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Dive into the research topics where Tim G. Moore is active.

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Featured researches published by Tim G. Moore.


Biomaterials | 2008

Biodegradable injectable polyurethanes: Synthesis and evaluation for orthopaedic applications

Raju Adhikari; Pathiraja A. Gunatillake; Ian Griffiths; Lisa Tatai; Malsha Wickramaratna; Shadi Houshyar; Tim G. Moore; Roshan T.M. Mayadunne; John Field; Margaret A. McGee; Tania Carbone

Biodegradable polyurethanes offer advantages in the design of injectable or preformed scaffolds for tissue engineering and other medical implant applications. We have developed two-part injectable prepolymer systems (prepolymer A and B) consisting of lactic acid and glycolic acid based polyester star polyols, pentaerythritol (PE) and ethyl lysine diisocyanate (ELDI). This study reports on the formulation and properties of a series of cross linked polyurethanes specifically developed for orthopaedic applications. Prepolymer A was based on PE and ELDI. Polyester polyols (prepolymer B) were based on PE and dl-lactic acid (PEDLLA) or PE and glycolic acid (PEGA) with molecular weights 456 and 453, respectively. Several cross linked porous and non-porous polyurethanes were prepared by mixing and curing prepolymers A and B and their mechanical and thermal properties, in vitro (PBS/37 degrees C/pH 7.4) and in vivo (sheep bi-lateral) degradation evaluated. The effect of incorporating beta-tricalcium phosphate (beta-TCP, 5 microns, 10 wt.%) was also investigated. The cured polymers exhibited high compressive strength (100-190 MPa) and modulus (1600-2300 MPa). beta-TCP improved mechanical properties in PEDLLA based polyurethanes and retarded the onset of in vitro and in vivo degradation. Sheep study results demonstrated that the polymers in both injectable and precured forms did not cause any surgical difficulties or any adverse tissue response. Evidence of new bone growth and the gradual degradation of the polymers were observed with increased implant time up to 6 months.


Journal of Biomedical Materials Research Part B | 2014

Properties and in vitro evaluation of high modulus biodegradable polyurethanes for applications in cardiovascular stents

Melissa Sgarioto; Raju Adhikari; Pathiraja A. Gunatillake; Tim G. Moore; Francois Malherbe; Marie-Danielle Nagel; John Patterson

This study examined the suitability of a family of biodegradable polyurethanes (PUs) NovoSorb developed for the vascular stent application. These segmented PUs are formulated to be biodegradable using degradable polyester and PU blocks. A series of PUs comprising different hard segment weight percentage ranging from 60 to 100 were investigated. The mechanical properties of the PUs were evaluated before and after gamma sterilization to assess their suitability for vascular implants. The real-time (PBS/37°C/pH 7.4) hydrolytic degradation studies were carried out under sterile conditions and PU glass transition temperature, molecular weight, and mass loss at 3, 6, and 9 months were determined. The viability and growth of Human Umbilical Vein Endothelial Cells (HUVEC) on PU surfaces were determined to assess the effect of PU degradation. The effect of coating of extracellular matrix (ECM) components on cell viability was also investigated. The study showed that the PUs possess excellent mechanical properties exhibiting high tensile strength (41-56 MPa) and tensile modulus (897-1496 MPa). The PU films maintained mechanical strength during the early phase of the degradation but lost strength at latter stages. The unmodified polymer surface of each PU promotes endothelial cell growth and proliferation, with a HUVEC retention rate of >70%.


Frontiers in Bioengineering and Biotechnology | 2015

High Modulus Biodegradable Polyurethanes for Vascular Stents: Evaluation of Accelerated in vitro Degradation and Cell Viability of Degradation Products.

Melissa Sgarioto; Raju Adhikari; Pathiraja A. Gunatillake; Tim G. Moore; John Patterson; Marie-Danielle Nagel; Francois Malherbe

We have recently reported the mechanical properties and hydrolytic degradation behavior of a series of NovoSorb™ biodegradable polyurethanes (PUs) prepared by varying the hard segment (HS) weight percentage from 60 to 100. In this study, the in vitro degradation behavior of these PUs with and without extracellular matrix (ECM) coating was investigated under accelerated hydrolytic degradation (phosphate buffer saline; PBS/70°C) conditions. The mass loss at different time intervals and the effect of aqueous degradation products on the viability and growth of human umbilical vein endothelial cells (HUVEC) were examined. The results showed that PUs with HS 80% and below completely disintegrated leaving no visual polymer residue at 18u2009weeks and the degradation medium turned acidic due to the accumulation of products from the soft segment (SS) degradation. As expected the PU with the lowest HS was the fastest to degrade. The accumulated degradation products, when tested undiluted, showed viability of about 40% for HUVEC cells. However, the viability was over 80% when the solution was diluted to 50% and below. The growth of HUVEC cells is similar to but not identical to that observed with tissue culture polystyrene standard (TCPS). The results from this in vitro study suggested that the PUs in the series degraded primarily due to the SS degradation and the cell viability of the accumulated acidic degradation products showed poor viability to HUVEC cells when tested undiluted, however particles released to the degradation medium showed cell viability over 80%.


Biomaterials | 2007

Thermoplastic biodegradable polyurethanes: The effect of chain extender structure on properties and in-vitro degradation

Lisa Tatai; Tim G. Moore; Raju Adhikari; Francois Malherbe; Ranjith Jayasekara; Ian Griffiths; Pathiraja A. Gunatillake


Biomaterials | 2005

Chemosynthesis of bioresorbable poly(γ-butyrolactone) by ring-opening polymerisation: a review

Tim G. Moore; Raju Adhikari; Pathiraja A. Gunatillake


Archive | 2005

Biodegradable polyurethane and polyurethane ureas

Tim G. Moore; Raju Adhikari; Pathiraja A. Gunatillake


Archive | 2008

High modulus polyurethane and polyurethane/urea compositions

Tim G. Moore; Pathiraja A. Gunatillake; Raju Adhikari; Shadi Houshyar


Archive | 2008

Hochmodulige polyurethan- und polyurethan/harnstoff-zusammensetzungen

Tim G. Moore; Pathiraja A. Gunatillake; Raju Adhikari; Shadi Houshyar


Archive | 2008

Compositions de polyuréthane et de po lyuréthane/urée à modules élevés

Tim G. Moore; Pathiraja A. Gunatillake; Raju Adhikari; Shadi Houshyar


Archive | 2005

Biologisch abbaubares polyurethan und polyurethan-harnstoffe

Raju Adhikari; Pathiraja A. Gunatillake; Tim G. Moore

Collaboration


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Pathiraja A. Gunatillake

Commonwealth Scientific and Industrial Research Organisation

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Raju Adhikari

Commonwealth Scientific and Industrial Research Organisation

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Francois Malherbe

Swinburne University of Technology

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John Patterson

Swinburne University of Technology

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Melissa Sgarioto

Swinburne University of Technology

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Marie-Danielle Nagel

Centre national de la recherche scientifique

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John Field

University of Adelaide

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Malsha Wickramaratna

Commonwealth Scientific and Industrial Research Organisation

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Ranjith Jayasekara

Swinburne University of Technology

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