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Alkhudhari OM, Wang R, Jia Z, Hodson NW, Alruwaili A, Altujjar A, Picheo E, Saunders BR. Structurally colored semitransparent perovskite solar cells using one-step deposition of self-ordering microgel particles. RSC Adv 2024; 14:6190-6198. [PMID: 38375014 PMCID: PMC10875278 DOI: 10.1039/d4ra00324a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 02/08/2024] [Indexed: 02/21/2024] Open
Abstract
Semitransparent perovskite solar cells (STPSCs) have excellent potential for widespread application as building integrated photovoltaics. Widespread application of STPSCs could result in decreased CO2 footprints for buildings. Unfortunately, STPSCs tend to have poor aesthetic qualities (being usually red-brown in color) and low stability. Building on our previous work, here we use new poly(N-isopropylacrylamide) microgels (PNP MGs) to provide highly ordered non-close packed arrays within perovskite films that reflect some of the incident light to provide structural color to STPSCs. (MGs are swellable crosslinked polymer colloid particles.) We introduce PNP MGs into two different perovskites and achieve a wide gamut of reflected color and iridescence from the perovskite films. Devices containing the MGs have average visible transparency (AVT) values of greater than 25%. The best PCE for a MG-containing STPSC is 10.60% compared to 9.14% for the MG-free control. The MGs not only introduce structural color to the STPSCs but increase the PCE and stability. Equations are provided that enable the reflected color to be predicted from the formulation used to deposit the films. Our work shows that the self-ordering tendency of PNP MGs gives a viable new method for introducing structural color into STPSCs. Because our one-step method for introducing structural color into STPSCs is general, does not introduce any additional processing steps and is scalable whilst also improving device stability, this study may bring deployment of STPSCs closer.
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Affiliation(s)
- Osama M Alkhudhari
- Department of Materials, University of Manchester Engineering Building A Manchester M1 7HL UK
| | - Ran Wang
- Department of Materials, University of Manchester Engineering Building A Manchester M1 7HL UK
| | - Zhenyu Jia
- Department of Materials, University of Manchester Engineering Building A Manchester M1 7HL UK
| | - Nigel W Hodson
- BioAFM Facility, Faculty of Biology, Medicine and Health, University of Manchester Stopford Building, Oxford Road Manchester M13 9PT UK
| | - Amal Alruwaili
- Department of Materials, University of Manchester Engineering Building A Manchester M1 7HL UK
| | - Amal Altujjar
- Department of Materials, University of Manchester Engineering Building A Manchester M1 7HL UK
- Basic Science Department, Deanship of Preparatory Year and Supporting Studies, Imam Abdulrahman Bin Faisal University Dammam 34221 Kingdom of Saudi Arabia
| | - Eugenio Picheo
- Department of Materials, University of Manchester Engineering Building A Manchester M1 7HL UK
| | - Brian R Saunders
- Department of Materials, University of Manchester Engineering Building A Manchester M1 7HL UK
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2
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Jokl E, Mullan AF, Simpson K, Birchall L, Pearmain L, Martin K, Pritchett J, Raza S, Shah R, Hodson NW, Williams CJ, Camacho E, Zeef L, Donaldson I, Athwal VS, Hanley NA, Piper Hanley K. PAK1-dependent mechanotransduction enables myofibroblast nuclear adaptation and chromatin organization during fibrosis. Cell Rep 2023; 42:113414. [PMID: 37967011 DOI: 10.1016/j.celrep.2023.113414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 09/14/2023] [Accepted: 10/25/2023] [Indexed: 11/17/2023] Open
Abstract
Myofibroblasts are responsible for scarring during fibrosis. The scar propagates mechanical signals inducing a radical transformation in myofibroblast cell state and increasing profibrotic phenotype. Here, we show mechanical stress from progressive scarring induces nuclear softening and de-repression of heterochromatin. The parallel loss of H3K9Me3 enables a permissive state for distinct chromatin accessibility and profibrotic gene regulation. Integrating chromatin accessibility profiles with RNA expression provides insight into the transcription network underlying the switch in profibrotic myofibroblast states, emphasizing mechanoadaptive regulation of PAK1 as key drivers. Through genetic manipulation in liver and lung fibrosis, loss of PAK1-dependent signaling impairs the mechanoadaptive response in vitro and dramatically improves fibrosis in vivo. Moreover, we provide human validation for mechanisms underpinning PAK1-mediated mechanotransduction in liver and lung fibrosis. Collectively, these observations provide insight into the nuclear mechanics driving the profibrotic chromatin landscape in fibrosis, highlighting actomyosin-dependent mechanisms as potential therapeutic targets in fibrosis.
