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Dr Joshua Chou

Biography

Dr. Joshua Chou is a Chancellor’s Postdoctoral Fellow in the Department of Medical and Molecular Bioscience as well as a core member of the Centre of Health Technology at UTS. Joshua finished his Ph.D. here at UTS where his research was based on using biomimetic materials for bone tissue regeneration. Currently his research is based on developing drug delivery systems for stimulating and guiding bone regeneration with particular emphasis in developing bioinspired biomaterials and applying stem cell technologies for tissue engineering. Furthermore, Dr. Chou holds a Graduate Certificate in Project Management from The University of Sydney and is currently undertaking a Graduate Certificate in Higher Education.

While still an Early Career Researcher, Dr. Chou’s interdisciplinary research has during the past 2 years been published in high impact journals including Journal of Tissue Engineering and Regenerative Medicine, Advanced Functional Materials, Advanced Healthcare Materials, Journal of Australia Ceramic Society.

Dr. Chou was awarded the Endeavour Award in 2011 where he spent 6 months with our industry collaborator in Japan. This research was presented at the 2011 Asian Bioceramic Symposium where he was awarded “Best Presentation Award”.

Dr. Chou is an Editor for the Journal of Australia Ceramic Society and the Journal of Advances in Ceramic Science and Engineering. He also serves as a member of the editorial board for Journal of Tissue Engineering and Regenerative Medicine and International Journal of Biomaterials.

Dr. Chou’s research has had publicity in the national media: radio (ABC), newspaper (Sydney Morning Herald (2010) and magazines (Materials Australia, U:Magazine, Researcher in Focus). Dr. Chou will also be speaking at the 2012 Ultimo Science Festival and at UTS Teacher’s Open Day.

Professional

  • Tissue Engineering and Regenerative Medicine Society (TERMIS) (Since 2010)
  • Australian Ceramic Society (Since 2007)
  • Australasian Society for Biomaterials & Tissue Engineering (Since 2007)
  • Australia Institute of Project Management (Since 2006)
Lecturer, School of Life Sciences
Core Member, Centre for Health Technologies
BSc in Nanotechnology, BSC in Honours, Grad Cert PM (USyd), Doctor of Philosophy
 
Phone
+61 2 9514 1729
Room
CB07.05.21

Dr. Chou is highly interested in teaching students and currently co-supervise 1 PhD student but is actively involved with other teaching duties.

1) Cell Biology and Genetics (91161)
Guest Lecturer/Lab demonstrator (Since 2007)

2) Essentials of Pathophysiology (99636)
Lab demonstrator (2007-2010)

3) Intro. Pharmacology and Microbiology (91604)
Lab demonstrator (2010)

4) Medical Devices and Diagnostics (91705)
Lab demonstrator (2010)

5) Introduction to Materials (68070)
Tutor/Lab demonstrator (Since 2007)

6) Chemistry and Materials Science (60101)
Tutor/Lab demonstrator (Since 2007)

Chapters

Ben-Nissan, B., Choi, A.H., Green, D.W., Latella, B.A., Chou, J. & Bendavid, A. 2011, 'Synthesis and Characterization of Hydroxyapatite Nanocoatings by Sol-Gel Method for Clinical Applications' in Sam Zhang (ed), Biological and Biomedical Coatings Handbook: Processing and Characterization, CRC Press, United States, pp. 37-79.
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Nanostructured materials are associated with a diversity of uses within the medical field, for instance, in drug-delivery systems, regenerative medicine, formation of surgical tools, medical devices, and diagnostic systems. It has long been established that porous bulk hydroxyapatite (HAp) cannot be used for load-bearing applications due to its unfavorable mechanical properties. As a result, HAp has been used instead as a coating in orthopedic surgery on metallic alloys, metals giving the support required. Of the metallic alloys used, titanium-based and cobalt chromium alloys are the preferred materials for these HAp coatings for orthopedic and maxillofacial implants (Figure 2.1).

Conferences

Green, D.W., Padula, M., Santos, J., Chou, J., Milthorpe, B. & Ben-Nissan, B. 2013, 'A new role for marine skeletal proteins in regenerative orthopaedics', Key Engineering Materials, pp. 654-659.
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Use of ready-made marine skeletons is one of the simplest possible remedies to major problems hindering the future development of regenerative orthopaedics- such as, providing a richness of framework designs and now a potentially rich, accessible source of osteopromotive analogues and biomineralisation proteins. It has already been shown that coral and marine sponge skeletons can support self-sustaining musculoskeletal tissues and that extracts of spongin collagen and nacre seashell organic matrices promote bone mineralisation. This should not be surprising given that the pivotal biomineralisation proteins, which orchestrate bone morphogenesis are also found in the earliest calcifying marine organisms. This is because they are representatives of the first molecular components established for calcification, morphogenesis and wound healing. In support of this notion, it has emerged that BMP molecules- the main cluster of bone growth factors for human bone morphogenesis- are secreted by endodermal cells into the developing skeleton. In addition, the regenerative signalling proteins, TGF-?and Wnt-prime targets in bone therapeutics- are also present in early marine sponge development and instrumental to stem cell activation in Cnidarians. Based on this match between vertebrate and invertebrate main developmental proteins, we review the nature and extent of this evolutionary relatedness and use it to support the development of a new strategy, which is to mine selected marine origin organic matrices for novel metabolic, signalling and structural proteins/peptides and protein analogues to apply in regenerative orthopaedics, particularly when using adult stem cells. To support such a proposal we show early stage evidence-gathered in our own laboratory- of the presence of fibrinogen fragments and early osteopromotive effects of a coral organic matrix extract on stem cells. In practice the discovery of new osteopromotive and osteo-accelerant protein analogues will require u...

