MODELLING AND SIMULATION OF MODELLING AND SIMULATION OF VASCULAR TISSUE ENGINEERING VASCULAR TISSUE ENGINEERING

USING THE FINITE VOLUME METHODUSING THE FINITE VOLUME METHOD C.S.KirkC.S.Kirk1, M.Horrocks2, A.R.Mileham3 & J.B.Chaudhuri4

1,4Depts. of Medical Sciences and Chemical Engineering, University of Bath, UK2 Dept. of Vascular Surgery, Royal United Hospital, and

Dept. of Medical Sciences, Univ. of Bath, UK3Dept. of Mechanical Engineering, Univ. of Bath, UK

OVERVIEW: It is essential that vascular replacements have a sufficiently robust growth of tissue for a biologically functional material that can withstand the hydrodynamic forces encountered in vivo following transplantation. Growth of these tissue cultures use bioreactors that have been designed and constructed specifically to recreate the chemical and physical environment suitable for tissue growth. Current research programmes are the subject of computer simulation of the diffusion, adsorption and growth rates which occur in typical cultivation systems with a view to enhancing the design capability and functionality of bioreactors. This will enable improvement in patient care through reduction in time to surgery and an improved in vitro cultivation method which more closely resembles that of the in vivo condition. It is considered that improvements in the predictive capability of process control, such as the control of oxygen (critical) and nutrient adsorption are vital to maintain progress of advancements in this internationally leading research sector.

CONCLUSIONS: The development of an FVM simulation that can rapidly handle computationally intense problems in a 3-dimensional material model has been based on the outputs of previous work. The model provides a basis for the assessment of the finite volume method to simulate problems which include diffusion of nutrients through human cells, and provide useful analysis to assess the effectiveness of its use with similar, transport dominant, problems. Assessment of the FVM to handle human cell structures and metabolism has been indicated. This has enabled steps to optimise the bioreactor with a view to providing suitable grafts for transplanting.

METHODOLOGY:

•The methodologies involved in using the finite volume method, (FVM) to model and simulate bioreactor and tissue culture performance were reviewed. As a basis for the current examination, an existing code, (a thermal and atomic diffusion simulator), was translated from that dealing with metallurgical problems in power reactors, to that dealing with this specialist area of human cell behaviour and tissue engineering. The code performed exceptionally well despite deficiencies in availability of basic data. The ‘layered’ concept has provided insight into the diffusion/reaction stability when differing coefficients are used and suggests that growth is glucose limited rather than oxygen limited.

Translation of layered methodologies and concepts