Mar 30, 2016 - 1 Cochin University of Science and Technology, Department of Polymer ... 2 Sree Chitra Tirunal Institute for Medical Sciences and Technology, ...
Surface phosphorylated polyethylene terephthalate fibrous matrix: an efficient scaffold with biomineralization potential for bone tissue engineering applications Sailaja Gs1, Ramesh P2, Francis B. Fernandez2, Muraleedharan Cv2 and Harikrishna Varma2
1
Cochin University of Science and Technology, Department of Polymer Science and Rubber Technology, India 2
Sree Chitra Tirunal Institute for Medical Sciences and Technology, Biomedical Technology Wing, India
Introduction: Tissue engineering scaffolds with indigenous biomineralization potential is of great interest, particularly when holding a good balance of surface and bulk properties. Considering the huge demand on osteoinductive trabecular bone graft scaffolds, several attempts were made with electrospun polymeric substrates of both natural and synthetic origin towards this purpose particularly due to the intrinsic 3D interconnecting configurations of electrospun substrates[1]. But their non-woven nature presents challenges in retaining long term mechanical stability. Polyethylene terephthalate (PET) has characteristic favourable features including good biocompatibility and excellent mechanical properties and clinically used as vascular prosthesis[2], for immobilizing biomolecules[3], culturing hMSCs[4] and embryonic stem cells[5]. Nevertheless, surface functionalization of PET towards calcium phosphate mineralization and its efficacy evaluation for bone tissue regeneration application is hardly explored. Herein we propose surface phosphorylated PET fibre matrix as a 3D culture platform for bone tissue engineering application. In the preliminary phase, PET is surface functionalized by phosphorylation and investigated for biomimetic mineralization of Hydroxyapatite (HAP) in simulated physiological fluid (SBF) having ionic concentration as that of human blood plasma. In subsequent investigation, the in vitro cytocompatibility as well as cell proliferation were analyzed followed by assessment of in vitro biological biomineralization. Experimental: Surface hydrolysis of PET was performed with 1% NaOH for 60 min followed by surface phosphorylation at 80 oC for 90 min as per a procedure reported previously by our group[6]. In vitro mineralization of the surface phosphorylated PET (referred as SPPET) was assessed by subjecting SPPET to SBF treatment for 10 days and SEM-EDX analysis was employed to view the calcium phosphate nucleation and growth. To analyse cytocompatibility MTT analysis was performed using HeLa cells seeded in a 96 well plate (TPP, Germany). Assay was read by Chameleon Plate Reader at 24h post incubation and plotted as % activity. In vitro biomineralization (calcium deposition) was assessed using Human Osteosarcoma Cells (HOS) cells by von kossa staining method while alkaline phosphatase (ALP) activity upto 21 days measured using ALP kit. Results and Discussion: Phosphorylation and calcium phosphate formation was primarily ensured by Micro FT-IR spectroscopy. SEM analysis imparted insights into the homogeneous growth of calcium phosphate on SPPET fibrous matrix, corroborated by EDX analysis (Figure 1). MTT analysis confirmed the cytocompatibility nature of PET, HPET and SPPET samples exhibiting more than 80% viability at 24 hours demonstrating that neither surface phosphorylation, nor surface hydrolysis altered the biocompatibility profile (Figure 2). Cells exposed to materials retained morphology similar to that of control cells and indicated absence of any stress granulation or fibrillation. In vitro biomineralization was confirmed by von-kossa staining while ALP activity profile imparted information on the initial matrix mineralization characteristics. Conclusions: The results of the study impart valuable information on the feasibility of employing surface phoshorylated polyethylene terephthalate as a favourable matrix for bone cell in growth in the in vitro conditions. Future investigations could be performed for evaluating the in vivo efficacy of this potentially active substrate towards bone tissue engineering applications.
References: [1] Zhao G., Zhang X., Lu J. T. and Xu F. Adv. Funct. Mater.,2015, 25: 5726–5738. [2] Zarge J I, Huang P and Greisler H P 1997, Blood vessels, Principles of Tissue Engineering ed R P Lanza, R Langer and W L Chick (Austin, TX: Academic) pp 349–64 [3] Z Ma, M Kotaki, T. Yong, W. He, S. Ramakrishna, Biomaterials ,2005,6, 2527–2536 [4] Grayson W L, Zhao F, Reza I, Bunnell B and Ma T 2006, J. Cell. Physiol., 207 331–9 [5] Ouyang A L, Ng R and Yang S T, Stem Cells, 200725 447–54 [6] Sailaja G S, Mohanty M, Kumary T V, Mohanan PV, Ramesh P and Varma H K, Tissue engineering Part A, 2009 , 15, 3061-3069 Keywords: Surface modification, Calcium phosphate, 3D scaffold, Bone graft Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Biomimetic materials Citation: Gs S, P R, Fernandez FB, Cv M and Varma H (2016). Surface phosphorylated polyethylene terephthalate fibrous matrix: an efficient scaffold with biomineralization potential for bone tissue engineering applications. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.00596 Received: 27 Mar 2016; Published Online: 30 Mar 2016.
