A curcumin-sophorolipid nanocomplex inhibits Candida albicans filamentation and biofilm development

Candida albicans is an opportunistic fungal pathogen that is highly resistant to contemporary antifungals, due to their biofilm lifestyle. The ability of C. albicans to invade human tissues is due to its filamentation. Therefore, inhibition of biofilms and filamentation of the yeast are high value targets to develop the next-generation antifungals. Curcumin (CU) is a natural polyphenol with excellent pharmacological attributes, but limitations such as poor solubility, acid, and enzyme tolerance have impeded its practical utility. Sophorolipids (SL) are biologically-derived surfactants that serve as efficient carriers of hydrophobic molecules such as curcumin into biofilms. Here, we synthesized a curcumin-sophorolipid nanocomplex (CU-SL), and comprehensively evaluated its effects on C. albicans biofilms and filamentation. Our results demonstrated that sub-inhibitory concentration of CU-SL (9.37 µg/mL) significantly inhibited fungal adhesion to substrates, and subsequent biofilm development, maturation, and filamentation. This effect was associated with significant downregulation of a select group of biofilm, adhesins, and hyphal regulatory genes. In conclusion, the curcumin-sophorolipid nanocomplex is a potent inhibitor of the two major virulence attributes of C. albicans, biofilm formation and filamentation, thus highlighting its promise as a putative anti-fungal agent with biofilm penetrative potential

Trans-Cinnamaldehyde Eluting Porous Silicon Microparticles Mitigate Cariogenic Biofilms

Dental caries, a preventable disease, is caused by highly-adherent, acid-producing biofilms composed of bacteria and yeasts. Current caries-preventive approaches are ineffective in controlling biofilm development. Recent studies demonstrate definite advantages in using natural compounds such as trans-cinnamaldehyde in thwarting biofilm assembly, and yet, the remarkable difficulty in delivering such hydrophobic bioactive molecules prevents further development. To address this critical challenge, we have developed an innovative platform composed of components with a proven track record of safety. We fabricated and thoroughly characterised porous silicon (pSi) microparticles to carry and deliver the natural phenyl propanoid trans-cinnamaldehyde (TC). We investigated its effects on preventing the development of cross-kingdom biofilms (Streptococcus mutans and Candida albicans), typical of dental caries found in children. The prepared pSi microparticles were roughly cubic in structure with 70–75% porosity, to which the TC (pSi-TC) was loaded with about 45% efficiency. The pSi-TC particles exhibited a controlled release of the cargo over a 14-day period. Notably, pSi-TC significantly inhibited biofilms, specifically downregulating the glucan synthesis pathways, leading to reduced adhesion to the substrate. Acid production, a vital virulent trait for caries development, was also hindered by pSi-TC. This pioneering study highlights the potential to develop the novel pSi-TC as a dental caries-preventive material