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Robinson L, Salma-Ancane K, Stipniece L, Meenan BJ, Boyd AR. The deposition of strontium and zinc Co-substituted hydroxyapatite coatings. J Mater Sci Mater Med 2017; 28:51. [PMID: 28197823 DOI: 10.1007/s10856-017-5846-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 01/04/2017] [Indexed: 06/06/2023]
Abstract
The in vitro and in vivo performance of hydroxyapatite (HAp) coatings can be modified by the addition of different trace ions, such as silicon (Si), lithium (Li), magnesium (Mg), zinc (Zn) or strontium (Sr) into the HAp lattice, to more closely mirror the complex chemistry of human bone. To date, most of the work in the literature has considered single ion-substituted materials and coatings, with limited reports on co-substituted calcium phosphate systems. The aim of this study was to investigate the potential of radio frequency magnetron sputtering to deposit Sr and Zn co-substituted HAp coatings using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The FTIR and XPS results highlight that all of the Sr, Zn and Sr-Zn co-substituted surfaces produced are all dehydroxylated and are calcium deficient. All of the coatings contained HPO42- groups, however; only the pure HAp coating and the Sr substituted HAp coating contained additional CO32- groups. The XRD results highlight that none of the coatings produced in this study contain any other impurity CaP phases, showing peaks corresponding to that of ICDD file #01-072-1243 for HAp, albeit shifted to lower 2θ values due to the incorporation of Sr into the HAp lattice for Ca (in the Sr and Sr-Zn co-substituted surfaces only). Therefore, the results here clearly show that RF magnetron sputtering offers a simple means to deliver Sr and Zn co-substituted HAp coatings with enhanced surface properties. (a) XRD patterns for RF magnetron sputter deposited hydroxyapatite coatings and (b)-(d) for Sr, Zn and Sr-Zn co-substituted coatings, respectively. The XPS spectra in (b) confirms the presence of a HA sputter deposited coating as opposed to
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Affiliation(s)
- L Robinson
- Nanotechnology and Integrated Bioengineering Centre (NIBEC), School of Engineering, University of Ulster, Shore Road, Newtownabbey, Co. Antrim, BT37 0QB, Northern Ireland, UK
| | - K Salma-Ancane
- Rudolfs Cimdins Riga Biomaterials Innovations and Development Centre of RTU, Institute of General Chemical Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Pulka 3, Riga, LV, 1007, Latvia
| | - L Stipniece
- Rudolfs Cimdins Riga Biomaterials Innovations and Development Centre of RTU, Institute of General Chemical Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Pulka 3, Riga, LV, 1007, Latvia
| | - B J Meenan
- Nanotechnology and Integrated Bioengineering Centre (NIBEC), School of Engineering, University of Ulster, Shore Road, Newtownabbey, Co. Antrim, BT37 0QB, Northern Ireland, UK
| | - A R Boyd
- Nanotechnology and Integrated Bioengineering Centre (NIBEC), School of Engineering, University of Ulster, Shore Road, Newtownabbey, Co. Antrim, BT37 0QB, Northern Ireland, UK.
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Boyd AR, Rutledge L, Randolph LD, Mutreja I, Meenan BJ. The deposition of strontium-substituted hydroxyapatite coatings. J Mater Sci Mater Med 2015; 26:65. [PMID: 25631262 DOI: 10.1007/s10856-014-5377-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 09/10/2014] [Indexed: 06/04/2023]
Abstract
Strontium substituted hydroxyapatite (SrHA) coatings have received a lot of interest recently as strontium (Sr) has been shown to have the dual benefit of promoting bone formation and reducing bone resorption, in vivo. In this work, SrHA coatings were deposited onto polycrystalline titanium surfaces using radio frequency (RF) magnetron co-sputtering and compared to those deposited from HA alone. In particular, the influence of different levels of Sr-substitution of the sputtering targets (5 and 13% Sr-substituted HA targets) on the properties of the deposited coatings produced at a low discharge power level (150 W) were investigated using FTIR, XPS, XRD, ToFSIMS and AFM techniques (both before and after annealing at 500 °C). The results show that Sr could be successfully incorporated into the HA lattice to form SrHA coatings and that they contained no other impurities. However, the coating produced from the 13% Sr-substituted target had a higher Ca+Sr/P ratio (1.95±0.14) and Sr content when compared to the coating produced from the 5% Sr-substituted target (1.58±0.20). The deposition rate also decreased with increasing Sr content of the sputtering targets. Furthermore, as the Sr content of the coatings increased, so did the preferred 002 orientation of the coating along with increased surface roughness and heterogeneity of the surface features. Therefore, this study has shown that RF magnetron sputtering offers a means to control attendant properties of Sr-substituted HA, such as the crystallinity, stoichiometry, phase purity and surface topography.