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Affiliation(s)
- Elliot Jokl
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine & Health, Manchester Academic Health Science Centre, University of Manchester, Oxford Road, Manchester, UK; Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine & Health, University of Manchester, Manchester Academic Health Science Centre, Oxford Road, Manchester, UK
| | - Aoibheann F Mullan
- Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine & Health, University of Manchester, Manchester Academic Health Science Centre, Oxford Road, Manchester, UK
| | - Kara Simpson
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine & Health, Manchester Academic Health Science Centre, University of Manchester, Oxford Road, Manchester, UK; Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine & Health, University of Manchester, Manchester Academic Health Science Centre, Oxford Road, Manchester, UK
| | - Lindsay Birchall
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine & Health, Manchester Academic Health Science Centre, University of Manchester, Oxford Road, Manchester, UK; Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine & Health, University of Manchester, Manchester Academic Health Science Centre, Oxford Road, Manchester, UK
| | - Laurence Pearmain
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine & Health, Manchester Academic Health Science Centre, University of Manchester, Oxford Road, Manchester, UK; Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine & Health, University of Manchester, Manchester Academic Health Science Centre, Oxford Road, Manchester, UK
| | - Katherine Martin
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine & Health, Manchester Academic Health Science Centre, University of Manchester, Oxford Road, Manchester, UK; Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine & Health, University of Manchester, Manchester Academic Health Science Centre, Oxford Road, Manchester, UK
| | - James Pritchett
- Department of Life Sciences, Manchester Metropolitan University, Manchester, UK
| | - Sayyid Raza
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine & Health, Manchester Academic Health Science Centre, University of Manchester, Oxford Road, Manchester, UK; Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine & Health, University of Manchester, Manchester Academic Health Science Centre, Oxford Road, Manchester, UK
| | - Rajesh Shah
- Manchester University NHS Foundation Trust, Oxford Road, Manchester, UK
| | - Nigel W Hodson
- Core Facilities, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - Craig J Williams
- Department of Materials, University of Manchester, Manchester, UK
| | - Elizabeth Camacho
- Division of Population Health, Health Services Research and Primary Care, School of Health Sciences, University of Manchester, Manchester, UK
| | - Leo Zeef
- Core Facilities, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - Ian Donaldson
- Core Facilities, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - Varinder S Athwal
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine & Health, Manchester Academic Health Science Centre, University of Manchester, Oxford Road, Manchester, UK; Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine & Health, University of Manchester, Manchester Academic Health Science Centre, Oxford Road, Manchester, UK; Manchester University NHS Foundation Trust, Oxford Road, Manchester, UK
| | - Neil A Hanley
- Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine & Health, University of Manchester, Manchester Academic Health Science Centre, Oxford Road, Manchester, UK; Manchester University NHS Foundation Trust, Oxford Road, Manchester, UK; College of Medical & Dental Sciences, University of Birmingham, Birmingham, UK
| | - Karen Piper Hanley
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine & Health, Manchester Academic Health Science Centre, University of Manchester, Oxford Road, Manchester, UK; Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine & Health, University of Manchester, Manchester Academic Health Science Centre, Oxford Road, Manchester, UK.
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3
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Vitale M, Ligorio C, McAvan B, Hodson NW, Allan C, Richardson SM, Hoyland JA, Bella J. Hydroxyapatite-decorated Fmoc-hydrogel as a bone-mimicking substrate for osteoclast differentiation and culture. Acta Biomater 2022; 138:144-154. [PMID: 34781025 PMCID: PMC8756142 DOI: 10.1016/j.actbio.2021.11.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/19/2021] [Accepted: 11/09/2021] [Indexed: 12/25/2022]
Abstract
Hydrogels are water-swollen networks with great potential for tissue engineering applications. However, their use in bone regeneration is often hampered due to a lack of materials' mineralization and poor mechanical properties. Moreover, most studies are focused on osteoblasts (OBs) for bone formation, while osteoclasts (OCs), cells involved in bone resorption, are often overlooked. Yet, the role of OCs is pivotal for bone homeostasis and aberrant OC activity has been reported in several pathological diseases, such as osteoporosis and bone cancer. For these reasons, the aim of this work is to develop customised, reinforced hydrogels to be used as material platform to study cell function, cell-material interactions and ultimately to provide a substrate for OC differentiation and culture. Here, Fmoc-based RGD-functionalised peptide hydrogels have been modified with hydroxyapatite nanopowder (Hap) as nanofiller, to create nanocomposite hydrogels. Atomic force microscopy showed that Hap nanoparticles decorate the peptide nanofibres with a repeating pattern, resulting in stiffer hydrogels with improved mechanical properties compared to Hap- and RGD-free controls. Furthermore, these nanocomposites supported adhesion of Raw 264.7 macrophages and their differentiation in 2D to mature OCs, as defined by the adoption of a typical OC morphology (presence of an actin ring, multinucleation, and ruffled plasma membrane). Finally, after 7 days of culture OCs showed an increased expression of TRAP, a typical OC differentiation marker. Collectively, the results suggest that the Hap/Fmoc-RGD hydrogel has a potential for bone tissue engineering, as a 2D model to study impairment or upregulation of OC differentiation. STATEMENT OF SIGNIFICANCE: Altered osteoclasts (OC) function is one of the major cause of bone fracture in the most commonly skeletal disorders (e.g. osteoporosis). Peptide hydrogels can be used as a platform to mimic the bone microenvironment and provide a tool to assess OC differentiation and function. Moreover, hydrogels can incorporate different nanofillers to yield hybrid biomaterials with enhanced mechanical properties and improved cytocompatibility. Herein, Fmoc-based RGD-functionalised peptide hydrogels were decorated with hydroxyapatite (Hap) nanoparticles to generate a hydrogel with improved rheological properties. Furthermore, they are able to support osteoclastogenesis of Raw264.7 cells in vitro as confirmed by morphology changes and expression of OC-markers. Therefore, this Hap-decorated hydrogel can be used as a template to successfully differentiate OC and potentially study OC dysfunction.
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Affiliation(s)
- Mattia Vitale
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United Kingdom
| | - Cosimo Ligorio
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United Kingdom
| | - Bethan McAvan
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United Kingdom
| | - Nigel W Hodson
- BioAFM Facility, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Chris Allan
- Biogelx Ltd-BioCity Scotland, Bo'Ness Rd, Newhouse, Chapelhall, Motherwell ML1 5UH, United Kingdom
| | - Stephen M Richardson
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United Kingdom.
| | - Judith A Hoyland
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United Kingdom.
| | - Jordi Bella
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United Kingdom.
