BazTech - Yadda

1

Immobilization with Ca–Alg@gelatin hydrogel beads enhances the activity and stability of recombinant thermoalkalophilic lipase

Yildiz Dalginli Kezban, Atakisi Onur

Chemical and Process Engineering : New Frontiers

|

2023

|

Vol. 44, nr 1

art. no. e2

EN

This study aims at the immobilization and characterization of thermoalkalophilic lipases produced recombinantly from Bacillus thermocatenulatus BTL2 and Bacillus pumilus MBB03. For this purpose, immobilization of the produced enzymes in calcium-alginate@gelatin (Ca–Alg@gelatin) hydrogel beads, immobilization optimization and characterization measurements of the immobilized-enzyme hydrogels were conducted. Optimum temperature and pH values were determined for B. thermocatenulatus and B. pumilus MBB03 immobilized-enzyme hydrogels (60–70 °C, 55 °C and pH 9.5, pH 8.5). Thermal stability was determined between 65 °C and 60 °C of B. thermocatenulatus and B. pumilus MBB03 immobilized enzymes, respectively. The pH stability was determined between pH 7.0–11.0 at +4°C and pH 8.0–10.0 at +4 °C, respectively. In conclusion, the entrapment technique provided controlled production of small diameter hydrogel beads (~ 0:19 and ~ 0:29) with negligible loss of enzyme. These beads retained high lipase activity at high pH and temperature. The activity of Ca–Alg@gelatin-immobilized lipase remained relatively stable for up to three cycles and then markedly decreased. With this enzyme immobilization, it may have a potential for use in esterification and transesterification reactions carried out in organic solvent environments. We can conclude that it is one of the most promising techniques for highly efficient and economically competent biotechnological processes in the field of biotransformation, diagnostics, pharmaceutical, food and detergent industries.

2

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

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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.

3

Biomimetic alginate/perfluorocarbon microcapsules - tthe effect on in vitro metabolic activity and long-term cell culture

Stefanek Agata, Kulikowska-Darłak Aleksandra, Bogaj Karolina, Nowak Aleksandra, Dembska Joanna, Ciach Tomasz

Chemical and Process Engineering

|

2022

|

Vol. 43, nr 1

81-–95

EN

Cell encapsulation seems to be a promising tool in tissue engineering. However, it has been shown to have several limitations in terms of long-term cell cultures due to an insufficient oxygen supply. In this study we propose the use of novel microcapsules designed for long-term cell culture consisting of an alginate shell and perfluorocarbon (PFC) core, which works as a synthetic oxygen carrier and reservoir. The influence of PFC presence in the culture as well as the size of structures on cell metabolism was evaluated during 21-day cultures in normoxia and hypoxia. We showed significant improvement in cell metabolism in groups where cells were encapsulated in hydrogel structures with a PFC core. The cells maintained a typical metabolism (oxidative phosphorylation) through all 21 days of the culture, overcoming the oxygen supply shortage even in large structures (diameter ¡ 1 mm). Applying PFC in alginate matrices can improve cell metabolism and adaptation in long-term cell cultures.

4

ZnO coatings ON Ti6Al4V substrate: structural and antibacterial properties in literature review and research

Sukhodub Leonid, Sukhodub Luidmila, Kumeda Mariia, Panda Anton, Baron Petr

Management Systems in Production Engineering

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2020

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nr 4 (28)

318--324

EN

ZnO, ZnO/Alginate coatings were obtained on the pre-anodized Ti6Al4V substrates by the thermal substrate deposition method (TSD). In the frame of this work, the TSD method was at first applied for obtaining ZnO coating from aqueous alginate-containing and alginate-free solutions on a metal surface. XRD, SEM analyses show that the biopolymer has a significant influence on the formation of the coating, their morphology, texture, structure of ZnO nanoparticles. The average rate of ZnO deposition from alginate containing solution is 30 μm/min, while from alginate-free solutions – 6 μm/min. In the presence of alginate, spherical particles with flower-shaped inclusions are formed, while from the polymer-free solution, single crystals in the form of tetrahedral were obtained. Zone of inhibition test against Gram-positive S. aureus ATCC 25923 and Gram-negative E. coli ATCC 25922 proves the antibacterial activity of the ZnO/Alg coatings.

