As sessile cells of fungal biofilms are at least 500-fold more resistant to antifungal drugs than their planktonic counterparts, there is a requirement for new antifungal agents. Olygostyrylbenzenes (OSBs) are the first generation of poly(phenylene)vinylene dendrimers with a gram-positive antibacterial activity. Thus, this study aimed to investigate the antifungal activity of four OSBs (1, 2, 3, and 4) on planktonic cells and biofilms of Candida tropicalis. The minimum inhibitory concentration (MIC) for the planktonic population and the sessile minimum inhibitory concentrations (SMIC) were determined. Biofilm eradication was studied by crystal violet stain and light microscopy (LM), and confocal laser scanning microscopy (CLSM) was also utilized in conjunction with the image analysis software COMSTAT. Although all the OSBs studied had antifungal activity, the cationic OSBs were more effective than the anionic ones. A significant reduction of biofilms was observed at MIC and supraMIC50 (50 times higher than MIC) for compound 2, and at supraMIC50 with compound 3. Alterations in surface topography and the three-dimensional architecture of the biofilms were evident with LM and CLSM. The LM analysis revealed that the C. tropicalis strain produced a striking biofilm with oval blastospores, pseudohyphae, and true hyphae. CLSM images showed that a decrease occurred in the thickness of the mature biofilms treated with the OSBs at the most effective concentration for each one. The results obtained by microscopy were supported by those of the COMSTAT program. Our results revealed an antibiofilm activity, with compound 2 being a potential candidate for the treatment of C. tropicalis infections.

中文翻译：

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寡苯乙烯基苯化合物对热带念珠菌生物膜的新型抗真菌活性。

由于真菌生物膜的固着细胞对抗真菌药物的抗药性至少是浮游生物的 500 倍，因此需要新的抗真菌药物。聚苯乙烯基苯 (OSB) 是具有革兰氏阳性抗菌活性的第一代聚苯撑乙烯树枝状大分子。因此，本研究旨在研究四种 OSB（1、2、3 和 4）对热带念珠菌浮游细胞和生物膜的抗真菌活性. 确定了浮游种群的最低抑菌浓度 (MIC) 和固着最低抑菌浓度 (SMIC)。通过结晶紫染色和光学显微镜 (LM) 研究生物膜的根除，并结合图像分析软件 COMSTAT 使用共聚焦激光扫描显微镜 (CLSM)。尽管研究的所有 OSB 都具有抗真菌活性，但阳离子 OSB 比阴离子 OSB 更有效。在化合物 2 的 MIC 和 supraMIC50（比 MIC 高 50 倍）和化合物 3 的 supraMIC50 下观察到生物膜的显着减少。LM 和 CLSM 的表面形貌和生物膜的三维结构的变化是明显的。LM 分析显示，C.tropicalis菌株产生了具有椭圆形胚芽、假菌丝和真菌丝的引人注目的生物膜。CLSM 图像显示，用 OSB 以最有效浓度处理的成熟生物膜的厚度发生了减少。通过显微镜获得的结果得到了 COMSTAT 程序的支持。我们的结果揭示了一种抗生物膜活性，化合物 2 是治疗热带念珠菌感染的潜在候选者。