Porous Bio-ceramics

Preparation of porous inorganic solids

Dr. Dominic Walsh (Email: d.walsh@bristol.ac.uk)

His research is centered around the preparation and development of porous inorganic structures suitable for use as implant materials such as artificial bones and teeth, as supports for drug delivery or as catalysts or catalyst supports. Previously he had employed various approaches to the preparation of these materials including the use of crystal altering additives in solution, microemulsions, carbonated water systems or other gas releasing reactions or sacrificial dextran templates. This research has included collaborations with NIMS Institute in Tsukuba, Japan, with the NCCR Institute, Osaka, Japan, the University of Bologna, Italy and the Orthopaedics Unit at Southampton University.

Some specific highlights in the research include the preparation of calcium phosphate bone mimic reticulated structures by the mineralization of water channels within a water/oil continuous microemulsion. Porous calcium carbonate spherical sponges were also prepared from mineralizing emulsion system and this system was also used to prepare hollow spherical clay structures. More recently metallic silver and gold foams were formed from dextran/metal salt mixtures that were heated to remove the organic component. A development of this principle was the preparation of frameworks of zeolite crystals contained within interlocked silica fibres. More recently sponge films of tricalcium phosphate bioceramic were prepared by a controlled precipitation at the air/water interface from a carbonated water mineralizing system.

Currently, as an EPSRC Advanced Research Fellow he is investigating the use of cold isotatic presssing (CIP) for the preparation of bioceramic tissue scaffolds suitable for cell seeding and also the preparation of catalysts and catalyst supports with an application in fuel cells. Overal CIP is a novel approach and suitable for scaling up for large scale production.