Publications by authors named "Colin Sherborne"

10 Publications

  • Page 1 of 1

Considerations Using Additive Manufacture of Emulsion Inks to Produce Respiratory Protective Filters Against Viral Respiratory Tract Infections Such as the COVID-19 Virus.

Int J Bioprint 2021 13;7(1):316. Epub 2021 Jan 13.

The Kroto Research Institute, North Campus, University of Sheffield, Broad Lane, Sheffield, S3 7HQ, UK.

This review paper explores the potential of combining emulsion-based inks with additive manufacturing (AM) to produce filters for respiratory protective equipment (RPE) in the fight against viral and bacterial infections of the respiratory tract. The value of these filters has been highlighted by the current severe acute respiratory syndrome coronavirus-2 crisis where the importance of protective equipment for health care workers cannot be overstated. Three-dimensional (3D) printing of emulsions is an emerging technology built on a well-established field of emulsion templating to produce porous materials such as polymerized high internal phase emulsions (polyHIPEs). PolyHIPE-based porous polymers have tailorable porosity from the submicron to 100 s of µm. Advances in 3D printing technology enables the control of the bulk shape while a micron porosity is controlled independently by the emulsion-based ink. Herein, we present an overview of the current polyHIPE-based filter applications. Then, we discuss the current use of emulsion templating combined with stereolithography and extrusion-based AM technologies. The benefits and limitation of various AM techniques are discussed, as well as considerations for a scalable manufacture of a polyHIPE-based RPE.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18063/ijb.v7i1.316DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7875060PMC
January 2021

Combined Porogen Leaching and Emulsion Templating to produce Bone Tissue Engineering Scaffolds.

Int J Bioprint 2020 30;6(2):265. Epub 2020 Apr 30.

Department of Materials Science and Engineering, INSIGNEO Institute for in silico Medicine, University of Sheffield, UK.

Bone has a hierarchy of porosity that is often overlooked when creating tissue engineering scaffolds where pore sizes are typically confined to a single order of magnitude. High internal phase emulsion (HIPE) templating produces polymerized HIPEs (polyHIPEs): highly interconnected porous polymers which have two length scales of porosity covering the 1-100 μm range. However, additional larger scales of porosity cannot be introduced in the standard emulsion formulation. Researchers have previously overcome this by additively manufacturing emulsions; fabricating highly microporous struts into complex macroporous geometries. This is time consuming and expensive; therefore, here we assessed the feasibility of combining porogen leaching with emulsion templating to introduce additional macroporosity. Alginate beads between 275 and 780 μm were incorporated into the emulsion at 0, 50, and 100 wt%. Once polymerized, alginate was dissolved leaving highly porous polyHIPE scaffolds with added macroporosity. The compressive modulus of the scaffolds decreased as alginate porogen content increased. Cellular performance was assessed using MLO-A5 post-osteoblasts. Seeding efficiency was significantly higher and mineralized matrix deposition was more uniformly deposited throughout porogen leached scaffolds compared to plain polyHIPEs. Deep cell infiltration only occurred in porogen leached scaffolds as detected by histology and lightsheet microscopy. This study reveals a quick, low cost and simple method of producing multiscale porosity scaffolds for tissue engineering.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18063/ijb.v6i2.265DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7415854PMC
April 2020

UV-Casting on Methacrylated PCL for the Production of a Peripheral Nerve Implant Containing an Array of Porous Aligned Microchannels.

Polymers (Basel) 2020 Apr 22;12(4). Epub 2020 Apr 22.

Tekniker, C/Iñaki Goenaga 5, 20600 Eibar, Spain.

