Event Abstract Back to Event Osteoblast responses of Poly (octanediol citrate)/Gallium-containing bioglass composite scaffolds Ehsan Zeimaran1, Sara Pourshahrestani1, Belinda Pingguan-Murphy1, Nahrizul A. Kadri1 and Mark R. Towler1, 2 1 University of Malaya, Biomedical Engineering, Malaysia 2 Ryerson University, Mechanical & Industrial Engineering, Canada Introduction: Engineered scaffolds for self-regenerative applications should provide the necessary support for cells to attach, proliferate and facilitate ingrowth [1]. Gallium compounds have shown to inhibit resorption and differentiation of osteoclast without negatively affecting osteoblast activity as well as increasing the synthesis and content of type I collagen [2][3]. This work considers the osteoblast-like cells responses of composite scaffolds made up poly (octanediol citrate) (POC) and gallium-containing bioglass. Materials and Methods: Composite scaffolds of POC and different portions (10, 20 and 30 wt%) of a melt-derived bioglass (0.48SiO2-0.12CaO-0.32ZnO-0.08Ga2O3,molar fraction) were prepared by employing a salt-leaching method. The scaffolds were sterilised and human Osteoblast cells were cultured for 7 days into the scaffolds (1×105/scaffold) and then fixed with 3% glutaraldehyde. After that, the scaffolds were washed with PBS and dehydrated in a serial ethanol. Then the samples were freeze-dried, sputtercoatedwith gold and observed under SEM (HitachiS-530). Real-Time PCR was carried out using Syber green™ fluorescent dye (Applied Biosystems, USA.) to evaluate the expression of genes of interest. The primers used as follows: type I collagen (COLI-F-5-CCTGGATGCCATCAAAGTCT-3 and COLI-R-5- GAATCCATCGGTCATGCTCT-3) and type III collagen (COLIII-F-5- CTAAAGGCGAAGATGGCAAG-3 and COLIII-R-5-TTTCCCATCACTTCCTGGTC-3).After 7 days in culture indirect Immunostaining was performed using a mouse antibody specific to type I collage (abcam, USA, cat. # ab90395) or type III collagen (abcam, USA, cat. # ab3610). The mouse antibodies were added separately and the cells were incubated overnight at 4ºC. The cells were washed with PBS and incubated for 30 min with an anti-mouse IgG labeled with FITC fluorescent dye (Invitrogen, USA, cat. # 62-6511). Results and discussion: Figure 1a shows the cell morphology on the scaffold seeded for 7 days. The results indicate that the cells are well-adhered and spread throughout the surface and the walls of pores of POC-BG-10% and formed a confluent cells sheet on the scaffold. Figure 1b exhibits the comparison of osteoblast type I and III collagen expression for composite scaffolds. The POC-BG-10% composite showed a remarkably higher expression of type I and III collagens compared to the other composites. The green fluorescence indicated the expression of both type I and III collagen proteins (Figure 2). Although all the scaffolds cultured by osteoblasts positively expressed both type I and III collagens, the staining had significantly higher intensity and distribution for POC-BG-10% for both collagen types. This can be attributed to the ionicdissolution products of bioglass which may upregulate the gene expression and enhance the collagen synthesis [4]. Conclusions: This paper proposes that gallium can positively influence osteoblast responses. Composite scaffolds had favorable influence on collagen formation by seeded osteoblast cells. However composite containing 10% bioglass indicated enhanced both type I and III collagen expression in comparison to the other samples. Thus it can be concluded that there is a threshold for bioglass concentration in which osteoblast cell attachment and collagen secretion increase. This research is supported by a High Impact Research MoE Grant (UM.C/625/1/HIR/MoE/ENG/58) from the Ministry of Higher Education Malaysia and University of Malaya Research Grant (UMRG, RG156-12AET).