Papers by Author: Y.M. Jiang

Abstract: Biological sealing is a key factor for successful development of percutaneous device (PD). A new device with arc-perforated flange as subcutaneous part and groove-shaped percutaneous part, was intended to improve integration of soft tissue and implant. Material and surface properties are known to have great impact on tissue-implant integration. To understand how a material and its surface property can influence tissue reaction, and to find the appropriate material for PD fabrication, five different kinds of materials were prepared for in vivo animal tests with corresponding histological evaluation. Results revealed that a more stable junction was formed between the soft tissue and HA coated titanium implant than other combinations.

Abstract: The surface of synthetic calcium hydroxyapatite (HA, Ca10(PO4)6(OH)2) was modified through combining freeze-drying, solvent replacement and surface modification methods in an effort to obtain the deaggregative n-HA crystallites. Three surface modification agents: Polyethylene glycol (PEG, Mw: 6000), poly(propyl oxide)-poly (ethyl oxide)-co-poly(propyl oxide)(Pluronic F-127, Mw: 12,000) and poly(d, l-lactide)-co-poly (ethylene glycol) (PELA, Mw: 20,000)were selected. The dispersion of the modified n-HA was characterized by sedimentation time in distilled water, acetone and dimethyl formamide (DMF). The results indicate that the three surface modification agents influence the dispersion of n-HA crystallites in various solvent based on different mechanisms. Transmission electron microscopy (TEM) observation shows that the dried and acetone-replacement powders are composed of needle-like HA crystallites isolated individually. The chosen solvents have a profound effect on the sedimentation time. In distilled water, the dispersion of as-synthesized n-HA crystallites is increased greater by F127 than by PEG. After freeze-drying, the two n-HA particles show homogeneous dispersion in acetone. The colloid stability of freeze-dried HA/PEG, solution-replaced HA/F127 and solution-replaced HA/PELA in DMF were improved significantly. The suspensions remained stable after 30 days with only a blue transparent sol being observed.