No abstract

Oral candidiasis as a highly prevalent and recurrent infection in medically compromised individuals is mainly caused by the opportunistic fungal pathogen Candida albicans. This epithelial infection, if not controlled effectively, can progress to life-threatening systemic conditions and complications. The efficacy of current frontline antifungals is limited due to their poor bioavailability and systemic toxicity. As such, an efficient intervention is essential for controlling disease progression and recurrence. Herein, a theranostic nanoplatform (CD-Gu+-AmB) was developed to track the penetration of antifungals and perturb the invasion of C. albicans at oral epithelial tissues, via decorating the homemade red-emissive carbon dots (CD) with positively charged guanidine groups (Gu+) followed by conjugation with antifungal polyene (amphotericin B, AmB) in a reacting site-controllable manner. The generated CD-Gu+-AmB favorably gathered within the Candida cells and exhibited potent antifungal effects in both planktonic and biofilm forms. It selectively accumulated in the nuclei of human oral keratinocytes and exhibited undetectable toxicity to the host cells. Moreover, we reported for the first time the penetration and exfoliation profiles of CD in a three-dimensional organotypic model of human oral epithelial tissues, demonstrating that the extra- and intracellular accumulation of CD-Gu+-AmB effectively resisted the invasion of C. albicans by forming a “shielding” layer throughout the entire tissue. This study establishes a multifunctional CD-based theranostic nanoplatform functioning as a traceable and topically applied antifungal to arm oral epithelia, thereby shedding light on early intervention of mucosal candidiasis for oral and general health.

A novel BODIPY-based fluorescent sensor PS was designed for imaging Pt2+, cisplatin and nedaplatin in aqueous medium and biological environments, providing great potential for studying the Pt-drug metabolism and the development of new platinum drugs.

We report herein the G-quadruplex-selective property of a luminescent cyclometallated iridium(III) complex for the detection of adenosine-5′-triphosphate (ATP) in aqueous solution. The ATP-binding aptamer was employed as the ATP recognition unit, while the iridium(III) complex was used to monitor the formation of the G-quadruplex structure induced by ATP. The sensitivity and fold enhancement of the assay were higher than those of the previously reported assay using the organic dye crystal violet as a fluorescent probe. This label-free luminescent switch-on assay exhibits high sensitivity and selectivity towards ATP with a limit of detection of 2.5 µM.