Fungal infections represent a significant global health challenge. Candida albicans is a particularly widespread pathogen, with both molecular and biofilm-based mechanisms making it resistant to or tolerant of available antifungal drugs. This study reports a combination therapy, active against C. albicans, utilizing terbinafine and essential oils incorporated into a gelatin-based nanoemulsion system (T-GNE). Eugenol and methyl eugenol/terbinafine T-GNEs had an additive efficacy, while carvacrol (CT-GNE) worked synergistically with terbinafine, providing effective antifungal treatment with minimal mammalian cell toxicity. Confocal microscopy demonstrated that CT-GNE penetrated the dense C. albicans biofilm and disrupted the fungal cell membrane. Overall, the combination of essential oils with terbinafine in GNE provided a promising treatment for fungal biofilms.

Macrophages are multifunctional immune cells essential for both innate and adaptive immune responses. Tumor-associated macrophages (TAMs) often adopt a tumor-promoting M2-like phenotype, aiding tumor progression and immune evasion. Reprogramming TAMs to a tumoricidal M1-like phenotype is an emerging target for cancer immunotherapy. Resiquimod, a TLR7/8 agonist, can repolarize macrophages from the M2- to M1-like phenotype but is limited by poor solubility. We developed a gelatin nanoemulsion for the loading and delivery of resiquimod, utilizing eugenol oil as the liquid phase and riboflavin-crosslinked gelatin as a scaffold. These nanoemulsions showed high stability, low toxicity, and effective macrophage repolarization, significantly enhancing pro-inflammatory markers and anticancer activity in co-culture models.

Multi-drug-resistant (MDR) bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), pose a significant challenge in healthcare settings. Small molecule antimicrobials (SMAs) such as α-pyrones have shown promise as alternative treatments for MDR infections. However, the hydrophobic nature of many SMAs limits their solubility and efficacy in complex biological environments. In this study, we encapsulated pseudopyronine analogs (PAs) in biodegradable polymer nanoemulsions (BNEs) for efficient eradication of biofilms. We evaluated a series of PAs with varied alkyl chain lengths and examined their antimicrobial activity against Gram-positive pathogens (S. aureus, MRSA, and B. subtilis). The selected PA with the most potent antibiofilm activity was incorporated into BNEs for enhanced solubility and penetration into the EPS matrix (PA-BNEs). The antimicrobial efficacy of PA-BNEs was assessed against biofilms of Gram-positive strains. The BNEs facilitated the solubilization and effective delivery of the PA deep into the biofilm matrix, addressing the limitations of hydrophobic SMAs. Our findings demonstrated that the PA2 exhibited synergistic antibiofilm activity when it was loaded into nanoemulsions. This study presents a promising platform for addressing MDR infections by combining pseudopyronine analogs with antimicrobial biodegradable nanoemulsions, overcoming challenges associated with treating biofilm infections.