Journal articles

Hao, J., Acharya, A., Chen, K., Chou, J., Kasugai, S. & Lang, N.P. 2015, 'Novel bioresorbable strontium hydroxyapatite membrane for guided bone regeneration', Clinical Oral Implants Research, vol. 26, no. 1, pp. 1-7.
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© 2013 John Wiley & Sons A/S. Objectives: Membrane materials have been widely used for guided bone regeneration (GBR). However, due to bio-functional limitation of the current membranes, the ideal resorbable membrane that can stimulate bone regeneration has yet to be developed. This study seeks to investigate the effects of a strontium hydroxyapatite (SrHA)-containing membrane for GBR. Material and methods: Strontium hydroxyapatite powder was synthesized and mixed with gelatin solution to the final concentration of 10 mg/ml (Sr10) and 20 mg/ml (Sr20). Approximately 100-?m-thick membranes were fabricated, and the mechanical properties and strontium ion release pattern were analyzed. Rat bone marrow stromal cell (BMSC) responses were investigated in vitro. Bilaterial rat calvarial defects were used in vivo to compare the SrHA membranes against commercially available collagen membranes and evaluated radiologically and histologically. Results: Strontium hydroxyapatite membranes exhibited higher elasticity and strength than the collagen membrane, and slow strontium ion release was also confirmed. No BMSC cytotoxicity was found on the SrHA membranes, and the alkaline phosphatase positively stained area was significantly greater than the collagen membrane at earlier time point. At 4 weeks, both micro-CT and histological analyses revealed that the Sr20 group yielded significantly greater bone formation. Conclusions: The SrHA-containing membrane developed in this study was found to be a biocompatible material that can stimulate BMSC differentiation as well as bone regeneration and maturation in rat calvarial defects at early time point compared with collagen membrane. The best result was observed in Sr20 group, which can be potentially effective for GBR.
Hao, J., Chou, J., Kuroda, S., Otsuka, M., Kasugai, S. & Lang, N.P. 2015, 'Strontium hydroxyapatite in situ gel-forming system - a new approach for minimally invasive bone augmentation', Clinical Oral Implants Research, vol. 26, no. 5, pp. 581-585.
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To achieve ideal functional and aesthetic requirements, ridge augmentation is often required before dental implant placement. Bone augmentation (especially vertical), which normally consists of complex and invasive surgeries, still remains challenge. This study seeks to investigate the feasibility of an injectable in situ gel-forming system containing strontium hydroxyapatite (SrHA) and alginate for minimally invasive bone augmentation in a rat calvarial model. Material and methods: SrHA-alginate solution was prepared by mixing SrHA powder with alginate solution (20 mg/mL) to the final concentration of 0.5% (w/v). Each animal received a 200-?L single subperiosteal injection of either SrHA-alginate solution or alginate solution. The new bone formation was assessed at 0, 4, and 8 weeks histologically and radiologically. Results: The SrHA-alginate solution materials could form solid gel once injected. As such, no sutures were required to close the injection site. Significantly greater amount of new bone formation was observed in the SrHA-alginate group compared with the alginate group both by micro-CT and by histological section. The newly formed bone in the SrHA-alginate group originated both from the underlying original bone and from the elevated periosteum. A 2.3-fold increase of the vertical bone height was observed in the SrHA-alginate group compared with 1.3-fold increase in the alginate group. Conclusions: Rat calvarial bone augmentation was achieved by a single subperiosteal injection of SrHA-alginate solution without any administration of stem cells or growth factors. The in situ gel-forming material may hold potential therapeutic benefits for local bone augmentation in a minimally invasive manner.
Chou, J., Valenzuela, S., Green, D.W., Kohan, L., Milthorpe, B., Otsuka, M. & Ben-Nissan, B. 2014, 'Antibiotic delivery potential of nano-and micro-porous marine structure-derived ?-tricalcium phosphate spheres for medical applications', Nanomedicine, vol. 9, no. 8, pp. 1131-1139.
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Aims: This study gives a detailed evaluation of the antibiotic potential of a marine structure-based new drug delivery system produced by hydrothermally converting foraminifera exoskeletons to ?-tricalcium phosphate (?-TCP) to treat clinical strain Staphylococcus aureus (MW2). Materials & methods: Foraminifera precursor materials were hydrothermally converted at 250°C for 48 h to produce ?-TCP and loaded with gentamicin sulfate by adsorption for 24 h. The physicochemical properties of the material were characterized by scanning electron microscopy, powder X-ray diffraction and for pore size distribution profiles. The antibacterial efficacy of the system was tested for inhibition of S. aureus growth and in vitro cellular behavior were tested with human osteoblast cells (MG63) for cell viability. Discussion: Pore size distribution profiles showed that the structure allows the uniform distribution of nanopores of 1.5 nm and micropores of approximately 5 ?m. The in vitro release profile indicates an initial burst release of 5% of total incorporated gentamicin. A time-delayed antibacterial efficacy test was designed to introduce the bacteria at predetermined time intervals from 0 to 60 min and showed that gentamicin prevents S. aureus grown in the same culture within 30 min, with no evidence of bacterial regrowth within 24 h. Human osteoblast cell (MG63) studies showed no detrimental effect on cell viability. Conclusion: In the light of these results nano-and micro-pores containing ?-TCP spheres show promise as potential bone void filler particles with antibacterial effects. © 2014 Future Medicine Ltd.
