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001-es BibID:BIBFORM116532
035-os BibID:(WoS)001070439900001 (Scopus)85169291237 (cikkazonosító)105702
Első szerző:Benea, Ioana Cristina
Cím:Biocatalytic synthesis of new polyesteramides from ?-caprolactam and hydroxy acids: Structural characterization, biodegradability, and suitability as drug nanocarriers / Ioana Cristina Benea, Izolda Kántor, Anamaria Todea, Alessandro Pellis, Ioan Bîtcan, Lajos Nagy, Sandor Kéki, Diana Maria Dreavā, Francisc Péter, Tivadar Feczkó
Dátum:2023
ISSN:1381-5148
Megjegyzések:The synthesis of polyesters and polyamides by enzyme-catalyzed processes in vitro was developed in the last decades as a green alternative to obtain biodegradable synthetic polymers with various applications, such as nanoparticle-sized carriers for drug delivery. Polyesteramides were much less studied in this respect, although having the presumable advantage of increased mechanical and thermic resistance brought by the amide moieties. In this work, polyesteramides were synthesized for the first time employing as raw materials epsilon-caprolactam and a hydroxy acid. L-malic, 3-hydroxybutyric, 12-hydroxystearic and 16-hydroxyhexadecanoic acid, respectively, were investigated as co-monomers in solventless or organic medium, using the immobilized lipase Novozyme 435 as catalyst. The short chain hydroxy acids holding secondary hydroxyl groups yielded oligomers with average degree of polymerization no higher than 4, while in the case of the long-chain 12-hydroxystearic acid this value increased to 7. The best results were achieved by using 16-hydroxyhexadecanoic acid in 2:1 M excess at 80. C, yielding a product with 75% copolymer content and average molecular weight higher than 3000 Da. The emulsion-solvent evaporation method allowed the efficient production of nanoparticles based on this copolymer, with sizes around 230 nm, used for the encapsulation of a model bioactive compound, the anticancer drug sorafenib. Production yields of >70% and encapsulation efficiencies of around 60% are very promising for further development of this approach.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Polyesteramide
Biocatalysis
Lipase
Polymer nanoparticle
Encapsulation
Megjelenés:Reactive & Functional Polymers. - 191 (2023), p. 1-17. -
További szerzők:Kántor Izolda Todea, Anamaria Pellis, Alessandro Bîtcan, Ioan Nagy Lajos (1979-) (vegyész) Kéki Sándor (1964-) (polimer kémikus) Dreava, Diana-Maria Péter, Francisc Feczkó Tivadar
Pályázati támogatás:TKP2021-EGA-20
Egyéb
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DOI
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2.

001-es BibID:BIBFORM089704
035-os BibID:(cikkazonosító)1928 (WoS)000581332400001 (Scopus)85090594322
Első szerző:Czifrák Katalin (vegyész)
Cím:Block Copolymers of Poly(omega-Pentadecalactone) in Segmented Polyurethanes : Novel Biodegradable Shape Memory Polyurethanes / Katalin Czifrák, Csilla Lakatos, Marcell Árpád Kordován, Lajos Nagy, Lajos Daróczi, Miklós Zsuga, Sándor Kéki
Dátum:2020
ISSN:2073-4360
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
copolymerization
pentadecalactone
poly(omega-pentadecalactone)
polyurethane copolymers
shape memory
Megjelenés:Polymers. - 12 : 9 (2020), p. 1-17. -
További szerzők:Lakatos Csilla (1990-) (környezetmérnök) Kordován Marcell Árpád (1994-) (okleveles vegyészmérnök) Nagy Lajos (1979-) (vegyész) Daróczi Lajos (1965-) (fizikus) Zsuga Miklós (1944-) (polimer kémikus) Kéki Sándor (1964-) (polimer kémikus)
Pályázati támogatás:GINOP-2.3.2-15-2016-00041
GINOP
GINOP-2.3.3-15-2016-00021
GINOP
Internet cím:Szerző által megadott URL
DOI
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3.