5

Właściwości fizykochemiczne i funkcjonalne biokompozytów polimerowych

Wiśniewska-Wrona Maria, El Fray Mirosława

Polimery

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2019

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T. 64, nr 1

23--33

PL

Otrzymano błony biokompozytowe wytworzone na bazie chitozanu (Chit) i alginianu sodu (Alg) z udziałem substancji leczniczych o działaniu przeciwzapalnym (siarczan cynku) i przeciwbakteryjnym (sulfanilamid). Metodami spektrofotometrii w podczerwieni (FT-IR), magnetycznego rezonansu jądrowego (NMR) oraz różnicowej kalorymetrii skaningowej (DSC) oceniono wpływ zawartości chitozanu i alginianu na budowę chemiczną i temperaturę przemian fazowych biokompozytów. Analiza termiczna wykazała, że dodatek substancji leczniczych do materiałów biokompozytowych wpływa zarówno na obniżenie ich temperatury topnienia, jak i na zmniejszenie entalpii związanej z tą przemianą.

EN

Biocomposite films based on chitosan (Chit) and sodium alginate (Alg) and containing anti-inflammatory (zinc sulfate) and antimicrobial (sulfanilamide) pharmaceutical ingredients were prepared. The effects of variable chitosan and alginate contents on the chemical structure and phase transition temperatures of biocomposites were studied using infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC). Thermal analysis showed that the addition of pharmaceuticals decreased the melting temperature and melting enthalpy of polymer biocomposites.

6

The influence of storage conditions on the physicochemical properties and dimensional accuracy of the alginate impressions

Żelezińska K., Nowak M., Żmudzki J., Krawczyk C., Chladek G.

Journal of Achievements in Materials and Manufacturing Engineering

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2018

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Vol. 87, nr 2

68--76

EN

Purpose: Alginate impression materials are the most commonly used masses for taking impressions. They are characterized by good relation of properties to the price. However, the main problem associated with use of the impression masses is dimensions stability. Manufacturers of alginate masses recommend storage impression without any source of moisture, but dentists frequently store impressions wrapped in a wet materials. This may be the a reason of changes in dimensions and other properties. Moreover, it is recognized, that casting the model in the soon after making impression guarantee better dimensional accuracy. However, models are made usually after 24h. For some masses producers claim unequivocally, that the impressions can be stored for up to 168 h without changing the dimensions. So in this study was investigates how storage conditions affect chosen properties of alginate mass, including the accuracy of the models. Design/methodology/approach: Samples were prepared according to the manufacturer instruction and divided into 5 groups. Measurements were made 20 min after taking the impression and after 24h/168h of storage with/ without the resource of moisture. The measurements of Shore A hardness, tensile strength, mass changes and dimensional changes were made. Accuracies of the dental stone models were investigated with models manufactured after 20 min and 168 h after impressions, in comparison to the master model. Findings: The study showed that the storage conditions and time of storage had influence on properties of alginate impression mass. The resource of moisture has got an influence on dimensions and mass changes, tensile strength, elongation and shore A hardness. The results show that the use of the resource of moisture may be a cause of unfavourable changes in the gypsum model dimensions. Research limitations/implications: The storing of the alginate impressions with the resource of moisture is commonly practiced by the doctors, but it inconsistent with the manufacturer's recommendation. Practical implications: The method storing of the alginate impressions determined not only the materials properties, but also the clinical properties of final products like dentures. Originality/value: The significant of the method of the storing of alginate impression materials on the chosen properties of the materials and the accuracy of the dental stone models were shown.

7

Impact of sintering temperature of hydroxyapatite on biological and physicochemical properties of alginate/HA biomaterials for regenerative medicine applications

Kazimierczak P., Syta E., Sochan J., Ginalska G., Przekora A.

