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Müller M, Wöltje M, Hofmaier M, Tarpara B, Urban B, Aibibu D, Cherif C. In Situ ATR-FTIR Studies on the β-Sheet Formation of Native and Regenerated Bombyx mori Silk Material in Solution and Its Potential for Drug Releasing Coatings. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 39073396 DOI: 10.1021/acs.langmuir.4c00920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Dynamic attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy at both solutions and coatings of a semicrystalline silk material derived from Bombyx mori was applied to monitor the β-sheet conformation, which is known to correlate with silk protein crystallinity. The secondary structure-sensitive Amide I band was analyzed. Two silk protein samples were studied: native-based silk buffer fibroin (NSF) was extracted from silk glands and regenerated silk fibroin (RSF) was extracted from degummed cocoons. Solutions of both NSF and RSF at 2 mg/mL featured low initial β-sheet contents of 5-12%, which further increased to 47-53% after 24 h. RSF and NSF solutions at 23 mg/mL also featured low initial β-sheet contents of 9-10%, which yet only slightly increased to 16-17% after 24 h. Coatings deposited from RSF solutions showed high surface integrity (Q > 99%) after rinsing in mineralized water, enabling interfacial drug delivery applications. RSF coatings were post-treated with either formic acid (FA) or pure methanol (MeOH) vapor to showcase inducibility of crystalline domains in RSF coatings. Such coatings were loaded with the model antibiotic drugs tetracycline (TCL) and streptomycin (STRP), and the sustained release of TCL was followed in contact with (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) (HEPES) buffer. RSF/TCL coatings post-treated with formic acid (FA) vapor followed by methanol (MeOH) vapor showed a significantly lower (52%) initial burst of rather hydrophobic TCL compared to untreated RSF/TCL coatings (72%), while no such significant release difference was observed for hydrophilic STRP. This was rationalized by a specific interaction between nonpolar TCL and hydrophobic crystalline RSF domains.
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Affiliation(s)
- M Müller
- Department Functional Colloidal Materials, Leibniz Institute of Polymer Research Dresden, Hohe Straße 6, 01069 Dresden, Germany
- Department Chemistry and Food Chemistry, TUD Dresden University of Technology, 01062 Dresden, Germany
| | - M Wöltje
- TUD Dresden University of Technology, Institute of Textile Machinery and High-Performance Material Technology, 01062 Dresden, Germany
| | - M Hofmaier
- Department Functional Colloidal Materials, Leibniz Institute of Polymer Research Dresden, Hohe Straße 6, 01069 Dresden, Germany
- Department Chemistry and Food Chemistry, TUD Dresden University of Technology, 01062 Dresden, Germany
| | - B Tarpara
- Department Functional Colloidal Materials, Leibniz Institute of Polymer Research Dresden, Hohe Straße 6, 01069 Dresden, Germany
- Department Processing Technology, Leibniz Institute of Polymer Research Dresden, Hohe Straße 6, 01069 Dresden, Germany
| | - B Urban
- Department Functional Colloidal Materials, Leibniz Institute of Polymer Research Dresden, Hohe Straße 6, 01069 Dresden, Germany
| | - D Aibibu
- TUD Dresden University of Technology, Institute of Textile Machinery and High-Performance Material Technology, 01062 Dresden, Germany
| | - C Cherif
- TUD Dresden University of Technology, Institute of Textile Machinery and High-Performance Material Technology, 01062 Dresden, Germany
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Moreno-Tortolero RO, Luo Y, Parmeggiani F, Skaer N, Walker R, Serpell LC, Holland C, Davis SA. Molecular organization of fibroin heavy chain and mechanism of fibre formation in Bombyx mori. Commun Biol 2024; 7:786. [PMID: 38951579 PMCID: PMC11217467 DOI: 10.1038/s42003-024-06474-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 06/19/2024] [Indexed: 07/03/2024] Open
Abstract
Fibroins' transition from liquid to solid is fundamental to spinning and underpins the impressive native properties of silk. Herein, we establish a fibroin heavy chain fold for the Silk-I polymorph, which could be relevant for other similar proteins, and explains mechanistically the liquid-to-solid transition of this silk, driven by pH reduction and flow stress. Combining spectroscopy and modelling we propose that the liquid Silk-I fibroin heavy chain (FibH) from the silkworm, Bombyx mori, adopts a newly reported β-solenoid structure. Similarly, using rheology we propose that FibH N-terminal domain (NTD) templates reversible higher-order oligomerization driven by pH reduction. Our integrated approach bridges the gap in understanding FibH structure and provides insight into the spatial and temporal hierarchical self-assembly across length scales. Our findings elucidate the complex rheological behaviour of Silk-I, solutions and gels, and the observed liquid crystalline textures within the silk gland. We also find that the NTD undergoes hydrolysis during standard regeneration, explaining key differences between native and regenerated silk feedstocks. In general, in this study we emphasize the unique characteristics of native and native-like silks, offering a fresh perspective on our fundamental understanding of silk-fibre production and applications.
