The Study Of Antimicrobial Activity Of Sodium Aescinate-loaded Nanomesoporous Silica On Enterococcus Taecalis In Vitro

Objective:To compare the bacteriostasis of sodium aescinate loaded nanomesoporous silica before and after animo-modified (SA-SBA-15and SA-NH2-SBA-15) with calcium hydroxide (Ca(OH)2) on Enterococcus faecalis in vitro, provided a new way in development of root canal sealing materials.Methods:1. Purchased mesoporous silicon material SBA-15, observed its morphology, IR images, adsorption-desorption capacity for drug research.2. Using the direct grafting preparation to gain amino-modified SBA-15(NH2-SBA-15), observed its morphology, IR images, adsorption-desorption capacity for drug research.3. SA-NH2-SBA-15and SA-SBA-15were made by the ethanol solution-ultrasonic bath-motor method, then determined their morphology, particle-size distribution, drug loading amount and the characteristics of drug release in vitro.4. The minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of SA-NH2-SBA-15、SA-SBA-15and Ca(OH)2each on Enterococcus faecalis were determined by the liquid dilution susceptibility experiment and MTT colorimetry. The diameter of inhibition zone on Enterococcus faecalis was observed and measured with the method of Liquid dilution, to evaluate the bacteriostatic effect of the these three kinds of drugs.2mL of3.5mg/mL SA-NH2-SBA-15,3.5mg/mL SA-SBA-15,4.0mg/mL Ca(OH)2were prepared, anaerobic cultured168hours at37degree centigrade after adding the Enterococcus faecalis solution in, every24hours, the explants were cultured to observed the CFU. Use the SPSS18.0statistical analysis software for statistical analysis.Results:1. The framework of nanomesoporus silica remain consistent before and after animo-modified, these two mesoporous silica materials were suitable for drug loading. The sodium aescinate-loaded SA-NH2-SBA-15and SA-SBA-15remained the ruled structure, uniform particle size distribution. However, the drug loading capacity of NH2-SBA-15is27.72%, that of SBA-15is18.01%, the animo-modified mesopourous silica gained more capacity for drug loading, the difference was statistically significant (P＜0.05); From48to96hours, the drug release of SA-NH2-SBA-15was lower than that of SA-SBA-15,while the realease time of SA-NH2-SBA-15was longer than that of SA-SBA-15, the difference was statistically significant (P<0.05),2. The liquid dilution test showed:the MIC of SA-NH2-SBA-15was3.5mg/mL and the MBC was4.0mg/mL, the MIC of SA-SBA-15was3.5mg/mL and the MBC was4.0mg/mL, the MIC of Ca(OH)2was4.0mg/mL and the MBC was4.5mg/mL. These was similar to the result by MTT colorimetry.3. These three kinds of drug had a certain inhibitory effect, with the increase of the drug concentration, the diameter of inhibition zone increased, the difference was statistically significant (p<0.05). In some concentration (4.0mg/mL、4.5mg/mL�'�5.0mg/mL), the result of the diameter of inhibition zone showed:SA-SBA-15>SA-NH2-SBA-15> Ca(OH)2, the difference was statistically significant (p<0.05).4. From24hours to144hours, the CFU of3.5mg/mL SA-NH2-SBA-15decreased with time, the difference was statistically significant (p<0.05); From24hours to96hours, the CFU of3.5mg/mL SA-SBA-15decreased with time, the difference was statistically significant (p<0.05); From72hours to168hours, the CFU of SA-NH2-SBA-15and SA-SBA-15was less than that of Ca(OH)2, the difference was statistically significant (p<0.05); after96hours, the CFU of SA-NH2-SBA-15was obviously less than SA-SBA-15, the difference was statistically significant (p<0.05). In120hours, the CFU of Ca(OH)2remained steady, while significantly increased after120hours.Conclusion:1. The nanomesoporous silica before and after animo-modified had the ability of drug delivery and release, the drug loading amount and the release time of NH2-SBA-15is better than that of SBA-15.2. The antimicrobial test in vitro showed:these three kinds of drug had a certain inhibitory effect on Enterococcus faecalis. The bacteriostatic effect of SA-NH2-SBA-15and SA-SBA-15was better than that of Ca(OH)2.3. The bacteriostasis of SA-NH2-SBA-15and SA-SBA-15was better than that of calcium hydroxide. The efficacy of SA-NH2-SBA-15on Enterococcus faecalis was longer than that of SA-SBA-15and calcium hydroxide.