Vectorización de nanocarriers fotosensibilizados con potencial aplicación en terapia combinada para el tratamiento del cáncer.
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Date
2026
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Universidad de Concepción
Abstract
El cáncer es un conjunto de enfermedades que ha causado una alta tasa de mortalidad a nivel mundial, por lo que resulta de vital importancia desarrollar diversas estrategias de tratamiento debido al gran impacto que tiene en la sociedad. En ese sentido, el uso de nanomateriales ha surgido como un enfoque prometedor para el desarrollo de sistemas capaces de propiciar tratamientos combinados que mejoren la eficacia y superen las limitaciones de los tratamientos convencionales. Por lo anterior, en la presente tesis doctoral se obtuvieron nanotransportadores basados en nanotubos de haloisita (HNT) y dendrímeros de poli-[amidoamina] (PAMAM) de cuarta generación modificados superficialmente con Chlorin e6 (Ce6) como agente fotodinámico y vectorizados con poli-[etilenglicol] funcionalizado con ácido fólico (PFOL) para generar sistemas que posean la capacidad de actuar como agentes nanotransportadores de fármacos (quimioterapia) y que posean la capacidad de inducir efecto fototóxico (terapia fotodinámica) mediante irradiación de luz LED en líneas celulares de cáncer que sobreexpresen el receptor de ácido fólico. La caracterización realizada en las distintas etapas de preparación de los nanomateriales confirma la obtención de HNT−Ce6−PFOL y de PAMAM−Ce6−PFOL. Los sistemas que poseen Ce6 inmovilizado covalentemente en su superficie evidenciaron la generación de ROS, específicamente 1O2 y ·OH bajo irradiación con luz LED visible a 150 mW cm−2. Los experimentos de encapsulación de doxorrubicina (DOX), como fármaco quimioterapéutico modelo, demostraron que las nanoestructuras encapsulan eficazmente el fármaco y que las formulaciones de DOX@HNT−Ce6−PFOL y DOX@PAMAM−Ce6−PFOL presentan una liberación dependiente del pH del medio simulado. Los perfiles de liberación se ajustaron a un modelo cinético de Korsmeyer-Peppas y se encontró que, en ambas formulaciones, la máxima liberación del fármaco ocurre a pH = 5.0.
Los experimentos de viabilidad celular in vitro con células HeLa y MCF−7 mostraron que los nanomateriales HNT−Ce6−PFOL y PAMAM−Ce6−PFOL no exhiben citotoxicidad intrínseca (oscuridad), mientras que bajo irradiación con luz LED visible (150 mW cm−2) manifiestan fototoxicidad en ambas líneas celulares. De ellos, la actividad fotodinámica fue mayor en el sistema PAMAM−Ce6−PFOL, donde se observaron valores de concentración inhibitoria media máxima (IC50) ~10 veces menores que en Ce6 libre. Para las formulaciones DOX@HNT−Ce6−PFOL y DOX@PAMAM−Ce6−PFOL se detectaron efectos quimiotóxicos en las células HeLa y MCF−7, con valores de IC50 significativamente inferiores a los del DOX libre, excepto en el sistema DOX@HNT−Ce6−PFOL en la línea MCF−7, donde no se observó una disminución de la viabilidad inferior al 60% a las concentraciones evaluadas. Los experimentos combinados de fotoquimiotoxicidad demostraron efectos sinérgicos en la reducción de la viabilidad de las células estudiadas, lo que indica que los sistemas DOX@HNT−Ce6−PFOL y DOX@PAMAM−Ce6−PFOL con fotosensibilizadores son plataformas prometedoras para su uso en terapia combinada y dirigida inducida por la irradiación con luz LED visible.