Peripheral nerves are basic communication structures guiding motor and sensory information from the central nervous system to receptor units. Severed peripheral nerve injuries represent a large clinical problem with relevant challenges to successful synthetic nerve repair scaffolds as substitutes to autologous nerve grafting. Numerous studies reported the use of hollow tubes made of synthetic polymers sutured between severed nerve stumps to promote nerve regeneration while providing protection for external factors, such as scar tissue formation and inflammation. Few approaches have described the potential use of a lumen structure comprised of microchannels or microfibers to provide axon growth avoiding misdirection and fostering proper healing. Here, we report the use of a 3D porous microchannel-based structure made of a photocurable methacrylated polycaprolactone, whose mechanical properties are comparable to native nerves. The neuro-regenerative properties of the polymer were assessed in vitro, prior to the implantation of the 3D porous structure, in a 6-mm rat sciatic nerve gap injury. The manufactured implants were biocompatible and able to be resorbed by the host's body at a suitable rate, allowing the complete healing of the nerve. The innovative design of the highly porous structure with the axon guiding microchannels, along with the observation of myelinated axons and Schwann cells in the in vivo tests, led to a significant progress towards the standardized use of synthetic 3D multichannel-based structures in peripheral nerve surgery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/polym12040971DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7240584PMC
April 2020

Assessment of the Angiogenic Potential of 2-Deoxy-D-Ribose Using a Novel 3D Dynamic Model in Comparison With Established Assays.

Front Bioeng Biotechnol 2019 17;7:451. Epub 2020 Jan 17.

Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, Sheffield, United Kingdom.

Angiogenesis is a highly ordered physiological process regulated by the interaction of endothelial cells with an extensive variety of growth factors, extracellular matrix components and mechanical stimuli. One of the most important challenges in tissue engineering is the rapid neovascularization of constructs to ensure their survival after transplantation. To achieve this, the use of pro-angiogenic agents is a widely accepted approach. The study of angiogenesis has gained momentum over the last two decades. Although there are various , and angiogenesis models that enable testing of newly discovered pro-angiogenic agents, the problem with researching angiogenesis is the choice of the most appropriate assay. assays are the most representative and reliable models, but they are expensive, time-consuming and can cause ethical concerns whereas assays are relatively inexpensive, practical, and reproducible, but they are usually lack of enabling the study of more than one aspect of angiogenesis, and they do not fully represent the complexity of physiological angiogenesis. Therefore, there is a need for the development of an angiogenesis model that allows the study of angiogenesis under physiologically more relevant, dynamic conditions without causing ethical concerns. Accordingly, in this study, we developed 3D dynamic angiogenesis model, and we tested the angiogenic potential of 2-deoxy-D-ribose (2dDR) in comparison with vascular endothelial growth factor (VEGF) using newly developed 3D dynamic model and well-established models. Our results obtained using conventional assays demonstrated that 2dDR promoted proliferation, migration and tube formation of human aortic endothelial cells (HAECs) in a dose-dependent manner. Then, the angiogenic activity of 2dDR was further assessed using the newly developed 3D model, which enabled the monitoring of cell proliferation and infiltration simultaneously under dynamic conditions. Our results showed that the administration of 2dDR and VEGF significantly enhanced the outgrowth of HAECs and the cellular density under either static or dynamic conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fbioe.2019.00451DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6978624PMC
January 2020

Porous microspheres support mesenchymal progenitor cell ingrowth and stimulate angiogenesis.

APL Bioeng 2018 Jun 26;2(2):026103. Epub 2018 Apr 26.

Department of Materials Science and Engineering, Insigneo Institute for in silico Medicine, The University of Sheffield, Sheffield S1 3JD, United Kingdom.