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4
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Ligorio C, O'Brien M, Hodson NW, Mironov A, Iliut M, Miller AF, Vijayaraghavan A, Hoyland JA, Saiani A. TGF-β3-loaded graphene oxide - self-assembling peptide hybrid hydrogels as functional 3D scaffolds for the regeneration of the nucleus pulposus. Acta Biomater 2021; 127:116-130. [PMID: 33831573 DOI: 10.1016/j.actbio.2021.03.077] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/30/2021] [Accepted: 03/30/2021] [Indexed: 12/14/2022]
Abstract
Intervertebral disc (IVD) degeneration is a process that starts in the central nucleus pulposus (NP) and leads to inflammation, extracellular matrix (ECM) degradation, and progressive loss of disc height. Early treatment of IVD degeneration is critical to the reduction of low back pain and related disability. As such, minimally invasive therapeutic approaches that can halt and reverse NP degeneration at the early stages of the disease are needed. Recently, we developed an injectable graphene oxide (GO) - self-assembling peptide FEFKFEFK (F: phenylalanine; K: lysine; E: glutamic acid) hybrid hydrogels as potential delivery platform for cells and/or drugs in the NP. In this current study, we explored the possibility of using the GO present in these hybrid hydrogels as a vehicle for the sequestration and controlled delivery of transforming growth factor beta-3 (TGF-β3), an anabolic growth factor (GF) known to direct NP cell fate and function. For this purpose, we first investigated the potential of GO to bind and sequestrate TGF-β3. We then cultured bovine NP cells in the new functional scaffolds and investigated their response to the presence of GO and TGF-β3. Our results clearly showed that GO flakes can sequestrate TGF-β3 through strong binding interactions resulting in a slow and prolonged release, with the GF remaining active even when bound to the GO flakes. The adsorption of the GF on the GO flakes to create TGF-β3-loaded GO flakes and their subsequent incorporation in the hydrogels through mixing, [(GO/TGF-β3Ads)-F8] hydrogel, led to the upregulation of NP-specific genes, accompanied by the production and deposition of an NP-like ECM, rich in aggrecan and collagen II. NP cells actively interacted with TGF-β3-loaded GO flakes and remodeled the scaffolds through endocytosis. This work highlights the potential of using GO as a nanocarrier for the design of functional hybrid peptide-based hydrogels. STATEMENT OF SIGNIFICANCE: Intervertebral disc (IVD) degeneration is a process that starts in the central nucleus pulposus (NP) and leads to inflammation, extracellular matrix (ECM) degradation, and progressive loss of disc height. As such, minimally invasive therapeutic approaches that can halt and reverse NP degeneration at the early stages of the disease are needed. In this current study, we explored the possibility of using peptide - GO hybrid hydrogels as a vehicle for the sequestration and controlled delivery of transforming growth factor beta-3 (TGF-β3), an anabolic growth factor (GF) known to direct NP cell fate and function.
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5
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Friedman D, Simmonds P, Hale A, Bere L, Hodson NW, White MRH, Davis DM. Natural killer cell immune synapse formation and cytotoxicity are controlled by tension of the target interface. J Cell Sci 2021; 134:jcs258570. [PMID: 33712452 PMCID: PMC8077183 DOI: 10.1242/jcs.258570] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 03/03/2021] [Indexed: 12/11/2022] Open
Abstract
Natural killer (NK) cells can kill infected or transformed cells via a lytic immune synapse. Diseased cells may exhibit altered mechanical properties but how this impacts NK cell responsiveness is unknown. We report that human NK cells were stimulated more effectively to secrete granzymes A and B, FasL (also known as FasLG), granulysin and IFNγ, by stiff (142 kPa) compared to soft (1 kPa) planar substrates. To create surrogate spherical targets of defined stiffness, sodium alginate was used to synthesise soft (9 kPa), medium (34 kPa) or stiff (254 kPa) cell-sized beads, coated with antibodies against activating receptor NKp30 (also known as NCR3) and the integrin LFA-1 (also known as ITGAL). Against stiff beads, NK cells showed increased degranulation. Polarisation of the microtubule-organising centre and lytic granules were impaired against soft targets, which instead resulted in the formation of unstable kinapses. Thus, by varying target stiffness to characterise the mechanosensitivity of immune synapses, we identify soft targets as a blind spot in NK cell recognition. This article has an associated First Person interview with the co-first authors of the paper.
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Affiliation(s)
- Daniel Friedman
- The Lydia Becker Institute, Faculty of Biology, Medicine and Health, University of Manchester, Core Technology Facility building, 46 Grafton Street, Manchester M13 9NT, United Kingdom
| | - Poppy Simmonds
- The Lydia Becker Institute, Faculty of Biology, Medicine and Health, University of Manchester, Core Technology Facility building, 46 Grafton Street, Manchester M13 9NT, United Kingdom
| | - Alexander Hale
- The Lydia Becker Institute, Faculty of Biology, Medicine and Health, University of Manchester, Core Technology Facility building, 46 Grafton Street, Manchester M13 9NT, United Kingdom
| | - Leoma Bere
- The Lydia Becker Institute, Faculty of Biology, Medicine and Health, University of Manchester, Core Technology Facility building, 46 Grafton Street, Manchester M13 9NT, United Kingdom
| | - Nigel W. Hodson
- BioAFM Facility, Faculty of Biology, Medicine and Health, Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Michael R. H. White
- Michael Smith Building, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Daniel M. Davis
- The Lydia Becker Institute, Faculty of Biology, Medicine and Health, University of Manchester, Core Technology Facility building, 46 Grafton Street, Manchester M13 9NT, United Kingdom
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6
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Simmonds P, Friedman D, Hale A, Hodson NW, White MRH, Davis DM. Natural Killer cell immune synapse formation and cytotoxicity is controlled by mechanical tension of the target. The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.74.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Natural Killer (NK) cells can kill infected or transformed cells directly via the formation of a lytic synapse at the cell-cell interface. Diseased cells often present with altered mechanical properties, and cell stiffness is a feature of tumour cell migratory potential. However, little is known about how target cell stiffness impacts the assembly of the NK cell synapse or the subsequent functional response.
To study this, we set out to create surrogate targets with specific ligands presented on cell-sized beads of different stiffness. Sodium alginate cell-sized microbeads were synthesised where chemical composition was altered to produce beads of low (9kPa), medium (34kPa), or high (254kPa) stiffness. These were coated with antibodies against the NK cell activating receptor NKp30 and the integrin LFA-1 to model the 3D interaction between NK cells and target cells.