Engineering of Biomaterials

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2018

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Vol. 21, no. 145

16--19

EN

Synthetic hydroxyapatite (HA) has gained considerable attention in regenerative medicine over recent decades. It is widely used as a bone filler and constituent of various biomaterials. HA possesses high biocompatibility, osteoconductivity, bioactivity, and bioresorbability. There are many different synthesis methods for HA described in the available literature. It is worth noticing that even slight changes in pH, reaction conditions or chemical composition during synthesis, can influence biological, physicochemical, and mechanical properties of resultant HA. The aim of this study was to evaluate the impact of sintering temperature of hydroxyapatite on biological and physicochemical properties of biomaterial made of alginate and hydroxyapatite granules. Alginate/HA material was produced using HA sintered at temperature of 800oC and HA sintered at temperature of 1150oC. Microstructure of the fabricated biomaterials was visualized by SEM. Osteoblast growth on the composites was assessed using human foetal osteoblast cell line. Moreover, ion reactivity, plasma/serum protein adsorption ability as well as water/NaCl uptake capability of the biomaterials were compared. Obtained results demonstrated that although both biomaterials had the same chemical composition, composite comprising hydroxyapatite sintered at temperature of 1150oC had smoother surface, revealed lower ion reactivity, was more favourable to osteoblast growth, and adsorbed lower amount of fibrinogen (which is known to promote biomaterial-induced inflammatory response), compared to the material made of hydroxyapatite sintered at temperature of 800oC. Thus, the type of bioceramics used for the production of biomaterials should be tailored to their specific applications – bone fillers for primarily in vivo implantation or in vitro cell-seeded scaffolds.

8

Biosorption of Ni(II), Pb(II) and Zn(II) on calcium alginate beads: equilibrium, kinetic and mechanism studies

Nastaj J., Przewłocka A., Rajkowska-Myśliwiec M.

Polish Journal of Chemical Technology

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2016

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Vol. 18, nr 3

81-87

EN

The biosorption process of three divalent metal ions – nickel, lead and zinc- from on calcium alginate from aqueous solution was studied, in single component systems. The biosorbent were investigated by Fourier Transform Infrared Spectroscopy. The batch mode experiments of the adsorption process were carried out as a function of pH, initial metal ions concentration, sorbent dosage and contact time. The adsorption influencing parameters for the maximum removal of metal ions were optimized. The experimental data were analyzed using the Langmuir, Freundlich, Langmuir-Freundlich, Koble-Corrigan and Redlich-Peterson models. The kinetic data of biosorption process were evaluated using pseudo-first and pseudo-second order equations. The Weber and Morris model was employed to interpret the metal ions diffusion in biosorption process.

9

The mechanical properties of gelatin/alginate hydrogels

Skopińska-Wiśniewska J., Korkosz J., Sionkowska A.

Engineering of Biomaterials

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2016

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Vol. 19, no. 138 spec. iss.

49

10

Synteza i aplikacja nowych pochodnych wybranych polisacharydów. Cz. II, Badania laboratoryjne

Szuster L., Wyrębska Ł., Stawska H., Lasoń-Rydel M., Krępska M.

Technologia i Jakość Wyrobów

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2015

|

R. 60

5--12

PL

W artykule przedstawiono wyniki prac laboratoryjnych poświęconych syntezie i badaniu możliwości wytwarzania form aplikacyjnych pochodnych polisacharydów celem poprawy możliwości praktycznego ich zastosowania. Jako surowców użyto trzech naturalnych polisacharydów – chityny, chitozanu i alginianu sodu. Modyfikacja chemiczna miała na celu nadanie produktom wyższej od substratów rozpuszczalności, a tym samym łatwiejszej ich aplikacji. Polegała ona na zwiększeniu hydrofilowości poprzez reakcję otrzymywania fosforowych pochodnych chityny, biguanidynowania chitozanu, wytworzenia kompleksów polielektrolitowych chitozan/alginian oraz utworzeniu kopolimerów kwas mlekowy/chitozan. W przedstawionych badaniach opisano opracowany sposób syntezy tych pochodnych oraz możliwości wytwarzania ich form aplikacyjnych. Budowę otrzymanych związków potwierdzono spektrofotometrycznie widmami w podczerwieni. Wyniki przeprowadzonych badań nie odbiegają od wyników prezentowanych w literaturze. W części dotyczącej wniosków określono możliwości aplikacyjne otrzymanych pochodnych polisacharydów.