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Affiliation(s)
- Rafael O Moreno-Tortolero
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
- Max Planck-Bristol Centre for Minimal Biology, University of Bristol, Bristol, BS8 1TS, UK.
| | - Yijie Luo
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
- School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Fabio Parmeggiani
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
- School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, King Edward VII Ave, Cardiff, CF10 3NB, UK
| | - Nick Skaer
- Orthox Ltd, Milton Park, 66 Innovation Drive, Abingdon, OX14 4RQ, UK
| | - Robert Walker
- Orthox Ltd, Milton Park, 66 Innovation Drive, Abingdon, OX14 4RQ, UK
| | - Louise C Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| | - Chris Holland
- Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - Sean A Davis
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
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De Giorgio G, Matera B, Vurro D, Manfredi E, Galstyan V, Tarabella G, Ghezzi B, D'Angelo P. Silk Fibroin Materials: Biomedical Applications and Perspectives. Bioengineering (Basel) 2024; 11:167. [PMID: 38391652 PMCID: PMC10886036 DOI: 10.3390/bioengineering11020167] [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: 12/14/2023] [Revised: 01/13/2024] [Accepted: 02/05/2024] [Indexed: 02/24/2024] Open
Abstract
The golden rule in tissue engineering is the creation of a synthetic device that simulates the native tissue, thus leading to the proper restoration of its anatomical and functional integrity, avoiding the limitations related to approaches based on autografts and allografts. The emergence of synthetic biocompatible materials has led to the production of innovative scaffolds that, if combined with cells and/or bioactive molecules, can improve tissue regeneration. In the last decade, silk fibroin (SF) has gained attention as a promising biomaterial in regenerative medicine due to its enhanced bio/cytocompatibility, chemical stability, and mechanical properties. Moreover, the possibility to produce advanced medical tools such as films, fibers, hydrogels, 3D porous scaffolds, non-woven scaffolds, particles or composite materials from a raw aqueous solution emphasizes the versatility of SF. Such devices are capable of meeting the most diverse tissue needs; hence, they represent an innovative clinical solution for the treatment of bone/cartilage, the cardiovascular system, neural, skin, and pancreatic tissue regeneration, as well as for many other biomedical applications. The present narrative review encompasses topics such as (i) the most interesting features of SF-based biomaterials, bare SF's biological nature and structural features, and comprehending the related chemo-physical properties and techniques used to produce the desired formulations of SF; (ii) the different applications of SF-based biomaterials and their related composite structures, discussing their biocompatibility and effectiveness in the medical field. Particularly, applications in regenerative medicine are also analyzed herein to highlight the different therapeutic strategies applied to various body sectors.