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Affiliation(s)
- Adrian R Boyd
- Nanotechnology and Integrated Bioengineering Centre (NIBEC), School of Engineering, University of Ulster, Room 25B14, Shore Road, Newtownabbey, Co. Antrim, BT37 0QB, UK,
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Boyd AR, O'Kane C, O'Hare P, Burke GA, Meenan BJ. The influence of target stoichiometry on early cell adhesion of co-sputtered calcium-phosphate surfaces. J Mater Sci Mater Med 2013; 24:2845-2861. [PMID: 23918527 DOI: 10.1007/s10856-013-5021-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 07/26/2013] [Indexed: 06/02/2023]
Abstract
The nature of the initial interaction between calcium phosphate (Ca-P) thin films and osteoblasts can be influenced by a number of different properties including the phase, crystallinity, stoichiometry and composition of the surface. There is still a strong interest in developing and studying Ca-P surfaces that have the ability to accurately control the osteoblast response. Radio frequency (RF) magnetron sputtering is a technique that allows for accurate control of the properties of deposited Ca-P coatings and has been studied extensively because of this fact. In this work, Ca-P coatings were co-deposited using RF magnetron sputtering in order to study the effect of changing the target stoichiometry on the initial in vitro behavior of MG63 osteoblast-like cells. The samples produced were analysed both as-deposited and after thermal annealing to 500 °C. After annealing XPS analyses of the samples co-deposited using tricalcium phosphate (TCP) materials gave a Ca/P ratio of 1.71 ± 0.01, as compared to those co-deposited from hydroxyapatite (HA) materials, with a Ca/P of 1.82 ± 0.06. In addition to this, the curve fitted XPS data indicated the presence of low levels of carbonate in the coatings. Despite this the XRD results for all of the annealed coatings were shown to be characteristic of pure HA with a preferred 002 orientation. The atomic force microscopy results also highlighted that both types of coatings had surface features of a similar size (200-220 nm). Both surfaces exhibited a degree of surface degradation, even after 1 h of cell culture. However, the TCP derived surfaces showed an enhanced osteoblastic cell response in terms of cell adhesion and cell proliferation in the earlier stages of cell culture than the surfaces deposited from HA. An improvement in the initial cell attachment and a potential for increased cell proliferation rates is viewed as a highly advantageous result in relation to controlling the osteoblast response on these surfaces.