EN

The article presents the results of laboratory experiments on the synthesis of polysaccharides derivatives to increase the possibilities of their practical application. As substrates to the synthesis have been used three natural polysaccharides- chitin, chitosan and sodium alginate. This article describes in detail the methods of synthesis of polysaccharide derivatives, i.a. the formation of phosphate derivatives, polyelectrolyte complexation of chitosan-alginate and formation of chitosan/alginate copolymers. The chemical modification would result in a higher solubility of products and therefore easier application of them. The structure of products (polysaccharides derivatives) was confirmed by spectrophotometry infrared spectra and the results of experiments carried out do not differ from the results presented in the literature. It allows to determine the possibility of application of these compounds and conducting further researches in the future.

11

Temperature effect on properties of β-galactosidase entrapped in alginate matrix: an experimental research supported by molecular modeling

Labus K., Radosiński Ł., Kuchta B., Trusek-Hołownia A.

Inżynieria i Aparatura Chemiczna

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2015

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Nr 3

98--100

PL

Badania składały się z dwu części: eksperymentalnego wyznaczenia wpływu temperatury na właściwości immobilizowanej β-galaktozydazy oraz wstępnego modelowania dynamiki zmian w strukturze matrycy alginian-Ca2+ w zależności od temperatury na poziomie molekularnym. Na podstawie uzyskanych wyników można stwierdzić, że takie połączenie badań eksperymentalnych z symulacjami komputerowymi na poziomie cząsteczkowym pozwala na uzyskanie bardziej szczegółowej wiedzy na temat dynamiki układu, co w konsekwencji stwarza możliwość lepszej kontroli i optymalizacji procesu prowadzonego z wykorzystaniem immobilizowanego enzymu.

EN

The current study was separated into two parts: experimental study of temperature impact on activity and stability of immobilized β-galactosidase and preliminary modeling of changes generated in alginate-Ca2+ matrix with respect to temperature using molecular dynamics approach. On the basis of obtained results it can be stated that combination of experimental research and computer simulations on molecular level provides an additional insight greatly enhancing capabilities to control and optimize the process using immobilized biocatalyst.

12

Biomimetyczne matryce do przestrzennej hodowli komórek

Stefanek A, Ciach T.

Inżynieria i Aparatura Chemiczna

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2014

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Nr 4

294--295

PL

Celem badań było opracowanie biomimetycznej matrycy z nośnikiem tlenu do długoterminowej hodowli komórek. Przedstawiono wyniki wstępne obejmujące opracowanie warunków procesu produkcji dwufazowych matryc oraz przeprowadzenie hodowli ludzkich chondrocytów w uproszczonej matrycy. Przeprowadzone badania dowodzą, iż rozmiar produkowanych mikrokapsułek maleje wraz ze wzrostem częstotliwości drgań dyszy. Hodowla komórek CP5 wykazuje konieczność zwiększenia stopnia dotlenienia enkapsulowanych komórek.

EN

The purpose of this work was to develop biomimetic matrix with oxygen carrier for long-term cell culture. Preliminary research results including: microcapsules production conditions and results of human chondrocytes culture in simplified matrices are presented. The size of microcapsules decreases with the increase of nozzle vibration frequency. The chondrocytes culture showed that a greater oxygen supply to the cultured cells is needed.

13

Algi – przyszłość z morza

Kępska D, Olejnik Ł.

