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Fazal F, Raghav S, Callanan A, Koutsos V, Radacsi N. Recent advancements in the bioprinting of vascular grafts. Biofabrication 2021; 13. [PMID: 34102613 DOI: 10.1088/1758-5090/ac0963] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 06/08/2021] [Indexed: 02/07/2023]
Abstract
Recent advancements in the bioinks and three-dimensional (3D) bioprinting methods used to fabricate vascular constructs are summarized herein. Critical biomechanical properties required to fabricate an ideal vascular graft are highlighted, as well as various testing methods have been outlined to evaluate the bio-fabricated grafts as per the Food and Drug Administration (FDA) and International Organization for Standardization (ISO) guidelines. Occlusive artery disease and cardiovascular disease are the major causes of death globally. These diseases are caused by the blockage in the arteries, which results in a decreased blood flow to the tissues of major organs in the body, such as the heart. Bypass surgery is often performed using a vascular graft to re-route the blood flow. Autologous grafts represent a gold standard for such bypass surgeries; however, these grafts may be unavailable due to the previous harvesting or possess a poor quality. Synthetic grafts serve well for medium to large-sized vessels, but they fail when used to replace small-diameter vessels, generally smaller than 6 mm. Various tissue engineering approaches have been used to address the urgent need for vascular graft that can withstand hemodynamic blood pressure and has the ability to grow and remodel. Among these approaches, 3D bioprinting offers an attractive solution to construct patient-specific vessel grafts with layered biomimetic structures.
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Affiliation(s)
- Faraz Fazal
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, EH9 3FB Edinburgh, United Kingdom.,Department of Mechanical Engineering, University of Engineering and Technology, Lahore, (New Campus) Pakistan
| | - Sakshika Raghav
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, EH9 3FB Edinburgh, United Kingdom
| | - Anthony Callanan
- School of Engineering, Institute for Bioengineering, The University of Edinburgh, The King's Buildings, EH9 3JL Edinburgh, United Kingdom
| | - Vasileios Koutsos
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, EH9 3FB Edinburgh, United Kingdom
| | - Norbert Radacsi
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, EH9 3FB Edinburgh, United Kingdom
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Fazal F, Diaz Sanchez FJ, Waqas M, Koutsos V, Callanan A, Radacsi N. A modified 3D printer as a hybrid bioprinting-electrospinning system for use in vascular tissue engineering applications. Med Eng Phys 2021; 94:52-60. [PMID: 34303502 DOI: 10.1016/j.medengphy.2021.06.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 06/04/2021] [Accepted: 06/09/2021] [Indexed: 12/31/2022]
Abstract
There is a high demand for small diameter vascular grafts having mechanical and biological properties similar to that of living tissues. Tissue-engineered vascular grafts using current methods have often failed due to the mismatch of mechanical properties between the implanted graft and living tissues. To address this limitation, a hybrid bioprinting-electrospinning system is developed for vascular tissue engineering applications. The setup is capable of producing layered structure from electrospun fibres and cell-laden hydrogel. A Creality3D Ender 3D printer has been modified into a hybrid setup having one bioprinting head and two electrospinning heads. Fortus 250mc and Flashforge Creator Pro 3D printers were used to print parts using acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) polymers. An Arduino mega 2560 and a Ramps 1.4 controller board were selected to control the functions of the hybrid bioprinting setup. The setup was tested successfully to print a tubular construct around a rotating needle.
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Affiliation(s)
- Faraz Fazal
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom; Department of Mechanical Engineering, University of Engineering and Technology, Lahore, (new campus) Pakistan.
| | - Francisco Javier Diaz Sanchez
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom.
| | - Muhammad Waqas
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom.
| | - Vasileios Koutsos
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom.
| | - Anthony Callanan
- School of Engineering, Institute for Bioengineering, The University of Edinburgh, The King's Buildings, Edinburgh, EH9 3JL, United Kingdom.
| | - Norbert Radacsi
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom.
