Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-903, São Paulo, Brazil.
Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-903, São Paulo, Brazil.
Molecules. 2019 May 10;24(9):1808. doi: 10.3390/molecules24091808.
(1) Background: The effectiveness of chitosan to improve the action of antimicrobial compounds against planktonic bacteria and young biofilms has been widely investigated in Dentistry, where the biofilm lifecycle is a determining factor for the success of antibacterial treatment. In the present study, mature biofilms were treated with chitosan dispersion (CD) or chitosan microparticles (CM). (2) Methods: CD at 0.25% and 1% were characterized by texture analysis, while CD at 2% was spray-dried to form CM, which were characterized with respect to particle size distribution, zeta potential, and morphology. After determining the minimum inhibitory and bactericidal concentrations, biofilms were grown on glass slides exposed 8×/day to 10% sucrose and 2×/day to CD or CM at 0.25% and 1%. Biofilm viability and acidogenicity were determined, using appropriate control groups for each experiment. (3) Results: CD had high viscosity and CM were spherical, with narrow size distribution and positive zeta potential. CM affected bacterial viability and acidogenicity in mature biofilms more strongly than CD, especially at 1%. (4) Conclusions: Both chitosan forms exerted antimicrobial effect against mature biofilms. CM at 1% can reduce bacterial viability and acidogenicity more effectively than CD at 1%, and thereby be more effective to control the growth of mature biofilms in vitro.
（1）背景：壳聚糖提高抗菌化合物对浮游细菌和年轻生物膜作用的有效性在牙科领域得到了广泛研究，生物膜生命周期是抗菌治疗成功的决定因素。在本研究中，成熟生物膜用壳聚糖分散体（CD）或壳聚糖微球（CM）处理。（2）方法：用质构分析对 0.25%和 1%的 CD 进行了表征，2%的 CD 经喷雾干燥形成 CM，对其粒径分布、zeta 电位和形态进行了表征。在确定最小抑菌和杀菌浓度后，将生物膜在玻片上生长，每天暴露 8 次 10%蔗糖，每天 2 次用 0.25%和 1%的 CD 或 CM 处理。使用每个实验的适当对照组，测定生物膜的存活能力和产酸能力。（3）结果：CD 具有高粘度，CM 呈球形，粒径分布较窄，zeta 电位为正。CM 对成熟生物膜中的细菌存活能力和产酸能力的影响比 CD 更强烈，尤其是在 1%时。（4）结论：两种壳聚糖形式都对成熟生物膜发挥了抗菌作用。1%的 CM 比 1%的 CD 更有效地降低细菌的存活能力和产酸能力，从而更有效地控制体外成熟生物膜的生长。
