Sequential growth factor delivery from complexed microspheres for bone tissue engineering

Başmanav, Fitnat Buket
Complexed microspheres of poly(4-vinyl pyridine) (P4VN) and alginic acid were prepared by internal gelation method and subsequent freeze drying. The 4% and 10% microspheres were loaded with Bone Morphogenetic Protein-2 (BMP-2) and Bone Morphogenetic Protein-7 (BMP-7), respectively for in vitro studies and were entrapped in PLGA foams. Foams containing only 4%, BMP-2 microspheres, only 10%, BMP-7 microspheres and both populations were prepared. Control samples of each group were prepared with drug free microspheres. Bone marrow derived stem cells from rat femur and tibia isolated by a surgical operation, were seeded onto foams. Proliferation of cells on foams containing both microsphere populations was higher at all time points regardless of the presence of BMPs. This was attributed to different porosity characteristics. Proliferation was higher at all times in control samples in comparison to their positive samples for all groups, suggesting proliferation attenuation related enhancement in osteogenic activity due to BMP supply. Alkaline phosphatase (ALP) activities were lower at all time points for foams containing both microsphere populations regardless of BMP presence. This was attributed to different physical characteristics of foams confirmed by the inverse correlation between proliferation and osteogenic differentiation. Total and specific ALP activity results demonstrated the significant positive influence of all BMP containing types in enhancing osteogenic differentiation. Best results were obtained with co-administration of sequential delivery performing 4% and 10% microspheres loaded with BMP-2 and BMP-7, respectively.


Optimization of supercritical CO2 extraction of Thymbra spicata oil
Sonsuzer, S; Şahin, Serpil; Yılmaz, Levent (Elsevier BV, 2004-07-01)
The supercritical fluid extraction (SFE) of aroma compounds from Thymbra spicata was studied. Response surface methodology (RSM) was used to optimize the parameters of the supercritical fluid extraction. Independent variables were temperature (40, 50 and 60 degreesC), pressure (80, 100 and 120 bar) and time (30, 60 and 90 min). Dependent variables were yield, monoterpene, sesquiterpene and oxygenated monoterpene contents.
Surfactant modified zinc borate synthesis and its effect on the properties of PET
Baltaci, Berk; ÇAKAL, GAYE ÖZGÜR; Bayram, Göknur; Eroglu, Inci; Özkar, Saim (Elsevier BV, 2013-08-01)
Zinc borate was prepared from the reaction of zinc oxide and boric acid in the absence or presence of cumene terminated poly(styrene-co-maleic anhydride), PSMA, added as a surfactant at varying concentrations (0.1-1 wt.% of water) to the reaction medium to investigate its effect on the growth and agglomeration of particles during reaction. Synthesized zinc borates were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) in comparison to unmodifie...
Gas sensing property of a conducting copolymer
Ak, Metin; Yigitsoy, Basak; Yagci, Yusuf; Toppare, Levent Kamil (Walter de Gruyter GmbH, 2007-05-02)
A bifunctional amido thiophene, namely hexamethylene (bis-3-thiophene acetamide) (HMTA) was synthesized and its copolymer with pyrrole was electrochemically prepared in water/ PTSA solvent/ electrolyte medium. Sensory behavior of this copolymer against ammonia, methanol, dichloromethane (DCM) and n-hexane vapors was investigated. The methanol vapor, which can form hydrogen bonds with the polar groups on the copolymer surface, showed the maximum response. DCM, which is less polar, yielded relatively lower re...
Dynamic and steady-state analysis of oxidative dehydrogenation of ethane
Karamullaoğlu, Gülsün; Doğu, Timur; Department of Chemical Engineering (2005)
In this research, oxidative dehydrogenation of ethane to ethylene was studied over Cr-O and Cr-V-O mixed oxide catalysts through steady-state and dynamic experiments. The catalysts were prepared by the complexation method. By XRD, presence of Cr2O3 phase in Cr-O; and the small Cr2O3 and V2O4 phases of Cr-V-O were revealed. In H2-TPR, both catalysts showed reduction behaviour. From XPS the likely presence of Cr+6 on fresh Cr-O was found. On Cr-V-O, the possible reduction of V+5 and Cr+6 forms of the fresh sa...
Mixed alpha-Fe2O3/Bi2WO6 oxides for photoassisted hetero-Fenton degradation of Methyl Orange and Phenol
Jaramillo-Paez, C.; Navio, J. A.; Hidalgo, M. C.; Bouzıanı, Asmae; El Azzouzi, Mohammed (2017-01-01)
Mixed oxides, alpha-Fe2O3/Bi2WO6, were prepared using a mechanical mixing procedure by adding to the Bi2WO6 previously obtained by hydrothermal method the corresponding amount of a prepared alpha-Fe2O3, the latter obtained by thermal decomposition of Fe(NO3)center dot 9H(2)O. The physicochemical surface, structural, morphological characteristics and optical properties of the samples, single and mixed, were determined by BET, XRD, FE-SEM, XPS and UV-vis diffuse reflectance spectroscopy. UV-vis diffuse reflec...
Citation Formats
F. B. Başmanav, “Sequential growth factor delivery from complexed microspheres for bone tissue engineering,” M.S. - Master of Science, Middle East Technical University, 2007.