[Experimental research of antibacterial property and release characteristics of Titania and Ag containing nano-hydroxyapatite/polyamide 66 composite bone filling material in vitro].
OBJECTIVE
Titania and Ag containing nano-hydroxyapatite/polyamide 66 (TiO2-Ag-nHA/PA66) composite bone filling material has good biocompatibility and biological safety. To investigate the antibacterial effect and Ag+ release characteristics of TiO2-Ag-nHA/PA66 composite bone filling material containing different concentrations of Ag+ in vitro.


METHODS
The n-HA/PA66 composite bone filling material A1 (material A1) was prepared by co-polymerization method, and TiO2-Ag-nHA/PA66 composite bone filling materials A2 and A3 (materials A2 and A3) were prepared by the same way containing Ag+ of 0.22wt% and 0.64wt%, respectively, and the TiO2 content was 2.35wt%. The materials A2 and A3 were respectively immersed in 50 mL simulated body fluid (SBF), and Ag+ concentration was measured by atomic absorption spectrometry at 1, 3, 7, 14, 21, and 49 days. The inhibition ring test and colony count method were used to evaluate antibiotic effect against Staphylococcus aureus and Escherichia coli, the anti-adhesion capacity of Staphylococcus aureus and Escherichia coli was observed by scanning electron microscope (SEM).


RESULTS
There was no significant difference in the Ag+ concentration between materials A2 and A3 at 1 day and 3 days (P > 0.05); and there were significant differences in the Ag+ concentration between materials A2 and A3 after 7 days (P < 0.05). The inhibition ring diameters of materials A2 and A3 to Staphylococcus aureus and Escherichia coli reached the maximum at 1 day, which were (13.40 +/- 2.88), (9.40 +/- 1.14) mm and (23.60 +/- 1.14), (18.80 +/- 0.84) mm, showing significant difference (P < 0.05) between materials A2 and A3 respectively; and then, the diameter of inhibition ring reduced with the time. The antibacterial effect of materials A2 and A3 against Staphylococcus aureus and Escherichia coli lasted 15, 33 days and 9, 24 days, respectively. No inhibition ring was observed around material A1 all the time. And the inhibitory rates of materials A2 and A3 were 89.74% +/- 3.62%, 94.18% +/- 2.05% and 78.65% +/- 5.64%, 85.96% +/- 2.50%; showing significant differences (P < 0.05) among materials A1, A2, and A3. SEM showed that bacterial adhesion of materials A2 and A3 was obviously fewer than that of material A1.


CONCLUSIONS
TiO2-Ag-nHA/PA66 composite bone filling material has antibacterial property against Staphylococcus aureus and Escherichia coli, and it has a good release effect in SBF.
Lu
Minpeng
M
Department of Orthopedics, the First Affiliated Hospital, Chongqing Medical University, Chongqing, 400016, P.R. China.
Jiang
Dianming
D
Quan
Zhengxue
Z
Li
Guangzhou
G
Cao
He
H
Liu
Mingfang
M
Kuang
Shangru
S
Li
Jidong
J
Li
Yubao
Y
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018786:Bone Substitutes / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D004926:Escherichia coli / Q000187:drug effects; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry*; D009757:Nylons / Q000737:chemistry*; D012834:Silver; D013211:Staphylococcus aureus / Q000187:drug effects; D014025:Titanium
D000900:Anti-Bacterial Agents; D018786:Bone Substitutes; D009757:Nylons; C009495:titanium dioxide; D012834:Silver; D017886:Durapatite; D014025:Titanium