Chou, J., Hao, J., Kuroda, S., Ben-Nissan, B., Milthopre, B. & Otsuka, M. 2014, 'Bone regeneration of calvarial defect using marine calcareous-derived beta-tricalcium phosphate macrospheres.', J Tissue Eng, vol. 5, p. 2041731414523441.
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The aim of this study was to examine the bone regeneration properties of beta-tricalcium phosphate hydrothermally converted from foraminifera carbonate exoskeleton in the repair of rat calvarial defect. These natural materials possess unique interconnected porous network with uniform pore size distribution, which can be potentially advantageous. In total, 20 adult male Wistar rats received full-thickness calvarial defect with a diameter of 5 mm. The rate of newly formed bone was measured radiologically by X-ray and micro-computed tomography and by histologic examination. After 2 weeks, the beta-tricalcium phosphate group exhibited full closure of the defect site, while control group remained unrestored at the end of the 6-week experimentation. It was observed that the newly regenerated bone thickened over the course of the experiment in the beta-tricalcium phosphate group. No soft tissue reaction was observed around the beta-tricalcium phosphate implant and the rats remained healthy. These results showed that repair of the calvarial defect can be achieved by biomimetic beta-tricalcium phosphate macrospheres, which hold potential for application as bone grafts for bone augmentation surgeries.
Chou, J., Chou, J., Hao, J., Hatoyama, H., Ben-Nissan, B., Milthorpe, B. & Otsuka, M. 2014, 'Effect of biomimetic zinc-containing tricalcium phosphate (Zn-TCP) on the growth and osteogenic differentiation of mesenchymal stem cells', Journal of Tissue Engineering and Regenerative Medicine.
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Several studies have shown the effectiveness of zinc-tricalcium phosphate (Zn-TCP) for bone tissue engineering. In this study, marine calcareous foraminifera possessing uniform pore size distribution were hydrothermally converted to Zn-TCP. The ability of a scaffold to combine effectively with mesenchymal stem cells (MSCs) is a key tissue-engineering aim. In order to demonstrate the osteogenic ability of MSCs with Zn-TCP, the scaffolds were cultured in an osteogenic induction medium to elicit an osteoblastic response. The physicochemical properties of Zn-TCP were characterized by XRD, FT-IR and ICP-MS. MSCs were aspirated from rat femurs and cultured for 3 days before indirectly placing four samples into each respective well. After culture for 7, 10 and 14 days, osteoblastic differentiation was evaluated using alizarin red S stain, measurement of alkaline phosphatase (ALP) levels, cell numbers and cell viability. XRD and FT-IR patterns both showed the replacement of CO3 2- with PO4 3-. Chemical analysis showed zinc incorporation of 5 mol%. Significant increases in cell numbers were observed at 10 and 14 days in the Zn-TCP group, while maintaining high levels of cell viability (> 90%). ALP activity in the Zn-TCP group was statistically higher at 10 days. Alizarin red S staining also showed significantly higher levels of calcium mineralization in Zn-TCP compared with the control groups. This study showed that MSCs in the presence of biomimetically derived Zn-TCP can accelerate their differentiation to osteoblasts and could potentially be useful as a scaffold for bone tissue engineering. © 2014 John Wiley & Sons, Ltd.
Yamamoto, M., Nakata, H., Hao, J., Chou, J., Kasugai, S. & Kuroda, S. 2014, 'Osteogenic Potential of Mouse Adipose-Derived Stem Cells Sorted for CD90 and CD105 In Vitro.', Stem Cells Int, vol. 2014, p. 576358.
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Adipose tissue-derived stromal cells, termed ASCs, play an important role in regenerative applications. They resemble mesenchymal stem cells owing to their inexhaustibility, general differentiation potential, and plasticity and display a series of cell-specific and cluster-of-differentiation (CD) marker profiles similar to those of other somatic stem cells. Variations in phenotypes or differentiation are intimately associated with CD markers. The purpose of our study was to exhibit distinct populations of ASCs with differing characteristics for osteogenic differentiation. The primary cell batch of murine-derived ASCs was extracted from subcutaneous adipose tissue and the cells were sorted for the expression of the surface protein molecules CD90 and CD105 using flow cytometry. Each cell population sorted for CD90 and CD105 was analyzed for osteogenic potency after cell culture. The results suggested that ASCs exhibit distinct populations with differing characteristics for osteogenic differentiation: unsorted ASCs stimulated comparable mineralized nodule formation as bone marrow stromal cells (BMSCs) in osteogenic medium and viral transfection for BMP2 accelerated the formation of mineralized nodules in CD90 and/or CD105 positive ASCs with observation of decrease in CD105 expression after 14 days. Future studies assessing different immunophenotypes of ASCs should be undertaken to develop cell-based tissue engineering.
Chou, J., Austin, C., Doble, P., Ben-Nissan, B. & Milthorpe, B. 2014, 'Trace elemental imaging of coralline hydroxyapatite by laser-ablation inductively coupled plasma-mass spectroscopy', Journal of Tissue Engineering and Regenerative Medicine, vol. 8, no. 7, pp. 515-520.
