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Synthesis and Characterization of Nanofibrous Polymeric Composite Containing Two-dimensional MXene and Capable of Drug Release for Tissue Engineering Applications

Koohkhezri, Morvarid | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55500 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Simchi, Abdolreza
  7. Abstract:
  8. Nowadays, biocompatible composites are being utilized as scaffolds supporting cell growth promotion and features with the aim of organs regeneration or substitution based on tissue engineering principals. Moreover, in order to improve bioscaffolds features and function, various two-dimensional composite fillers have been under investigation; for instance, Graphene, Boron nitride, Metal dichalcogenides and oxides and black phosphorous and also electrospinning is mentioned as one of the most compatible and conventional processes of scaffold design that is also the main method of fabrication in this study. In addition, it should be pointed that biocompatible polymers and particularly natural polymers have been introduced as suitable choices of biological scaffold building materials. In this study, a biocomposite is prepared through coaxial electrospinning of core-shell nanofibers containing a blend of natural polymer of Pectin and synthetic polymer of Poly (vinyl alcohol) as shell fibers and Polycaprolactone polymer as core fibers component. To improve mechanical, electrical, antibacterial and drug release properties of electrospun mat, synthesized two-dimensional titanium carbide known as Ti3C2TX MXene, have been used as shell fibers filler. Additionally, to investigate the drug release capability of prepared films, shell fibers are loaded with Berberine chloride (BBR) drug. Post-electrospinning processes are including ionic and covalent cross-linking of PVA and Pectin polymeric fibers by calcium chloride aqueous solution and Glutheraldehyde, respectively. Crosslinked fibers have been investigated using Fourier Transform Infrared Spectroscopy (FTIR). The outcome results of Field Emission Scanning Electron Microscopy(FESEM) and electrospinning parameter optimization, indicate that MXene presence leads to wider fiber distribution and approximately defectless fibers. In addition, the effect of simultaneous presence of MXene nanosheets and BBR drug have been discussed. Moreover, core-shell morphology of Electrospun mat has directly positively affect the scaffold required mechanical properties. The tensile mechanical test also demonstrates that MXene has improved the ultimate mechanical strength of films in both wet and dry testing conditions to 7 and 4 times more than scaffolds without nanosheets in shell fibers. Furthermore, according to addition of covalent bonds, ultimate strength of crosslinked mats for wet and dry condition increased to 378 and 1028, respectively. In addition, MXene presence stands for examined antibacterial feature in the prepared films. Due to the electrostatic forces appeared between negatively charged MXene nanosheets and cations produced from BBR drug, MXene conjugation leads to the capability of preparing fibers loaded with higher drug doses and consequently 6% higher amount of drug release. Finally, cell toxicity of films has been investigated through MTT assay and results indicates for more than 80% cell viability in 24 and 48. In order to study the hydrophilicity of these scaffolds, the contact angle analysis shows that fabricated films are hydrophilic and this feature is directly related to MXene and BBR drug presence which generates a contact angle of 60° due to the 0.1% wt/v MXene and 0.06% wt/v BBR addition. The biodegradation of fibers also demonstrates that simultaneous ionic and covalent cross-linking has resulted in an optimal and desirable degradation of Electrospun mats decreasing from 39% in non-crosslinked samples to 27% in dual crosslinked ones. Finally, proper cell attachment on core-shell fibers observed after 24 hours cultivation.
  9. Keywords:
  10. Pectin ; Polymeric Complexes ; Tissue Engineering ; Electrospinning ; Mechanical Properties ; Nanostructure ; MXene Nanosheets ; Structure Modification ; Biological Properties ; Core-Shell Structure

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