Chemik

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2014

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Vol. 68, nr 11

967--972

PL

Algi są organizmami fotosyntetyzującymi, prokariotycznymi albo eukariotycznymi. Ich komórki zawierają aminokwasy, witaminy, składniki mineralne, NNKT, aosainę,polifenole, kwasy o silnym działaniu nawilżającym i pobudzające krążenie krwi polisacharydy, a także β- karoten i karotenoidy. Ze względu na swój bogaty skład chemiczny, biomasa glonów znalazła zastosowanie w przemyśle spożywczym, farmaceutycznym i kosmetycznym. Preparaty z alg, stosowane jako suplementy diety i składniki środków upiększających, cechuje wysoka czystość chemiczna i efektywność działania. Do najlepiej poznanych polisacharydów alg należą: agar oraz alginian. Ponadto, prowadzone są badania dotyczące zastosowania alg jako źródła alternatywnej energii w postaci biopaliw, a także w procesie oczyszczania ścieków.

EN

Algae are photosynthetic prokaryotic or eukaryotic organisms. Their cells contain amino acids, vitamins, minerals, essential fatty acids, aosain, polyphenols, a potent moisturizing acids, polysaccharides, which are stimulating blood circulation, β-carotene and carotenoids. With such a rich chemical composition, biomass of algae has been used in food, pharmaceutical and cosmetic industries. Preparations of algae used as dietary supplements and beauty measures are characterized by high chemical purity and effectiveness. The best known algal polysaccharides are: agar and alginate. In addition, there is a research conducted on the use of algae as an alternative source of energy in the form of biofuels as well as in waste water treatment.

14

Evaluation of repair of osteochondral defects in rabbits using new composite biomaterials during three-month observation

Żylińska B., Stodolak-Zych E., Nowicka K., Silmanowicz P.

Engineering of Biomaterials

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2012

|

Vol. 15, no. 116-117 spec. iss.

118--119

EN

In this work nanocomposite porous pins were implanted into rabbit knees. The pins were made of biodegradable synthetic poly-L/DL-lactide (80:20) which was modified with nanometric hydroksyapatite particles (HAp) and covered with biopolymer layer of sodium alginate (NA). In vivo experiments were conducted on a 4-element group of the New Zealand rabbits. Osteogenesis was observed using scanning electron microscope (SEM/EDS) after 12 weeks of implantation.

15

Evaluation of repair of osteochondral defects in rabbits using new composite biomaterials during three-month observation

Żylińska B., Stodolak-Zych E., Nowicka K., Silmanowicz P.

Engineering of Biomaterials

|

2012

|

Vol. 15, no. 116-117 spec. iss.

141--143

EN

In this work nanocomposite porous pins were implanted into rabbit knees. The pins were made of biodegradable synthetic poly-L/DL-lactide (80:20) which was modified with nanometric hydroksyapatite particles (HAp) and covered with biopolymer layer of sodium alginate (NA). In vivo experiments were conducted on a 4-element group of the New Zealand rabbits. Osteogenesis was observed using scanning electron microscope (SEM/EDS) after 12 weeks of implantation.

16

Formation and preclinical evaluation of a new alloplastic injectable bone substitute material

Bojar W., Kucharska M., Bubak G., Ciach T., Koperski Ł., Jastrzębski Z., Gruber B.M., Krzysztoń-Russjan J., Marczewska J., Anuszewska E., Drozd E., Brynk T.

Acta of Bioengineering and Biomechanics

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2012

|

Vol. 14, no. 1

39-44

EN

Alloplastic bone substitute materials are raising some more interest as an alternative for autologic transplants and xenogenic materials especially in oral surgery over the last few years. These non-immunogenic and completely resorbable biomaterials are the basis for complete and predictable guided bone regeneration. In the majority of cases, such a material is chosen because of its convenient application by surgeons. The main objective of our project was to design and fabricate an osteoconductive, injectable and readily tolerable by human tissues biomaterial for guided bone regeneration. For this purpose, a self-setting composite consisting of chitosan/tricalcium phosphate microparticles and sodium alginate was made. The material obtained was characterized by microsphere and agglomerate morphology and microstructure. Its features relating to setting time and mechanical properties were precisely investigated. Our material was also evaluated according to PN-EN ISO 10993 Biological evaluation of medical devices, i.e., the in vitro tests for genotoxicity and cytotoxicity were conduced. Then, the following examinations were performed: subchronic systemic toxicity, skin sensitization, irritation and delayed-type hypersensitivity and local effects after implantation. The material tested showed a high degree of cytocompatibility, fulfilled the requirements of International Standards and seemed to be a "user friendly" material for oral surgeons.