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Affiliation(s)
- Giuseppe De Giorgio
- IMEM-CNR, Institute of Materials for Electronics and Magnetism-National Research Council, Parco Area delle Scienze 37/A, 43124 Parma, Italy
| | - Biagio Matera
- Center of Dental Medicine, Department of Medicine and Surgery, University of Parma, Via Gramsci 14/A, 43126 Parma, Italy
| | - Davide Vurro
- IMEM-CNR, Institute of Materials for Electronics and Magnetism-National Research Council, Parco Area delle Scienze 37/A, 43124 Parma, Italy
| | - Edoardo Manfredi
- Center of Dental Medicine, Department of Medicine and Surgery, University of Parma, Via Gramsci 14/A, 43126 Parma, Italy
| | - Vardan Galstyan
- IMEM-CNR, Institute of Materials for Electronics and Magnetism-National Research Council, Parco Area delle Scienze 37/A, 43124 Parma, Italy
- Department of Engineering "Enzo Ferrari", University of Modena and Reggio Emilia, Via Vivarelli 10, 41125 Modena, Italy
| | - Giuseppe Tarabella
- IMEM-CNR, Institute of Materials for Electronics and Magnetism-National Research Council, Parco Area delle Scienze 37/A, 43124 Parma, Italy
| | - Benedetta Ghezzi
- IMEM-CNR, Institute of Materials for Electronics and Magnetism-National Research Council, Parco Area delle Scienze 37/A, 43124 Parma, Italy
- Center of Dental Medicine, Department of Medicine and Surgery, University of Parma, Via Gramsci 14/A, 43126 Parma, Italy
| | - Pasquale D'Angelo
- IMEM-CNR, Institute of Materials for Electronics and Magnetism-National Research Council, Parco Area delle Scienze 37/A, 43124 Parma, Italy
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Wang X, Ye X, Guo J, Dai X, Yu S, Zhong B. Modeling the 3-dimensional structure of the silkworm's spinning apparatus in silk production. Acta Biomater 2024; 174:217-227. [PMID: 38030101 DOI: 10.1016/j.actbio.2023.11.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 11/07/2023] [Accepted: 11/21/2023] [Indexed: 12/01/2023]
Abstract
The silk-spinning process of the silkworms transforms the liquid silk solution to a solid state under mild conditions, making it an attractive model for bioinspiration However, the precise mechanism behind silk expulsion remains largely unknown. Here we selected the silkworms as representative models to investigate the silk-spinning mechanism. We used serial block-face scanning electron microscopy (SBF-SEM) to reconstruct the three-dimensional structures of the spinnerets in silkworms at various stages and with different gene backgrounds. By comparing the musculature and duct deformation of these spinneret models during the spinning process, we were able to simulate the morphological changes of the spinneret. Based on the results, we proposed three essential factors for silkworm spinning: the pressure generated by the silk gland, the opening duct, and the pulling force generated by head movement. Understanding the silkworm spinning process provides insights into clarify the fluid-ejecting mechanism of a group of animals. Moreover, these findings are helpful to the development of biomimetic spinning device that mimics the push-and-pull dual-force system in silkworms. STATEMENT OF SIGNIFICANCE: The silkworms' spinning system produces fibers under mild conditions, making it an ideal candidate for bioinspiration. However, the mechanism of silk expulsion is unknown, and the three-dimensional structure of the spinneret is still uncertain. In this study, we reconstructed a detailed 3-dimensional model of the spinneret at near-nanometer resolution, and for the first time, we observed the changes that occur before and during the silk-spinning process. Our reconstructed models suggested that silkworms have the ability to control the spinning process by opening or closing the spinning duct. During the continuously spinning period, both the pressure generated by the silk gland and the pulling force resulting from head movement work in tandem to expel the silk solution. We believe that gaining a full understanding of the spinning process steps can advance our ability to spin synthetic fibers with properties comparable to those of native fibers by mimicking the natural spinning process.