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The determination of trace element concentrations, as well as their distribution in different biomaterials aimed for clinical applications, is a challenging task in both the areas of biological and materials research. In this research, LA-ICP-MS was employed for image mapping of the trace element distribution in a hydrothermally converted coralline hydroxyapatite material aimed for tissue-scaffolding applications. Quantification using synthetic matrix-matched standards was successfully applied for the determination and distribution of elements of interest, Sr and Mg, that influences the mechanical and biological properties of hydroxyapatite-based bone graft materials. The results showed that the instrument can successfully analyse trace elements and a relatively good image can be produced that identifies their distribution. The LA-ICP-MS method can provide an easy and effective tool, in the field of biomaterials with respect to distribution of trace elements, to better understand tissue-implant interactions, and will open up a new window for in vitro and in vivo analysis and imaging of different tissues and structures. © 2012 John Wiley & Sons, Ltd.
Chou, J., Valenzuela, S.M., Santos, J., Bishop, D., Milthorpe, B., Green, D.W., Otsuka, M. & Ben-Nissan, B. 2014, 'Strontium- and magnesium-enriched biomimetic ?-TCP macrospheres with potential for bone tissue morphogenesis', Journal of Tissue Engineering and Regenerative Medicine, vol. 8, no. 10, pp. 771-778.
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During the last two decades, biogenic mineral ions have become important additives in treatments for bone regeneration and repair. Prominent among these is strontium, which is a potent suppressor of osteoclast bone resorption. Another is magnesium, which has a key influence in mineralization processes. The shells of benthic foraminiferans, hydrothermally converted into ?-TCP, have been shown to effectively release a number of bone-promoting drugs at clinically relevant levels. In this study we characterized the effects of converted foraminiferan calcium dissolution and the concomitant release profile of intrinsic strontium and magnesium. We tested the effects of strontium- and magnesium-enriched macrospheres on human osteoblast (SaOS-2) and monocytoid (U937) cell lines, which can be induced to express equivalent phagocytic activities to osteoclasts. On dissolution in a biomimetic physiological solution, the macrospheres released biologically significant quantities of calcium and phosphate ions in the first 18days. At 3days, during which biogenic mineral ions are released, the number of U937 osteoclast-like monocyte cells decreased, while 4days later the osteoblast cell number increased. These results show that strontium and magnesium naturally enriched macrospheres are capable of altering the metabolic activities of the cells regulating bone homeostasis. These unique macrospheres are natural origin bone void filler particles that resorb, and release physiologically significant levels of incorporated strontium, magnesium and calcium, which together make a uniquely multifunctional in situ remedy for bone regeneration and repair and the treatment of bone-wasting diseases.
Hao, J., Chou, J., Kuroda, S., Otsuka, M., Kasugai, S. & Lang, N.P. 2014, 'Strontium hydroxyapatite in situ gel-forming system - a new approach for minimally invasive bone augmentation', Clinical Oral Implants Research.
View/Download from: UTS OPUS or Publisher's site
Objectives: To achieve ideal functional and aesthetic requirements, ridge augmentation is often required before dental implant placement. Bone augmentation (especially vertical), which normally consists of complex and invasive surgeries, still remains challenge. This study seeks to investigate the feasibility of an injectable in situ gel-forming system containing strontium hydroxyapatite (SrHA) and alginate for minimally invasive bone augmentation in a rat calvarial model. Material and methods: SrHA-alginate solution was prepared by mixing SrHA powder with alginate solution (20 mg/mL) to the final concentration of 0.5% (w/v). Each animal received a 200-?L single subperiosteal injection of either SrHA-alginate solution or alginate solution. The new bone formation was assessed at 0, 4, and 8 weeks histologically and radiologically. Results: The SrHA-alginate solution materials could form solid gel once injected. As such, no sutures were required to close the injection site. Significantly greater amount of new bone formation was observed in the SrHA-alginate group compared with the alginate group both by micro-CT and by histological section. The newly formed bone in the SrHA-alginate group originated both from the underlying original bone and from the elevated periosteum. A 2.3-fold increase of the vertical bone height was observed in the SrHA-alginate group compared with 1.3-fold increase in the alginate group. Conclusions: Rat calvarial bone augmentation was achieved by a single subperiosteal injection of SrHA-alginate solution without any administration of stem cells or growth factors. The in situ gel-forming material may hold potential therapeutic benefits for local bone augmentation in a minimally invasive manner. © 2014 John Wiley & Sons A/S.
Chou, J., Komuro, M., Hao, J., Kuroda, S., Hattori, Y., Ben-Nissan, B., Milthorpe, B. & Otsuka, M. 2014, 'Bioresorbable zinc hydroxyapatite guided bone regeneration membrane for bone regeneration', Clinical Oral Implants Research, pp. n/a-n/a.
