Influence of micropatterns on human mesenchymal stem cell fate /

Hastürk, Onur
Mesenchymal stem cells (MSCs) are promising cell sources for tissue engineering applications as they can differentiate into a variety of adult cells types including osteoblasts. In vivo microenvironment of stem cells is known to provide both biochemical signals and micro- and nanoscale physical cues that influence the behavior and fate of stem cells. The use of soluble chemical factors is the most common strategy to guide the commitment of MSCs to specific lineages, but it is a cause of concern such as unsatisfactory results or potential side effects. Therefore, engineering of the substrate surfaces with the aim of mimicking in vivo physical cues is a promising approach to understand cell-substrate interactions and modulate the fate of MSCs. For this purpose, poly(methyl methacrylate) films were designed to have surfaces decorated with 4x4 µm² (P4G4), 8x8 µm² (P8G8) and 16x16 µm² (P16G16) square prism pillars of 8 µm height separated by 4, 8 and 16 µm gaps, respectively. One set of the substrates were treated with oxygen plasma to improve surface hydrophilicity. Human MSCs isolated from dental pulp tissues were cultured on these substrates and the influence of the dimension and hydrophilicity of micropatterns on attachment, conformational changes, proliferation and differentiation of cells were studied. The results showed that micropatterns increased cell attachment but decreased proliferation rate on the hydrophobic substrates; however, oxygen plasma modification promoted both attachment and proliferation rate on all substrates. Confocal micrographs and the following digital analysis of cell shapes revealed distinct deformations in varying degrees in the cytoskeleton induced by topographical features. These deformations were found to occur earlier and to a higher degree on plasma modified hydrophilic substrates. Cells cultured on substrates with smaller pillar and gap dimensions displayed significant deformations of their nuclei. The proliferation rates on these substrates were significantly lower compared to the control surfaces. The influence of micropatterns on the expression of stemness and osteogenesis related genes was determined by real time quantitative PCR method. Plasma modified substrates were found to downregulate the expression of stemness markers and did not lead to an increase in the expression of bone markers. Hydrophobic P4G4 and P8G8 surfaces having no oxygen plasma modification, however, caused a significant increase in the expression of the bone marker alkaline phosphatase (ALP) and demonstrated that unmodified hydrophobic micropillar structures induce osteogenesis without using any chemical osteogenic factors.  


Influence of microenvironment on tissue engineering applications
Sayın, Esen; Hasırcı, Vasıf Nejat; Baran, Erkan Türker; Department of Biotechnology (2017)
Cues of microenvironment that guide both mature and stem cells determine the success of tissue engineered constructs. To prove and emphasize this expectation, various parameters such as surface topography, scaffold (cell carrier, scaffold) chemistry, 2D vs 3D microenvironments and mechanical stimulation were included into the microenvironment. Surfaces with two distinct physical cues pillar and groove-ridge type micropatterns were transferred to the surfaces of the films by casting the collagen type I and s...
Characterization and identification of human mesenchymal stem cells at molecular level
Aksoy, Ceren; Severcan, Feride; Çetinkaya, Duygu Uçkan; Department of Biotechnology (2012)
Bone marrow mesenchymal stem cells (BM-MSCs) are pluripotent cells that can differentiate into a variety of non-hematopoietic tissues. They also maintain healthy heamatopoiesis by providing supportive cellular microenvironment into BM. In this thesis, MSCs were characterized in terms of their morphological, immunophenotypical and differentiation properties. Then, they were examined by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy together with hierarchical clustering, and FT...
Effect of double growth factor release on cartilage tissue engineering
Ertan, Ayse Burcu; Yilgor, Pinar; Bayyurt, Banu; Calikoglu, Ayse Ceren; Kaspar, Cigdem; Kök, Fatma Neşe; KÖSE, GAMZE; Hasırcı, Vasıf Nejat (2013-02-01)
The effects of double release of insulin-like growth factor I (IGF-I) and growth factor 1 (TGF1) from nanoparticles on the growth of bone marrow mesenchymal stem cells and their differentiation into cartilage cells were studied on PLGA scaffolds. The release was achieved by using nanoparticles of poly(lactic acid-co-glycolic acid) (PLGA) and poly(N-isopropylacrylamide) (PNIPAM) carrying IGF-I and TGF1, respectively. On tissue culture polystyrene (TCPS), TGF-1 released from PNIPAM nanoparticles was found to ...
Influence of co-culture on osteogenesis and angiogenesis of bone marrow mesenchymal stem cells and aortic endothelial cells
Pekozer, Gorke Gurel; KÖSE, GAMZE; Hasırcı, Vasıf Nejat (2016-11-01)
Co-culture of bone forming cells and endothelial cells to induce pre-vascularization is one of the strategies used to solve the insufficient vascularization problem in bone tissue engineering attempts. In the study, primary cells isolated from 2 different tissues of the same animal, rat bone marrow stem cells (RBMSCs) and rat aortic endothelial cells (RAECs) were co-cultured to study the effects of co-culturing on both osteogenesis and angiogenesis. The formation of tube like structure in 2D culture was obs...
Role of Vibrational Spectroscopy in Stem Cell Research
Aksoy, Ceren; Severcan, Feride (2012-01-01)
Recent researches have mainly displayed the significant role of stem cells in tissue renewal and homeostasis with their unique capacity to develop different cell types. These findings have clarified the importance of stem cells to improve the effectiveness of any cell therapy for regenerative medicine. Identification of purity and differentiation stages of stem cells are the greatest challenges of stem cell biology and regenerative medicine. The existing methods to carefully monitor and characterize the ste...
Citation Formats
O. Hastürk, “Influence of micropatterns on human mesenchymal stem cell fate /,” M.S. - Master of Science, Middle East Technical University, 2016.