Imaging revealed that later steps in NK-cell activation differed significantly, including the degree of cytoskeletal arrangement, F-actin accumulation, microtubule organising centre polarisation and perforin accumulation. Stiffer beads induced polarisation of the MTOC in 59% of conjugates analysed compared to only 7% with low stiffness targets. Functionally, NK cell degranulation was higher when forming conjugates with stiffer targets. The metabolic profiles were similar between NK cells stimulated overnight by antibody-coated beads, regardless of their stiffness. Altogether, these data imply that stiffer targets are more potent in triggering the initial activating signals in NK cells. Thus, immune synapse mechanosensitivity represents a novel form of NK cell regulation.
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7
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Lian Q, Mokhtar MZ, Lu D, Zhu M, Jacobs J, Foster AB, Thomas AG, Spencer BF, Wu S, Liu C, Hodson NW, Smith B, Alkaltham A, Alkhudhari OM, Watson T, Saunders BR. Using Soft Polymer Template Engineering of Mesoporous TiO 2 Scaffolds to Increase Perovskite Grain Size and Solar Cell Efficiency. ACS Appl Mater Interfaces 2020; 12:18578-18589. [PMID: 32237709 DOI: 10.1021/acsami.0c02248] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The mesoporous (meso)-TiO2 layer is a key component of high-efficiency perovskite solar cells (PSCs). Herein, pore size controllable meso-TiO2 layers are prepared using spin coating of commercial TiO2 nanoparticle (NP) paste with added soft polymer templates (SPT) followed by removal of the SPT at 500 °C. The SPTs consist of swollen crosslinked polymer colloids (microgels, MGs) or a commercial linear polymer (denoted as LIN). The MGs and LIN were comprised of the same polymer, which was poly(N-isopropylacrylamide) (PNIPAm). Large (L-MG) and small (S-MG) MG SPTs were employed to study the effect of the template size. The SPT approach enabled pore size engineering in one deposition step. The SPT/TiO2 nanoparticle films had pore sizes > 100 nm, whereas the average pore size was 37 nm for the control meso-TiO2 scaffold. The largest pore sizes were obtained using L-MG. SPT engineering increased the perovskite grain size in the same order as the SPT sizes: LIN < S-MG < L-MG and these grain sizes were larger than those obtained using the control. The power conversion efficiencies (PCEs) of the SPT/TiO2 devices were ∼20% higher than that for the control meso-TiO2 device and the PCE of the champion S-MG device was 18.8%. The PCE improvement is due to the increased grain size and more effective light harvesting of the SPT devices. The increased grain size was also responsible for the improved stability of the SPT/TiO2 devices. The SPT method used here is simple, scalable, and versatile and should also apply to other PSCs.
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Affiliation(s)
- Qing Lian
- Department of Materials, University of Manchester, Manchester M1 3BB, United Kingdom
| | - Muhamad Z Mokhtar
- Department of Materials, University of Manchester, Manchester M1 3BB, United Kingdom
| | - Dongdong Lu
- Department of Materials, University of Manchester, Manchester M1 3BB, United Kingdom
| | - Mingning Zhu
- Department of Materials, University of Manchester, Manchester M1 3BB, United Kingdom
| | - Janet Jacobs
- Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Andrew B Foster
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Andrew G Thomas
- Department of Materials, University of Manchester, Manchester M1 3BB, United Kingdom
- Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- The Henry Royce Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Ben F Spencer
- Department of Materials, University of Manchester, Manchester M1 3BB, United Kingdom
- The Henry Royce Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Shanglin Wu
- Department of Materials, University of Manchester, Manchester M1 3BB, United Kingdom
| | - Chen Liu
- Department of Materials, University of Manchester, Manchester M1 3BB, United Kingdom
| | - Nigel W Hodson
- BioAFM Facility, Faculty of Biology, Medicine and Health, Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Benjamin Smith
- SPECIFIC, College of Engineering, Swansea University Bay Campus, Swansea SA1 8EN, United Kingdom
| | - Abdulaziz Alkaltham
- Department of Materials, University of Manchester, Manchester M1 3BB, United Kingdom
| | - Osama M Alkhudhari
- Department of Materials, University of Manchester, Manchester M1 3BB, United Kingdom
| | - Trystan Watson
- SPECIFIC, College of Engineering, Swansea University Bay Campus, Swansea SA1 8EN, United Kingdom
| | - Brian R Saunders
- Department of Materials, University of Manchester, Manchester M1 3BB, United Kingdom
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Wang P, Dreger M, Madrazo E, Williams CJ, Samaniego R, Hodson NW, Monroy F, Baena E, Sánchez-Mateos P, Hurlstone A, Redondo-Muñoz J. WDR5 modulates cell motility and morphology and controls nuclear changes induced by a 3D environment. Proc Natl Acad Sci U S A 2018; 115:8581-8586. [PMID: 29987046 PMCID: PMC6112728 DOI: 10.1073/pnas.1719405115] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cell migration through extracellular matrices requires nuclear deformation, which depends on nuclear stiffness. In turn, chromatin structure contributes to nuclear stiffness, but the mechanosensing pathways regulating chromatin during cell migration remain unclear. Here, we demonstrate that WD repeat domain 5 (WDR5), an essential component of H3K4 methyltransferase complexes, regulates cell polarity, nuclear deformability, and migration of lymphocytes in vitro and in vivo, independent of transcriptional activity, suggesting nongenomic functions for WDR5. Similarly, depletion of RbBP5 (another H3K4 methyltransferase subunit) promotes similar defects. We reveal that a 3D environment increases the H3K4 methylation dependent on WDR5 and results in a globally less compacted chromatin conformation. Further, using atomic force microscopy, nuclear particle tracking, and nuclear swelling experiments, we detect changes in nuclear mechanics that accompany the epigenetic changes induced in 3D conditions. Indeed, nuclei from cells in 3D environments were softer, and thereby more deformable, compared with cells in suspension or cultured in 2D conditions, again dependent on WDR5. Dissecting the underlying mechanism, we determined that actomyosin contractility, through the phosphorylation of myosin by MLCK (myosin light chain kinase), controls the interaction of WDR5 with other components of the methyltransferase complex, which in turn up-regulates H3K4 methylation activation in 3D conditions. Taken together, our findings reveal a nongenomic function for WDR5 in regulating H3K4 methylation induced by 3D environments, physical properties of the nucleus, cell polarity, and cell migratory capacity.