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Wang, X., Zakaria, O., Madi, M., Hao, J., Chou, J. & Kasugai, S. 2014, 'Vertical bone augmentation induced by ultrathin hydroxyapatite sputtered coated mini titanium implants in a rabbit calvaria model.', J Biomed Mater Res B Appl Biomater.
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BACKGROUND: The purpose of this study was to evaluate the vertical new bone formation induced by sputtered HA-coated titanium implants (HA-coated) compared with sandblasted acid-etched titanium implants (noncoated) in a rabbit calvarial model. MATERIALS AND METHOD: Twenty HA-coated and 20 noncoated titanium implants were divided equally into four groups as HA-coated implant (HA); noncoated implant (NC); HA-coated implant with membrane (HA/M); noncoated implant with membrane (NC/M). All implants were placed 5 mm above the original bone (OB). Collagen membranes were placed over the implants in HA/M and NC/M groups. The animals were sacrificed at 4 weeks (n?=?5) and 8 weeks (n?=?5). Vertical bone height above OB (VBH, mm) and augmented bone area (ABA, mm(2) ) were analyzed histologically and radiographically. RESULTS: At 4 weeks, VBH reached significantly higher level in HA/M group compared with other three groups (p?<?0.05). At 8 weeks, significant difference was detected between HA/M and NC groups (p?<?0.05). At 4 and 8 weeks, ABA in HA/M group was significantly larger compared with other three groups (p?<?0.05). CONCLUSION: The present results indicated that sputtered HA-coated titanium implant together with collagen membrane could be a novel and effective approach for vertical bone augmentation. &copy; 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2014.
Macha, I.J., Ozyegin, L.S., Chou, J., Samur, R., Oktar, F.N. & Ben-Nissan, B. 2013, 'An alternative synthesis method for di calcium phosphate (monetite) powders from mediterranean mussel (mytilus galloprovincialis) shells', Journal of the Australian Ceramic Society, vol. 49, no. 2, pp. 122-128.
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Marine species, such as corals, sea shells and nacres, attract special interest in bioceramics field for bone graft, bone cements and drug delivery applications. Most of the marine structures are made up of pure calcium carbonate (calcite or aragonite) with a very small amount of an organic matrix. In the past the most common way to transform these structures to hydroxyapatite was hydrothermal transformation method. This current work introduces a new approach for producing fine powders of calcium phosphates from Mediterranean mussel (Mytilus galloprovincialis) shells. A comparative study was carried out to investigate the differences of these powders under only hot plate heating and hot plate heating together with ultrasonic agitation while H3PO4 was added. The temperature of the hotplate was kept constant at 80 oC and then, H3PO4 was added drop wise into the solution for 2 hrs. The mixture was then placed into an oven at 100 oC for 24 hrs. They were further calcined at 800 oC for 3 hrs. XRD, FTIR and ICP-MS were used to identify the structure and composition. It was found that the final powders were predominantly monetite, with some tricalcium phosphate as a secondary phase. This relatively simple and efficient method can be easily applied to produce calcium phosphate precursor powders for a range of biomedical applications.
Chou, J., Green, D.W., Singh, K., Hao, J., Ben-Nissan, B. & Milthorpe, B. 2013, 'Adipose Stem Cell Coating of Biomimetic ?-TCP Macrospheres by Use of Laboratory Centrifuge.', Biores Open Access, vol. 2, no. 1, pp. 67-71.
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Biomimetic materials such as coral exoskeletons possess unique architectural structures with a uniform and interconnected porous network that can be beneficial as a scaffold material. In addition, these marine structures can be hydrothermally converted to calcium phosphates, while retaining the original structural properties. The ability of biomaterials to stimulate the local microenvironment is one of the main focuses in tissue engineering, and directly coating the scaffold with stem cells facilitates future potential applications in therapeutics and regenerative medicine. In this article we describe a new and simple method that uses a laboratory centrifuge to coat hydrothermally derived beta-tricalcium phosphate macrospheres from coral exoskeleton with stem cells. In this research the optimal seeding duration and speed were determined to be 1?min and 700 g. Scanning electron micrographs showed complete surface coverage by stem cells within 7 days of seeding. This study constitutes an important step toward achieving functional tissue-engineered implants by increasing our understanding of the influence of dynamic parameters on the efficiency and distribution of stem cell attachment to biomimetic materials and how stem cells interact with biomimetic materials.
Chou, J., Chou, J., Hao, J., Ben-Nissan, B., Milthorpe, B. & Otsuka, M. 2013, 'Coral exoskeletons as a precursor material for the development of a calcium phosphate drug delivery system for bone tissue engineering', Biological and Pharmaceutical Bulletin, vol. 36, no. 11, pp. 1662-1665.