001-es BibID:BIBFORM099589
Első szerző:Kéki Sándor (polimer kémikus)
Cím:New types of α-amylase enzyme-inhibitory polysaccharides from d-glucal / Kéki Sándor, Batta Gyula, Bereczki Ilona, Fejes Zsolt, Nagy Lajos, Zajácz Ágnes, Kandra Lili, Kiricsi Imre, Deák György, Zsuga Miklós, Herczegh Pál
Dátum:2006
ISSN:0144-8617
Megjegyzések:We describe the synthesis of new types of a-amylase enzyme-inhibitory polysaccharides obtained by polycondensation of 3,6-Di-O-acetyl-Dglucal followed by deacetylation. The structure of the resulting new polysaccharides containing unique 2,3-unsaturated hexopyranose repeating units were unambiguously determined by NMR and MALDI-TOF MS methods. The deacetylated polysaccharides proved to be a semicompetitive inhibitor of the human salivary amylase enzyme.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Ferrier rearrangement
Unsaturated glycals
Polycondensation
NMR
MALDI-TOF MS
Megjelenés:Carbohydrate Polymers. - 63 : 1 (2006), p. 136-140. -
További szerzők:Batta Gyula (1953-) (molekula-szerkezet kutató) Bereczki Ilona (1981-) (vegyész, antibiotikumkémikus) Fejes Zsolt (1977-) (vegyész) Nagy Lajos (1979-) (vegyész) Zajácz Ágnes Kandra Lili (1943-) (biokémikus) Kiricsi Imre (1946-) (vegyész) Deák György (1954-) (polimer kémikus) Zsuga Miklós (1944-) (polimer kémikus) Herczegh Pál (1947-) (vegyész, antibiotikumkémikus)
Pályázati támogatás:T 42512
OTKA
T 42740
OTKA
T 37448
OTKA
T 42567
OTKA
NKFP 3/A0036/2002
Egyéb
RET 006/2004
Egyéb
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4.

001-es BibID:BIBFORM104056
035-os BibID:(WoS)000480531700080 (Scopus)85066821056 (cikkazonosító)825
Első szerző:Nagy Lajos (vegyész)
Cím:Designed Polyurethanes for Potential Biomedical and Pharmaceutical Applications : Novel Synthetic Strategy for Preparing Sucrose Containing Biocompatible and Biodegradable Polyurethane Networks / Lajos Nagy, Miklós Nagy, Bence Vadkerti, Lajos Daróczi, György Deák, Miklós Zsuga, Sándor Kéki
Dátum:2019
ISSN:2073-4360
Megjegyzések:In this paper the preparation and detailed characterization of designed polyurethanes (SPURs) are reported for potential biological, biomedical and/or pharmaceutical applications. Importantly, in order to fulfill these goals all reactants and solvents used were selected according to the proposal of EUR-8 Pharmacopoeia. For the synthesis, a novel strategy was introduced and elaborated. A series of SPUR samples was prepared from poly(-caprolactone)-diol, 1,6-hexamethylene diisocyanate and sucrose as a chain extender/crosslinking agent to obtain sucrose containing polyurethanes. In addition, the mol ratios of the sucrose were varied within an order of magnitude. The prepolymers and the products of the syntheses were investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and infrared spectroscopy (IR), respectively. It was found that the reactivity of the eight free hydroxyl groups of sucrose are different, and after curing the SPUR samples at 60 C no free isocyanate groups can be observed. Furthermore, swelling experiments performed with various solvents of different polarities revealed that the highest degree of swelling took place in dimethyl-sulfoxide. However, low degrees of swelling were recognized in water and hexane. It is important to note that the gel contents were around 90% in all cases, which demonstrate that the crosslinking was almost complete. In addition, the kinetics of swelling were also evaluated and successfully modeled. The crosslink densities were calculated from the data of the swelling experiments by means of the Flory-Rehner equation. Unexpectedly, it was found that the crosslink density decreased with the increasing sucrose content also in line with the results obtained by relaxation modulus experiments and dynamic mechanical analysis (DMA). The Tg and Tm of SPUR samples, determined from DSC and DMA measurements, were around 57 C and 27 C, respectively. According to the mechanical tests the SPUR samples showed high elongation at break values, i.e., high flexibilities. Furthermore, the stress-strain curves were also modeled and discussed.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
poly(epsilon-caprolactone)
1,6-hexamethylene-diisocyanate
sucrose
polyurethane
swelling
mechanical testing
Megjelenés:Polymers. - 11 : 5 (2019), p. 1-19. -
További szerzők:Nagy Miklós (1976-) (vegyész) Vadkerti Bence (1994-) (okleveles vegyészmérnök) Daróczi Lajos (1965-) (fizikus) Deák György (1954-) (polimer kémikus) Zsuga Miklós (1944-) (polimer kémikus) Kéki Sándor (1964-) (polimer kémikus)
Pályázati támogatás:GINOP-2.3.3-15-2016-00021
GINOP
FK-128783
Egyéb
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DOI
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5.