17

Ocena własności fizycznych i biologicznych samoorganizującego się biomateriału otrzymanego z chitozanu/fosforanu wapnia/alginianu do zastosowań stomatologicznych

Kucharska M., Bubak G., Kowalczyk M., Bojar W., Brynk T., Koperski Ł., Ciach T.

Engineering of Biomaterials

|

2011

|

Vol. 14, no. 105

20-24

PL

Celem niniejszej pracy było zaprojektowanie i otrzymanie wstrzykiwalnego biomateriału o własnościach osteokondukcyjnych, który potencjalnie mógłby znaleźć zastosowanie w procesach augmentacji kości przed leczeniem implantologicznym z wykorzystaniem sterowanej regeneracji kości (GBR). W tym celu opracowano samoorganizujący się biomateriał otrzymany z granulatu chitozan/fosforan trójwapnia oraz soli sodowej kwasu alginowego (CH/TCP/Alg). Opracowany materiał przebadano pod względem morfologii i mikrostruktury, zarówno granulatu, jak i uformowanych aglomeratów. Własności fizyczne, takie jak czas żelowania oraz wytrzymałość mechaniczna na ściskanie były przedmiotem niniejszych badań. Przeprowadzono także testy in vivo opracowanego biomateriału na modelu szczura. Dokonano oceny odpowiedzi modelu zwierzęcego na zaimplantowany biomateriał, a wyniki porównano z alloplastycznym materiałem komercyjnie dostępnym. Otrzymane wyniki wskazały, że opracowany wstrzykiwalny system spełnia wymagania pod kątem zastosowań w sterowanej regeneracji kości.

EN

The main objective of the work was to design and fabricate an injectable biomaterial with osteoconductive properties for bone augmentation and potential to be used in dental applications in peri-implant therapy concerning guided bone regeneration. For this purpose, a self-setting biomaterial consisting of chitosan/ tricalcium phosphate microparticles and sodium alginate was formulated (CH/TCP/Alg). The obtained material was characterized as far as microsphere and formed agglomerates morphology and microstructure. Physical properties relating to setting time and mechanical properties were also investigated. Finally, in vivo response to implanted biomaterial was studied on rat model and compared with commercially available alloplastic material. The obtained results showed that designed injectable biomaterial fulfilled main requirements for guided bone regeneration application.

18

Ewaluacja procedury alginanowo-chitozanowo-alginanowej enkapsulacji chondrocytów

Wasiak I., Ciach T.

Engineering of Biomaterials

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2011

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Vol. 14, no. 106-108

167--171

PL

Celem niniejszej pracy była ewaluacja mikroenkapsułek otrzymanych z warstw alginianowo-chitozanowo-alginianowej (ACA) jako matrycy do unieruchamiania chondrocytów. Przygotowanie ACA mikroenkapsułek obejmuje przygotowanie kapsułek z alginianu wapnia, adsorpcji dodatnio naładowanego chitozanu na ich powierzchni, tworząc w ten sposób alginianowo-chitozanową membranę, i ostatecznie wytworzenie wierzchniej alginianowej warstwy. Zbadano własności otrzymanych mikrokapsułek, między innymi ich właściwości mechaniczne, porowatość i szybkość dyfuzji substancji małocząsteczkowej. Kapsułki alginianowe otrzymano za pomocą elektrostatycznej metody generowania kropli. Technika ta wykorzystuje wytłaczanie roztworu alginianu w połączeniu z siłami elektrostatycznymi, które zakłócają powierzchnię cieczy na końcu kapilary / igły, tworząc strumień małych kropelek. Prowadzi to do produkcji jednolitych kulek o małej średnicy.