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Affiliation(s)
- Xinqiu Wang
- College of Animal Sciences, Zhejiang University, 310058 Hangzhou, China; Key Laboratory of Silkworm and Bee Resource Utilization and Innovation of Zhejiang Province, 310058 Hangzhou, China
| | - Xiaogang Ye
- College of Animal Sciences, Zhejiang University, 310058 Hangzhou, China; Key Laboratory of Silkworm and Bee Resource Utilization and Innovation of Zhejiang Province, 310058 Hangzhou, China.
| | - Jiansheng Guo
- Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, 310058 Hangzhou, China; Center of Cryo-Electron Microscopy, Zhejiang University School of Medicine, 310058 Hangzhou, China
| | - Xiangping Dai
- College of Animal Sciences, Zhejiang University, 310058 Hangzhou, China; Key Laboratory of Silkworm and Bee Resource Utilization and Innovation of Zhejiang Province, 310058 Hangzhou, China
| | - Shihua Yu
- College of Animal Sciences, Zhejiang University, 310058 Hangzhou, China; Key Laboratory of Silkworm and Bee Resource Utilization and Innovation of Zhejiang Province, 310058 Hangzhou, China
| | - Boxiong Zhong
- College of Animal Sciences, Zhejiang University, 310058 Hangzhou, China; Key Laboratory of Silkworm and Bee Resource Utilization and Innovation of Zhejiang Province, 310058 Hangzhou, China.
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Wöltje M, Isenberg KL, Cherif C, Aibibu D. Continuous Wet Spinning of Regenerated Silk Fibers from Spinning Dopes Containing 4% Fibroin Protein. Int J Mol Sci 2023; 24:13492. [PMID: 37686298 PMCID: PMC10487761 DOI: 10.3390/ijms241713492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/23/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
The wet spinning of fibers from regenerated silk fibroin has long been a research goal. Due to the degradation of the molecular structure of the fibroin protein during the preparation of the regenerated silk fibroin solution, fibroin concentrations with at least 10% protein content are required to achieve sufficient viscosity for wet spinning. In this study, a spinning dope formulation of regenerated silk fibroin is presented that shows a rheological behavior similar to that of native silk fibroin isolated from the glands of B. mori silkworm larvae. In addition, we present a wet-spinning process that enables, for the first time, the continuous wet spinning of regenerated silk fibroin with only 4% fibroin protein content into an endless fiber. Furthermore, the tensile strength of these wet-spun regenerated silk fibroin fibers per percentage of fibroin is higher than that of all continuous spinning approaches applied to regenerated and native silk fibroin published so far.
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Affiliation(s)
- Michael Wöltje
- Institute of Textile Machinery and High-Performance Material Technology, Faculty of Mechanical Science and Engineering, TUD Dresden University of Technology, 01069 Dresden, Germany
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6
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Bioengineering silk into blood vessels. Biochem Soc Trans 2021; 49:2271-2286. [PMID: 34495327 DOI: 10.1042/bst20210359] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/05/2021] [Accepted: 08/11/2021] [Indexed: 11/17/2022]
Abstract
The rising incidence of cardiovascular disease has increased the demand for small diameter (<6 mm) synthetic vascular grafts for use in bypass surgery. Clinically available synthetic grafts (polyethylene terephthalate and expanded polytetrafluorethylene) are incredibly strong, but also highly hydrophobic and inelastic, leading to high rates of failure when used for small diameter bypass. The poor clinical outcomes of commercial synthetic grafts in this setting have driven significant research in search of new materials that retain favourable mechanical properties but offer improved biocompatibility. Over the last several decades, silk fibroin derived from Bombyx mori silkworms has emerged as a promising biomaterial for use in vascular applications. Progress has been driven by advances in silk manufacturing practices which have allowed unprecedented control over silk strength, architecture, and the ensuing biological response. Silk can now be manufactured to mimic the mechanical properties of native arteries, rapidly recover the native endothelial cell layer lining vessels, and direct positive vascular remodelling through the regulation of local inflammatory responses. This review summarises the advances in silk purification, processing and functionalisation which have allowed the production of robust vascular grafts with promise for future clinical application.