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Waqas M, Keirouz A, Sanira Putri MK, Fazal F, Diaz Sanchez FJ, Ray D, Koutsos V, Radacsi N. Design and development of a nozzle-free electrospinning device for the high-throughput production of biomaterial nanofibers. Med Eng Phys 2021; 92:80-87. [PMID: 34167715 DOI: 10.1016/j.medengphy.2021.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 04/10/2021] [Accepted: 04/29/2021] [Indexed: 12/13/2022]
Abstract
This technical note provides a step-by-step guide for the design and construction of a temperature-controlled nozzle-free electrospinning device. The equipment uses a rotating mandrel partially immersed within a polymer solution to produce fibers in an upward motion by inducing the formation of multiple Taylor cones and subsequently multi-jetting out of an electrified open surface. Free-surface electrospinning can overcome limitations and drawbacks associated with single and multi-nozzle spinneret configurations, such as low yield, limited production capacity, nonuniform electric field distribution, and clogging. Most importantly, this lab-scaled high-throughput device can provide an alternative economical route for needleless electrospinning research, in contrast to the high costs associated with industrially available upscaling equipment. Among the device's technical specifications, a key feature is a cryo-collector mandrel, capable of collecting fibers in sub-zero temperatures, which can induce ultra-porous nanostructures, wider pores, and subsequent in-depth penetration of cells. A multi-channel gas chamber allows the conditioning of the atmosphere, temperature, and airflow, while the chamber's design averts user exposure to the high-voltage components. All the Computer-Aided Design (CAD) files and point-by-point assembly instructions, along with a list of the materials used, are provided.
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Affiliation(s)
- Muhammad Waqas
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom
| | - Antonios Keirouz
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom
| | - Maria Kana Sanira Putri
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom
| | - Faraz Fazal
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom.; Department of Mechanical Engineering, University of Engineering and Technology, Lahore, (city campus) Pakistan
| | - Francisco Javier Diaz Sanchez
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom
| | - Dipa Ray
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom
| | - Vasileios Koutsos
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom
| | - Norbert Radacsi
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Robert Stevenson Road, Edinburgh, EH9 3FB, United Kingdom..
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Fazal F, Mittal A, Ray A, Gupta N. Haemophagocytic lymphohistiocytosis (HLH) in human immunodeficiency virus (HIV): A systematic review of literature. Int J Infect Dis 2020. [DOI: 10.1016/j.ijid.2020.09.773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Abstract
This study is focused towards developing a global consensus sequence of nonstructural protein 2 (NSP2), a protease of Chikungunya Virus (CHIKV) and predict immunogenic promiscuous T-cell epitopes based on various bioinformatics tools. To date, no epitope data is available for the Chikungunya virus in the IEDB database. In this study, 100 available nucleotide sequences of NSP2-CHIKV belonging to different strains were downloaded from the National Centre for Biotechnology Information (NCBI) database. The nucleotide sequences were subjected to translated sequencing using the EXPASY tool followed by protein alignment using the CLC workbench and a global consensus sequence for the respective protein was developed. IEDB tool was used to predict HLA-I and HLA-II binding promiscuous epitopes from the consensus sequence of NSP2-CHIKV. Thirty-four B-cell based epitopes are predicted and the promiscuous epitope is VVDTTGSTKPDPGD at position 341-354. Twenty-six MHC-I short peptide epitopes are predicted to bind with HLA-A. The promiscuous epitopes predicted to bind with HLA-A*01:01 are VTAIVSSLHY, SLSESATMVY, FSKPLVYY, QPTDHVVGEY at positions 317-326, 84-93, 535-544 and 15-24 with percentile ranks 0.17, 0.39, 0.51 and 0.81, respectively. Twenty-four MHC-II short peptide epitopes are predicted for HLA-DRB. The promiscuous epitope predicted to bind with HLA-DRB*01:01 is VVGEYLVLSPQTVLRS from 20-35 with a lowest percentile rank of 0.01. These predicted epitopes can be effective targets towards development of vaccine against CHIKV. Epitopes predicted in this study displayed good binding affinity, antigenicity and promiscuity for the HLA classes. These predicted epitopes can prove to be translationally important towards the development of CHIKV.
