Navegando por Autor "Siqueira, Raoni Pais"

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In vitro interaction of polyethylene glycol‐block‐poly (D,L‐lactide) nanocapsule devices with host cardiomyoblasts and trypanosoma cruzi‐infective forms.
(2022) Siqueira, Raoni Pais; Milagre, Matheus Marques; Oliveira, Maria Alice de; Branquinho, Renata Tupinambá; Torchelsen, Fernanda Karoline Vieira da Silva; Lana, Marta de; Machado, Marina Guimarães Carvalho; Andrade, Margareth Spangler; Bahia, Maria Terezinha; Mosqueira, Vanessa Carla Furtado
Chagas disease, caused by the protozoan Trypanosoma cruzi, is an important public health problem in Latin America. Nanoencapsulation of anti-T. cruzi drugs has signifcantly improved their efcacy and reduced cardiotoxicity. Thus, we investigated the in vitro interaction of polyethylene glycol-block-poly(D,L-lactide) nanocapsules (PEG-PLA) with trypomas- tigotes and with intracellular amastigotes of the Y strain in cardiomyoblasts, which are the infective forms of T. cruzi, using fuorescence and confocal microscopy. Fluorescently labeled nanocapsules (NCs) were internalized by non-infected H9c2 cells toward the perinuclear region. The NCs did not induce signifcant cytotoxicity in the H9c2 cells, even at the highest concentrations and interacted equally with infected and non-infected cells. In infected cardiomyocytes, NCs were distrib- uted in the cytoplasm and located near intracellular amastigote forms. PEG-PLA NCs and trypomastigote form interactions also occurred. Altogether, this study contributes to the development of engineered polymeric nanocarriers as a platform to encapsulate drugs and to improve their uptake by diferent intra- and extracellular forms of T. cruzi, paving the way to fnd new therapeutic strategies to fght the causative agent of Chagas disease.
Lipid-based nanocarriers co-loaded with artemether and triglycerides of docosahexaenoic acid : effects on human breast cancer cells.
(2020) Lanna, Elisa Gomes; Siqueira, Raoni Pais; Machado, Marina Guimarães Carvalho; Souza, Aline de; Trindade, Izabel Cristina; Branquinho, Renata Tupinambá; Mosqueira, Vanessa Carla Furtado
Artemether (ART) was combined with triglyceride of docosahexaenoic acid (DHA) as the lipid-core in nano emulsions (NE), nanostructured lipid carriers (NLC), and PEG-PLA nanocapsules (NC) formulations, and their effects on human breast cancer cells were evaluated. ART has been extensively used for malaria and has also therapeutic potential against different tumor cells in a repositioning strategy. The concentration-dependent cytotoxicity in vitro was determined in tumor lineages, MDA-MB-231 and MCF-7, and non-tumor MCF-10A cells for free-ART/DHA combination and its formulations. The cells were monitored for viability, effects on cell migration and clonogenicity, cell death mechanism, and qualitative and quantitative cell uptake of nanocarriers. The lipid-nanocarriers showed mean sizes over the range of 110 and 280 nm with monodisperse populations and zeta potential values ranging from − 21 to − 67 mV. The ART encapsulation efficiencies varied from 57 to 83 %. ART/DHA co-loaded in three different lipid nanocarriers reduced the MDA-MB-231 and MCF-7 viability in a dose-dependent manner with enhanced selectivity toward tumor cell lines. They also reduced clonogenicity and the ability of cells to migrate showing antimetastatic potential in both cell lines and triggered apoptosis in MCF-7 cells. Confocal microscopy and flow cytometry analysis showed that NC, NLC, and NE were rapidly internalized by cells, with higher interaction displayed by NE with MCF-7 cells compared to NC and NLC that was correlated with the strongest NE-fluorescence in cells. Therefore, this study not only demonstrated the value of this new combination of ART/DHA as a new strategy for breast cancer therapy but also showed enhanced cytotoxicity and potential metastatic activity of lipid-based formulations against human breast cancer cells that indicate great potential for pre-clinical and clinical translation.