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Affiliation(s)
- A R Boyd
- Nanotechnology and Integrated Bioengineering Centre (NIBEC), School of Engineering, University of Ulster, Shore Road, Newtownabbey, Co. Antrim, BT37 0QB, Northern Ireland, UK,
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Mutreja I, Kumar D, Boyd AR, Meenan BJ. Titania nanotube porosity controls dissolution rate of sputter deposited calcium phosphate (CaP) thin film coatings. RSC Adv 2013. [DOI: 10.1039/c3ra40898a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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Davey SM, Brennan M, Meenan BJ, McAdam R. Innovation in the medical device sector: an open business model approach for high-tech small firms. Technology Analysis & Strategic Management 2011. [DOI: 10.1080/09537325.2011.604152] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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McManus LL, Boyd AR, Burke GA, Meenan BJ. Raman spectroscopy of primary bovine aortic endothelial cells: a comparison of single cell and cell cluster analysis. J Mater Sci Mater Med 2011; 22:1923-1930. [PMID: 21670997 DOI: 10.1007/s10856-011-4383-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 06/04/2011] [Indexed: 05/19/2023]
Abstract
There are many techniques that allow in vitro interactions among cells and their environment to be monitored, including molecular, biochemical and immunochemical techniques. Traditional techniques for the analysis of cells often require fixation or lysis from substrates; however, use of such destructive methods is not feasible where the expanded cell cultures are required to be used for clinical implantation. Several studies have previously highlighted the potential of Raman spectroscopy to provide useful information on key biochemical markers within cells. As such, we highlight the capability of Raman spectroscopy with different laser spot sizes for use as a non-invasive, rapid, and specific method to perform in situ analysis of primary bovine aortic endothelial cells (BAECs). Raman spectra were collected from both individual live cells cultured on fused silica substrates and on clusters of live cells placed on fused silica substrates, measured at 532 and 785 nm. The results obtained show notable spectral differences in DNA/RNA region indicative of the relative cytoplasm and nucleus contributions. Raman spectra of cell clusters show slight variations in the intensity of the phenylalanine peak (1004 cm(-1)) indicating variations in protein contribution. These spectra also highlight contributions from other cellular components such as, proteins, lipids, nucleic acids and carbohydrates, respectively.
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Affiliation(s)
- L L McManus
- Nanotechnology and Integrated Bioengineering Centre, University of Ulster, Shore Road, Newtownabbey, Antrim, BT37 0QB, Northern Ireland.
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McManus LL, Boyd AR, Burke GA, Meenan BJ. Raman spectroscopy of primary bovine aortic endothelial cells: a comparison of single cell and cell cluster analysis. J Mater Sci Mater Med 2011; 22:1923-1930. [PMID: 21670997 DOI: 10.1007/s10856-011-4371-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 06/04/2011] [Indexed: 05/30/2023]
Abstract
There are many techniques that allow in vitro interactions among cells and their environment to be monitored, including molecular, biochemical and immunochemical techniques. Traditional techniques for the analysis of cells often require fixation or lysis from substrates; however, use of such destructive methods is not feasible where the expanded cell cultures are required to be used for clinical implantation. Several studies have previously highlighted the potential of Raman spectroscopy to provide useful information on key biochemical markers within cells. As such, we highlight the capability of Raman spectroscopy with different laser spot sizes for use as a non-invasive, rapid, and specific method to perform in situ analysis of primary bovine aortic endothelial cells (BAECs). Raman spectra were collected from both individual live cells cultured on fused silica substrates and on clusters of live cells placed on fused silica substrates, measured at 532 and 785 nm. The results obtained show notable spectral differences in DNA/RNA region indicative of the relative cytoplasm and nucleus contributions. Raman spectra of cell clusters show slight variations in the intensity of the phenylalanine peak (1004 cm(-1)) indicating variations in protein contribution. These spectra also highlight contributions from other cellular components such as, proteins, lipids, nucleic acids and carbohydrates, respectively.
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Affiliation(s)
- L L McManus
- Nanotechnology and Integrated Bioengineering Centre, University of Ulster, Shore Road, Newtownabbey, Antrim, BT37 0QB, Northern Ireland.
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Abstract
Technological advances such as computer navigation systems and robotics, including support systems for minimally invasive surgery, have the potential to revolutionise how orthopaedic surgery is carried out. However uptake has so far been limited. Increased awareness of user requirements in adoption decision-making will be useful. In this regard, the opinion of the individual surgeon regarding his or her willingness to engage in a novel technology has rarely been garnished. This paper analyses the opinions of orthopaedic consultants from the UK and USA about technological advances in hip and knee arthroplasty, factors contributing to successful short-term and long-term surgical outcome, and patient preferences. The survey, using a web-based questionnaire, was carried out in 2006-2007 and followed up in 2010. The results of this research give a greater insight into why surgical technologies that have the potential to improve patient outcome are not more speedily adopted in the health service.