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Affiliation(s)
- F Fazal
- Department of Biosciences, COMSATS University Islamabad, Pakistan
| | - T Anwar
- Department of Biosciences, COMSATS University Islamabad, Pakistan
| | - Y Waheed
- Foundation University Medical College, Foundation University Islamabad, Pakistan
| | - F Parvaiz
- Department of Biosciences, COMSATS University Islamabad, Pakistan
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Adami C, Pooley J, Glomb J, Stecker E, Fazal F, Fleming JO, Baker SC. Evolution of mouse hepatitis virus (MHV) during chronic infection: quasispecies nature of the persisting MHV RNA. Virology 1995; 209:337-46. [PMID: 7778268 PMCID: PMC7131440 DOI: 10.1006/viro.1995.1265] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Coronavirus infection of mice has been used extensively as a model for the study of acute encephalitis and chronic demyelination. To examine the evolution of coronavirus RNA during chronic demyelinating infection, we isolated RNA from intracerebrally inoculated mice at 4, 6, 8, 13, 20, and 42 days postinfection and used reverse transcription-polymerase chain reaction amplification methods (RT-PCR) to detect viral sequences. RNA sequences from two viral structural genes, the spike gene and the nucleocapsid gene, were detected throughout the chronic infection. In contrast, infectious virus was not detectable from brain homongenates beyond 13 days postinfection. These results indicate that coronavirus RNA persists in the brain at times when infectious virus is not detected. To determine if genetic changes were occurring during viral replication in the host, we cloned and sequenced the RT-PCR products from the spike and nucleocapsid regions and analyzed the sequences for mutations. Sequencing of the cloned products revealed that a variety of mutant forms of viral RNA persisted in the CNS, including point mutants, deletion mutants, and termination mutants. The mutations accumulated during persistent infection in both the spike and the nucleocapsid sequences, with greater than 65% of the mutations encoding amino acid changes. These results show that a diverse population or quasispecies consisting of mutant and deletion variant viral RNAs (which may not be capable of producing infectious virus particles) persists in the central nervous system of mice during chronic demyelinating infection. The implications of these results for the role of persistent viral genetic information in the pathogenesis of chronic demyelination are discussed.
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Affiliation(s)
- C Adami
- Department of Microbiology and Immunology, Loyola University of Chicago Stritch School of Medicine, Maywood, Illinois 60153, USA
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Fleming JO, Adami C, Pooley J, Glomb J, Stecker E, Fazal F, Baker SC. Mutations associated with viral sequences isolated from mice persistently infected with MHV-JHM. Adv Exp Med Biol 1995; 380:591-5. [PMID: 8830547 DOI: 10.1007/978-1-4615-1899-0_94] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Mouse hepatitis virus JHM (JHMV or MHV-4) induces subacute and chronic demyelination in rodents and has been studied as a model human demyelinating diseases, such a multiple sclerosis. However, despite intensive investigation, the state of JHMV during chronic disease is poorly understood. Using reverse transcription-polymerase chain reaction amplification (RT-PCR) to "rescue" viral RNA, we have found that JHMV-specific sequences persist for at least 787 days after intracerebral inoculation of experimental mice. Analysis of persisting viral RNA reveals that it is extensively mutated, and we hypothesize that the mutations observed reflect adaptation of the viral quasispecies to low-level intracellular replication during chronic disease.
