The Preparation,Character And Application Of Halloysite Nanotubes/Chlorhexidine Gluconate Composite Antibacterial Agent

Halloysite nanotubes(HNTs)are naturally occurring hollow tubular clay aluminosilicate.With the unique structure,the antibacterial agent chlorhexidine gluconate(CG)was successfully ecapsulated onto HNTs forming HNTs/CG composite.The structure of HNTs/CG composite were characterized by Fourier transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD),and in vitro drug release assay was preliminary detected by UV-Vis spectroscopy.The antibacterial activity of HNTs/CG composite was evaluated by inhibition zone test.The results indicated that CG was successfully loaded in the lumen of HNTs and on the outer surface through electrostatic interaction.In vitro drug release assay showed that CG could be released from HNTs in a sustainable manner and could last as long as about ten days.The new composite displayed significant bacterial killing activity against representative Staphylococcus aureus,Escherichia coli and Pseudomonas aeruginosa,what’s more,after released for one week,the HNTs/CG composite still had significant antibacterial effect.In addition,HNTs/CG composite was further explored by coating on cotton fabric as an antibacterial protective agent.The surface morphology,thermal stability and hydrophilicity properties were characterized by scanning electron microscope(SEM)thermogravimetric analysis(TGA)and capillary effect.The antibacterial effect of HNTs/CG coated cotton was quantitatively detected by viable cell counting techique.The safety of HNTs/CG-coated cotton fabric was evaluated by animal skin irritation tests and acute oral toxicity test.The cytocompatibility of HNTs/CG-coated cotton fabric was also studied by in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium(MTT)assay.It was found that the thermal stability and hydrophilicity properties were improved as compared to uncoated fabric.The antibacterial effect of HNTs/CG-coated cotton exhibited over 98%bacterial reduction of S.aureus,E,coli,and P.aeruginosa.After washing 20 times,the HNTs/CG-coated cotton fabric was still showed over 90%antibacterial activity.it showed nontoxic to mouse fibroblast cells(L929).The skin irritation test and acute oral toxicity test indicated that HNTs/CG-coated cotton fabric have no irritation to animal skin and the HNTs/CG composite did not cause histopathologic changes to the various organs of tested mice.MTT test showed that HNTs/CG-coated cotton fabric was nontoxic to mouse fibroblast cells(L929).Thus,HNTs/CG composite has the potential as a safe,environmentally friendly antibacterial agent in textile field to control bacterial contamination.