Porous microspheres have the potential for use as injectable bone fillers to obviate the need for open surgery. Successful bone fillers must be able to support vascularisation since tissue engineering scaffolds often cease functioning soon after implantation due to a failure to vascularise rapidly. Here, we test the angiogenic potential of a tissue engineered bone filler based on a photocurable acrylate-based high internal phase emulsion (HIPE). Highly porous microspheres were fabricated via two processes, which were compared. One was taken forward and investigated for its ability to support human mesenchymal progenitor cells and angiogenesis in a chorioallantoic membrane (CAM) assay. Porous microspheres with either a narrow or broad size distribution were prepared via a T-junction microfluidic device or by a controlled stirred-tank reactor of the HIPE water in oil in water (w/o/w), respectively. Culture of human embryonic stem cell-derived mesenchymal progenitor (hES-MP) cells showed proliferation over 11 days and formation of cell-microsphere aggregates. , hES-MP cells were found to migrate into microspheres through their surface pores over time. The presence of osteoblasts, differentiated from the hES-MP cells, was evidenced through the presence of collagen and calcium after 30 days. Microspheres pre-cultured with cells were implanted into CAM for 7 days and compared with control microspheres without pre-cultured cells. The hES-MP seeded microspheres supported greater angiogenesis, as measured by the number of blood vessels and bifurcations, while the empty scaffolds attracted host chick cell ingrowth. This investigation shows that controlled fabrication of porous microspheres has the potential to create an angiogenic, bone filling material for use as a cell delivery vehicle.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1063/1.5008556DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6481713PMC
June 2018

A methodology for the production of microfabricated electrospun membranes for the creation of new skin regeneration models.

J Tissue Eng 2018 Jan-Dec;9:2041731418799851. Epub 2018 Sep 21.

Biomaterials and Tissue Engineering Group, Department of Materials Science and Engineering, Kroto Research Institute, The University of Sheffield, Sheffield, UK.

The continual renewal of the epidermis is thought to be related to the presence of populations of epidermal stem cells residing in physically protected microenvironments (rete ridges) directly influenced by the presence of mesenchymal fibroblasts. Current skin in vitro models do acknowledge the influence of stromal fibroblasts in skin reorganisation but the study of the effect of the rete ridge-microenvironment on epidermal renewal still remains a rich topic for exploration. We suggest there is a need for the development of new in vitro models in which to study epithelial stem cell behaviour prior to translating these models into the design of new cell-free biomaterial devices for skin reconstruction. In this study, we aimed to develop new prototype epidermal-like layers containing pseudo-rete ridge structures for studying the effect of topographical cues on epithelial cell behaviour. The models were designed using a range of three-dimensional electrospun microfabricated scaffolds. This was achieved via the utilisation of polyethylene glycol diacrylate to produce a reusable template over which poly(3-hydrroxybutyrate--3-hydroxyvalerate) was electrospun. Initial investigations studied the behaviour of keratinocytes cultured on models using plain scaffolds (without the presence of intricate topography) versus keratinocytes cultured on scaffolds containing microfeatures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/2041731418799851DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6153546PMC
September 2018

Photocurable high internal phase emulsions (HIPEs) containing hydroxyapatite for additive manufacture of tissue engineering scaffolds with multi-scale porosity.

Mater Sci Eng C Mater Biol Appl 2016 Oct 25;67:51-58. Epub 2016 Apr 25.

Department of Materials Science and Engineering, The Kroto Research Institute, North Campus, University of Sheffield, Broad Lane, Sheffield, S3 7HQ, UK.

Porous composites containing hydroxyapatite (HA) were templated from high internal phase emulsions (HIPEs) and were further structured using direct-write UV stereolithography to produce composite scaffolds with multi-scale porosity. FTIR, TGA and SEM analyses confirmed that HA was retained after photocuring and subsequent treatments and was incorporated within the polymerised HIPE (polyHIPE). The addition of HA particles to the polyHIPE caused changes in the mechanical properties of the material. An increase in both the Young's modulus and maximum stress at yield was observed compared with the pure polyHIPE from 1.544±0.231 to 4.614±0.775 and 0.177±0.009 to 0.267±0.034MPa, respectively. Except at very high concentrations, adding HA did not adversely cause the phase separation of the HIPE or the porous microstructure of the resulting polyHIPE. In combination with a photoinitiator, the HIPE emulsion containing HA was investigated as a photocurable resin for stereolithography-based additive manufacturing. The material was readily processable into "woodpile" structures via direct-write UV stereolithography, producing scaffolds with multi-scale porosity which may be useful for medical applications such as tissue engineering. In conclusion, HA was successfully added into polyHIPEs, producing a similar porous structure to that of the pure polyHIPE whilst improving the mechanical performance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2016.04.087DOI Listing
October 2016

Data for the analysis of PolyHIPE scaffolds with tunable mechanical properties for bone tissue engineering.

