- MSc, (2014-2016): Fabrication and Characterization of Bi-layer Polymeric Nanocomposite Scaffolds for development of Nerve Conduit consist of Poply vinyl alcohol-Sodium Alginate:Graphene/eggshell membrane-PCLF double network
Damages in the peripheral nervous system could be occurred due to the sporting activities, accident and sudden impacts. Although the application of nerve guidance conduit is an effective way to regenerate the peripheral nerves, due to inappropriate biomaterial selection and conduit design, they could not successfully rebuild damaged tissue. The aim of this study is to fabricate bi-layer scaffold with appropriate mechanical, structural, electrical and biological features in order to improve the peripheral nerve repair. In this study, the fabricated bi-layer nerve guidance conduit consisted of fibrous nanocomposite scaffold of sodium alginate-polyvinyl alcohol:graphene (PVA-Alg:Gr) (inner layer) and the double network scaffold made of eggshell memrbare-polycaprolactone fumarate.(ESM-PCLF)(the outer layer). In this way, PVA-Alg:Gr was developed using electrospining and optimized. Moreover, the effect of different amounts of Gr nanoparticles (0, 0.5, 1, 2 and 5 wt%) on the mechanical, electrical, biological and chemical properties as well as degradation rate were studied. In addition, due to the importance of directional growth of nerve cells to accelerate nerve regeneration process, the arrangement of fibers (parallel or perpendicular) on the mechanical properties of scaffolds were evaluated. Moreover, due to low thickness and fibrous artitucture, electrospun fibrous scaffolds usually do note have mechanical stability during surgery. Therefore, double network of eggshell membrane- polycaprolactone fumarate(PCLF) was developed via PCLF penetration into the egg membrane and applied as the outer layer of nerve chanells. In this way, the effect of solvent type of PCLF (dichloromethane and acetic acid) on the penetration of PCLF solution into the eggshell membrane was evaluaed based on their physical and mechanical properties. After the optimization of two layers, the ability to adhere two layers using a scarified fibrous polycaprolactone layer was assessed. Inner membrane showed that graphene nanocomposites containing 1 wt% (1 Gr-AP) have highest electrical conductivity and mechanical properties compared to other nanocomposites. Moreover, Gr nanosheets had a significant role on the degradation rate of scaffolds via controlling the water contact angle. In this regards, the degradation rate of the scaffold decreased from 23.3 ±2.6% (in AP scaffold) to % 11.7±2.1 (in 1Gr-AP scaffold). The results of cell culture also revealed that the ptomoted attachment and proliferation of PC12 cells on the scaffold 1Gr-AP due to its superior electrical and mechanical properties. Morover, the cells on the scaffold cell with aligned fibers revealed improved attachment, growth and proliferation than random one. The results of the evaluation of outer layer of channel (eggshell membrane-PCLF) showed that the addition of PCLF did not significantly change the biological properties of egg membrane while could significantly improve its mechanical properties. The tensile strength of ESM-PCLF with the acetic acid as solvent also revaled that the strength and toughness of membrane increased 12 and 26 times compared to egg shell membrane. Moreover, the strength, toughness and elastic modulus of the two layered scaffold (PVA-Alg:Gr/ESM-PCLF) were about 31.8±4.1 MPa, 16.5 ±0.4 MPa and 52.3±19.2 MPa, respectily which was higher than the mechanical properties of fibrous scaffolds. It could be indicated the higher ability of double-layer scaffold to withstand mechanical load during surgery. Accordingly, bi-layer nerve guidance conduit consist of PVA-Alg:Gr as inner layer and ESM-PCLF as outer layer by sufficient mechanical, electrical, structural, chemical and biological could be a suitable clinical method to regenerate peripheral nerve system.
Outcome: 1st Paper, 2nd Paper, 3rd Paper, 4th Paper, 5th Paper
1-M. Alehosseini, N. Golafshan, T. Ahmadi, M. Kharaziha, Fabrication Hemocompatible (PCL-1α)-heparin Nanocomposite Fibrous membrane for bone tissue Regeneration. International Biennial Conference on UltraFine Grained and NanoStructures Mateirlas, November 2017, Kish.
2-M. Alehosseini, N. Golafshan, T. Ahmadi, M. Kharaziha, Controlled release of heparin from fibrous membrane of biomineralized Polycaprolactone:ɑ-Tricalcium Phosphate. International conference on Nanofibers, October 2017, Tehran.
3-M. Alehosseini, N. Golafshan, M. Kharaziha, Development of an electrospun ɑ-TCP/PCL nanocomposite membrane for Guided Bone Regeneration application. International conference on Nanotechnology and Nanomedicine, April 2017, Tehran.
4-N. Golafshan, M. Kharaziha, M.H. Fathi, Fabrication and Evaluation of Sodium Alginate: Poly Vinyl Alcohol/Graphene Nanocomposite Fibrous Scaffold for Nerve Tissue Engineering Application. Proceedings of the 6th International Congress on Nanoscience & Nanotechnology, March 2016. Kish Island.
5-N. Golafshan, R. Rezahassani, M. Kharaziha, Fabrication and characterization of Polyvinyl alcohol: sodium Alginate/ Laponiote nanodisc for the soft tissue applications. International Conference on materials engineering and metallurgy. November 2016. Shiraz University.
6-N. Golafshan, M. Kharaziha, M. Fathi, Bi-layer conductive ESM-PCLF/PVA-Alg:Gr electrospun fibrous conduit for neural tissue engineering, 2nd national conference of stem cell, Tehran, Iran, 2017.
7-N. Golafshan, H. R. Gharibi, M. Kharaziha, M. H. Fathi, Fabrication and Evaluation of Novel Double Network Fibrous Scaffold of eggshell:Polycaprolactone Fumarate for nerve tissue engineering Application. 3rd Iranian Congress on process in tissue engineering and regenerative medicine, 19-21 Oct., 2016. Tehran, Iran.
8-N. Golafshan, F. Karimzadeh, M. Enayati, Study of Mechanochemical Synthesis and Formation Mechanism of Iron Boride and Alumina Nano Composite, Proceeding of 2nd Iranian conference of Nano Technology, Tehran, Iran, 2013.