Cancer is a group of diseases that has caused a high mortality rate worldwide, making it vitally important to develop diverse treatment strategies due to its significant impact on society. In this regard, the use of nanomaterials has emerged as a promising approach to developing systems that enable combination therapies to improve efficacy and overcome the limitations of conventional treatments. Therefore, in this doctoral thesis, nanocarriers based on halloysite nanotubes (HNTs) and fourth-generation poly-[amidoamine] (PAMAM) dendrimers were obtained, surface-modified with Chlorin e6 (Ce6) as a photodynamic agent and vectorized with folic acid-functionalized poly-[ethylene glycol] (PFOL). These systems were designed to act as drug nanocarriers (chemotherapy) and to induce a phototoxic effect (photodynamic therapy) through LED light irradiation in cancer cell lines that overexpress the folic acid receptor. The characterization performed at the different stages of nanomaterial preparation confirms the production of HNT−Ce6−PFOL and PAMAM−Ce6−PFOL. Systems with Ce6 covalently attached to their surface produced ROS, specifically 1O2 and ·OH under visible LED light at 150 mW cm−2. Experiments with doxorubicin (DOX) encapsulation, using it as a model chemotherapeutic, showed that the nanostructures effectively loaded the drug. Additionally, the DOX@HNT−Ce6−PFOL and DOX@PAMAM−Ce6−PFOL formulations display pH-dependent release in the simulated medium. The release profiles were fitted to a Korsmeyer-Peppas kinetic model, and it was found that, in both formulations, maximum drug release occurs at pH = 5.0. In vitro cell viability experiments with HeLa and MCF−7 cells showed that the HNT−Ce6−PFOL and PAMAM−Ce6−PFOL nanomaterials do not exhibit intrinsic cytotoxicity (darkness), while under irradiation with visible LED light (150 mW cm−2) they exhibit phototoxicity in both cell lines. Among these, the PAMAM−Ce6−PFOL system exhibited greater photodynamic activity, with maximum mean IC50 values approximately ten times lower than those of free Ce6. Chemotoxic effects were detected in HeLa and MCF−7 cells for the DOX@HNT−Ce6−PFOL and DOX@PAMAM−Ce6−PFOL formulations, with IC50 values significantly lower than those of free DOX, except in the DOX@HNT−Ce6−PFOL system in the MCF−7 cell line, where no viability reduction of less than 60% was observed at the evaluated concentrations. Combined photochemotoxicity experiments demonstrated synergistic effects in reducing the viability of the studied cells, indicating that the DOX@HNT−Ce6−PFOL and DOX@PAMAM−Ce6−PFOL systems with photosensitizers are promising platforms for use in combination and targeted therapy induced by visible LED irradiation.
Cancer is a group of diseases that has caused a high mortality rate worldwide, making it vitally important to develop diverse treatment strategies due to its significant impact on society. In this regard, the use of nanomaterials has emerged as a promising approach to developing systems that enable combination therapies to improve efficacy and overcome the limitations of conventional treatments. Therefore, in this doctoral thesis, nanocarriers based on halloysite nanotubes (HNTs) and fourth-generation poly-[amidoamine] (PAMAM) dendrimers were obtained, surface-modified with Chlorin e6 (Ce6) as a photodynamic agent and vectorized with folic acid-functionalized poly-[ethylene glycol] (PFOL). These systems were designed to act as drug nanocarriers (chemotherapy) and to induce a phototoxic effect (photodynamic therapy) through LED light irradiation in cancer cell lines that overexpress the folic acid receptor. The characterization performed at the different stages of nanomaterial preparation confirms the production of HNT−Ce6−PFOL and PAMAM−Ce6−PFOL. Systems with Ce6 covalently attached to their surface produced ROS, specifically 1O2 and ·OH under visible LED light at 150 mW cm−2. Experiments with doxorubicin (DOX) encapsulation, using it as a model chemotherapeutic, showed that the nanostructures effectively loaded the drug. Additionally, the DOX@HNT−Ce6−PFOL and DOX@PAMAM−Ce6−PFOL formulations display pH-dependent release in the simulated medium. The release profiles were fitted to a Korsmeyer-Peppas kinetic model, and it was found that, in both formulations, maximum drug release occurs at pH = 5.0. In vitro cell viability experiments with HeLa and MCF−7 cells showed that the HNT−Ce6−PFOL and PAMAM−Ce6−PFOL nanomaterials do not exhibit intrinsic cytotoxicity (darkness), while under irradiation with visible LED light (150 mW cm−2) they exhibit phototoxicity in both cell lines. Among these, the PAMAM−Ce6−PFOL system exhibited greater photodynamic activity, with maximum mean IC50 values approximately ten times lower than those of free Ce6. Chemotoxic effects were detected in HeLa and MCF−7 cells for the DOX@HNT−Ce6−PFOL and DOX@PAMAM−Ce6−PFOL formulations, with IC50 values significantly lower than those of free DOX, except in the DOX@HNT−Ce6−PFOL system in the MCF−7 cell line, where no viability reduction of less than 60% was observed at the evaluated concentrations. Combined photochemotoxicity experiments demonstrated synergistic effects in reducing the viability of the studied cells, indicating that the DOX@HNT−Ce6−PFOL and DOX@PAMAM−Ce6−PFOL systems with photosensitizers are promising platforms for use in combination and targeted therapy induced by visible LED irradiation.
Description
Tesis presentada para optar al grado de Doctor/a en Ciencias con mención en Química.
Keywords
Cáncer, Quimioterapia, Fotoquimioterapia, Nanotubos, Dendrímeros, Nanomedicina, Nanociencia