Photodynamic therapy with the dual-mode association of IR780 to PEG-PLA nanocapsules and the effects on human breast cancer cells.
(2022) Machado, Marina Guimarães Carvalho; Oliveira, Maria Alice de; Lanna, Elisa Gomes; Siqueira, Raoni Pais; Lana, Gwenaelle Elza Nathalie Pound; Branquinho, Renata Tupinambá; Mosqueira, Vanessa Carla Furtado
IR780 is a near-infrared fluorescent dye, which can be applied as a photosensitizer in photodynamic (PDT) and photothermal (PTT) therapies and as a biodistribution tracer in imaging techniques. We investigated the growth and migration inhibition and mechanism of death of breast tumor cells, MCF-7 and MDA-MB-231, exposed to polymeric nanocapsules (NC) comprising IR780 covalently linked to the biodegradable polymer PLA (IR-PLA) and IR780 physically encapsulated (IR780-NC) in vitro. Both types of NC had mean diameters around 120 nm and zeta potentials around − 40 mV. IR-PLA-NC was less cytotoxic than IR780 NC to a non-tumorigenic mammary epithelial cell line, MCF-10A, which is an important aspect of selectivity. Free-IR780 was more cytotoxic than IR- PLA-NC for MCF-7 and MDA-MB-231 cells after illumination with a 808 nm laser. IR-PLA NC was effective to inhibit colony formation (50%) and migration (30–40%) for both cancer cell lines. MDA-MB-231 cells were less sensitive to all IR780 formulations compared to MCF-7 cells. Cell uptake was higher with IR-PLA-NC than with IR780-NC and free-IR780 in both cancer cell lines (p < 0.05). NC uptake was higher in MCF-7 than in MDA-MB- 231 cells. IR-PLA-NC induced a higher percentage of apoptosis upon illumination in MDA-MB-231 than in MCF-7 cells. The necrosis mechanism of death predominated in treatments with free-IR780 and with encapsulated IR780 NC, suggestive of damages at the plasma membrane. IR780 conjugated with PLA increased the apoptotic pathway and demonstrated potential as a multifunctional theranostic agent for breast cancer treatment with increased cellular uptake, photodynamic activity and more reliable tracking in cell-image studies.
PLA-b-SMA as an amphiphilic diblock copolymer for encapsulation of lipophilic cargo.
(2023) Ball, Lauren Elizabeth; Pfukwa, Rueben; Siqueira, Raoni Pais; Mosqueira, Vanessa Carla Furtado; Klumperman, Bert
The encapsulation of active pharmaceutical ingredients (APIs) within drug delivery systems such as polymeric nanoparticles (PNPs) vastly improves the therapeutic efficiency of the incorporated APIs. PNPs synthesized using amphiphilic block copolymers are efficient drug delivery systems as the hydrophobic block facilitates the encapsulation of lipophilic components and the hydrophilic block constitutes the hairy corona of the PNP that stabilizes the nanocarriers against aggregation in solution. Poly(styrene-alt-maleic acid) (SMA) is an attractive polymer for the hydrophilic corona of PLA-based nanoparticles as it allows for post polymerization functionalization and aids in the prevention of NP aggregation. The synthesis of a novel PLA-b-SMA block copolymer, via sequential ring opening polymerization (ROP) and reversible addition–fragmentation chain transfer (RAFT) polymerization, is presented. PLA macro-CTAs, synthesized via ROP, can be chain extended via RAFT copolymerization of styrene and maleic anhydride to yield PLA-b-SMAnh and via RAFT polymerization of N-vinylpyrrolidone to yield PLA-b-PVP block copolymers. Controlled hydrolysis of the anhydride moieties converts PLA-b-SMAnh into PLA-b-SMA. Monodisperse PLA-b-SMA and PLA-b-PVP nanoparticles (NPs) ranging in diameter between 60 and 220 nm are prepared. The lipophilic fluorescent dye DiI is encapsulated within the NPs successfully and these fluorescent NPs are used in a preliminary cell uptake study.