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Affiliation(s)
- Pengbo Wang
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Biology, Medicine and Health, School of Medical Sciences, Division of Cell Matrix Biology and Regenerative Medicine, The University of Manchester, M13 9PT Manchester, United Kingdom
- Prostate Oncobiology Group, Cancer Research UK Manchester Institute, SK10 4TG Manchester, United Kingdom
| | - Marcel Dreger
- Faculty of Biology, Medicine and Health, Division of Cancer Sciences, School of Medical Sciences, The University of Manchester, M13 9PT Manchester, United Kingdom
| | - Elena Madrazo
- Section of Immuno-oncology, Instituto de Investigación Sanitaria Gregorio Marañón, Complutense University, School of Medicine, 28007 Madrid, Spain
- Department of Immunology, Hospital 12 de Octubre Health Research Institute (imas12), Complutense University, School of Medicine, 28040 Madrid, Spain
| | - Craig J Williams
- School of Materials, The University of Manchester, M13 9PL Manchester, United Kingdom
| | - Rafael Samaniego
- Confocal Microscopy Unit, Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain
| | - Nigel W Hodson
- BioAFM Facility, The University of Manchester, M13 9PG Manchester, United Kingdom
| | - Francisco Monroy
- Department of Physical Chemistry, Hospital 12 de Octubre Health Research Institute (imas12), Complutense University, 28040 Madrid, Spain
| | - Esther Baena
- Prostate Oncobiology Group, Cancer Research UK Manchester Institute, SK10 4TG Manchester, United Kingdom
| | - Paloma Sánchez-Mateos
- Section of Immuno-oncology, Instituto de Investigación Sanitaria Gregorio Marañón, Complutense University, School of Medicine, 28007 Madrid, Spain
| | - Adam Hurlstone
- Faculty of Biology, Medicine and Health, Division of Cancer Sciences, School of Medical Sciences, The University of Manchester, M13 9PT Manchester, United Kingdom
| | - Javier Redondo-Muñoz
- Department of Immunology, Hospital 12 de Octubre Health Research Institute (imas12), Complutense University, School of Medicine, 28040 Madrid, Spain;
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9
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Shanks HR, Zhu M, Milani AH, Turton J, Haigh S, Hodson NW, Adlam D, Hoyland J, Freemont T, Saunders BR. Core-shell-shell cytocompatible polymer dot-based particles with near-infrared emission and enhanced dispersion stability. Chem Commun (Camb) 2018; 54:9364-9367. [PMID: 30079412 DOI: 10.1039/c8cc04310h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polymer dots (PDs) are promising fluorescent probes for biomaterials applications. Here, novel cytocompatible composite PD particles have been synthesised with a core-shell-shell morphology. The particles show near-infrared emission, improved fluorescent brightness and enhanced colloidal stability compared to pure PDs. The particles also show non-radiative resonance energy transfer (NRET) with a model dye.
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Affiliation(s)
- Hannah R Shanks
- School of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, UK.
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10
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Craddock RJ, Hodson NW, Ozols M, Shearer T, Hoyland JA, Sherratt MJ, Sherratt MJ. Extracellular matrix fragmentation in young, healthy cartilaginous tissues. Eur Cell Mater 2018; 35:34-53. [PMID: 29424418 DOI: 10.22203/ecm.v035a04] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Although the composition and structure of cartilaginous tissues is complex, collagen II fibrils and aggrecan are the most abundant assemblies in both articular cartilage (AC) and the nucleus pulposus (NP) of the intervertebral disc (IVD). Whilst structural heterogeneity of intact aggrecan ( containing three globular domains) is well characterised, the extent of aggrecan fragmentation in healthy tissues is poorly defined. Using young, yet skeletally mature (18-30 months), bovine AC and NP tissues, it was shown that, whilst the ultrastructure of intact aggrecan was tissue-dependent, most molecules (AC: 95 %; NP: 99.5 %) were fragmented (lacking one or more globular domains). Fragments were significantly smaller and more structurally heterogeneous in the NP compared with the AC (molecular area; AC: 8543 nm2; NP: 4625 nm2; p < 0.0001). In contrast, fibrillar collagen appeared structurally intact and tissue-invariant. Molecular fragmentation is considered indicative of a pathology; however, these young, skeletally mature tissues were histologically and mechanically (reduced modulus: AC: ≈ 500 kPa; NP: ≈ 80 kPa) comparable to healthy tissues and devoid of notable gelatinase activity (compared with rat dermis). As aggrecan fragmentation was prevalent in neonatal bovine AC (99.5 % fragmented, molecular area: 5137 nm2) as compared with mature AC (95.0 % fragmented, molecular area: 8667 nm2), it was hypothesised that targeted proteolysis might be an adaptive process that modified aggrecan packing (as simulated computationally) and, hence, tissue charge density, mechanical properties and porosity. These observations provided a baseline against which pathological and/or age-related fragmentation of aggrecan could be assessed and suggested that new strategies might be required to engineer constructs that mimic the mechanical properties of native cartilaginous tissues.
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Affiliation(s)
| | | | | | | | | | - M J Sherratt
- Faculty of Biology Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PT,
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11
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Dokkhan C, Mokhtar MZ, Chen Q, Saunders BR, Hodson NW, Hamilton B. Using microgels to control the morphology and optoelectronic properties of hybrid organic–inorganic perovskite films. Phys Chem Chem Phys 2018; 20:27959-27969. [DOI: 10.1039/c8cp05148h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spin coating mixed microgel/perovskite precursor solutions gives disordered inverse opal perovskite films with morphologies and optoelectronic properties that are controlled by the microgel particles.