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Affiliation(s)
- J O Fleming
- Department of Neurology, University of Wisconsin School of Medicine, Madison, USA
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Said Ahmad M, Fazal F, Rahman A, Hadi SM, Parish JH. Activities of flavonoids for the cleavage of DNA in the presence of Cu(II): correlation with generation of active oxygen species. Carcinogenesis 1992; 13:605-8. [PMID: 1315626 DOI: 10.1093/carcin/13.4.605] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The activities of several flavonoids and the related nonflavonoid compound epicatechin were compared with respect to Cu(II)-induced strand scission of DNA by using two different assays. The same series of compounds was used to study the stoichiometry of Cu(II) reduction in the absence of DNA. The compounds were compared for their ability to generate superoxide, hydrogen peroxide and the Cu(II)-dependent production of hydroxyl radicals. Flavonoids were examined to assess the production of a charge-transfer complex with Cu and the rate of decay of the complexes were compared. All the compounds tested had some ability to cause DNA strand scission in the presence of Cu(II), with myricetin being the most active and galangin the least active. The ability to cause such scission correlated with the rate of decay of the charge-transfer complex, the ability to generate active oxygen species and with the stoichiometry of Cu(II) binding. Analysis of the data in the light of the structural differences between the flavonoids led to a discussion of alternative Cu(II)-sequestering mechanisms.
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Affiliation(s)
- M Said Ahmad
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University
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Rahman A, Fazal F, Greensill J, Ainley K, Parish JH, Hadi SM. Strand scission in DNA induced by dietary flavonoids: role of Cu(I) and oxygen free radicals and biological consequences of scission. Mol Cell Biochem 1992; 111:3-9. [PMID: 1588940 DOI: 10.1007/bf00229567] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The naturally occurring flavonoid, quercetin, in the presence of Cu(II) and molecular oxygen caused breakage of calf thymus DNA, supercoiled pBR322 plasmid DNA and single stranded M13 phage DNA. In the case of the plasmid, the product(s) were relaxed circles or a mixture of these and linear molecules depending upon the conditions. For the breakage reaction, Cu(II) could be replaced by Fe(III) but not by other ions tested [Fe(II), Co(II), Ni(II), Mn(II) and Ca(II)]. Structurally related flavonoids, rutin, galangin, apigenin and fisetin were effective or less effective than quercetin in causing DNA breakage. In the case of the quercetin-Cu(II) reaction, Cu(I) was shown to be essential intermediate by using the Cu(I)-sequestering reagent, bathocuproine. By using Job plots we established that, in the absence of DNA, five Cu(II) ions were reduced by one quercetin molecule; in contrast two ions were reduced per quercetin molecule in the DNA breakage reaction. Equally neocuproine inhibited the DNA breakage reaction. The involvement of active oxygen in the reaction was established by the inhibition of DNA breakage by superoxide dismutase, iodide, mannitol, formate and catalase (the inhibition was complete in the last case). The strand scission reaction was shown to account for the biological activity of quercetin as assayed by bacteriophage inactivation. From these data we propose a mechanism for the DNA strand scission reaction of quercetin and related flavonoids.
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Affiliation(s)
- A Rahman
- Interdisciplinary Biotechnology Unit, Faculty of Life Sciences, Aligarh Muslim University, India
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Fazal F, Rahman A, Greensill J, Ainley K, Hadi SM, Parish JH. Strand scission in DNA by quercetin and Cu(II): identification of free radical intermediates and biological consequences of scission. Carcinogenesis 1990; 11:2005-8. [PMID: 2171797 DOI: 10.1093/carcin/11.11.2005] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Quercetin was shown to reduce oxygen to superoxide. In the presence of Cu(II), the hydroxyl radical was formed. The strand scission of DNA was shown to occur under conditions in which Cu(II), quercetin and either hydrogen peroxide or oxygen were present and superoxide was not a necessary intermediate. Strand scission involved the hydroxyl radical and a radical DNA intermediate. The strand scission reaction was shown to account for the biological activity of quercetin as assayed by bacteriophage inactivation.
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Affiliation(s)
- F Fazal
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, India
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