Periodic Report Summary - BIODESIGN (Rational bioactive materials design for tissue regeneration) Project context and objectives: Project objectives The overall objective of the BIODESIGN project is to develop new and rational design criteria for advanced biomaterials used as scaffolds for bone, skeletal muscle and cardiac muscle. These will involve defined chemistries and physics and aims to be generally applicable to many scaffold components. These should be evaluated in a multiparametric in-vitro environment that mimics the complexity of the natural tissue prior entering into animal models to reduce the number of animals required and hence the cost for bringing new biomaterials to the clinic. To address this the following work components need to be in place: 1. A methodology to correlate biomaterial design with functional in vivo outcomes. 2. Defined and non-toxic chemistries that allow assembly of a broad range of scaffold matrix components. 3. Functional matrix components allowing assembly in vivo after injection. 4. Functional matrix components that control the delivery of biological cues such as growth factors and small interfering ribolucleic acid (siRNA). 5. Scaffold components that allow in situ and in vivo imaging. 6. In vitro evaluation methods ranging from two-dimensional (2D), over screening techniques to more in vivo mimetic. 7. In vivo evaluation methods allowing studies of correlation with in vitro outcomes, limiting the number of animals required. 8. Methods, based on correlation analysis, to select tests that can be predictive of in vivo animal outcome. As a result of the objectives, the scientific work has been divided into distinct but interdependent areas to which Individual partners bring in specific scientific expertise and resources that are collectively leveraged to achieve our aims. These include: 1. correlation analysis for rational design 2. scaffold design 3. in-vitro scaffold model development and evaluation 4. tissue specific in vitro and in vivo scaffold evaluation and imaging 5. selecting in vitro screens for replacement, refinement and reduction (3Rs). Area one assembles, analyses and draws conclusions from the present limitations seen for biomaterials in clinical trials or large animal testing. The aim is to understand the link between scaffold design and the final clinical outcome and to translate knowledge between biomaterials scientists and the clinical users. Presently this is not appreciated and is difficult to promote, but with regenerative medicine moving to the forefront of therapeutic strategies, integrating those project specialists who have performed these studies, including human clinical studies, is the key to success. Area two designs methods to prepare scaffolds, in a modular context, in the form of injectable soft gels, compliant extra-cellular matrix (ECM) composites and load bearing ceramics. Materials prepared using these novel methods will be developed for specific evaluation purposes e.g. monitoring degradation, studying effect of material properties on cell and tissue behaviours and for implantation to correlate in vitro evaluation methods with in vivo outcome. Area three develops test methods to evaluate the potency and function of cell/scaffold products before clinical use. The structure and function of specific products will drive product-testing matrices, which will be individualised for each cell/scaffold construct. The aim is to assemble, develop and apply in vitro screening tools for screening scaffold materials development in vitro so that reliable and convenient protocols for monitoring engineered tissues can be used on-line and non-destructively. Area four refines existing, or if required develops new methods for imaging in vitro and ex vivo tissue engineered structures, with capabilities for determining the scaffold parameters that can be measured before animal experiments have to be conducted and that are predictive of the scaffolds in vivo performance. These parameters will be used to ascertain the scaffolds in vivo performance without further animal testing. Before a novel matrix is used for ex vivo/in vivo tests, a set of biocompatibility tests will also be conducted. Area five establishes correlations between in vitro evaluation tools that mimic the in vivo milieu (i.e. bioreactors) and the in vivo outcomes in the animal models, that helps reduce the ethical challenge and costly use of animal models. Advanced in vitro tissue models will be developed potentially based on decellularised skeletal muscle, cardiac muscle and/or intact bone, to use the native morphological, mechanical and ECM carried cues. These will be employed in bioreactor systems using scaffolds from area two and external stimuli and advanced monitoring techniques from area three for tissue mimetic models. Project results: Work performed since beginning of project Area one. Correlation analysis for rational design The consortium has assembled, analysed and drawn initial conclusions from the present limitations seen for biomaterials in clinical trials and large animal models for bone, skeletal muscle and cardiac muscle regeneration. This has resulted in a better understanding of the links between scaffold design and final outcome, as well as where a lack of knowledge is prevalent. For bone regeneration, correlations are found between transport properties (porosity and permeability) of the matrix and functional outcome, whereas; for skeletal muscle and cardiac muscle data are still too scattered to draw conclusions regarding any possible correlations. Area two. Scaffold design The procedure for making the gels is premised on a modular synthesis of rationally designed in vivo injectable ECM mimics. The consortium developed the modular design of the ECM-mimicking hyaluronic acid (HA) gels using orthogonal chemical 'click' transformations. Importantly, this implies low degree of chemical modification, reactions that can be performed under physiological conditions (in water at pH 7.4) without formation of toxic products. These transformations permit the simultaneous assembly of multicomponent systems with a defined connectivity between the components. In this context, the incorporation of heparin and adhesion ligands was validated, although in principle, many other biofunctional components can be similarly