Data Brief 2015 Dec 23;5:616-20. Epub 2015 Oct 23.

Department of Materials Science and Engineering, University of Sheffield, The Kroto Research Institute, North Campus, Broad Lane, Sheffield S3 7HQ, United Kingdom.

This article presents data related to the research article titled, 'Emulsion templated scaffolds with tunable mechanical properties for bone tissue engineering' (Owen et al., in press) [1]. This data article contains excel files with the results obtained during the mechanical characterisation of 20 acrylate-based PolyHIPE compositions, giving the Young's modulus, ultimate tensile stress and strain at failure for each specimen tested. Also included are the measurements taken to determine the degree of openness (DOO) of each composition, and the data for the cell viability and alkaline phosphatase (ALP) activity on the emulsion templated scaffolds.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.dib.2015.09.051DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4773382PMC
December 2015

Emulsion templated scaffolds with tunable mechanical properties for bone tissue engineering.

J Mech Behav Biomed Mater 2016 Feb 25;54:159-72. Epub 2015 Sep 25.

Department of Materials Science and Engineering, University of Sheffield, The Kroto Research Institute, North Campus, Broad Lane, Sheffield S3 7HQ, United Kingdom. Electronic address:

Polymerised High Internal Phase Emulsions (PolyHIPEs) are manufactured via emulsion templating and exhibit a highly interconnected microporosity. These materials are commonly used as thin membranes for 3D cell culture. This study uses emulsion templating in combination with microstereolithography to fabricate PolyHIPE scaffolds with a tightly controlled and reproducible architecture. This combination of methods produces hierarchical structures, where the microstructural properties can be independently controlled from the scaffold macrostructure. PolyHIPEs were fabricated with varying ratios of two acrylate monomers (2-ethylhexyl acrylate (EHA) and isobornyl acrylate (IBOA)) and varying nominal porosity to tune mechanical properties. Young's modulus, ultimate tensile stress (UTS) and elongation at failure were determined for twenty EHA/IBOA compositions. Moduli ranged from 63.01±9.13 to 0.36±0.04MPa, UTS from 2.03±0.33 to 0.11±0.01MPa and failure strain from 21.86±2.87% to 2.60±0.61%. Selected compositions were fabricated into macro-porous woodpile structures, plasma treated with air or acrylic acid and seeded with human embryonic stem-cell derived mesenchymal progenitor cells (hES-MPs). Confocal and two-photon microscopy confirmed cell proliferation and penetration into the micro- and macro-porous architecture. The scaffolds supported osteogenic differentiation of mesenchymal cells and interestingly, the stiffest IBOA-based scaffolds that were plasma treated with acrylic acid promoted osteogenesis more strongly than the other scaffolds.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jmbbm.2015.09.019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4717122PMC
February 2016

Macrostructuring of emulsion-templated porous polymers by 3D laser patterning.

Adv Mater 2013 Jun 19;25(23):3178-81. Epub 2013 Apr 19.

Department of Chemistry & Biophysical Sciences Institute, Durham University, South Road, Durham, DH1 3LE, UK.

Micro-stereolithography (μSL) is used to produce 3D porous polymer structures by templating high internal phase emulsions. A variety of structures are produced, including lines, squares, grids, and tubes. The porosity matches that of materials produced by conventional photopolymerization.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adma.201300552DOI Listing
June 2013
-->