Day 2 :
University of Cambridge, UK
Keynote: New concept of bioresorbable polymer-based ceramic hybrids for cardiovascular stent applications
Time : 09:00-09:25
Xiang Zhang, Royal Society Industry Fellow of University of Cambridge, has over 34 years combined academia (17 years) and industrial (17 years) experience in advanced materials science and technology, an expert in polymer and polymeric hybrid materials science and technology. Prof. Zhang is also Head of the Lucideon Cambridge School of Advanced Materials and Head of Medical Materials and Devices. He is the author of three books “Inorganic Biomaterials”, “Inorganic Controlled Release Technology” and “Science and Principles of Biodegradable and Bioresorbable Medical Polymers - Materials and Properties”. As a materials scientist, he is passionate on “Science for Industry “and believes fundamental but applied sciences are the keys to industry R&D and problem solving. Prof. Zhang undertook his PhD and postdoctoral research at Cranfield University where he studied materials physics and nano/micro-mechanics and nano/micro-fracture mechanics of polymeric hybrid (organic and inorganic) materials. After spending a further four years on research for industrial applications, he was awarded an industrial fellowship at the University of Cambridge in 1995, where he carried out research on fundamental nanomechanisms of polymeric ductile to brittle transitions, which is first time in the world ever employing synchrotron SAXS, WAXS (wide angle and small angel X-ray scattering) to study in situ deformation and fracture down to nanometre scales, the results of which lead to completion of ductile to brittle transition theories in view of nano-mechanics and nano-fracture mechanics. Prof. Zhang’s industry experience was gained in leading international healthcare companies, where, as Principal Scientist/Technologist, his work covered almost all aspects of medical materials and devices from R&D and manufacturing support to failure analysis and QC. Prior to joining Lucideon, Prof. Zhang worked as Director of a technology company, in the field of nano-conductive materials and diagnostic medical devices.
This presentation will introduce new theories and industry practice for design and development of polymer-based ceramic hybrids. The evolution from pure polymer-based medical devices to polymer-based ceramic hybrids is to meet unmet market needs for better clinical performance over existing systems. There are many factors that can affect medical implant performance and, historically, most of them have been well studied, such as bioactivities and biocompatibility. In this presentation, new concept will be mainly addressing issue surround biomechanics, biofracture mechanucs and biofunctionality for design and development of new hybrid biomaterials for implant applications. It will report the principles on formulations for two type of the new systems. One family is of biodegradable and bioresorbable hybrids and 2nd is of non-biodegradable hybrids. It will be followed by design and development of medical devices in view of industry practice with clinical performance considerations of medical devices. The main topics covered in the presentation include: (a) New concepts and synthetic pathway of polymer-based ceramic hybrids; (b) Nano/Micro mechanics and nano/micro fracture mechanics; (c) Industry practice – two case studies will be used to demonstrate on how to design and develop polymer-based ceramic hybrid biomaterials and relevant processing technology for the applications of medical implants. Cardiovascular stent, as an example is traditionally made of metal such as Bare Metal Stents (BMS) or with drug coatings, i.e. Drug Eluting Stents (DES). There are, however, clinical complications associated with these technologies, such as, early stage restenosis, very late thrombosis and risk associated with revision surgery. In light of these challenges research focus has turned to the development of bioresorbable vascular scaffold (BVS) technologies.
We have developed new bioresorbable polymer-based ceramic stent that has been reinforced resorbable therapeutic cardiovascular stent to address the known limitations of cardiovascular technologies. We have developed a bioresorbable stent with intrinsic toughness for handling and deployment via balloon angioplasty, radial strength, controlled drug-release technology to suppress restenosis and surface functionalisation to promote endothelialisation to reduce risk of thrombosis. We present the novel synthetic polymer-ceramic composites developed as candidate stent-core materials, both their preparation and the characterisation of their mechanical behaviour, in vitro degradation will be presented.
