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Template-Free Growth of Novel Hydroxyapatite Nanorings: Formation Mechanism and Their Enhanced Functional Properties
journal contribution
posted on 2012-07-03, 00:00 authored by A. Joseph Nathanael, Sun Ig Hong, D. Mangalaraj, N. Ponpandian, Pao Chi ChenTemplate-free, single crystalline novel hydroxyapatite
(HAp) nanorings
with an inner diameter of 70 nm were grown by a combined high gravity
and hydrothermal approach. Nanodisks were suggested to be formed by
oriented aggregation and Ostwald ripening of mostly calcium pyrophosphate
nanospheres prepared initially by the high gravity method with a stepwise
increase of flow rate of phosphate solution. The prolonged hydrothermal
treatment of nanodisks appeared to induce the nanoring formation via
acid penetration along the dislocations in HAp nanodisks. The presence
of edge dislocations in the central region of nanodisks was confirmed
by high resolution transmission electron microscopy. The mechanical
evaluation of high molecular weight polyethylene (HMWPE) composite
with various shaped HAp nanocrystals and in vitro cellular analysis
of HAp nanocrystals revealed that mechanical and bioactive performances
improved with an increase of the specific surface area of HAp nanocrystals.
The enhanced mechanical performance of HMWPE/HAp nanoring composite
and the excellent cell viability for HAp nanorings are attributed
to the superior interface bonding and cell activity, respectively,
both of which are enhanced by the high specific surface area.