Chong Wen Xin, Lai Yee Xuan, Choudhury Minati, Amalraj Fabian Davamani
Graduate student, School of Dentistry, International Medical University, Kuala Lumpur, Malaysia.
Senior Lecturer, Clinical Dentistry, International Medical University, Kuala Lumpur, Malaysia.
J Prosthet Dent. 2022 Nov;128(5):1114-1120. doi: 10.1016/j.prosdent.2021.01.010. Epub 2021 Mar 6.
The presence of biofilms on maxillofacial silicone increases the risk of infections and reduces durability. Whether silver nanoparticles (AgNPs) with potent antimicrobial effects help reduce biofilm formation is unclear.
The purpose of this in vitro study was to assess the antimicrobial effect of sub 10-nm AgNPs in maxillofacial silicone against Staphylococcus aureus, Candida albicans, and mixed species biofilms containing both and to test the effectiveness of different AgNP concentrations against all 3 biofilms in vitro.
Silicone disks (M511; Technovent Ltd) containing 0.0% (control), 0.1%, and 0.5% AgNPs were fabricated and treated with S. aureus, C. albicans, and mixed species strains of both in 24-well culture plates containing appropriate media. Each well received a 0.1-mL aliquot of the standardized suspension of microorganisms. The plates were incubated for 21 consecutive days, and colony-forming units per milliliter (CFU/mL) were measured on the first, third, fifth, seventh, fifteenth, and twenty-first day with the Miles and Misra method. Data were analyzed by 2-way ANOVA and the paired t test to evaluate the relationship between AgNP concentration, microbial strain, and time (α=.05). Mean CFU/mL differences for each time and for each biofilm category were assessed by repeated measure ANOVA.
AgNPs decreased the mean CFU/mL in both concentrations compared with the control. The 0.1% concentration showed sustained efficacy throughout the test, while the 0.5% concentration had high efficacy initially with a gradual decrease. However, the results were inconsistent for the mixed biofilm. The paired sample t test at day 3 and 15 and day 3 and 21 showed statistically significantly different results (P<.001) in all but 1 group in the 0.5% concentration. The 2-way mixed ANOVA showed statistically significant (P<.001) interaction between AgNP concentration and time in all groups. The 1-way ANOVA of AgNP concentrations was statistically significantly different (P<.001) for all time points. A statistically significant (P<.001) effect of time on CFU/mL was found for all the AgNP concentration groups in all 3 biofilms.
Silicone elastomers with sub 10-nm AgNPs displayed antimicrobial properties in vitro against S. aureus, C. albicans, and mixed species strains. AgNPs (0.1%) were effective against both microbial strains and can provide a baseline for further long-term studies regarding antimicrobial efficacy, silver ion leaching, and cellular internalization. Mixed species biofilm needs further exploration with standardized study parameters.
颌面硅胶上生物膜的存在增加了感染风险并降低了耐用性。具有强大抗菌作用的银纳米颗粒（AgNPs）是否有助于减少生物膜形成尚不清楚。
本体外研究的目的是评估10纳米以下的AgNPs在颌面硅胶中对金黄色葡萄球菌、白色念珠菌以及包含这两种菌的混合菌种生物膜的抗菌效果，并测试不同AgNP浓度对所有三种生物膜的体外有效性。
制备含有0.0%（对照）、0.1%和0.5% AgNPs的硅胶圆盘（M511；Technovent有限公司），并在含有适当培养基的24孔培养板中用金黄色葡萄球菌、白色念珠菌以及这两种菌的混合菌种菌株进行处理。每个孔接受0.1 mL标准化微生物悬液的等分试样。将培养板连续孵育21天，并在第1、3、5、7、15和21天用迈尔斯和米斯拉法测量每毫升菌落形成单位（CFU/mL）。通过双向方差分析和配对t检验分析数据，以评估AgNP浓度、微生物菌株和时间之间的关系（α = 0.05）。通过重复测量方差分析评估每个时间点和每种生物膜类别中平均CFU/mL的差异。
与对照相比，两种浓度的AgNPs均降低了平均CFU/mL。0.1%浓度在整个测试过程中显示出持续的疗效，而0.5%浓度最初具有高效，随后逐渐下降。然而，混合生物膜的结果不一致。在0.5%浓度下，除1组外，第3天与第15天以及第3天与第21天的配对样本t检验显示出统计学上显著不同的结果（P <.001）。双向混合方差分析显示所有组中AgNP浓度和时间之间存在统计学上显著的（P <.001）相互作用。AgNP浓度的单向方差分析在所有时间点均具有统计学上显著的差异（P <.001）。在所有三种生物膜的所有AgNP浓度组中，均发现时间对CFU/mL有统计学上显著的（P <.001）影响。
含有10纳米以下AgNPs的硅橡胶在体外对金黄色葡萄球菌、白色念珠菌以及混合菌种菌株具有抗菌性能。AgNPs（0.1%）对两种微生物菌株均有效，并可为进一步关于抗菌功效、银离子浸出和细胞内化的长期研究提供基线。混合菌种生物膜需要用标准化研究参数进行进一步探索。