EN

The objective of this paper was to verify microcapsules obtained from alginate-chitosan-alginate (ACA) system as a matrix for chondrocytes immobilization. Preparation of ACA microencapsules includes formation of the calcium alginate beads, adsorption of a positively charged chitosane on their surface, to form alginate – chitosane membrane, and finally coating with alginate. Properties of obtained microcapsules, their mechanical properties, porosity and diffusion rate were investigated. Electrostatic droplet generation method was employed for microbeads production. This technique employs extrusion combined with electrostatic forces to disrupt a liquid surface at the capillary/needle tip, forming a charged stream of small droplets. This leads to the production of uniform small-diameter beads.

19

Wyznaczanie efektywnego współczynnika dyfuzji soli kadmu w biosorbencie alginianowym

Kwiatkowska-Marks S., Kopinski L., Wójcik M.

Ekologia i Technika

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2011

|

R. 19, nr 1

3-10

PL

Sorpcja na materiałach pochodzenia biologicznego jest uznawana za jedną z najbardziej obiecujących technik usuwania metali ciężkich ze ścieków. Bardzo efektywnymi biosorbentami jonów metali ciężkich są alginiany, (odnosi się to szczególnie do rozcieńczonych roztworów wodnych) , a ich dodatkową zaletą jest możliwość ponownego użycia po regeneracji. Przez odpowiednią obróbkę można otrzymać żele alginianów w postaci kulistych granulek. Szybkość sorpcji jonów metali ciężkich na granulkach alginianowych jest z reguły limitowana szybkością dyfuzji wewnętrznej, którą charakteryzuje efektywny współczynnik dyfuzji De. Istniejące metody wyznaczania De związane są ze stosowaniem pracochłonnych procedur analitycznych przy pomiarze stężenia jonów metali ciężkich. Opracowano nową metodę wyznaczania efektywnego współczynnika dyfuzji metali ciężkich w granulkach biosorbentu, która polega na zastosowaniu konduktometru do wyznaczania zmian stężenia danego metalu w roztworze i powiązaniu tych pomiarów z efektywnym współczynnikiem dyfuzji. Do badań używano alginianu sodu o niskiej lepkości, pochodzącego z firmy Sigma-Aldrich. Granulki alginianowe otrzymano przez wkraplanie roztworu biopolimeru do 0,05M chlorku wapnia, uzyskując granulki alginianu wapnia o zawartości alginianu: 1,5, 3,7 i 5,7% suchej masy. Otrzymane granulki zanurzano w O, IM roztworze siarczanu lub chlorku kadmu w celu zastąpienia jonów wapniowych kadmowymi. Badania prowadzono w układzie zamkniętym w stałej temperaturze 25°C. Sole kadmu znajdujące się w porach granulek alginianowych dyfundowały do wody destylowanej, a o szybkości procesu decydował efektywny współczynnik dyfuzji. Wzrost stężenia soli kadmu w roztworze prowadził do wzrostu przewodnictwa, które mierzono w odpowiednich odstępach czasu, używając konduktometru CPC-551 firmy Elmetron. Wyznaczony nową metodą efektywny współczynnik dyfuzji De soli kadmu w granulkach alginianowych wynosił od 0,37 do 0,73-10-9 [m2/s]. Wzrost zawartości alginianu w granulkach prowadził do zmniejszenia się wartości De i współczynnika spowolnienia, zgodnie z mechanizmem dyfuzji w porowatych nośnikach.