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Affiliation(s)
| | | | - Qian Chen
- School of Materials
- University of Manchester
- Manchester
- UK
| | | | - Nigel W. Hodson
- BioAFM Facility
- Faculty of Biology
- Medicine and Health
- Stopford Building
- University of Manchester
| | - Bruce Hamilton
- Photon Science Institute
- University of Manchester
- Alan Turing Building
- Manchester
- UK
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12
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Davies HS, Pudney PDA, Georgiades P, Waigh TA, Hodson NW, Ridley CE, Blanch EW, Thornton DJ. Reorganisation of the salivary mucin network by dietary components: insights from green tea polyphenols. PLoS One 2014; 9:e108372. [PMID: 25264771 PMCID: PMC4180932 DOI: 10.1371/journal.pone.0108372] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 08/19/2014] [Indexed: 01/20/2023] Open
Abstract
The salivary mucins that include MUC5B (gel-forming) and MUC7 (non-gel-forming) are major contributors to the protective mucus barrier in the oral cavity, and it is possible that dietary components may influence barrier properties. We show how one dietary compound, the green tea polyphenol epigallocatechin gallate (EGCG), can substantially alter the properties of both the polymeric MUC5B network and monomeric MUC7. Using rate-zonal centrifugation, MUC5B in human whole saliva and MUC5B purified from saliva sedimented faster in the presence of EGCG. The faster sedimentation by EGCG was shown to be greater with increasing MUC5B concentration. Particle tracking microrheology was employed to determine the viscosity of purified MUC5B solutions and showed that for MUC5B solutions of 200-1600 µg/mL, EGCG caused a significant increase in mucin viscosity, which was greater at higher MUC5B concentrations. Visualisation of the changes to the MUC5B network by EGCG was performed using atomic force microscopy, which demonstrated increased aggregation of MUC5B in a heterogeneous manner by EGCG. Using trypsin-resistant, high-molecular weight oligosaccharide-rich regions of MUC5B and recombinant N-terminal and C-terminal MUC5B proteins, we showed that EGCG causes aggregation at the protein domains of MUC5B, but not at the oligosaccharide-rich regions of the mucin. We also demonstrated that EGCG caused the majority of MUC7 in human whole saliva to aggregate. Furthermore, purified MUC7 also underwent a large increase in sedimentation rate in the presence of EGCG. In contrast, the green tea polyphenol epicatechin caused no change in the sedimentation rate of either MUC5B or MUC7 in human whole saliva. These findings have demonstrated how the properties of the mucin barrier can be influenced by dietary components. In the case of EGCG, these interactions may alter the function of MUC5B as a lubricant, contributing to the astringency (dry puckering sensation) of green tea.
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Affiliation(s)
- Heather S. Davies
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
- Manchester Institute of Biotechnology, Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
| | | | - Pantelis Georgiades
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
- Biological Physics, Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Thomas A. Waigh
- Biological Physics, Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Nigel W. Hodson
- BioAFM Facility Centre for Tissue Injury and Repair, Faculty of Medical and Human Sciences, University of Manchester, Manchester, United Kingdom
| | - Caroline E. Ridley
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Ewan W. Blanch
- Manchester Institute of Biotechnology, Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
| | - David J. Thornton
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
- * E-mail:
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13
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Strassburg S, Hodson NW, Hill PI, Richardson SM, Hoyland JA. Bi-directional exchange of membrane components occurs during co-culture of mesenchymal stem cells and nucleus pulposus cells. PLoS One 2012; 7:e33739. [PMID: 22438989 PMCID: PMC3305345 DOI: 10.1371/journal.pone.0033739] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 02/16/2012] [Indexed: 02/07/2023] Open
Abstract
Mesenchymal stem cell (MSC)-based therapies have been proposed as novel treatments for intervertebral disc (IVD) degeneration. We have previously demonstrated that when MSCs are co-cultured with nucleus pulposus (NP) cells with direct cell-cell contact, they differentiate along the NP lineage and simultaneously stimulate the degenerate NP cell population to regain a normal (non-degenerate) phenotype, an effect which requires cell-cell communication. However, the mechanisms by which NP cells and MSCs interact in this system are currently unclear. Thus, in this study we investigated a range of potential mechanisms for exchange of cellular components or information that may direct these changes, including cell fusion, gap-junctional communication and exchange of membrane components by direct transfer or via microvesicle formation. Flow cytometry of fluorescently labeled MSCs and NP cells revealed evidence of some cell fusion and formation of gapjunctions, although at the three timepoints studied these phenomena were detectable only in a small proportion of cells. While these mechanisms may play a role in cell-cell communication, the data suggests they are not the predominant mechanism of interaction. However, flow cytometry of fluorescently dual-labeled cells showed that extensive bi-directional transfer of membrane components is operational during direct co-culture of MSCs and NP cells. Furthermore, there was also evidence for secretion and internalization of membrane-bound microvesicles by both cell types. Thus, this study highlights bi-directional intercellular transfer of membrane components as a possible mechanism of cellular communication between MSC and NP cells.
