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Fabrication and Photocatalytic Properties of Electrospun Fe-Doped TiO 2 Nanofibers Using Polyvinyl Pyrrolidone Precursors. Polymers (Basel) 2021; 13:polym13162634. [PMID: 34451174 PMCID: PMC8398590 DOI: 10.3390/polym13162634] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/04/2021] [Accepted: 08/05/2021] [Indexed: 11/17/2022] Open
Abstract
For the removal of pollutants, a modified TiO2 photocatalyst is attracting attention. Fe-doped TiO2 nanofibers were prepared through a combination of electrospinning and calcination. Morphological characterization of the sample was conducted using field-emission scanning electron and transmission electron microscopy. The crystal structure of each sample was analyzed using high-resolution transmission electron microscopy, selected area electron diffraction, and Fast Fourier Transform imaging. The average diameter of the Fe-doped TiO2 nanofibers was measured to be 161.5 nm and that of the pure TiO2 nanofibers was 181.5 nm. The crystal phase when heat treated at 350 °C was anatase for TiO2 nanofibers and rutile for Fe-doped TiO2 nanofibers. The crystal phase of the TiO2 matrix was easily transitioned to rutile by Fe-doping. The photocatalytic performance of each sample was compared via the photodegradation of methylene blue and acid orange 7 under ultraviolet and visible light irradiation. In the Fe-doped TiO2 nanofibers, photodegradation rates of 38.3% and 27.9% were measured under UV irradiation and visible light, respectively. Although other catalysts were not activated, the photodegradation rate in the Fe-doped TiO2 nanofibers was 9.6% using acid orange 7 and visible light. For improved photocatalytic activity, it is necessary to study the concentration control of the Fe dopant.
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de Oliveira FCS, do Amaral RJFC, Dos Santos LEC, Cummins C, Morris MM, Kearney CJ, Heise A. Versatility of unsaturated polyesters from electrospun macrolactones: RGD immobilization to increase cell attachment. J Biomed Mater Res A 2021; 110:257-265. [PMID: 34322978 DOI: 10.1002/jbm.a.37282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 07/19/2021] [Accepted: 07/21/2021] [Indexed: 11/10/2022]
Abstract
Poly(globalide) (PGl), an aliphatic polyester derived from unsaturated macrocylic lactone, can be cross-linked during electrospinning and drug-loaded for regenerative medicine applications. However, it lacks intrinsic recognition sites for cell adhesion and proliferation. In order to improve their cell adhesiveness, and therefore their therapeutic potential, we aimed to functionalize electrospun PGl fibers with RGD sequence generating a biomimetic scaffold. First, an amine compound was attached to the surface double bonds of the PGl fibers. Subsequently, the amino groups were coupled with RGD sequences. X-ray photoelectron spectroscopy (XPS) analysis confirmed the functionalization. The obtained fibers were more hydrophilic, as observed by contact angle analysis, and presented smaller Young's modulus, although similar tensile strength compared with non-functionalized cross-linked fibers. In addition, the functionalization process did not significantly alter fibers morphology, as observed by scanning electron microscopy (SEM). Finally, in vitro analysis evidenced the increase in human mesenchymal stromal cells (hMSC) adhesion (9.88 times higher DNA content after 1 day of culture) and proliferation (3.57 times higher DNA content after 8 days of culture) compared with non-functionalized non-cross-linked fibers. This is the first report demonstrating the functionalization of PGl fibers with RGD sequence, improving PGl therapeutic potential and further corroborating the use of this highly versatile material toward regenerative medicine applications.
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Affiliation(s)
| | - Ronaldo Jose Farias Correa do Amaral
- Kearney Lab, Department of Anatomy and Regenerative Medicine, RCSI University of Medicine and Health Science, Dublin, Ireland.,Tissue Engineering Research Group (TERG), Department of Anatomy, RCSI University of Medicine and Health Science, Dublin, Ireland.,CÚRAM, SFI Research Centre for Medical Devices, National University of Ireland Galway (NUIG) & RCSI, Galway, Ireland
| | - Luiza Erthal Cardoso Dos Santos
- School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin (TCD), Dublin, Ireland.,Trinity Biomedical Sciences Institute, TCD, Dublin, Ireland
| | - Cian Cummins
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Dublin, Ireland.,AMBER, The SFI Centre for Advanced Materials and Bioengineering, TCD & RCSI, Dublin, Ireland
| | - Michael M Morris
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Dublin, Ireland.,AMBER, The SFI Centre for Advanced Materials and Bioengineering, TCD & RCSI, Dublin, Ireland
| | - Cathal J Kearney
- Kearney Lab, Department of Anatomy and Regenerative Medicine, RCSI University of Medicine and Health Science, Dublin, Ireland.,Tissue Engineering Research Group (TERG), Department of Anatomy, RCSI University of Medicine and Health Science, Dublin, Ireland.,AMBER, The SFI Centre for Advanced Materials and Bioengineering, TCD & RCSI, Dublin, Ireland
| | - Andreas Heise
- Department of Chemistry, RCSI University of Medicine and Health Science, Dublin, Ireland.,CÚRAM, SFI Research Centre for Medical Devices, National University of Ireland Galway (NUIG) & RCSI, Galway, Ireland.,AMBER, The SFI Centre for Advanced Materials and Bioengineering, TCD & RCSI, Dublin, Ireland
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Effect of POSS-Modified Montmorillonite on Thermal, Mechanical, and Electrical Properties of Unsaturated Polyester Nanocomposites. Polymers (Basel) 2020; 12:polym12092031. [PMID: 32906616 PMCID: PMC7564685 DOI: 10.3390/polym12092031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 08/28/2020] [Accepted: 09/01/2020] [Indexed: 11/21/2022] Open
Abstract
Montmorillonite (MMT) displays excellent cohesion with an unsaturated polyester (UP) matrix to generate a material which exhibits an extensive range of commercial applications. The organic modification of MMT using polyhedral oligomeric silsesquioxanes (POSS) and the effect of POSS-MMT on the thermal, mechanical, and electrical properties of UP are reported here. Transmission electron microscopy (TEM) images were used to characterize the modification of MMT using POSS. Modified MMT (POSS-MMT) was incorporated, at different wt.% (0.5, 1, 3, 5), into UP via in-situ polymerization. The presence of POSS-MMT enhanced the characteristic properties of UP as a consequence of good dispersion in the polymer matrix. Scanning electron microscopy (SEM) images support effective POSS-MMT dispersion leading to tensile strength enhancement of a UP/POSS-MMT nanocomposite (3 wt.% POSS-MMT) by 54.7% as compared to that for unmodified UP. TGA displays a 35 °C improvement of thermal stability (10% mass loss) at 5% POSS-MMT incorporation, while the electrical conductivity is improved by 108 S/m (3 wt.% POSS-MMT) in comparison to that for unmodified UP. The conventional obstacle of UP associated with shrinkage weight loss during curing seems to be moderated with POSS-MMT incorporation (3%) resulting in a 27.8% reduction in shrinkage weight loss. These fabricated nanocomposites expand the versatility of UP as a high-performance material owing to enhancements of properties.
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