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001-es BibID:	BIBFORM095727
Első szerző:	Shi, Xiangyang
Cím:	Electrophoretic mobility and molecular distribution studies of poly(amidoamine) dendrimers of defined charges / Xiangyang Shi, István Bányai, Keyla Rodriguez, Mohammad T. Islam, Wojciech Lesniak, Peter Balogh, Lajos P. Balogh, James R. Baker
Dátum:	2006
ISSN:	0173-0835 1522-2683
Megjegyzések:	Generation 5 ethylenediamine (EDA)-cored poly(amidoamine) (PAMAM) dendrimers(E5, E d enotes the EDA core and 5 the generation number) with different degrees of acetylation and carboxylation were synthesized and used as a model system to investigate the effect of charge and the influence of dendrimer surface modifications on electrophoretic mobility (EM) and molecular distribution. The surface-modified dendrimers were characterized by size-exclusion chromatography, 1H NMR, MALDITOF-MS, PAGE, and CE. The focus of our study was to determine how EM changes as a function of particle charge and molecular mass, and how the molecular distribution changes due to surface modifications. We demonstrate that partially modified dendrimers have much broader migration peaks than those of fully surface functionalized or unmodified E5 dendrimers due to variations in the substitution of individual dendrimer surfaces. EM decreased nonlinearly with increases in surface acetylation for both PAMAM acetamides and PAMAM succinamic acids, indicating a complex migration activity in CE separations that is not solely due to charge/mass ratio changes. These studies provide new insights into dendrimer properties under an electric field, as well as into the characterization of dendrimer-based materials being developed for medical applications.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Capillary electrophoresis Electrophoretic mobility Molecular distribution Poly(amidoamine) dendrimers
Megjelenés:	Electrophoresis. - 27 : 9 (2006), p. 1758-1767. -
További szerzők:	Bányai István (1953-) (vegyész) Rodriguez, Keyla Islam, Mohammad T. Lesniak, Wojciech G. Balogh Péter Balogh Lajos P. Baker, James R.
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM085630
Első szerző:	Shi, Xiangyang
Cím:	Generational, skeletal and substitutional diversities in generation one poly(amidoamine) dendrimers / Xiangyang Shi, István Bányai, Mohammad T. Islam, Wojciech Lesniak, Denzel Z. Davis, James R. Baker, Lajos P. Balogh
Dátum:	2005
ISSN:	0032-3861
Megjegyzések:	Structural deviations of ethylenediamine core polyamidoamine (PAMAM) dendrimers and derivatives can be defined as skeletal and/or substitutional diversities. Detailed analysis of dendrimer starting materials and derivatives is necessary to understand the intrinsic characteristics of commercial dendrimer materials and their variations related to subsequent surface modifications. In this paper, structural deviations of ethylenediamine core generation 1 PAMAM dendrimers (PAMAM_E1 or E1) are studied and determined in a frame of a systematic investigation using combined characterization techniques. A primary amine-terminated PAMAM dendrimer of generation 1 (E1.NH2) was used as a starting material to synthesize glycidol (E1.N(Gly)OH) and acetamide-terminated (E1.NHAc) dendrimers. The purity and homogeneity of these dendrimers were extensively characterized by polyacrylamide gel electrophoresis (PAGE), capillary electrophoresis (CE), gel permeation chromatography (GPC), acid?base titration, nuclear magnetic resonance (NMR), matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) and electrospray ionization (ESI) mass spectrometry. PAGE and CE studies showed that electrophoretic mobilities at pH 2.5 are in the order of E1.NH2>E1.N(Gly)OH>E1.NHAc. Mass spectrometry and NMR investigations (1H, 13C DEPT-135, and 13C NMR, COSY, HETCOR, NOESY) suggested that (a) the studied E1 dendrimers were generationally pure, (b) E1.NHAc and E1.N(Gly)OH dendrimers, and essentially had the same defects and skeletal diversity as E1.NH2 did. The broad distribution of the main peak in the CE electropherogram of E1.N(Gly)OH revealed the incomplete hydroxylation of E1.NH2 resulting in additional substitutional diversity between the dendrimer molecules. Potentiometric titration studies proved that overall numbers of terminal and tertiary amine groups also deviated from the theoretical values. NMR spectroscopy was applied for both qualitative and quantitative analysis of the structural defects of dendrimers and derivatives. E1.NH2 and E1.NHAc exhibited only minor deviations from ideal structures and, respectively, displayed a narrow distribution; while E1.N(Gly)OH had a much broader distribution centered around 14?3 glycidol substituents. The study of structural variations in generation 1 PAMAMs provides new insights for the characterization of higher generation PAMAM dendrimers and derivatives both in terms of the skeletal deviations as well as other resulting diversities related to dendrimer surface functionalization.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk dendrimer distribution Characterization
Megjelenés:	Polymer. - 46 : 9 (2005), p. 3022-3034. -
További szerzők:	Bányai István (1953-) (vegyész) Islam, Mohammad T. Lesniak, Wojciech G. Davis, Denzel Z. Baker, James R. Balogh Lajos P.
Pályázati támogatás:	T-035127 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM085273
Első szerző:	Shi, Xiangyang
Cím:	Capillary electrophoresis of polycationic poly(amidoamine) dendrimers / Xiangyang Shi, István Bányai, Wojciech G. Lesniak, Mohammad T. Islam, István Országh, Peter Balogh, James R. Baker, Jr. Lajos P. Balogh
Dátum:	2005
ISSN:	0173-0835 1522-2683
Megjegyzések:	Generation 2 to generation 5 poly(amidoamine) (PAMAM) dendrimers having different terminal functionalities were analyzed by capillary electrophoresis (CE). Polyacrylamide gel electrophoresis was also used to assess the composition of the individual generations for comparison with the CE results. Separation of PAMAMs can be accomplished by either using uncoated silica or silanized silica capillaries, although reproducibility is poor using the uncoated silica capillary. To improve run-to-runreproducibility,silanizedcapillarywas usedandvariousinternalstandardswere alsotested. Relative and normalized migration times of primary amine terminated PAMAM dendrimers were then determined using 2,3-diaminopyridine (2,3-DAP) as an internal standard. Using silanized capillaries and internal standards, the relative and normalized migration times are fully reproducible and comparable between runs. Apparent dimensionless electrophoretic mobilities were determined and the results were compared to theoretical calculations. It is concluded that for PAMAMs a complex separation mechanism has to be considered in CE, where the movement of the ions is due to the electric field, but the separation is rather the consequence of the adsorption/desorptionequilibriaonthecapillarywall("electrokineticcapillarychromatography").The described method may be used for quality control and may serve as an effective technique to analyze polycationic PAMAM dendrimers and their derivatives with different surface modifications.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Capillary electrophoresis Internal standards Poly(amidoamine) dendrimers
Megjelenés:	Electrophoresis. - 26 : 15 (2005), p. 2949-2959. -
További szerzők:	Bányai István (1953-) (vegyész) Lesniak, Wojciech G. Islam, Mohammad T. Országh István Balogh Péter Baker, James R. Balogh Lajos P.
Pályázati támogatás:	T-035127 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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