EN

Sorption by material of biological origin is recognized as an emerging technique for elimination of heavy metals from polluted streams. Very effective biosorbents of heavy metal ions are alginates, especially in the case of the diluted aqueous solutions. The alginate gels are obtained in the form of spherical beads by a suitable treatment. The rate of the heavy metal ions sorption by alginate beads is as a rule limited by the rate of internal diffusion characterized by the effective diffusivity De. Commonly used methods of De determination apply the labour-consuming procedures allowing to measure the heavy metal ions concejitration. In this work a method was developed which depends on using a con-ductometer to determine the changes of cadmium salts concentrations in solution and connection of these determinations with effective diffusivity. Sodium alginate purchased from Sigma-Aldrich was used in preparation of alginate biosorbent. In the first step the calcium alginate beads were obtained by dripping the sodium alginate solution into 0.05M CaCl2. By this procedure biosorbent beads of three different concentrations (1.5, 3.7 and 5.7% w/w) were prepared. In the next step the beads were soaked in 0.1 M CdSO4or CdCl2 solutions to replace calcium with cadmium ions. The determination of effective diffusity was carried out in a closed system, at a constant temperature 25°C. Cadmium salts diffused from the pores of beads to distilled water and the process was limited by diffusion. The increase of CdSO4 or CdCl2 concentration in solution causes the increase of conductivity. At selected time intervals conductMry of sołution was measured by microcomputer conductometer CPC-551 from Elmetron. These data were used for calculation of effective diffusivity De which ranged from 0,37-10 9 to 0,73-10 9 [m2/s]. The effective diffusivity decrease with the increase of alginate concentration. It is in accordance with a mechanism of diffusion in porous carriers.

20

Kinetics of Releasing Herbicide Metazachlor from Hydrogel Microcapsules to Aquatic Environments

Włodarczyk M.

Ecological Chemistry and Engineering. A

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2011

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Vol. 18, nr 8

1147-1156

EN

Formulation of metazachlor in the form of hydrogel capsules was carried out in the Packaging and Biopolymers Center at the West Pomeranian University of Technology in Szczecin. To produce the hydrogel matrix sodium alginate was used in 1.5 % solution. Kinetics of releasing metazachlor from the matrix was carried out for various aquatic environments (distilled water Wd and two natural waters W1 and W2) at 4 1 oC and 20 1 oC under laboratory condition. The release data were fitted to the generalized model proposed by Ritger and Peppas. For all the combinations in study, the high values of the correlation coefficient R (from 0.9254 to 0.9997) show a very good adjustment between the experimental data and the model applied. It was found that amount of metazachlor released from the capsules to water increased exponentially in time and depended on type of the aquatic environment and temperature of storage. For metazachlor, the highest values of time T50, were recorded for the distilled water. For the natural waters, time T50 is significantly shorter, and, comparing with the distilled water, it was decreased by 83–90 % at 20 oC and by 69–96 % at 4 oC.

PL

W badaniach wykorzystano hydrożelowe mikrokapsułki herbicydu metazachlor otrzymane w Zakładzie Opakowalnictwa i Biopolimerów Zachodniopomorskiego Uniwersytetu Technologicznego w Szczecinie. Badania kinetyki uwalniania przeprowadzono w warunkach laboratoryjnych, w różnych środowiskach wodnych (woda destylowana Wd, dwie wody powierzchniowe W1, W2) w temperaturze 4 oC 1 i 20 oC 2. Kinetykę uwalniania metazachloru do środowiska wodnego z hydrożelowych mikrokapsułek opracowano, wykorzystując model matematyczny zaproponowany przez Ritgera i Peppasa. Uzyskane dla wszystkich analizowanych kombinacji duże wartości współczynnika korelacji R od 0,9254 do 0,9997 wskazują na bardzo dobre dopasowanie danych eksperymentalnych z zastosowanym modelem. Stwierdzono, iż ilość uwolnionego metazachloru z hydrożelowych mikrokapsuł do środowiska wodnego wzrasta wykładniczo w czasie i zależy od rodzaju środowiska wodnego i temperatury przechowywania. Otrzymane czasy T50 pozwalają na stwierdzenie, iż szybkość uwalniania metazachloru zależy zarówno od temperatury procesu, jak i właściwości fizykochemicznych wód. Największe wartości czasu T50 metazachloru, w przypadku obu temperatur, uzyskano dla wody destylowanej. Uzyskany dla wód naturalnych czas T50 herbicydu jest znacznie niższy i uległ zmniejszeniu o 83-90 % w temp. 20 oC i o 69-96 % w temp. 4 oC.