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7
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Wan Q, Yang M, Hu J, Lei F, Shuai Y, Wang J, Holland C, Rodenburg C, Yang M. Mesoscale structure development reveals when a silkworm silk is spun. Nat Commun 2021; 12:3711. [PMID: 34140492 PMCID: PMC8211695 DOI: 10.1038/s41467-021-23960-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 04/29/2021] [Indexed: 11/14/2022] Open
Abstract
Silk fibre mechanical properties are attributed to the development of a multi-scale hierarchical structure during spinning. By careful ex vivo processing of a B. mori silkworm silk solution we arrest the spinning process, freezing-in mesoscale structures corresponding to three distinctive structure development stages; gelation, fibrilization and the consolidation phase identified in this work, a process highlighted by the emergence and extinction of 'water pockets'. These transient water pockets are a manifestation of the interplay between protein dehydration, phase separation and nanofibril assembly, with their removal due to nanofibril coalescence during consolidation. We modeled and validated how post-draw improves mechanical properties and refines a silk's hierarchical structure as a result of consolidation. These insights enable a better understanding of the sequence of events that occur during spinning, ultimately leading us to propose a robust definition of when a silkworm silk is actually 'spun'.
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Affiliation(s)
- Quan Wan
- College of Animal Science, Zhejiang University, Hangzhou, China
| | - Mei Yang
- College of Animal Science, Zhejiang University, Hangzhou, China
| | - Jiaqi Hu
- College of Animal Science, Zhejiang University, Hangzhou, China
| | - Fang Lei
- College of Animal Science, Zhejiang University, Hangzhou, China
| | - Yajun Shuai
- College of Animal Science, Zhejiang University, Hangzhou, China
| | - Jie Wang
- College of Animal Science, Zhejiang University, Hangzhou, China
| | - Chris Holland
- Department of Material Science and Engineering, University of Sheffield, Sheffield, UK.
| | - Cornelia Rodenburg
- Department of Material Science and Engineering, University of Sheffield, Sheffield, UK.
| | - Mingying Yang
- College of Animal Science, Zhejiang University, Hangzhou, China.
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Toprakcioglu Z, Knowles TPJ. Shear-mediated sol-gel transition of regenerated silk allows the formation of Janus-like microgels. Sci Rep 2021; 11:6673. [PMID: 33758259 PMCID: PMC7988050 DOI: 10.1038/s41598-021-85199-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 02/08/2021] [Indexed: 01/31/2023] Open
Abstract
Microcapsules and microgels consisting of macromolecular networks have received increasing attention due to their biomedical and pharmaceutical applications. Protein microgels and in particular silk-based microcapsules have desirable properties due to their biocompatibility and lack of toxicity. Typically such structures formed through emulsion templating are spherical in geometry due to interfacial tension. However, approaches to synthesis particles with more complex and non-spherical geometries are sought due to their packing properties and cargo release characteristics. Here, we describe a droplet-microfluidic strategy for generating asymmetric tubular-like microgels from reconstituted silk fibroin; a major component of native silk. It was determined using fluorescence microscopy, that the shear stress within the microchannel promotes surface protein aggregation, resulting in the asymmetric morphology of the microgels. Moreover, the structural transition that the protein undergoes was confirmed using FTIR. Crucially, the core of the microgels remains liquid, while the surface has fully aggregated into a fibrillar network. Additionally, we show that microgel morphology could be controlled by varying the dispersed to continuous phase flow rates, while it was determined that the radius of curvature of the asymmetric microgels is correlated to the wall shear stress. By comparing the surface fluorescence intensity of the microgels as a function of radius of curvature, the effect of the shear stress on the amount of aggregation could be quantified. Finally, the potential use of these asymmetric microgels as carriers of cargo molecules is showcased. As the core of the microgel remains liquid but the shell has gelled, this approach is highly suitable for the storage of bio-active cargo molecules such as antibodies, making such a delivery system attractive in the context of biomedical and pharmaceutical applications.
