21 research outputs found
Membrane Supported Poly(butylene Adipate-Co Nanofibrous Matrices as Cardiac Patch: Effect of Basement Membrane for the Fiber Deposition and Cellular Behavior
No full textElectrospun nanofibrous matrices are convenient biomaterials that mimic extracellular matrices for adhesion, migration, proliferation, and differentiation of cells. The aim of this study is to optimize the electrospinning parameters for poly(butylene adipate-co-terephthalate) (PBAT) nanofiber production by the response surface methodology (RSM) and to develop a suitable material design for the usability of PBAT in cardiac tissue engineering. Therefore, electrospun PBAT nanofibrous matrices collected on solvent-casted polycaprolactone (PCL) or PBAT basement membranes at optimized conditions. The attachment and proliferation behavior of the H9C2 rat cardiomyoblasts investigated on different PBAT and PCL surface features as a model cell line. For this purpose, neat PBAT and PCL films have been used comparatively with both random (R-PBAT) and aligned PBAT (A-PBAT) nanofibers coated films. The effect of polymer concentration, flow rate, applied voltage, and needle tip -connector distance on fiber diameter and alignment was examined in the electrospinning process and optimum processing parameters were determined by RSM. The PBAT nanofibers were spun on basement membranes with 10% (w/v) polymer concentration, 1 mL/h volumetric flow rate, 2000 rpm collector rotation velocity (for aligned ones), 15 kV applied voltage, and 20 cm needle tip-collector distance. The average diameter of random (R-PBAT) and aligned (A-PBAT) nanofibers was calculated as 555 +/- 126 nm and 417 +/- 137 nm. The mechanical test results showed that the alignment topography increased the elastic modulus of PBAT nanofibers compared to random matrices. The alignment of fibers found as 91% and 75% within the +/- 10? range for A-PBAT/SC-PBAT and A-PBAT/SC-PCL, respectively. These findings showed that usage of PCL, instead of PBAT, as basement membrane decrease the alignment of deposited nanofibers. A 7-day cell culture study conducted with H9C2 cells seeded samples to investigate the influence of these differences on cell behavior. The results indicated that the alignment of fibers provides a suitable topography to proliferate and spread in myocyte morphology for H9C2 cells especially compared to neat films. Cellular behavior and nanofiber deposition have been affected by the usage of various basement membrane polymers. These findings demonstrated that the usage of basement membrane as support material provides the required thickness and mechanical properties to the aligned PBAT nanofiber matrices, and this double layer structure might be a promising candidate for cardiac tissue engineering with further studiesHacettepe University Research Fund [FDK-2020 -18721]This study was conducted within the scope of the doctoral thesis of Tug ??e G?ltan G?rb?z. This work has been financially assisted by Hacettepe University Research Fund (Project No: FDK-2020 -18721) . The authors declare that there is no conflict of interest
Synthesis and characterization of dextran hydrogels prepared with chlor- and nitrogen-containing crosslinkers
No full textIn this study, we have synthesized dextran hydrogels by the crosslinking reactions of dextran with some selective Cl-, and N-containing functional monomers, such as epichlorohydrin (ECH), N,N'-methylenebisacrylamide (MBAm), and glutaraldehyde (GA). Crosslinking reactions were carried out in the basic aqueous solutions (2.8N NaOH) at 25-50 degrees C. The optimum conditions for effective crosslinking, i.e., temperature, crosslinking time, and amount of crosslinker, were determined for each system. The hydrogel discs of 3 mm diameter and 1.5 mm thickness were subjected to a number of Tris-buffer solutions of desired pH (2.0-9.0) at 37 degrees C. Swelling kinetics of the hydrogels were evaluated with second-order swelling model. The pH-dependent swelling of hydrogels was strongly influenced by the functional group of crosslinker and crosslinker content. While the hydrogels prepared with ECH and MBAm shows higher swelling ability at basic medium than that of acidic medium, GA-containing hydrogels exhibited just the opposite behavior. Mesh sizes (xi) and average molecular weights between crosslinks (M-c) were estimated from swelling data using the Flory-Rehner theory. Characterization studies were completed by Fourier transform infrared spectroscopy and thermal gravimetric analysis. (c) 2006 Wiley Periodicals, Inc
