Thermoresponsive smart polymeric cell carriers of pnipan and elp for bone tissue engineering

Öztürk, Nihan
This study was aimed at designing a cell carrier from an intelligent polymer to achieve loading of mechanical stress for the purpose of improving the tissue engineering capability in vitro. Ethyleneglycoldimethacrylate (EGDMA) crosslinked poly(Nisopropylacrylamide) (pNIPAM) films were prepared by radical polymerization with ultraviolet light (UV) in the presence of photoinitiator 2,2'-azoisobutyronitrile (AIBN) in isopropanol/water (1:1). Patterns were formed on the surface of the polymers by using silicon wafers with microridges (2 μm) and grooves (10 μm) that were prepared by photolithography technique as the template. The surfaces of the films were also modified by adsorption of ELP-RGD6 polypeptide. Bone marrow stem cells (BMSCs) isolated from 6 week old Sprague-Dawley rats were seeded onto the pNIPAM films with different surface topography and chemistry and cultured under static and dynamic conditions. Dynamic conditions were generated by cyclic temperature changes (15 min at 29°C, 30 min at 37°C) for 10 times a day during 5 days starting on the second day post-cell seeding. ELP-RGD6 on the films enhanced initial cell attachment but had no effect on proliferation in long term culturing. However, for the dynamic culturing, ELP was crucial for both retaining cells attached on the surface when the surface became hydrophilic and resulted in weakened cell attachment, and for better communication between cell and material which enhanced the ability of pNIPAM films to transfer mechanical stress on the cells. Dynamic conditions improved cell proliferation but decreased differentiation. Presence of the patterns also influenced the differentiation but did not affected proliferation.


Sequential growth factor delivery from polymeric scaffolds for bone tissue engineering
Yılgör, Pınar; Hasırcı, Nesrin; Department of Biotechnology (2009)
Tissue engineering is a promising alternative strategy to produce artificial bone substitutes; however, the control of the cell organization and cell behavior to create fully functional 3-D constructs has not yet been achieved. To overcome these, activities have been concentrated on the development of multi-functional tissue engineering scaffolds capable of delivering the required bioactive agents to initiate and control cellular activities. The aim of this study was to prepare tissue engineered constructs ...
In vitro and transdermal penetration of PHBV micro/nanoparticles
Eke, G.; Kuzmina, A. M.; Goreva, A. V.; Shishatskaya, E. I.; Hasırcı, Nesrin; Hasırcı, Vasıf Nejat (2014-06-01)
The purpose of this study was to develop micro and nano sized drug carriers from poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and study the cell and skin penetration of these particles. PHBV micro/nanospheres were prepared by o/w emulsion method and were stained with a fluorescent dye, Nile Red. The particles were fractionated by centrifugation to produce different sized populations. Topography was studied by SEM and average particle size and its distribution were determined with particle sizer. Cel...
Optimum Design of 6R Passive Haptic Robotic Arm for Implant Surgery
Yılmaz, Serkan; Konukseven, Erhan İlhan (2010-07-10)
The aim of this research was to design an optimum 6R passive haptic robotic arm (PHRA) to work in a limited workspace during dental implant surgery. Misplacement of an implant during dental surgery causes longer recuperation periods and functional disorders. In this study, a passive guidance robot arm was designed as a surgical aid tool for a dentist during the operation to reduce the surgical complications. Optimum design of a 6R robot is a complex issue since minimum energy has to be consumed while maximu...
Silicate-doped nano-hydroxyapatite/graphene oxide composite reinforced fibrous scaffolds for bone tissue engineering
Dalgıç, Ali Deniz; Tezcaner, Ayşen; Keskin, Dilek; Evis, Zafer (SAGE Publications, 2018-3-15)
In this study, novel graphene oxide-incorporated silicate-doped nano-hydroxyapatite composites were prepared and their potential use for bone tissue engineering was investigated by developing an electrospun poly(epsilon-caprolactone) scaffold. Nanocomposite groups were synthesized to have two different ratios of graphene oxide (2 and 4 wt%) to evaluate the effect of graphene oxide incorporation and groups with different silicate-doped nano-hydroxyapatite content was prepared to investigate optimum concentra...
Preparation and characterization of chitosanpolyethylene glycol microspheres and films for biomedical applications
Günbaş, İsmail Doğan; Hasırcı, Nesrin; Department of Polymer Science and Technology (2007)
In recent years, biodegradable polymeric systems have gained importance for design of surgical devices, artificial organs, drug delivery systems with different routes of administration, carriers of immobilized enzymes and cells, biosensors, ocular inserts, and materials for orthopedic applications. Polysaccharide-based polymers represent a major class of biomaterials, which includes agarose, alginate, dextran, and chitosan. Chitosan has found many biomedical applications, including tissue engineering, owing...
Citation Formats
N. Öztürk, “Thermoresponsive smart polymeric cell carriers of pnipan and elp for bone tissue engineering,” M.S. - Master of Science, Middle East Technical University, 2008.