Thanks to Prof. Ruth Cameron of University of Cambridge for assistance for materials characterization and Prof. Wenxin Wang of Vornia Ltd for synthesis some of the polymers used in the research. Thanks also to Dr Chris Lovell and Dr Mark Cresswell of Lucideon who have done most of the work in this presentation
1. Science and Principles of Biodegradable and Bioresorbable Medical Polymers - Materials and Properties, 2016 by Elsevier
2. Inorganic Controlled Release Technology, 1st Edition - Materials and Concepts for Advanced Drug Formulation, 2015 pub. by Elsevier
3. Inorganic Biomaterials: Structure, Properties and Applications, 2014 pub. By Smithers Rapra
4. Polymer, 41 (2000) 3797-3807, X C Zhang, M F Butler and R E Cameron, “The Ductile – Brittle Transition of Irradiated Isotactic Polypropylene Studies Using Small Angle X-ray Scattering and Tensile Deformation”
5. Advanced Materials, 12 December 2015, Yongjiu Lei, Ruize Sun, Xiangcheng Zhang, Xinjian Feng, Lei Jiang, “Oxygen-Rich Enzyme Biosensor Based on Superhydrophobic Electrode”
6. Polymer, 41 (2000) 3797-3807, X C Zhang, M F Butler and R E Cameron. “The Ductile – Brittle Transition of Irradiated Isotactic Polypropylene Studies Using Small Angle X-ray Scattering and Tensile Deformation”
Missouri State University, USA
Time : 09:25-09:50
Nick Gerasimchuk is Full Professor of Inorganic Chemistry at Missouri State University (USA). His research interests and expertise lay in the following areas: 1) the 1D coordination polymers as cytotoxic NIR emitters for theranostic applications; 2) mixed valence compounds; 3) novel antimicrobials based on silver and antimony oximates; 4) physical methods of investigation of inorganic and coordination compounds, including small molecules crystallography of inorganic and coordination compounds; 5) equipment design for synthetic inorganic/materials chemistry.
The definition is: “materials science is an interdisciplinary field concerned with the understanding and application of the properties of matter.” This area is dedicated to study of connections between the underlying structure of a material, its properties, its processing methods, and its performance in intended applications. Classic understanding of materials traditionally limits them to metals and their alloys [uses in: construction, catalysis, electric/conductance, magnetism], a variety of oxides [refractory materials, catalysts, ceramics/cements, quartz, conductance/semiconductance], thermally stable salts [silicates (including glass), phosphates, binary halides and halcogenides [optical materials, semiconductors], etc. Typically those classic materials are produced in large quantities from thousands- to multi-tons quantities.
However, during the last two decades a new type of chemical compounds vigorously claimed a well-deserved place in the vast world of materials. These are coordination compounds. There are two large sub-classes of the Werner-type complexes and organometallic compounds (Scheme 1) with principally very different chemical bonding in them. The first one adopts predominantly ionic/donor-acceptor type, while the latter represent covalently bonded species containing direct metal-carbon bond. Numerous coordination compounds of both types were employed as precursors for materials. Most common transformation of complexes includes their thermal decomposition leading to a product/material with desired properties for a specific application. However, only Werner-type complexes can be used as materials because of their stability at ambient conditions. Most of the organometallic species still are intrinsically unstable towards moisture and oxygen.
Applications of numerous complexes as materials (and specifically those as multifunctional materials) are reviewed in current presentation. These applications include usage of numerous Werner- type complexes in a variety of MOFs (gas sorption, purification of compounds, delivery), non-linear optical materials (second harmonic generation and optical limiters), catalysts, sensors and indicators, functional supramolecular materials, light harvesting/converting materials, molecular electronics.
Dr. Gerasimchuk authored and co-authored 112 publications and 7 patents on useful properties of a variety of the obtained compounds. Some representative works are shown below:
1. Cheadle C, Ratcliff J, Berezin M, Pal’shin V, Nemykin V.N., Gerasimchuk N. (2017) Shortwave infrared luminescent Pt- nanowires: a mechanistic study of emission in solution and in the solid state. Dalton Transactions: 46(39), 13562-13581.