Release characteristics of salmon calcitonin from dextran hydrogels for colon-specific delivery
No full textBiodegradable dextran hydrogels were synthesized by crosslinking dextran (T-70) with epichlorohydrin (ECH) for the in vitro colon-specific delivery of salmon calcitonin (sCT). Crosslinking reaction was performed in 2.8 M NaOH solution both in the presence and absence of ethanol at 10 and 23 degrees C. Biodegradation kinetics of dextran hydrogels were studied and, in the presence of 0.7 IU ml(-1) dextranase, dextran discs lost 71.0% and 56.5% of their dry weight within 80 h at pH 5.5 and 7.0, respectively. sCT was derivatized with the fluorescamine (FSM) at borate buffer (pH 9.0) and the quantitative determinations were performed using spectrofluorimetric method (lambda(ex): 390 nm, lambda(em): 475 nm). In vitro release studies for the hydrogels prepared in the presence of ethanol were carried out in simulated gastrointestinal fluids. Results indicated that 84.9% of the loaded-sCT was released for 17 h and dextran hydrogel prepared in the presence of ethanol may be a good delivery device for the colon-specific delivery of other peptide-type drugs as well as sCT. (c) 2006 Elsevier B.V. All rights reserved
Functionalization of Nonwoven Pet Fabrics by Water/O<sub>2< Plasma for Biomolecule Mediated Cell Cultivation
No full textTurkoglu Sasmazel, Hilal/0000-0002-0254-4541The main target of this study was to obtain COOH functionalities on the surface of 3D, nonwoven polyethylene terephthalate fabrics (NWPFs) by using low pressure water/O-2 plasma assisted treatment. The plasma treatments were performed in a cylindrical, capacitively coupled RF-plasma-reactor and then following steps were performed: in situ (oxalyl chloride vapors) gas/solid reaction to convert -OH functionalities into COCl groups; and hydrolysis under open laboratory conditions using air moisture for final-COOH functionalities. COOH and OH functionalities on the surfaces were detected quantitatively by fluorescent labeling techniques. The COOH-functionalized samples were biologically activated with insulin or heparin molecules by using spacer polyoxyethylene bis-amine (PEO). Successful immobilization was checked qualitatively using electron spectroscopy for chemical analysis (ESCA). The average amount of immobilized insulin and heparin onto NWPF surfaces were determined as 146.09 and 4.81 nmol.cm(-2), respectively. Our results showed that water/O-2 plasma assisted treatment worked very well for functionalization and biofunctionalization of 3D NWPF disks comparing with wet-chemistry methods. Cell culture experiments indicated that functionalization of NWPF disks and/or nanotopographies on the disk surfaces were effective on adhesion and proliferation of L929 mouse fibroblasts
FIXATION OF DISSOLVED AND COLLOIDAL SUBSTANCES ON FIBERS AND SILICON OXIDE SURFACES USING WATER SOLUBLE CROSSLINKED CATIONIC POLYMERS
No full textThe efficiency of water soluble crosslinked cationic polymers (CCP) in the fixation of dissolved and colloidal substances (DCS) onto fibers was investigated. Two different types of CCP were synthesized by dispersion polymerization of acrylamide (AAm) and diallyldimethylammonium chloride (DADMAC), with N,N'-methylene-bis-acrylamide (MBA) as a crosslinker. Relative turbidity, zeta potential and average diameter of the colloidal particles were determined to monitor their performance in DCS fixation. The results indicated that both polymers were able to fix a maximum amount of DCS particles onto fibers around a zero zeta potential, most probably clue to a patch-type flocculation mechanism. The conclusion reached was that flocculation was significant while the particles still