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Affiliation(s)
- Sandra Strassburg
- Regenerative Medicine, School of Biomedicine, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
| | - Nigel W. Hodson
- Regenerative Medicine, School of Biomedicine, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
| | - Patrick I. Hill
- School of Chemical Engineering, Faculty of Engineering and Physical Sciences, The University of Manchester, Manchester, United Kingdom
| | - Stephen M. Richardson
- Regenerative Medicine, School of Biomedicine, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
| | - Judith A. Hoyland
- Regenerative Medicine, School of Biomedicine, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
- * E-mail:
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14
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Graham HK, Hodson NW, Hoyland JA, Millward-Sadler SJ, Garrod D, Scothern A, Griffiths CEM, Watson REB, Cox TR, Erler JT, Trafford AW, Sherratt MJ. Tissue section AFM: In situ ultrastructural imaging of native biomolecules. Matrix Biol 2010; 29:254-60. [PMID: 20144712 PMCID: PMC2877882 DOI: 10.1016/j.matbio.2010.01.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 01/29/2010] [Accepted: 01/29/2010] [Indexed: 11/12/2022]
Abstract
Conventional approaches for ultrastructural high-resolution imaging of biological specimens induce profound changes in bio-molecular structures. By combining tissue cryo-sectioning with non-destructive atomic force microscopy (AFM) imaging we have developed a methodology that may be applied by the non-specialist to both preserve and visualize bio-molecular structures (in particular extracellular matrix assemblies) in situ. This tissue section AFM technique is capable of: i) resolving nm–µm scale features of intra- and extracellular structures in tissue cryo-sections; ii) imaging the same tissue region before and after experimental interventions; iii) combining ultrastructural imaging with complimentary microscopical and micromechanical methods. Here, we employ this technique to: i) visualize the macro-molecular structures of unstained and unfixed fibrillar collagens (in skin, cartilage and intervertebral disc), elastic fibres (in aorta and lung), desmosomes (in nasal epithelium) and mitochondria (in heart); ii) quantify the ultrastructural effects of sequential collagenase digestion on a single elastic fibre; iii) correlate optical (auto fluorescent) with ultrastructural (AFM) images of aortic elastic lamellae.
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Affiliation(s)
- Helen K Graham
- Unit of Cardiac Physiology, School of Biomedicine, The University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, UK
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15
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Jayawarna V, Richardson SM, Hirst AR, Hodson NW, Saiani A, Gough JE, Ulijn RV. Introducing chemical functionality in Fmoc-peptide gels for cell culture. Acta Biomater 2009; 5:934-43. [PMID: 19249724 DOI: 10.1016/j.actbio.2009.01.006] [Citation(s) in RCA: 220] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 12/23/2008] [Accepted: 01/07/2009] [Indexed: 10/25/2022]
Abstract
Aromatic short peptide derivatives, i.e. peptides modified with aromatic groups such as 9-fluorenylmethoxycarbonyl (Fmoc), can self-assemble into self-supporting hydrogels. These hydrogels have some similarities to extracellular matrices due to their high hydration, relative stiffness and nanofibrous architecture. We previously demonstrated that Fmoc-diphenylalanine (Fmoc-F(2)) provides a suitable matrix for two-dimensional (2D) or three-dimensional (3D) culture of primary bovine chondrocytes. In this paper we investigate whether the introduction of chemical functionality, such as NH(2), COOH or OH, enhances compatibility with different cell types. A series of hydrogel compositions consisting of combinations of Fmoc-F(2) and n-protected Fmoc amino acids, lysine (K, with side chain R=(CH(2))(4)NH(2)), glutamic acid (D, with side chain R=CH(2)COOH), and serine (S, with side chain R=CH(2)OH) were studied. All compositions produced fibrous scaffolds with fibre diameters in the range of 32-65 nm as assessed by cryo-scanning electron microscopy and atomic force microscopy. Fourier transform infrared spectroscopy analysis suggested that peptide segments adopt a predominantly antiparallel beta-sheet conformation. Oscillatory rheology results show that all four hydrogels have mechanical profiles of soft viscoelastic materials with elastic moduli dependent on the chemical composition, ranging from 502 Pa (Fmoc-F(2)/D) to 21.2 KPa (Fmoc-F(2)). All gels supported the viability of bovine chondrocytes as assessed by a live-dead staining assay. Fmoc-F(2)/S and Fmoc-F(2)/D hydrogels in addition supported viability for human dermal fibroblasts (HDF) while Fmoc-F(2)/S hydrogel was the only gel type that supported viability for all three cell types tested. Fmoc-F(2)/S was therefore investigated further by studying cell proliferation, cytoskeletal organization and histological analysis in 2D culture. In addition, the Fmoc-F(2)/S gel was shown to support retention of cell morphology in 3D culture of bovine chondrocytes. These results demonstrate that introduction of chemical functionality into Fmoc-peptide scaffolds may provide gels with tunable chemical and mechanical properties for in vitro cell culture.
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16
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Zhou M, Smith AM, Das AK, Hodson NW, Collins RF, Ulijn RV, Gough JE. Self-assembled peptide-based hydrogels as scaffolds for anchorage-dependent cells. Biomaterials 2009; 30:2523-30. [PMID: 19201459 DOI: 10.1016/j.biomaterials.2009.01.010] [Citation(s) in RCA: 470] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Accepted: 01/06/2009] [Indexed: 11/17/2022]
Abstract
We report here the design of a biomimetic nanofibrous hydrogel as a 3D-scaffold for anchorage-dependent cells. The peptide-based bioactive hydrogel is formed through molecular self-assembly and the building blocks are a mixture of two aromatic short peptide derivatives: Fmoc-FF (Fluorenylmethoxycarbonyl-diphenylalanine) and Fmoc-RGD (arginine-glycine-aspartate) as the simplest self-assembling moieties reported so far for the construction of small-molecule-based bioactive hydrogels. This hydrogel provides a highly hydrated, stiff and nanofibrous hydrogel network that uniquely presents bioactive ligands at the fibre surface; therefore it mimics certain essential features of the extracellular matrix. The RGD sequence as part of the Fmoc-RGD building block plays a dual role of a structural component and a biological ligand. Spectroscopic and imaging analysis using CD, FTIR, fluorescence, TEM and AFM confirmed that FF and RGD peptide sequences self-assemble into beta-sheets interlocked by pi-pi stacking of the Fmoc groups. This generates the cylindrical nanofibres interwoven within the hydrogel with the presence of RGDs in tunable densities on the fibre surfaces. This rapid gelling material was observed to promote adhesion of encapsulated dermal fibroblasts through specific RGD-integrin binding, with subsequent cell spreading and proliferation; therefore it may offer an economical model scaffold to 3D-culture other anchorage-dependent cells for in-vitro tissue regeneration.
