensitizer for photodegradation of pesticide paraoxon-ethyl (POE). The effective quenching of DEX-ICN fluorescence by POE and the rate of photosensitized degradation of POE by the polymer proved that hydrophobically-modified dextran can be an efficient photosensitizer in the processes of photodegradation of environmental pollutants.
13
Content available remote The application of thin-layer chromatography for the determination of dextran used as a marker of dialyzate volume in peritoneal dialysis
Błądek J., Rostkowski A., Baczyński D., Wańkowicz Z., Witkiewicz Z.
Chemia Analityczna
|
1999
|
Vol. 44, No. 6
985-991
EN
Dextran is used as a non-isotopic marker of intraperitoneal volume of dializate useful for the investigation of transperitoneal transport. The initial results of TLC application for the determi11ation of dextran concentration in dialysis solutions in vitro and in witro under conditions of clinical dialysis are demonstrated. The correctness of sample preparatio11 for analysis, the limit as well as the error of determi11ation were estimated.
PL
Dextran zastosowano jako nieizotopowy znacznik objętości wewnątrzotrzewnowej płynu dializacyjnego przydatny do badań transportu przezotrzewnowego. Przedstawiono wstępne wyniki badań nad wykorzystaniem TLC do oznaczania stężenia dekstranu w płynie dializacyjnym in vitro i in vitro, w warunkach klinicznej wymiany dializacyjej . Oceniono poprawność przygotowania próbek do analizy, graniczną oznaczalność i błąd oznaczeń.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.