Papers by Author: Kang Ning Sun

Abstract: Purpose: To assess determination of Bacillus Calmette-Guerin(BCG) concentration integrated in delivery materials for intravesical infusion therapy of superficial bladder cancer. Material and Methods: The standard BCG solution was prepared and divided into two groups. One group was measured by spectrophotometer direct, the other group was determined by using enzyme mark instrument after the solution had cultured. The preliminary experiment study on BCG integrated delivery materials was finished by XTT method. Results: The wavelength of the characteristic peak changes with the variety of the concentration measured by spectrophotometer direct. The concentration of BCG which was embeded in integrated delivery materials for intravesical infusion therapy of superficial bladder cancer was linear with absorbance at 450nm by XTT method in the selected range. Conclusions: It is an incorrect way to measure BCG concentration like determining other solutions by the spectrophotometer immediately and direct. It is the simple, rapid and reliable method by XTT method to study on the performance of the BCG concentration integrated in delivery materials for Intravesical infusion therapy of superficial bladder cancer.

Abstract: Oxide membranes are one kind of porous materials with many nano-sized pores. In our work, the two-step anodization method was used to fabricate Anodic aluminum oxide (AAO) membranes. The surface, cross-section micrographs and chemical composition were analyzed by field emission scanning electron microscopy (FESEM). From the FESEM micrographs, it can be easily seen that the self-ordered hexagonal pore channels were parallel and perpendicular to the surface of membrane when AAO membrane was prepared in oxalic acid at 0.2mol/L for 4h. In addition, the biggest pore diameter was 78nm, and the thickness ranged from a few microns to tens of microns in the suitable preparation parameters.

Abstract: Multi-walled carbon nanotubes (MWNTs) reinforced hydroxyapatite (HA) composite was fabricated by in-situ method and followed by hot-pressing sintering; the influence of MWNTs’ content on the mechanical and microstructure properties was explored. The results show that adding MWNTs within a certain range could enhance the mechanical properties of HA matrix significantly. The maximal increment of the bending strength and fracture toughness of the composites, compared with the pure HA, were 157% and 171% respectively. XRD and TEM showed that the primary crystal phase of the composite was HA together with the diffraction peaks of carbon nanotube. By SEM, we found that MWNTs are homogeneously dispersed within grains or at grain boundaries of the HA matrix in composites which MWNTs’ content was not more than 15vol%, otherwise MWNTs tended to be agglomerated. The reinforcement mechanism was discussed based on the microstructure investigation. The broken nanotubes and pullout of MWNTs at interfaces were efficient in transferring the load from the HA matrix to the nanotubes, leading to the improvement of the mechanical properties.

Abstract: In the present study, a simple method of regenerating microstructure of human tooth under near-physiological conditions (pH 7.0, 37 °C, 1 atm) was developed. Commercial gelatin was used as matrix materials in this method, which nucleated the formation of fluorapatite (FA) nanocrystals and regulated the growth of nanocrystals. As a result, the resulting thin FA coatings had been prepared on human tooth slices and sintered hydroxyapatite disks, which were in tight contact with the substrates. Besides, the morphologies of FA nanocrystals changed from acicular to hexagonal with the exchange cycle of gel increased. Electron dispersive spectrometer analysis indicated that some sodium and carbonate ions were incorporated into the FA crystal lattices and the calcium to phosphorus ratio was approximate 1.58. The mechanical properties of the resulting FA coating were investigated through nanoindentation system, which showed the similar hardness with dentin. In conclusion, this method demonstrated a potential application to repair tooth damage in dental clinics.