Application of Research Results


Susan Clarke

Research Programmes for Senior Post Doctoral Fellows:

 

Susan Clarke [email:- s.a.clarke@qub.ac.uk]

Marine organisms for bone repair

Clinically it remains a challenge to fill large bone defects such as those following tumour resection or revision of joint replacements. Calcium phosphate ceramics have been used as synthetic bone graft materials as they closely resemble the mineral phase of bone; however the clinical results with these commercially available materials leave room for improvement. Porous materials perform better than solid, bulk materials because they allow vascular and bony invasion. We are currently investigating the ability of mineralising marine organisms with porous structures, such as sponges, cuttlefish and red algae, to support bone growth, either directly or when converted to calcium phosphate structures.


SEMs of (a) cuttlefish (Sepia officinalis), (b) sponge (Spongia agaricina), (c) red algae (Corallina officinalis) and (d) coccolithophores (Emiliania huxleyi)demonstrating a range of macro and microporous structures.

 

Specific projects include:

  1. The in vitro and in vivo evaluation of the ability of a calcium phosphate scaffold derived from a marine sponge template to support bone growth;
  2. The potential of sponges from Irish Waters to act as scaffolds for bone tissue engineering;
  3. Optimisation and in vitro evaluation of red algae-derived ceramic- the calcium carbonate structure of Coralline officinalis is converted to calcium phosphate;
  4. Use of marine sponge-derived collagen to enhance bone substitute materials- specifically to augment the biocompatibility of an injectable cement designed for vertebroplasty and the surgical repair of burst spinal fractures.

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Alesandro Busetti

Research Programmes for PhD Students:

 

Alesandro Busetti [email:- a.busetti@qub.ac.uk]

Project Title

Isolation and identification of marine-derived anti-biofilm agents for medical device applications

Supervision Team

Prof. Brendan Gilmore, Prof. Christine Maggs and Prof. Sean Gorman

Overview

It is estimated that 65-80% of all infections are caused by biofilms, highly organised surface-associated microbial communities embedded in an exopolymeric matrix. Within the nosocomial environment, microbial biofilms are responsible for persistent, chronic, recurrent, device-related and catheter-related bloodstream infections, some with high mortality rates, and costing nations billions in health care. Microbial biofilm-related infections are difficult to treat due to their elevated resistance to conventional treatment with antibiotics and their capacity to escape detection by host immune defence systems. Quorum sensing inhibition (QSI) compounds isolated from several marine organisms seem to suggest that QSI may represent a natural, widespread, “antimicrobial” strategy utilized by marine organisms with significant impact on biofilm formation, making the marine ecosystems an ideal source for the discovery of QS inhibitors with potential use as non-antipathogenic compounds.

Overall project aims

The project aims to identify marine microbes and marine eukaryotes (e.g. algae) that produce anti-biofilm and anti-fouling compounds. This will involve the identification and characterisation of candidate microorganisms, algae and metagenomic clones (constructed from algal symbionts) with anti-biofilm and anti-fouling activity. In addition marine organisms that produce quorum sensing inhibitors (QSI) will also be targeted.  

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Kathryn Fee

Kathryn Fee [email:- k.fee@qub.ac.uk]

Project Title

Development of marine-derived biomaterials for bone tissue engineering applications

Supervision Team

Prof. Fraser Buchanan and Dr Nicholas Dunne

Overview

Calcium phosphate (CaP) ceramics, in particular hydroxyapatite, are well-established substitutes for bone tissue engineering applications. CaP ceramics with their excellent biocompatibility are potential alternatives to autogenous bone, xenograft or allograft materials. To ensure adequate sustainability of supply and predictable performance, there is a need for the development of chemically synthesised materials with reproducible structures and chemical composition.  CaPs derived from natural sources have previously been utilised due to their unique morphology but the harvesting of coral reefs is considered non-sustainable and can have a detrimental impact on marine ecology. Recent studies have investigated the use of mineralised red algae, as an alternative to coral. A successful low-pressure hydrothermal exchange has been developed to convert red algae into hydroxyapatite whilst maintaining the original morphology.  This project work will initially focus on coccoliths as the calcareous material, to establish their potential to be converted into hydroxyapatite particles suitable for bone tissue engineering. The shields of the individual coccoliths overlap forming a robust structure, known as the coccosphere.

Overall project aims

The project aims to obtain sufficient quantities of coccoliths, and determine the potential of converting calcium carbonate coccoliths into a biphasic CaP ceramic by way of ambient pressure, low temperature hydrothermal synthesis. The project will also determine whether microparticles of hydroxyapatite are useful to enable the release of ions into solution, to activate bone cells by increasing bioactivity. Finally the project will explore the potential for these biocompatible particles to interlock and thereby form a microporous filler with cohesive strength.