2. He S, Toukrakis G, Berezin O, Gerasimchuk N, Zhang H, Zhou H, Izraely A, Akers W.J, Berezin M.Y. (2016) Temperature-dependent shape-responsive fluorescent nanospheres for image guided drug delivery.” J. Mater. Chem. C, 4, 3028-3035.
3. Gerasimchuk N. (2014) Synthesis, Properties, and Applications of Light-Insensitive Silver(I) Cyanoximates. Eur. J. Inorg. Chem. 4518– 4531.
4. Gerasimchuk N, Berezin M. Near Infrared Emitters. US Patent Application No. 15/001,023; January 19, 2016.
Keynote: Multiscale 3D printing with polymers
Time : 09:50-10:15
Geoffrey Mitchell is Professor and Vice-Director of the Centre for Rapid and Sustainable Product Develop at the Institute Polytechnic of Leiria. Geoffrey Mitchell is passionate about direct digital manufacturing (DDM) which enables products to be manufactured directly from a digital design without the need for specialist tooling or moulds and the development of novel materials to support the emerging technologies. He is fascinated by the opportunities that arise from merging electrospinning in to the family of DDM technologies. He brings a wealth of experience working with polymer based materials both natural and synthetic. He is particularly interested in the scales of structure present in all materials and especially biopolymers. He has developed and made extensive use of x-ray and neutron scattering methods coupled to computational molecular modelling and electron microscopy techniques.
3D printing is part of the family of Direct Digital Manufacturing processes in which a part is prepared with a particular external form defined in a digital manner without the use of complex tooling or moulds. Such an approach is revolutionising manufacturing. It creates a new paradigm for design and in aerospace, the concept is already in use to prepare parts such as turbine blades with shapes which hitherto were impossible. The fact that each part can have an individual design identifies that this technology has much to offer to medical devices. Now of course a part is not just defined by its external form but also by the microscale structure which develops in the part during the manufacturing process. In this presentation we review the materials and molecular mechanisms available to deliver controlled and defined morphology during 3D printing technology and how this influences properties. We present a novel methodology for delivering orthogonal control of the semi-crystalline morphology of poly(e-caprolactone) in biomedical devices. We take examples from recent research at CDRSP and consider its impact on scaffolds for tissue engineering.
This work is supported by the Fundação para a Ciência e a Tecnologia (FCT) through the Project references: UID/Multi/04044/2013; PAMI - ROTEIRO/0328/2013 (Nº 022158), MATIS (CENTRO-01-0145-FEDER-000014 – 3362 and UC4EP PTDC/CTM-POL/7133/2014)
1. G.R.Mitchell and Ana Tojeira editors “Controlling Controlling the Morphology of Polymers: Multiple Scales of Structure and Processing." Springer 2016 ISBN 978-3-319-39320-9
2. G.R.Mitchell, Donatella Duraccio, Imran Khan, Aurora Nogales, R.H.Olley ‘Templated Crystallisation in Polymer Nanocomposites’ in “Controlling the Morphology of Polymers: Multiple Scales of Structure and Processing." Springer 2016 ed G.R.Mitchell and A.Tojeira ISBN 978-3-319-39320-9
3. G.R.Mitchell, F.J.Davis, R.H.Olley and S.Wangsoub ‘Directing the Crystallisation of Polymers using nanoparticles of sugar alcohol derivatives’ in “Controlling Controlling the Morphology of Polymers: Multiple Scales of Structure and Processing." Springer 2016 eds G.R.Mitchell and A.Tojeira ISBN 978-3-319-39320-9
4. Geoffrey R Mitchell and Robert H Olley Orthogonal templating control of the crystallisation of poly(ε-caprolactone) Polymers, 2018, 10(3), 300; doi:10.3390/polym10030300
5. Ana Tojeira and G.R.Mitchell “Controlling Morphology in 3-D Printing” in “Controlling Controlling the Morphology of Polymers: Multiple Scales of Structure and Processing." Springer 2016 ISBN 978-3-319-39320-9