had a negative zeta potential. The aggregation mechanism of a fiber-free DCS suspension occurred as Charge neutralisation, changed, by the addition of 10 mM NaCl to a patch-type mechanism. The CCPI consumption necessary to attain a maximum DCS removal was lower than the CCP2 consumption, as ascribed to the higher charge density and higher molecular mass of this polymer. The experiments performed on a quartz crystal microbalance equipment with dissipation (QCM-D) showed that the adsorbed charge and layer thickness of the polymers significantly affected fixation of the DCS particles onto the pre-adsorbed polymer layers on the SiO2 surface.</p
Influence of Water/O2 Plasma Treatment on Cellular Responses of Pcl and Pet Surfaces (vol 21, Pg 123, 2011)
No full textAday, Sezin/0000-0003-4396-7812[No Abstract Available
GRGDS-conjugated and curcumin-loaded magnetic polymeric nanoparticles for the hyperthermia treatment of glioblastoma cells
No full textThermally responsive and ligand-mediated drug delivery systems have the potential to improve the treatment of brain tumors, especially, most lethal one, glioblastoma multiform (GBM). Magnetic nanoparticle-mediated hyperthermia becomes one of the most promising alternative therapy for GBM treatment in cases where localized heating and targeted delivery of a therapeutic drug can be achieved on the tumor site. In this study, it is aimed to increase the therapeutic efficiency of multi-functionalized nanoparticles (NPs) in combination with radiofrequency hyperthermia (RF-HT) on GBM cells. For this purpose, firstly, a low-cost and portable home-built RFHT system suitable for in vitro/in vivo studies was successfully implemented and tested at 13.56 MHz frequency with power up to approximately 400 W. Subsequently, the highly monodispersed superparamagnetic iron oxide nanoparticles (SPIONs), which could interact with the RF magnetic field, were synthesized with the mean particle size of 5.6 +/- 0.9 nm. The obtained SPIONs were coated with poly (lactic-co-glycolic acid)-poly (ethylene glycol) di-block copolymer (PLGA-b-PEG). Most of the SPIONs were uniformly distributed in such a well-defined spherical-shaped polymeric NP. Moreover, curcumin (Cur), a potential agent for GBM treatment, was loaded into the magnetic polymeric nanoparticles (m-PNPs) with a loading capacity of 8% (w/w, Cur/NPs) and a mean diameter of Cur-loaded m-PNPs (Cur-m-PNPs) was 142 +/- 70 nm. To increase cellular uptake and targeting ability of NPs, glycine-arginine-glycine-aspartic acid-serine (GRGDS) peptide was immobilized on the Cur-m-PNPs and the amount of GRGDS was detected as 37 mu g/mg NPs. In vitro cytotoxicity studies revealed that the presence of GRGDS on Cur-m-PNPs (GRGDS-Cur-m-PNPs) improved the cytotoxic efficiency of Cur-m-PNPs by 6-fold in GBM-cells for all incubation times (24, 48 and 72 h). Furthermore, NPs with RF treatment exhibited higher antitumor activity than that of NPs without RF on GBM cells. This result may be attributed to the thermal (SPIONs) or non thermal (cellular membrane) effects or both of them on cells. Overall, this study showed that RF-HT in combination with GRGDS-Cur-m-PNPs could provide a feasible approach to improve GBM treatment.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [SBAG-118S027, SBAG119S137]This study was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) , Grant no: SBAG-118S027 and SBAG119S137. We are sincerely grateful for the assistance of the Cell and Tissue Engineering Research Group at Hacettepe University. We are also thankful to Dr. Anl Sera Cakmak for the support of cell culture studies
Osteogenic Differentiation Of Electrostimulated Human Mesenchymal Stem Cells Seeded On Silk-Fibroin Films