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Paul McEvilly [email:- p.mcevilly1@nuigalway.ie]

Project Title

Protein adhesion in pedunculate barnacles

Supervision Team

Dr Anne Marie Power

Overview

This project will study the bioadhesive structures of stalked barnacles and the glues produced by these structures.  Previous studies on pedunculate barnacles have to date not focused on the adhesive properties of barnacle cement and work in this area could  offer some advantages due to the pelagic habitats these animals occupy compared with acorn barnacles. Analyses in ultrastructure, histology and immunohistochemistry will be applied to stalked barnacles to identify the detail of the cement gland and its properties. The identification of the proteins comprising the glue/cement of pedunculate barnacles is a significant goal of this study, particularly with reference to Dosima fascicularis, the buoy barnacle. Protein chemistry will also be examined to determine the composition of the glue.  Mass spectroscopy, Edman degradation and sequencing will be used for protein chemistry, together with raman spectroscopy. Attempts will be made to cultivate pedunculate barnacles including Dosima fascicularis and Lepas anatifera, as this will provide a source of clean sample material. Successful production of larvae would allow larval glue (which is potentially different from adult glue) and details of the life history stages to be studied in these species.

Overall project aims

This project aims to perform a detailed analyses in ultrastructure, histology and immunohistochemistry to provide a greater understanding of the structures required for biological adhesion in stalked barnacle species. Work will focus on analysing the adhesive protein complex to discover how many proteins are involved in adhesion as well as the identity of those proteins. Stalked barnacles will also be cultured, thereby eliminating expensive and potentially risky field sampling missions. Finally data will be collected on the larval stages of stalked barnacles including (potentially) the glues produced by larval stages.

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Iwan Palmer [email:- i.palmer@qub.ac.uk]

Project Title

Use of Marine Sponge-Derived Collagen to Enhance Bone Substitute Materials

Supervision Team

Prof. Fraser Buchanan, Dr Susan Clarke, Dr Nicholas Dunne 

Overview

Calcium phosphate bone cements (CPCs) are currently of great interest in the field of bone repair due to their bioactivity, which can be used to induce positive responses in vivo. CPCs mimic the natural mineral phase of bone and are potentially resorbable, consequently promoting natural bone remodelling and ingrowth. They have the potential to be particularly valuable in treatment of bone defects in the younger population who, in general, have a greater capacity for bone remodelling. However, concerns remain regarding the use of CPCs in load-bearing regions due to shortcomings in their mechanical properties. Incorporation of collagen into CPCs has been shown as a method of improving their mechanical properties while potentially inducing biological benefits associated with the key role of collagen in bone formation and function.

Collagen from the marine Demosponge Chondrosia reniformis (Nardo, 1847) is thought to be suitable for this application. It has been identified worldwide, has high collagen content and a low risk of detrimental toxic compounds. The collagen exhibits many features associated with mammalian collagen and, in some aspects, has been shown to display significant similarities to bovine collagen – the main source of commercial collagen at present. The fact that C. reniformis also reproduces asexually suggests that harvesting of the sponge for collagen isolation could be conducted on a commercial scale.


Overall Project Aims

The primary aim of this project is to assess and quantify any biological benefits associated with the incorporation of C. reniformis collagen into CPCs. This will be done using both in vitro and in vivo methods to estimate the potential benefits of the use of marine collagen-reinforced CPCs to treat orthopaedic defects. Furthermore, the most suitable methods for sterilising this collagen will also be investigated. The sterilisation of sensitive biomolecules such as collagen is a well-known challenge, but one that is key to the future use of such materials in the clinical setting.

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Diana Tegazzini

Diana Tegazzini [email:- d.tegazzini@qub.ac.uk]

Project Title

Isolation and Characterisation of Novel Antimicrobial Compounds from Halophiles

Supervision Team

Prof. Brendan Gilmore

Overview

The need to discover novel antimicrobial compounds is becoming a pressing need due to the emergence and spread of resistance mechanisms to standard treatments in pathologically relevant strains. Halophilic microorganisms isolated from hypersaline environments represent a promising source of novel compounds for the medical and biotechnological fields. In particular, the microbial flora present in deep, ancient halite deposits has remained largely unexplored due to the limited accessibility of the sampling sites and the necessity to develop ad hoc laboratory culturing techniques. In order to survive in an extreme environment, halophiles are likely to produce a unique array of secondary metabolites uncovering a chemical diversity which has, so far, remained unexplored.