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Affiliation(s)
- Mi Zhou
- Materials Science Centre, School of Materials, The University of Manchester, Grosvenor Street, Manchester M1 7HS, UK
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17
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Bauminger ER, Treffry A, Hudson AJ, Hechel D, Hodson NW, Andrews SC, Levi S, Nowik I, Arosio P, Guest JR. Iron incorporation into ferritins: evidence for the transfer of monomeric Fe(III) between ferritin molecules and for the formation of an unusual mineral in the ferritin of Escherichia coli. Biochem J 1994; 302 ( Pt 3):813-20. [PMID: 7945207 PMCID: PMC1137303 DOI: 10.1042/bj3020813] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Iron that has been oxidized by H-chain ferritin can be transferred into other ferritin molecules before it is incorporated into mature ferrihydrite iron cores. Iron(III) dimers are formed at the ferroxidase centres of ferritin H chains at an early stage of Fe(II) oxidation. Mössbauer spectroscopic data now show that the iron is transferred as monomeric species arising from dimer dissociation and that it binds to the iron core of the acceptor ferritin. Human H-chain ferritin variants containing altered threefold channels can act as acceptors, as can the ferritin of Escherichia coli (Ec-FTN). A human H-chain ferritin variant with a substituted tyrosine (rHuHF-Y34F) can act as a donor of Fe(III). Since an Fe(III)-tyrosinate (first identified in bullfrog H-chain ferritin) is absent from variant rHuHF-Y34F, the Fe(III) transferred is not derived from this tyrosinate complex. Mössbauer parameters of the small iron cores formed within Ec-FTN are significantly different from those of mammalian ferritins. Analysis of the spectra suggests that they are derived from both ferrihydrite and non-ferrihydrite components. This provides further evidence that the ferritin protein shell can influence the structure of its iron core.
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Affiliation(s)
- E R Bauminger
- Racah Institute of Physics, Hebrew University, Jerusalem, Israel
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18
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Harrison PM, Bauminger ER, Hechel D, Hodson NW, Nowik I, Treffry A, Yewdall SJ. Mechanism of Fe(II) oxidation and core formation in ferritin. Adv Exp Med Biol 1994; 356:1-12. [PMID: 7887213 DOI: 10.1007/978-1-4615-2554-7_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- P M Harrison
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, U.K
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19
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Bauminger ER, Harrison PM, Hechel D, Hodson NW, Nowik I, Treffry A, Yewdall SJ. Iron (II) oxidation and early intermediates of iron-core formation in recombinant human H-chain ferritin. Biochem J 1993; 296 ( Pt 3):709-19. [PMID: 8280069 PMCID: PMC1137754 DOI: 10.1042/bj2960709] [Citation(s) in RCA: 73] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The paper describes a study of Fe(II) oxidation and the formation of Fe(III)-apoferritin complexes in recombinant human H-chain ferritin and its variants. The effects of site-directed changes in the conserved residues associated with a proposed ferroxidase centre have been investigated. A change in any of these residues is shown to reduce the rate of Fe(II) oxidation, confirming the importance of the ferroxidase centre in the catalysis of Fe(II) oxidation. Mössbauer and u.v.-difference spectroscopy show that in the wild-type protein Fe(II) oxidation gives rise to Fe(III) monomers, dimers and larger clusters. The formation of Fe(III) mu-oxo-bridged dimers occurs at the ferroxidase centre and is associated with fast oxidation: in three variants in which Fe(II) oxidation is especially slow, no Fe(III) dimers are seen. Within the time scale 0.5-20 min in wild-type human H-chain ferritin, dimer formation precedes that of the monomer and the progression dimer-->monomer-->cluster is observed, although not to completion. In a preliminary investigation of oxidation intermediates using a stopped-flow instrument, an Fe(III)-tyrosine complex reported by Waldo et al. (1993), is attributed to Tyr-34, a residue at the ferroxidase centre. The Fe(III)-Tyr-34 complex, forms in 0.5 s and then decays, as dimer absorbance increases. The relationship between Fe(III)-tyrosinate and the formation of Fe(III) dimers is uncertain.
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Affiliation(s)
- E R Bauminger
- Racah Institute of Physics, Hebrew University of Jerusalem, Israel
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20
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Treffry A, Bauminger ER, Hechel D, Hodson NW, Nowik I, Yewdall SJ, Harrison PM. Defining the roles of the threefold channels in iron uptake, iron oxidation and iron-core formation in ferritin: a study aided by site-directed mutagenesis. Biochem J 1993; 296 ( Pt 3):721-8. [PMID: 7506527 PMCID: PMC1137755 DOI: 10.1042/bj2960721] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This paper aims to define the role of the threefold intersubunit channels in iron uptake and sequestration processes in the iron-storage protein, ferritin. Iron uptake, measured as loss of availability of Fe(II) to ferrozine (due to oxidation), has been studied in recombinant human H-chain ferritins bearing amino acid substitutions in the threefold channels or ferroxidase centres. Similar measurements with recombinant horse L-chain ferritin are compared. It is concluded that significant Fe(II) oxidation occurs only at the H-chain ferroxidase centres and not in the threefold channels, although this route is used by Fe(II) for entry. Investigations by Mössbauer and u.v.-difference spectroscopy show that part of the iron oxidized by H-chain ferritin returns to the threefold channels as Fe(III). This monomeric Fe(III) can be displaced by addition of Tb(III). Fe(III) also moves into the cavity for formation of the iron-core mineral, ferrihydrite. Iron incorporated into ferrihydrite becomes kinetically inert.
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Affiliation(s)
- A Treffry
- Racah Institute of Physics, Hebrew University of Jerusalem, Israel
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