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Affiliation(s)
- S M Davey
- Multidisciplinary Assessment of Technology Centre for Healthcare (MATCH), Nanotechnology and Integrated BioEngineering Centre (NIBEC), School of Electrical and Mechanical Engineering, University of Ulster, Jordanstown campus, Shore Road, Newtownabbey, County Antrim, BT37 0QB, UK.
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Boyd AR, Burke GA, Duffy H, Holmberg M, O' Kane C, Meenan BJ, Kingshott P. Sputter deposited bioceramic coatings: surface characterisation and initial protein adsorption studies using surface-MALDI-MS. J Mater Sci Mater Med 2011; 22:71-84. [PMID: 21104194 DOI: 10.1007/s10856-010-4180-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Accepted: 10/25/2010] [Indexed: 05/30/2023]
Abstract
Protein adsorption onto calcium phosphate (Ca-P) bioceramics utilised in hard tissue implant applications has been highlighted as one of the key events that influences the subsequent biological response, in vivo. This work reports on the use of surface-matrix assisted laser desorption ionisation mass spectrometry (Surface-MALDI-MS) as a technique for the direct detection of foetal bovine serum (FBS) proteins adsorbed to hybrid calcium phosphate/titanium dioxide surfaces produced by a novel radio frequency (RF) magnetron sputtering method incorporating in situ annealing between 500°C and 700°C during deposition. XRD and XPS analysis indicated that the coatings produced at 700°C were hybrid in nature, with the presence of Ca-P and titanium dioxide clearly observed in the outer surface layer. In addition to this, the Ca/P ratio was seen to increase with increasing annealing temperature, with values of between 2.0 and 2.26 obtained for the 700°C samples. After exposure to FBS solution, surface-MALDI-MS indicated that there were significant differences in the protein patterns as shown by unique peaks detected at masses below 23.1 kDa for the different surfaces. These adsorbates were assigned to a combination of growth factors and lipoproteins present in serum. From the data obtained here it is evident that surface-MALDI-MS has significant utility as a tool for studying the dynamic nature of protein adsorption onto the surfaces of bioceramic coatings, which most likely plays a significant role in subsequent bioactivity of the materials.
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Affiliation(s)
- A R Boyd
- Nanotechnology and Integrated Bioengineering Centre (NIBEC), University of Ulster at Jordanstown, Newtownabbey, Co, Antrim, Northern Ireland, UK.
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Boyd AR, Burke GA, Meenan BJ. Monitoring cellular behaviour using Raman spectroscopy for tissue engineering and regenerative medicine applications. J Mater Sci Mater Med 2010; 21:2317-2324. [PMID: 20020185 DOI: 10.1007/s10856-009-3965-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 12/02/2009] [Indexed: 05/27/2023]
Abstract
Raman spectroscopy has been used to determine the chemical composition of materials for over 70 years. Recent spectacular advances in laser and CCD camera technology creating instruments with higher sensitivity and lower cost have initiated a strong resurgence in the technique, ranging from fundamental research to process control methodology. One such area of increased potential is in tissue engineering and regenerative medicine (TERM), where autologous cell culture, stem cell biology and growth of human cells on biomaterial scaffolds are of high importance. Traditional techniques for the in vitro analysis of biochemical cell processes involves cell techniques such as fixation, lysis or the use of radioactive or chemical labels which are time consuming and can involve the perpetuation of artefacts. Several studies have already shown the potential of Raman spectroscopy to provide useful information on key biochemical markers within cells, however, many of these studies have utilised micro- or confocal Raman to do this, which are not suited to the rapid and non-invasive monitoring of cells. For this study a versatile fit-for-purpose Raman spectrometer was used, employing a macro-sampling optical platform (laser spot size 100 mum at focus on the sample) to discriminate between different TERM relevant cell types and viable and non-viable cells. The results clearly show that the technique is capable of obtaining Raman spectra from live cells in a non-destructive, rapid and non-invasive manner, however, in these experiments it was not possible to discriminate between different cell lines. Despite this, notable differences were observed in the spectra obtained from viable and non-viable cells, showing significant changes in the spectral profiles of protein, DNA/RNA and lipid cell constituents after cell death. It is evident that the method employed here shows significant potential for further utilisation in TERM, providing data directly from live cells that fits within a quality assurance framework and provides the opportunity to analyse cells in a non-destructive manner.