No full textElectric field is known as an important regulator to guide the development and regeneration of many tissues. The aim of this study was to investigate the osteogenic differentiation potential of human mesenchymal stem cells (hMSCs) cultivated on silk-fibroin films in response to different parameters, i.e. frequency, voltage, distance between electrodes, and/or culture conditions (growth medium or osteogenic medium). Silk films were prepared in the presence of platinum wires to study the impact of exogenous electrostimulation on the cells for up to 14 days. The experimental groups can be defined as high voltage in osteogenic differentiation medium, low voltage in osteogenic differentiation medium, and low voltage in growth medium in this study. Compared to the unstimulated controls (silk films without platinum wires), low voltage (10 mV) did not influence proliferation, while it enhanced osteogenic differentiation according to early and late osteogenic markers in osteogenic differentiation medium. In growth medium, low voltage increased cell proliferation in contrast to osteogenic medium. On the other hand, high voltage (500 mV) stimulated cell proliferation and only late osteogenic markers in osteogenic medium. The results suggest the potential to exploit exogenous biophysical control of cell functions towards tissue-specific goals.Wo
Enhanced Osteogenic Activity With Boron-Doped Nanohydroxyapatite-Loaded Poly(Butylene Adipate-Co-Terephthalate) Fibrous 3D Matrix
No full textIn this study, three dimensional (3D) poly(butylene adipate-co-terephthalate) (PBAT) fibrous scaffolds with more than 90% porosity were fabricated via wet electrospinning method. Amorphous hydroxyapatite (HAp) and boron (B) doped hydroxyapatite (B-HAp) nanoparticles were produced by microwave-assisted biomimetic precipitation and encapsulated into PBAT fibres with the ratio of 5% (w/w) in order to enhance osteogenic activity of the scaffolds. Cell culture studies were carried out with human bone marrow derived stem cells (hBMSCs) and they showed that alkaline phosphatase (ALP) activity and the amounts of collagen and calcium were higher on B containing PBAT (B-HAp-PBAT) scaffolds during the 28-day culture period than that of the PBAT scaffolds. Moreover, hBMSCs cultivated on B-HAp-PBAT scaffolds showed significantly higher expression levels of both early and late stage osteogenic genes e.g. ALP, collagen I (COL-I), osteocalcin (OCN) and osteopontin (OPN) at day 28 than that of the PBAT scaffolds. Scanning electron microscope (SEM) photographs and energy dispersive X-ray (EDX) analysis indicated that hBMSCs produced high amounts of mineralized extracellular matrix (ECM) mainly on the surface of the 3D matrices. This study demonstrates that boron-containing 3D nanofibrous PBAT scaffolds with their osteoinductive and osteoconductive properties can be used as alternative constructs for bone tissue engineering.WoSScopu
LIF-immobilized nonwoven polyester fabrics for cultivation of murine embryonic stem cells
No full textEmbryonic stem (ES) cells have a great interest for tissue engineering because of their pluripotent nature and proliferative capacity. The objective of this study is to constitute a synthetic microenvironment to support the in vitro propagation of murine ES cells in an undifferentiated state. That is why we used a three-dimensional matrix, nonwoven polyester fabric (NWPF), which was formed from poly(ethylene terephthalate) (PET) fibers. NWPF discs were partially hydrolyzed, and then the carboxyl groups were coupled with leukemia inhibitory factor (LIF) in the presence of water-soluble carbodiimide. The effectiveness of immobilization process was checked with ATR-FTIR spectroscopy, fluorimetry, and cell culture studies. ES cell colony morphology, alkaline phosphatase (AP) activity, stage-specific embryonic antigen-1 (SSEA-1) immunoreactivity, and SEM analysis following a 72-96-h culture period upon hydrolyzed and LIF-immobilized surfaces were assessed to determine the pluripotent status of ES cells. Results revealed that LIF was active in immobilized form; undifferentiated colonies had not only a significant AP and SSEA-1 immunoreactivity, but also a higher undifferentiated colony ratio on LIF-immobilized surfaces than that of hydrolyzed surfaces. The immobilized LIF protein might be a good model to provide a feeder-free system, but the physical properties of the scaffold is more convenient for differentiation studies. (c) 2007 Wiley Periodicals, Inc. J Biomed Mater Res 81A: 911-919, 2007