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With the global rise in aging of populations, the occurrence of osteoporosis will continue to increase. Biomaterial and pharmaceutical scientists continue to develop innovative strategies and materials to address this disease. In this article, we describe a new perspective and approach into the use of coral exoskeletons as a precursor material to synthesize a calcium phosphate-based drug delivery system. Studies detailing the methodology of the conversion methods and the strategies and approach for the development of these novel drug delivery systems are described. Furthermore, in vivo studies in osteoporotic mice using a drug loaded and chemically modified version of the biomimetic delivery system showed significant cortical and cancellous bone increases. These studies support the notion and the rationale for future research and development of the use of coral exoskeletons as materials for drug delivery applications. &copy; 2013 The Pharmaceutical Society of Japan.
Chou, J., Ito, T., Otsuka, M., Ben-Nissan, B. & Milthorpe, B. 2013, 'Simvastatin-Loaded ?-TCP Drug Delivery System Induces Bone Formation and Prevents Rhabdomyolysis in OVX Mice', Advanced Healthcare Materials, vol. 2, no. 5, pp. 678-681.
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Chou, J., Ito, T., Otsuka, M., Ben-Nissan, B., Ben-Nissan, B. & Milthorpe, B. 2013, 'The controlled release of simvastatin from biomimetic macrospheres', Key Engineering Materials, vol. 529-530, no. 1, pp. 461-464.
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Simvastatin has been shown to succesfully stimulate bone regeneration and attention has being focussed on developing appropriate delivery carriers for its release. The challenge of deliverying therapeutic concentration of pharmaceutical compunds has being the centre of focus in drug delivery developments. This study examines the in-vivo effects of simvastatin released from ?-TCP macrospheres derived from coral exoxskeletons. The results indicates that the controlled release of simvastatin can promote bone formation comparable with direct injection. Furthermore the results showed that the release of simvastatin delivery rates can be controlled by additional coating of an apatite coating. Analysis by CT scans, SEM, amount of new bone formed and mechanical strength tests, showed that by controlling the release of simvastatin bone formation can be stimulated to a therapeutic level. &copy; (2013) Trans Tech Publications, Switzerland.
Chou, J., Chou, J., Hao, J., Hatoyama, H., Ben-Nissan, B., Milthorpe, B. & Otsuka, M. 2013, 'The Therapeutic Effect on Bone Mineral Formation from Biomimetic Zinc Containing Tricalcium Phosphate (ZnTCP) in Zinc-Deficient Osteoporotic Mice', PLoS ONE, vol. 8, no. 8.
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The aim of this study was to evaluate the therapeutic efficacy of biomimetic zinc-containing tricalcium phosphate (ZnTCP) produced by hydrothermally converting calcium carbonate exoskeletons from foraminifera, in the treatment of osteoporotic mice. X-Ray powder diffraction showed crystallographic structures matching JCPDS profile for tricalcium phosphate. Mass spectroscopy used to calculate total composition amount showed similar amount of calcium (5104 ?g/g) and phosphate (4104ppm) after conversion and the presence of zinc (5.18103 ?g/g). In vitro zinc release showed no release in PBS buffer and <1% zinc release in 7 days. In vivo evaluation was done in ovariectomized mice by implanting the ZnTCP samples in the soft tissues near the right femur bone for four weeks. Thirty ddY mice (5 weeks old, average weight of 21 g) were divided into six experimental groups (normal, sham, OVX, ?-TCP, ZnTCP and direct injection of zinc). CT images were taken every two weeks where the bone mineral density (BMD) and bone mineral content (BMC) were calculated by software based on CT images. The ZnTCP group exhibits cortical and cancellous bone growth of 45% and 20% respectively. While sham, OVX and ?-TCP suffered from bone loss. A correlation was made between the significant body weight increase in ZnTCP with the significant increase in plasma zinc level compared with OVX. The presented results indicate that biomimetic ZnTCP were effective in preventing and treating bone loss in osteoporotic mice model. &copy; 2013 Chou et al.
Green, D.W., Padula, M.P., Santos, J., Chou, J., Milthorpe, B. & Ben-Nissan, B. 2013, 'A therapeutic potential for marine skeletal proteins in bone regeneration', Marine Drugs, vol. 11, no. 4, pp. 1203-1220.
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A vital ingredient for engineering bone tissue, in the culture dish, is the use of recombinant matrix and growth proteins to help accelerate the growth of cultivated tissues into clinically acceptable quantities. The skeletal organic matrices of calcifying marine invertebrates are an untouched potential source of such growth inducing proteins. They have the advantage of being ready-made and retain the native state of the original protein. Striking evidence shows that skeleton building bone morphogenic protein-2/4 (BMP) and transforming growth factor beta (TGF-?) exist within various marine invertebrates such as, corals. Best practice mariculture and the latest innovations in long-term marine invertebrate cell cultivation can be implemented to ensure that these proteins are produced sustainably and supplied continuously. This also guarantees that coral reef habitats are not damaged during the collection of specimens. Potential proteins for bone repair, either extracted from the skeleton or derived from cultivated tissues, can be identified, evaluated and retrieved using chromatography, cell assays and proteomic methods. Due to the current evidence for bone matrix protein analogues in marine invertebrates, together with the methods established for their production and retrieval there is a genuine prospect that they can be used to regenerate living bone for potential clinical use. &copy; 2013 by the authors; licensee MDPI.