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Affiliation(s)
- A R Boyd
- School of Engineering, Nanotechnology, University of Ulster at Jordanstown, Newtownabbey, Co. Antrim, Northern Ireland, UK.
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Cairns ML, Meenan BJ, Burke GA, Boyd AR. Influence of surface topography on osteoblast response to fibronectin coated calcium phosphate thin films. Colloids Surf B Biointerfaces 2010; 78:283-90. [PMID: 20392613 DOI: 10.1016/j.colsurfb.2010.03.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 02/17/2010] [Accepted: 03/22/2010] [Indexed: 11/26/2022]
Abstract
The ability to engineer biomaterial surfaces that are capable of a dynamic interaction with cells and tissues is central to the development of medical implants with improved functionality. An important consideration in this regard is the role played by the extracellular proteins that bind to an implant surface in vivo. Deliberate use of an ad-layer of such proteins on an implant surface has been observed to guide and direct cell response. However, the role that changes in surface topography might play in determining the nature of this cell-protein-surface interaction has not been investigated in detail. In this study, calcium phosphate (CaP) thin films have been deposited onto substrates with varying topography such that this is reflected in the (conformal) CaP surface features. A fibronectin (FN) ad-layer was then deposited from solution onto each surface and the response of MG63 osteoblast-like cells investigated. The results revealed that in all cases, the presence of the adsorbed FN layer on the CaP thin films improved MG63 cell adhesion, proliferation and promoted early onset differentiation. Moreover, the nature and scale of the response were shown to be influenced by the underlying CaP surface topography. Specifically, MG63 cell on FN-coated CaP thin films with regular topographical features in the nanometer range showed statistically significant differences in focal adhesion assembly, osteocalcin expression and alkaline phosphase activity compared to CaP thin films that lacked these topographical features. As such, these data indicate that surface topography can be used to further influence cell adhesion and downstream differentiation by enhancing the effects of a surface adsorbed FN layer.
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Affiliation(s)
- M L Cairns
- Nanotechnology and Integrated Bio-Engineering Centre (NIBEC), University of Ulster, Shore Road, Newtownabbey, Co. Antrim, BT370QB, Northern Ireland, UK.
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Boyd AR, Burke GA, Duffy H, Cairns ML, O'Hare P, Meenan BJ. Characterisation of calcium phosphate/titanium dioxide hybrid coatings. J Mater Sci Mater Med 2008; 19:485-98. [PMID: 17607520 DOI: 10.1007/s10856-006-0031-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Accepted: 10/19/2006] [Indexed: 05/16/2023]
Abstract
The role of titanium dioxide (TiO2) as a means to engender enhanced stability into calcium phosphate (Ca-P) coatings has been well recognised. Several different methods have been used to create such Ca-P/TiO2 hybrid layers on a range of substrates. This paper reports the properties of a Ca-P/TiO2 system created by the sputter deposition of hydroxyapatite onto a titanium surface and the subsequent thermal diffusion of TiO2 through the porous Ca-P layer. The role of temperature in determining the surface contribution from TiO2 has been determined. Coatings annealed up to 600 degrees C did not exhibit any hybrid nature in the uppermost surface, however the coatings annealed to 700 degrees C did show the presence of both HA and rutile TiO2. The surfaces annealed to 800 degrees C were predominantly rutile TiO2. It was also observed that the Ca/P ratio decreased with increasing annealing temperature and that the coating annealed to 700 degrees C had a value of 1.82 +/- 0.07, which was closest to stoichiometric HA. Furthermore, the coatings that were annealed to 700 degrees C displayed a Ca-P/TiO2 hybrid nature, specifically in their uppermost surface and supported the growth and proliferation of osteoblast-like cells more readily when compared to the HA coatings or the rutile TiO2 surfaces.
