Chittratan Pakawat, Chalitangkoon Jongjit, Wongsariya Karn, Mathaweesansurn Arjnarong, Detsri Ekarat, Monvisade Pathavuth
Department of Chemistry, School of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
Polymer Synthesis and Functional Materials Research Unit, School of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
ACS Omega. 2022 Jul 19;7(30):26582-26590. doi: 10.1021/acsomega.2c02776. eCollection 2022 Aug 2.
Chitosan-grafted thymol (CST) coated on gold nanoparticles has been synthesized and characterized for the design of antimicrobial materials. CST was synthesized via adapting the Mannich reaction, and it acted as the capping agent for the synthesis of gold nanoparticles (AuNPs). The grafting of thymol onto the side chain of chitosan has provided a degree of substitution value (%DS) of 10.0%, calculated by nuclear magnetic resonance spectroscopy. UV-visible spectrometry and elemental analysis were used to confirm the successful synthesis of CST through adapting the Mannich reaction. The appropriate concentration of CST for AuNP synthesis was found to be 0.020%w/v. A red-wine colloidal AuNP solution of 2.41-3.30 nM particle size exhibits a strong surface plasmon resonance at 502 nm, which shows negative charges at pH = 9 of -36.37 mV. This result evidenced that the AuNPs showed electrostatic repulsion and CST played a role as a capping agent to provide a good dispersion and stability state. CST coated on the AuNP surface was successfully utilized for the control of cariogenic bacteria in the oral cavity. The results obtained from this study show that the tuning of the capping agent used in the synthesis step strongly influences the latter antimicrobial activity of the nanoparticles against ATCC 25175 and ATCC 33402 activity, with an inhibition zone of 15.90 and 14.25 mm, respectively. The average minimum inhibitory concentration values against ATCC 25175 and ATCC 33402 were found to be 25 and 100 mg/L, respectively, whereas the minimum bactericidal concentration values were 100 and 200 mg/L, respectively.
已合成了包覆在金纳米颗粒上的壳聚糖接枝百里酚（CST），并对其进行了表征，用于抗菌材料的设计。CST通过曼尼希反应合成，它作为合成金纳米颗粒（AuNPs）的封端剂。通过核磁共振光谱法计算，百里酚接枝到壳聚糖侧链上的取代度值（%DS）为10.0%。利用紫外-可见光谱法和元素分析来确认通过曼尼希反应成功合成了CST。发现用于AuNP合成的CST的合适浓度为0.020%w/v。粒径为2.41 - 3.30 nM的红酒色胶体AuNP溶液在502 nm处表现出强烈的表面等离子体共振，在pH = 9时显示出 - 36.37 mV的负电荷。该结果证明AuNPs表现出静电排斥，CST作为封端剂起到了提供良好分散和稳定状态的作用。包覆在AuNP表面的CST成功用于控制口腔中的致龋菌。本研究获得的结果表明，合成步骤中使用的封端剂的调整强烈影响纳米颗粒对ATCC 25175和ATCC 33402的抗菌活性，其抑菌圈分别为15.90和14.25 mm。发现对ATCC 25175和ATCC 33402的平均最低抑菌浓度值分别为25和100 mg/L，而最低杀菌浓度值分别为100和200 mg/L。