Chou, J., Chou, J., Hao, J., Kuroda, S., Bishop, D., Ben-Nissan, B., Milthorpe, B. & Otsuka, M. 2013, 'Bone regeneration of rat tibial defect by zinc-tricalcium phosphate (Zn-TCP) synthesized from porous foraminifera carbonate macrospheres', Marine Drugs, vol. 11, no. 12, pp. 5148-5158.
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Foraminifera carbonate exoskeleton was hydrothermally converted to biocompatible and biodegradable zinc-tricalcium phosphate (Zn-TCP) as an alternative biomimetic material for bone fracture repair. Zn-TCP samples implanted in a rat tibial defect model for eight weeks were compared with unfilled defect and beta-tricalcium phosphate showing accelerated bone regeneration compared with the control groups, with statistically significant bone mineral density and bone mineral content growth. CT images of the defect showed restoration of cancellous bone in Zn-TCP and only minimal growth in control group. Histological slices reveal bone in-growth within the pores and porous chamber of the material detailing good bone-material integration with the presence of blood vessels. These results exhibit the future potential of biomimetic Zn-TCP as bone grafts for bone fracture repair. &copy; 2013 by the authors; licensee MDPI.
Macha, I.J., Ozyegin, L.S., Chou, J., Samur, R., Oktar, F.N. & Ben-Nissan, B. 2013, 'An Alternative Synthesis Method for Di Calcium Phosphate (Monetite) Powders from Mediterranean Mussel (Mytilus galloprovincialis) Shells.', Journal of the Australian Ceramics Society, vol. 49, no. 2, pp. 122-128.
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Marine species, such as corals, sea shells and nacres, attract special interest in bioceramics field for bone graft, bone cements and drug delivery applications. Most of the marine structures are made up of pure calcium carbonate (calcite or aragonite) with a very small amount of an organic matrix. In the past the most common way to transform these structures to hydroxyapatite was hydrothermal transformation method. This current work introduces a new approach for producing fine powders of calcium phosphates from Mediterranean mussel (Mytilus galloprovincialis) shells. A comparative study was carried out to investigate the differences of these powders under only hot plate heating and hot plate heating together with ultrasonic agitation while H3PO4 was added. The temperature of the hotplate was kept constant at 80 &deg;C and then, H3PO4 was added drop wise into the solution for 2 hrs. The mixture was then placed into an oven at 100 &deg;C for 24 hrs. They were further calcined at 800 &deg;C for 3 hrs. XRD, FTIR and ICP-MS were used to identify the structure and composition. It was found that the final powders were predominantly monetite, with some tricalcium phosphate as a secondary phase. This relatively simple and efficient method can be easily applied to produce calcium phosphate precursor powders for a range of biomedical applications.
Chou, J., Ito, T., Otsuka, M., Ben-Nissan, B. & Milthorpe, B. 2013, 'The effectiveness of the controlled release of simvastatin from ?-TCP macrosphere in the treatment of OVX mice', Journal of Tissue Engineering and Regenerative Medicine.
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Simvastatin, a cholesterol treatment drug, has been shown to stimulate bone regeneration. As such, there has been an increase interest in the development of suitable materials and systems for the delivery of simvastatin. Without the appropriate dosage of simvastatin, the therapeutic effects on bone growth will be significantly reduced. Furthermore, similar to many pharmaceutical compounds, at high concentration simvastatin can cause various adverse side-effects. Given the associated side-effects with the usage of simvastatin, the development of suitable controlled drug release system is pertinent. Calcium phosphate in particularly beta-tricalcium phosphate (?-TCP) has been extensively studied and used as a carrier material for drug delivery system. In this study, Foraminifera exoskeletons were used as calcium carbonate precursor materials, which were hydrothermally converted to ?-TCP as a carrier material for simvastatin. Natural marine exoskeletons posses interconnected and uniformly porous network capable of improving drug loading and release rate. To prolong the r elease of simvastatin, an apatite coating was made around the ?-TCP sample and in vitro release studies in simulated body fluid (SBF) showed a significant decrease in release rate. Osteoporotic mice were used to examine the compare therapeutic effectiveness of ?-TCP, ?-TCP with simvastatin, apatite-coated ?-TCP with simvastatin and direct injection of simvastatin near the right femur of the mice. Localized and systemic effect were compared with the femur of the non-implanted side (left) and showed that ?-TCP with or without simvastatin was able to induce significant bone formation over 6weeks. Mechanical analysis showed that apatite-coated ?-TCP with simvastatin produced significantly stronger bones compared with other experimental groups. This study shows that natural exoskeletons with the appropriate structure can be successfully used as a drug delivery system for simvastatin and can its release ca...
Chou, J., Ito, T., Bishop, D., Otsuka, M., Ben-Nissan, B. & Milthorpe, B. 2013, 'Controlled Release of Simvastatin from Biomimetic ?-TCP Drug Delivery System', PLoS ONE, vol. 8, no. 1.