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Affiliation(s)
- A R Boyd
- Northern Ireland Bioengineering Centre/Nanotechnology and Advanced Materials Research Institute, University of Ulster at Jordanstown, Shore Road, Room 25A18, Newtownabbey, Co. Antrim, Northern Ireland, UK.
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Dixon D, Brown A, Meenan BJ, Eatock J. Experiences of new product development in the medical device industry. Med Device Technol 2006; 17:20-2. [PMID: 16736659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A survey of medical device professionals has revealed the factors that influence the development time and market success of new products. The vital elements that deliver commercial success are reported here.
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Affiliation(s)
- D Dixon
- Northern Ireland Biomedical Engineering Centre, University of Ulster, Newtownabbey, Northern Ireland.
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Boyd A, Akay M, Meenan BJ. Influence of target surface degradation on the properties of r.f. magnetron-sputtered calcium phosphate coatings. SURF INTERFACE ANAL 2003. [DOI: 10.1002/sia.1512] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Meenan BJ, McConnell J, Knight J, Boyd A, Bell A. Development of a sensitive whole blood chemiluminescence method for assessing the bioactivity of calcium phosphate powders. Biomaterials 2002; 23:2431-45. [PMID: 12033591 DOI: 10.1016/s0142-9612(01)00378-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The development of simple, but highly sensitive and accurate in vitro methods for assessing the bioactivity of biomaterials is a key requirement for assuring their successful clinical application. Moreover, screening techniques that will allow various materials to be recommended, or otherwise, for further testing, have the potential to make appreciable savings in the time and expense associated with product development. This paper gives details of a novel whole blood chemiluminescence method, based on the photoprotein Pholasin, which emits light in the presence of the free radical superoxide. other reactive oxygen species and the enzyme myeloperoxidase. This whole blood assay may have the potential as a screening method for assessing calcium phosphate (Ca-P) bioceramic powders according to their relative bioactivity. The method employed involves exposure of samples of anti-coagulated (heparinised) blood to the various Ca-P materials and stimulating the contacted leukocytes in the blood with phorbol-12-myristate-13-acetate (PMA). PMA stimulates protein kinase C directly and sets in motion a cascade of events in the leukocytes leading to the activation of the superoxide generating NADPH oxidase system. PMA also promotes degranulation, which is the fusion of the granule membrane with the plasma membrane and the extracellular release of granule enzymes. Changes in the free radical and degranulation activity of the cells, as measured by the luminescent response of Pholasin to cells stimulated with PMA, after exposure to the Ca-P powders, are presented as percentage differences from the response to (control) blood samples not exposed to the powders. The resultant data clearly indicate significant differences in the light detected via Pholasin from the blood exposed to the bioceramic materials compared to that from the relevant controls. These differences correlate well with the ascribed bioactivity of the Ca-P powders. as assigned from the measured chemical and structural properties. Furthermore, the method can also be applied to samples of blood, which have been diluted in the ratio 1:100 in standard blood dilution buffer. The light output response in the diluted blood experiments is exactly the same as that observed with undiluted whole blood but occurs immediately as compared to the many minutes required to give response in the latter case. Thermally processed (800 degrees C) Ca-P materials have also been studied. A relationship between the heat-induced properties of the powders and the chemiluminescence responses recorded from blood cells stimulated with PMA has been established.
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Affiliation(s)
- B J Meenan
- Northern Ireland Bio-Engineering Centre, School of Electrical and Mechanical Engineering, University of Ulster, Newtownabbey, Co. Antrim, UK.