001-es BibID:BIBFORM104069
035-os BibID:(WoS)000489104300028 (Scopus)85071906261 (cikkazonosító)1402
Első szerző:Todea, Annamaria
Cím:Biodegradable Oligoesters of epsilon-Caprolactone and 5-Hydroxymethyl-2-Furancarboxylic Acid Synthesized by Immobilized Lipases / Anamaria Todea, Ioan Bîtcan, Diana Aparaschivei, Iulia Păuşescu, Valentin Badea, Francisc Péter, Vasile Daniel Gherman, Gerlinde Rusu, Lajos Nagy, Sándor Kéki
Dátum:2019
ISSN:2073-4360
Megjegyzések:Following the latest developments, bio-based polyesters, obtained from renewable raw materials, mainly carbohydrates, can be competitive for the fossil-based equivalents in various industries. In particular, the furan containing monomers are valuable alternatives for the synthesis of various new biomaterials, applicable in food additive, pharmaceutical and medical field. The utilization of lipases as biocatalysts for the synthesis of such polymeric compounds can overcome the disadvantages of high temperatures and metal catalysts, used by the chemical route. In this work, the enzymatic synthesis of new copolymers of ?-caprolactone and 5-hydroxymethyl-2-furancarboxylic acid has been investigated, using commercially available immobilized lipases from Candida antarctica B. The reactions were carried out in solvent-less systems, at temperatures up to 80 C. The structural analysis by MALDI TOF-MS, NMR, and FT-IR spectroscopy confirmed the formation of cyclic and linear oligoesters, with maximal polymerization degree of 24 and narrow molecular weight distribution (dispersity about 1.1). The operational stability of the biocatalyst was explored during several reuses, while thermal analysis (TG and DSC) indicated a lower thermal stability and higher melting point of the new products, compared to the poly(epsilon-caprolactone) homopolymer. The presence of the heterocyclic structure in the polymeric chain has promoted both the lipase-catalyzed degradation and the microbial degradation. Although, poly(epsilon-caprolactone) is a valuable biocompatible polymer with important therapeutic applications, some drawbacks such as low hydrophilicity, low melting point, and relatively slow biodegradability impeded its extensive utilization. In this regard the newly synthesized furan-based oligoesters could represent a "green" improvement route.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
copolymerization
renewable
oligoester
lipase
furan-based
epsilon-caprolactone
Megjelenés:Polymers. - 11 : 9 (2019), p. 1-17. -
További szerzők:Bîtcan, Ioan Aparaschivei, Diana Pausescu, Iulia Badea, Valentin Francisc Péter Gherman, Vasile Daniel Rusu, Gerlinde Nagy Lajos (1979-) (vegyész) Kéki Sándor (1964-) (polimer kémikus)
Pályázati támogatás:GINOP-2.3.3-15-2016-00021
GINOP
Internet cím:DOI
Intézményi repozitóriumban (DEA) tárolt változat
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