Browsing by Author "Zúñiga Nuñez, Daniel"

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    Bioconjugates of toluidine blue derivatives with human serum albumin and their complexes with cucurbit[7]uril as drug delivery vehicles for photodynamic therapy
    (2025) Mariño Ocampo, Nory Johana; Duggon, José Robinson; Zúñiga Nuñez, Daniel; Daniel Guerra Díaz; Heyne, Belinda; Fuentealba Patino, Denis Alberto
    Photodynamic therapy (PDT) is a promising cancer treatment. The present work used two toluidine blue O (TBO) derivatives covalently conjugated to human serum albumin (HSA) as a drug delivery system and bound to cucurbit[7]uril (CB[7]) as a protective nanocapsule in order to study their effect of cellular uptake and phototoxicity in HeLa cells. This study explored covalent and noncovalent interactions with the delivery systems, including HSA-PS@CB[7] complexes, to optimize PDT efficacy. Supramolecular complexes between TBO derivatives and CB[7] exhibited high binding affinities, significantly improving the photophysical properties of the photosensitizers. In vitro studies in cancer cells demonstrated that HSA covalently bound to TBO derivatives led to significant increases in cellular uptake and was strongly influenced by the type of conjugation (disulfide bond versus thia-Michael adduct). The results suggest that combining the properties of HSA as a carrier and CB[7] as a protective nanocapsule could be exploited for improved PDT applications.
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    Memantine biotin conjugate with intra tumoral cell displacing ability for cucurbit[8]uril-based switchable photosensitizer
    (Elsevier B.V., 2025) González Torres, Diego Ariel; Zúñiga Nuñez, Daniel; Mariño Ocampo, Nory Johana; Díaz Canals, Martin Rodrigo; Muñoz, Constanza; Guerra Díaz, Daniel; Soto Arriaza, Marco; Fuentealba, Denis
    Switchable supramolecular photosensitizers have the potential to be more potent and decrease common side effects of photodynamic therapy such as patient's sensitivity to ambient light. Combining this supramolecular strategy with a cancer-targeting strategy would also improve selectivity towards tumoral cells. In this work, we take advantage of the strong binding ability of cucurbit[8]uril towards cationic photosensitizer methylene blue. Encapsulation of two molecules of methylene blue inside the cavity of cucurbit[8]uril leads to strong quenching of its photoactivity, particularly the generation of singlet oxygen. In order to release selectively the photosensitizer, we synthesized a new memantine-biotin conjugate that is able to cross a liposomal bilayer as a model for a biological membrane and bind to cucurbit[8]uril releasing the photosensitizer. This phenomenon leads to a sizable boost in singlet oxygen generation. In vitro phototoxicity studies in tumoral cells show a significant difference in cell killing after the addition of the memantine-biotin displacing agent. These studies have important potential for more selective photodynamic therapy of cancer.