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Meenan BJ, McClorey C, Akay M. Thermal analysis studies of poly(etheretherketone)/hydroxyapatite biocomposite mixtures. J Mater Sci Mater Med 2000; 11:481-489. [PMID: 15347998 DOI: 10.1023/a:1013005707430] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Biocomposite formulations which have the potential to combine the proven mechanical performance of poly(etheretherketone) (PEEK) with the inherent bioactivity of hydroxyapatite (HA), may have a utility as load-bearing materials in a medical implant context. The effect of thermal processing on the relevant properties of the PEEK and/or HA components in any fabricated composite structure is, however, an important consideration for their effective exploitation. This paper reports the results of a detailed thermal characterization study of a series of PEEK/HA mixtures using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and modulated differential scanning calorimetry (MDSC). The TGA analyses show minimal weight loss for all of the mixtures and for a pure PEEK sample up to approximately 530 degrees C. Above this point there is a sharp on-set of decomposition for the PEEK component in each case. The temperature at which this feature occurs varies for each mixture in the approximate range 539-556 degrees C. This observation is supported by the presence of exotherms in the corresponding DSC scans, in the same temperature region, which are also assigned to PEEK decomposition. The temperature at which the degradation on-set occurs is found to decrease with increasing HA contribution. The use of the modulated DSC technique allows a number of important thermal events, not easily identifiable from the data obtained by the conventional method, to be clearly observed. In particular, the glass transition temperature (Tg) of the polymer can now be accurately determined. Using these thermal analysis data, calculations of the % crystallinity of PEEK in the mixtures have been made and compared with that of a 100% polymer sample. From these studies it is evident that the presence of HA does not adversely affect the degree of crystallinity of the PEEK component in the mixtures of interest over the thermal range studied.
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Affiliation(s)
- B J Meenan
- Northern Ireland Bio-Engineering Center, School of Electrical and Mechanical Engineering, University of Ulster, Shore Road, Newtownabbey, Co. Antrim, Northern Ireland, BT37 0QB, UK.
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Lee TC, Shine JD, FitzPatrick DP, Bradley JA, O’Connor JJ, O’Kelly KU, Carr AJ, McCormack BAO, O’Neill P, Cole JS, Watterson JK, Raghunathan S, O’Reilly MJG, Pherwani A, Rice J, McCormack D, Maher SA, Prendergast PJ, Reid AJ, Waide DV, Chambers SD, Bartlett RH, Ceccio SL, Murphy LA, Lacroix D, Murphy BP, Mullett H, Shannon F, Lawlor G, O’Rourke SK, Connolly P, Maher S, Devitt A, McElwain J, O’Reilly P, McCarthy DR, Kernohan G, Buchanan FJ, Sim B, Downes S, Bennett DB, Orr JF, Dorrell PF, Fleming P, Stephens M, Moholkar K, Fenelon G, Doyle AM, Dockrell S, Normoyle P, Geraghty D, MacNamara S, Lacey G, Lally C, McGloughlin T, Grace P, Walsh M, McGIoughlin T, Colgan D, Daly S, Dolan B, Flynn MJ, Shuhaibar M, Neligan MC, McMillan ND, O’Mongain E, Walsh J, Miller R, Mitchell I, O’Neill M, Brennan F, Ridgway P, Blayney AW, Monkhouse WS, O’Brien FJ, Taylor D, Mushipe MT, Shelton JC, Revell PA, McCarthy MA, Pearse KM, O’Keefe DT, Lyons GM, Leane GE, Mulcahy E, Bray K, Conway BA, Halliday DM, Rosenberg JR, Anderson R, Grace PA, Kinsella SM, Harrison AJ, Lyons DJ, Wallace KE, Hill RG, Pembroke JT, Brown CJ, Hatton PV, Bryan K, Buggy M, Noe JM, Nico AC, McConnell LA, McGivern RC, Marsh DR, Meenan BJ, Workman A, Kuiper JH. Royal Academy of Medicine in Ireland Section of Bioengineering. Ir J Med Sci 1999. [DOI: 10.1007/bf02945855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Jansson C, Tougaard S, Beamson G, Briggs D, Davies SF, Rossi A, Hauert R, Hobi G, Brown NMD, Meenan BJ, Anderson CA, Repoux M, Malitesta C, Sabbatini L. Intercomparison of algorithms for background correction in XPS. SURF INTERFACE ANAL 1995. [DOI: 10.1002/sia.740230708] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Brown NMD, Meenan BJ, Affrossman S, Pethrick RA, Thomson B. Investigation of resin-substrate interactions: An IETS study of phenol- and cresol- formaldehyde model compounds. SURF INTERFACE ANAL 1987. [DOI: 10.1002/sia.740100403] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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