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Simvastatin have been shown to induce bone formation and there is currently a urgent need to develop an appropriate delivery system to sustain the release of the drug to increase therapeutic efficacy whilst reducing side effects. In this study, a novel drug delivery system for simvastatin by means of hydrothermally converting marine exoskeletons to biocompatible beta-tricalcium phosphate was investigated. Furthermore, the release of simvastatin was controlled by the addition of an outer apatite coating layer. The samples were characterized by x-ray diffraction analysis, fourier transform infrared spectroscopy, scanning electron microscopy and mass spectroscopy confirming the conversion process. The in-vitro dissolution of key chemical compositional elements and the release of simvastatin were measured in simulated body fluid solution showing controlled release with reduction of approximately 25% compared with un-coated samples. This study shows the potential applications of marine structures as a drug delivery system for simvastatin. &copy; 2013 Chou et al.
Chou, J., Ben-Nissan, B., Green, D.W., Valenzuela, S.M. & Kohan, L. 2011, 'Targeting and dissolution characteristics of bone forming and antibacterial drugs by harnessing the structure of microspherical shells from coral beach sand', Advanced Engineering Materials, vol. 13, no. 1-2, pp. 93-99.
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Pharmaceutical drugs for the treatment of metabolic bone diseases lead to a number of side effects due to the their uncontrollable dispersion throughout the body.1 Therefore, many groups directed their research to develop devices that are targeted to specific organs or tissues and release the encapsulated drug in a highly regulated way.2-7 The development of completely resorbable bone-filling biomaterials delivering drugs would offer a therapeutic approach of drug release and bone augmentation in a simple one-step process.8-11 The biomaterials selected needs custom designs, to control the quantity and the duration of drug release and at the same time inducing desirable host cell responses and preventing bacterial infection.12-15 Current synthetic biomaterials produced as drug delivery microspheres due to production difficulties contain not very well designed interconnected pores and fail to fill these pertinent requirements. Turning directly to nature such as marine structures for inventive solutions can help to solve these problems due to their structure, chemistry and architecture and their unique designs.16-20 We demonstrate -for the first time- the potential of unique coral shells with specific microspherical structure and highly organised interconnected intra-pore designs to offer a number of desired functions for targeted delivery of Bisphosphonate (BP) (paminodrate) and an antibiotic (Gentamicin) for bone regeneration, repair and preventive antibacterial slow drug delivery. &copy; 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Chou, J., Green, D.W. & Ben-Nissan, B. 2010, 'New slow drug delivery materials and systems for biomedical applications', Materials Australia, vol. 43, no. 3, pp. 37-41.
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Chou, J., Shimmon, R. & Ben-Nissan, B. 2009, 'Bisphosphonate determination using H-1-NMR spectroscopy for biomedical applications', Journal Of Tissue Engineering And Regenerative Medicine, vol. 3, no. 2, pp. 92-96.
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Bisphosphonate is known to be a very active drug in the treatment of osteoporosis and bone regeneration. A new method has been developed, utilizing nuclear magnetic resonance spectroscopy to identify and measure the amount of bisphosphonate in solution. A standard reference with similar functional group to that of the bisphosphonate was chosen and applied in the experimentation. The results showed that the use of nuclear magnetic resonance spectroscopy (H-1-NMR) in determining the solvent residues of various pharmaceutical drugs has proved to be effective. Unlike chromatography, it is possible to use a universal reference standard as an internal standard assayed by quantitative NMR. Using the same theory, this method is capable of both identifying and quantifying the bisphosphonate in various solutions. This paper is the first publication showing this unique measurement method, which can be used in a range of pharmaceutical and biomedical applications.
Chou, J., Ben-Nissan, B., Choi, A.H., Wuhrer, R. & Green, D. 2007, 'Conversion of coral sand to calcium phosphate for biomedical applications', Journal of the Australian Ceramic Society, vol. 43, no. 1, pp. 44-48.
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Coral sand grains were analyzed using simultaneous differential thermogravimetric analysis (DTA/TGA), Fourier-Transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and environmental scanning electron microscopy (ESEM). These techniques were performed to confirm the characteristics and properties as well as the composition of the coral sand grains. Imaging of the full surface topography were conducted in the ESEM. After characterization coral sand grains were treated for impurities and organic materials were subsequently removed. The materials were than converted to calcium phosphates utilizing hydrothermal treatment. The results have shown that the coral sand grains were composed of calcium carbonate with a network of uniform inner porous structure. The ESEM has provided valuable information through the imaging of the samples which in turn allowed a comparison of the pore sizes before and after the hydrothermal treatment. The current study shows that the coral sand to be a promising source of converted calcium carbonate to calcium phosphates for biomedical applications.
Lewis, K.C., Choi, A.H., Chou, J. & Ben-Nissan, B. 2007, 'Nanoceramics in medical applications', Materials Australia, vol. 40, no. 3, pp. 32-34.