Overall Project Aims

The project focuses on the isolation of novel compounds from halophilic bacteria and Archaea, isolated from the Carrickfergus salt mine, possessing antimicrobial activities against clinically relevant pathogens. The most promising hit compounds will be purified and characterized in terms of chemical structure and spectrum of activities, aiming to identify novel lead compounds that can progress within the consortium’s pipeline.  

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Nathalie Barroca [n.barroca@qub.ac.uk]

Project Title

3D composite scaffolds based on synthetic extracellular matrix and marine additives for in situ bone tissue engineering

Supervision Team

Prof. Fraser Buchanan and Dr Pamela Walsh

Overview

Synthetic polymers such as PLLA are widely used as scaffolds for bone tissue engineering and are successfully in use for a few clinical applications but these kind of synthetic polymer based scaffolds lack in osteogenic cues.

Silicon and calcium ions have been pointed to stimulate the activation of seven families of genes in osteoblasts and consequently increasing osteoblast proliferation and differentiation. Using marine diatoms and Lithothamnion red algae as a biogenic sources of silicon and calcium respectively is promising due to their abundance and inexpensive cost. Moreover, silicon from diatomaceous earth has shown to induce a higher osteoblast proliferation and activity than silicon from silica when introduced in bioactive coatings. Aquamin, in the other hand, has recently shown improved osteogenesis in collagen-aquamin structures.

In parallel, the utilization of 3D printing techniques has grown due to their potential to produce 3D scaffolds of controllable and variable design.  Notwithstanding their acceptance and broad utilization, they do not allow a topographic control at the nanometer level. Nanotopography is a crucial factor and has demonstrated more recently to enhance osteointegration and de novo bone formation.

Consequently, there is a clinical and scientific niche to be explored in order to fabricate 3D scaffolds that will integrate microscale but also nanoscale features and osteogenic cues towards a synergetic effect between the cellular and subcellular processes in directing regeneration.

Goals

We intend to reliably develop three dimensional PLLA architectures where 3 order of magnitude are controlled: the shape of the 3D porous structure (to match accurately the defect size), the interconnected microstructure geometry within the 3D scaffold but also provide the scaffolds walls with a nanofibrous texture. For that purpose, 3D printing technology are used in combination with the thermally induced phase separation technique.

Our 3D scaffolds will further integrate an osteogenic strategy by adding marine additives that are under current research for bone applications by the Marine Biodiscovery group. Silicon and calcium containing marine organisms such as marine diatoms, multi mineral Aquamin from the Lithothamnion red algae will be incorporated to the polymeric solutions. By incorporating and varying the content of those marine organisms or their derived products, it is expected to achieve a combined release of calcium and silicon to the in vivo bone environment and lead to a chemical signalling towards osteogenesis. 

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Pamela Walsh

Pamela Walsh [email:- pamela.walsh@qub.ac.uk]

Project title

Marine inspired biosilica-filled hydrogels for hard tissue repair

Overview

My research takes a biomimetic approach that mimic natural glues with synthetic materials, to offer solutions that are more suitable to the body. In nature, glues underpin many biological systems, often performing their function in wet and turbulent environments, e.g. the blue mussel (Mytilus edulis). Currently, there are no clinically available bioadhesives that are suitable for hard tissue applications. The long-term aim of my research is to develop a mussel-inspired bioadhesive system suitable for hard tissue repair. ‘Marie Sklodowska Curie International Outgoing Fellowship (IOF) from the European Union FP7’ funded my current research project, which has just finished. It investigated the addition of biosilica isolated from marine diatoms to enhance the mechanical properties and osteogenicity of a novel hydrogel system developed at Prof Philip Messersmith group, Northwestern University, (who has recently taken up a position at Berekeley - http://bioinspiredmaterials.berkeley.edu/). Results to date have been promising. We have identified strategies for effectively incorporating biosilica frustules into our chosen hydrogel system and have confirmed the non-toxic nature of the native biosilica in our system both in in vitro and in vivo testing. We hope to develop this research over the next few years in collaboration with ongoing Beaufort work. Prof Matt Julius at St. Cloud State (http://web.stcloudstate.edu/mljulius/) has also been invaluable in this project. Without his diatom expertise, this project would not have progressed. My original PhD research on calcified marine organisms with Prof Fraser Buchanan was also developed during the Beaufort Project. In my new PI position in the School of Chemistry and Chemical Engineering, at Queen's University, Belfast, I am looking forward to developing new ideas steaming from my previous work and mentors/collaborators.