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Affiliation(s)
- Zenon Toprakcioglu
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Tuomas P J Knowles
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
- Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK.
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Evans SE, Harrington T, Rodriguez Rivero MC, Rognin E, Tuladhar T, Daly R. 2D and 3D inkjet printing of biopharmaceuticals - A review of trends and future perspectives in research and manufacturing. Int J Pharm 2021; 599:120443. [PMID: 33675921 DOI: 10.1016/j.ijpharm.2021.120443] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 12/13/2022]
Abstract
There is an ongoing global shift in pharmaceutical business models from small molecule drugs to biologics. This increase in complexity is in response to advancements in our diagnoses and understanding of diseases. With the more targeted approach coupled with its inherently more costly development and manufacturing, 2D and 3D printing are being explored as suitable techniques to deliver more personalised and affordable routes to drug discovery and manufacturing. In this review, we explore first the business context underlying this shift to biopharmaceuticals and provide an update on the latest work exploring discovery and pharmaceutics. We then draw on multiple disciplines to help reveal the shared challenges facing researchers and firms aiming to develop biopharmaceuticals, specifically when using the most commonly explored manufacturing routes of drop-on-demand inkjet printing and pneumatic extrusion. This includes separating out how to consider mechanical and chemical influences during manufacturing, the role of the chosen hardware and the challenges of aqueous formulation based on similar challenges being faced by the printing industry. Together, this provides a review of existing work and guidance for researchers and industry to help with the de-risking and rapid development of future biopharmaceutical products.
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Affiliation(s)
| | | | | | - Etienne Rognin
- Institute for Manufacturing, Department of Engineering, University of Cambridge (UK), UK
| | | | - Ronan Daly
- Institute for Manufacturing, Department of Engineering, University of Cambridge (UK), UK.
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Fraternali F, Stehling N, Amendola A, Tiban Anrango BA, Holland C, Rodenburg C. Tensegrity Modelling and the High Toughness of Spider Dragline Silk. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E1510. [PMID: 32752054 PMCID: PMC7466511 DOI: 10.3390/nano10081510] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 01/21/2023]
Abstract
This work establishes a tensegrity model of spider dragline silk. Tensegrity systems are ubiquitous in nature, being able to capture the mechanics of biological shapes through simple and effective modes of deformation via extension and contraction. Guided by quantitative microstructural characterization via air plasma etching and low voltage scanning electron microscopy, we report that this model is able to capture experimentally observed phenomena such as the Poisson effect, tensile stress-strain response, and fibre toughness. This is achieved by accounting for spider silks' hierarchical organization into microfibrils with radially variable properties. Each fibril is described as a chain of polypeptide tensegrity units formed by crystalline granules operating under compression, which are connected to each other by amorphous links acting under tension. Our results demonstrate, for the first time, that a radial variability in the ductility of tensegrity chains is responsible for high fibre toughness, a defining and desirable feature of spider silk. Based on this model, a discussion about the use of graded tensegrity structures for the optimal design of next-generation biomimetic fibres is presented.
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Affiliation(s)
- Fernando Fraternali
- Department of Civil Engineering, University of Salerno, 84084 Fisciano (SA), Italy
| | - Nicola Stehling
- Department of Materials Science & Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, UK
| | - Ada Amendola
- Department of Civil Engineering, University of Salerno, 84084 Fisciano (SA), Italy
| | - Bryan Andres Tiban Anrango
- Centre for Biomedical and Chemical Science School of Science, Auckland University of Technology, Auckland 1010, New Zealand
| | - Chris Holland
- Department of Materials Science & Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, UK
| | - Cornelia Rodenburg
- Department of Materials Science & Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, UK
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