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Guimarães, Rafaela

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  • Overview of stimuli-responsive mesoporous organosilica nanocarriers for drug delivery
    Publication . Guimarães, Rafaela; Rodrigues, Ana Carolina Félix; Moreira, André F.; Correia, I.J.
    The application of nanomaterials is regarded nowadays as a highly promising approach for overcoming the limitations of the currently available cancer treatments, contributing for the creation of more effective, precise, and safer therapies. In the last years, organosilica nanoparticles arisen as alternatives to the most common mesoporous silica nanoparticles. The organosilica nanoparticles combine the advantages of the mesoporous silica, such as structural stability and mesoporous structure, with the increased biocompatibility and biodegradability of organic materials. Therefore, the variety of organic bridges that can be incorporated into the silica matrix allowed the development of new and exciting compositions, properties, and functions for improving the therapeutic effectiveness of the anticancer nanomedicines. In this review, the strategies that have been explored to create stimuli-responsive organosilica-based drug delivery systems are highlighted, describing the practical approaches and mechanisms controlling the drug release. Additionally, the organosilica nanoparticles surface modifications aimed for increasing the blood circulation time and the tumor targeting are also described.
  • Combinatorial delivery of doxorubicin and acridine orange by gold core silica shell nanospheres functionalized with poly(ethylene glycol) and 4- methoxybenzamide for cancer targeted therapy
    Publication . Guimarães, Rafaela; Rodrigues, Ana Carolina Félix; Fernandes, Natanael; Diogo, Duarte de Melo; Ferreira, Paula; Correia, I.J.; Moreira, André F.
    Combinatorial therapies based on the simultaneous administration of multiple drugs can lead to synergistic effects, increasing the efficacy of the cancer therapy. However, it is crucial to develop new delivery systems that can increase the drugs' therapeutic selectivity and efficacy. Gold core silica shell (AuMSS) nanoparticles present physicochemical properties that allow their simultaneous application as drug delivery and imaging agents. Herein, poly(ethylene glycol) was modified with 4-methoxybenzamide and 3- (triethoxysilyl)propyl isocyanate (TPANIS) to create a novel surface functionalization capable of improving the colloidal stability and specificity of AuMSS nanospheres towards cancer cells. Moreover, a dual drug combination based on Doxorubicin (DOX) and Acridine orange (AO) was characterized and administered using the AuMSS-TPANIS nanospheres. The obtained results show that the DOX:AO drug combination can mediate a synergistic therapeutic effect in both HeLa and MCF-7 cells, particularly at the 2:1, 1:1, and 1:2 ratios. Otherwise, the TPANIS functionalization increased the AuMSS nanospheres colloidal stability and selectivity towards MCF-7 cancer cells (overexpressing sigma receptors). Such also resulted in an enhanced cytotoxic effect against MCF-7 cells when administering the DOX:AO drug combination with the AuMSSTPANIS nanospheres. Overall, the obtained results confirm the therapeutic potential of the DOX:AO drug combination as well as the targeting capacity of AuMSS-TPANIS, supporting its application in the cancer targeted combinatorial chemotherapy.