incorporated. Additionally, the procedures for making the gels is straightforward; enabling consortium members to make use of these modular gels in their own laboratories with applications such as fluorescent imaging probes, fibrin and polyethylene glucol (PEG). Area three. In-vitro scaffold model development and evaluation In vitro and in vivo correlation can only be possible by standardising the variables. Each group in the BIODESIGN consortium has their own methodologies and resources available. We have therefore assembled information regarding the cell types and techniques used by each group. All institutions involved in providing cells for the project have described the cell types and culture techniques appropriate for those cell types. In addition, an indication of whether these cells are available for exchange between groups is now available. It is now possible to exchange cell types and test that the methodologies described within each institution are repeatable within separate institutions. This provides a strong foundation for the acquisition and correlation of data between groups. These standard operating procedures (SOPs) have been tested in several laboratories to ensure validity. Area four. Tissue specific in vitro and in vivo scaffold evaluation and imaging First systems to monitor scaffold degradation along with tissue formation have been established and successfully evaluated. Preliminary data for two ex vivo models of bone repair has been generated e.g. using chick bones as a culture template. A tissue engineering porous scaffold implanted into a living load-bearing tissue like bone is subjected to two main types of mechanical stimulations: shear stresses coming from the fluid flow inside the scaffold and mechanical loading directly transmitted from the surrounding tissue. In this work package, we established procedures for characterising mechanical stimulations and performed tests with selected materials. Drug release kinetics and potential control parameter were also investigated and successfully demonstrated feasibility to maximise drug-loading potential and duration of release resulting in planning of an animal trial. Area fivr. Selecting in vitro screens for 3Rs During the first year review of current data sets from within the consortium highlighted the importance of the central concept underlying the BIODESIGN project. Rationale biomaterial design that employs powerful predictive assays to streamline the design process and achieve reduction, refinement and replacement of animal models, is an urgently required, but as yet unrealised, experimental goal. One main focus is the reduction of the need for animal testing models by developing new in vitro alternative techniques. The decellularised matrix of the placenta has great potential for use as a scaffold for tissue engineering and has been investigated. The decellularised vascular network shall be preserved for a recellularisation with human stem cells in a bioreactor system that we are developing. We are also currently constructing a semi-open bioreactor system to optimise culture conditions and finally achieve better and thicker heart tissues. Potential impact: Expected final results and potential impact Bioscaffolds research has been significantly changed by the simultaneous development of biopharmaceuticals and the more profound knowledge of developmental processes and mechanisms in biological systems. The previous paradigm of developing scaffolds for tissues with easy access (such as skin) or with very similar chemical composite structures to the tissue being repaired (CaPO4 scaffolds and bone) has been increasingly replaced by advanced scaffold types that are bioactive alone, or are functionalised through the addition of factors or peptides that can be applied by injection to aid cell function and host repair. This has defined and refined tissue engineering concepts which now encourage tissue repair using scaffolds that serve a temporary purpose, similar to a development process or target a critical component of the repairing tissue itself such as its blood supply through endogenous cell stimulation. As a result of these exciting advances there has been a clouding of what were once distinct regulatory fields (medical device versus medicine), which has created its own bottlenecks. Bioactive scaffolds are assessed at the pre clinical to clinical transition using the same criteria once reserved exclusively for new chemical entities and new biopharmaceuticals which necessitate extensive animal studies and associated high costs. This is not an optimal situation in consideration of the pre investments made and matched with the sequential time and costs of the steps needed, therefore this call, NMP.2010.2.3-1 'Development of standard scaffolds for the rational design of bioactive materials for tissue regeneration', has been designed to address this specific issue with the following required impacts. Principal and major impacts: 1. development of new, rational design criteria for advanced biomaterials/implants, whereby the specific nano/micro-scale properties, as well as the presentation of signalling molecules, are specifically targeted for a defined clinical use; 2. achieve radical innovations in state-of-the-art biomaterials and to design highly performing bioinspired materials learning from natural processes; 3. reduction of our reliance on complex and costly in vivo experiments to predict the performance of bioactive materials; 4. enhanced competitiveness of the biomaterials and biomedical industries in the European Union (EU). Through successful preclinical evaluation during the first year, a first series of animal trials will be initiated towards the development of a product for participating companies. List of websites: http://www.biodesign.eu.com/index.html Documents connexes Periodic Report - BIODESIGN (Rational bioactive materials design for tissue regeneration) Other report summaries Periodic Report Summary 5 - BIODESIGN (Rational Bioactive Materials Design for Tissue Regeneration) Periodic Report Summary 4 - BIODESIGN (Rational Bioactive Materials Design for Tissue Regeneration) Periodic Report Summary 3 - BIODESIGN (Rational Bioactive Materials Design for Tissue Regeneration) Periodic Report Summary 2 - BIODESIGN (Rational Bioactive Materials Design for Tissue Regeneration)
