Papers by Author: W.Y. Ip

Abstract: Introduction: Peripheral nerve injury is common in clinical practice. Nerve defect is a challenging scenario. The current gold standard of managing a nerve defect is autologous nerve graft. However, due to the selection of nerve graft and donor site morbidity, artificial nerve conduits are gaining popularity. However, there are drawbacks of single hollow conduit such as lack of internal support to prevent conduit collapse and inability so as to recreate the proper native spatial arrangement of cells and extracellular matrix within the conduit. In this study, the biocompatibility and efficacy of five-channel and eight-channel Crosslinked Urethane-doped Polyester Elastomers (CUPEs) as nerve guidance conduit will be evaluated through a rat model with reconstruction of segmental peripheral nerve defect. Material and Method: Eighteen adult Sprague-Dawley rats were used. They were randomly allocated to three groups: autograft group, five-channel conduit group and eight-channel conduit group with each consisted of six rats. A 10mm nerve defects were created at the right sciatic nerve. They were bridged with reverse autograft, 5-channel conduit and 8-channel conduit. After eight weeks the rats were euthanized and the reconstructed nerves were harvested for histomorphometric analysis. Result: All conduits showed regenerated nerve tissue inside. There was no collapse of the conduits. There were no severe tissue reaction or scarring near the reconstructed nerve. No neuroma was formed. Histomorphometric analysis showed nerve regeneration was enhanced with increasing number of channels inside conduit. There was overall drop in fiber density between proximal and distal segment among all groups. Conclusion: CUPE nerve guidance conduit is biocompatible and shows good nerve regeneration in reconstructing nerve defect.

Abstract: The aim of this study was to investigate the feasibility of utilizing selective laser sintering (SLS) to build 3D porous tissue engineering scaffolds from small quantities of poly(L-lactide) (PLLA). PLLA microspheres with suitable particle sizes for the SLS process were produced by the oil-in-water emulsion solvent evaporation technique. A miniature build platform was designed, fabricated and incorporated in an existing Sinterstation® 2000 system to enable small quantities of polymer powder to be used for the production of 3D porous scaffolds. Trial runs were first performed using the DuraForm™ polyamide powder and interfacing problems between the miniature build platform and the existing machine were solved. Then 3D porous scaffolds were successfully built from the PLLA microspheres using the modified SLS machine. This study paved the way for further comprehensive studies on selective laser sintering of tissue engineering scaffolds using expensive biopolymers and their composites.