RESUMO
Glioblastoma (GBM) is the most aggressive malignant brain tumor and has a high mortality rate. Photodynamic therapy (PDT) has emerged as a promising approach for the treatment of malignant brain tumors. However, the use of PDT for the treatment of GBM has been limited by its low blood‒brain barrier (BBB) permeability and lack of cancer-targeting ability. Herein, brain endothelial cell-derived extracellular vesicles (bEVs) were used as a biocompatible nanoplatform to transport photosensitizers into brain tumors across the BBB. To enhance PDT efficacy, the photosensitizer chlorin e6 (Ce6) was linked to mitochondria-targeting triphenylphosphonium (TPP) and entrapped into bEVs. TPP-conjugated Ce6 (TPP-Ce6) selectively accumulated in the mitochondria, which rendered brain tumor cells more susceptible to reactive oxygen species-induced apoptosis under light irradiation. Moreover, the encapsulation of TPP-Ce6 into bEVs markedly improved the aqueous stability and cellular internalization of TPP-Ce6, leading to significantly enhanced PDT efficacy in U87MG GBM cells. An in vivo biodistribution study using orthotopic GBM-xenografted mice showed that bEVs containing TPP-Ce6 [bEV(TPP-Ce6)] substantially accumulated in brain tumors after BBB penetration via transferrin receptor-mediated transcytosis. As such, bEV(TPP-Ce6)-mediated PDT considerably inhibited the growth of GBM without causing adverse systemic toxicity, suggesting that mitochondria are an effective target for photodynamic GBM therapy.
RESUMO
By the third week of June 2020, more than 8,500,000 positive cases of COVID-19 and more than 450,000 deaths had been officially reported worldwide. The COVID-19 pandemic arrived in Latin America, India, and Africa--territories in which the mounted infrastructure for diagnosis is greatly underdeveloped. Here, we demonstrate the combined use of a three-dimensional (3D)-printed incubation chamber for commercial Eppendorf PCR tubes, and a colorimetric embodiment of a loop-mediated isothermal amplification (LAMP) reaction scheme for the detection of SARS-CoV-2 nucleic acids. We used this strategy to detect and amplify SARS-CoV-2 genetic sequences using a set of in-house designed initiators that target regions encoding the N protein. We were able to detect and amplify SARS-CoV-2 nucleic acids in the range of 62 to 2 x 105 DNA copies by this straightforward method. Using synthetic SARS-CoV-2 samples and a limited number of RNA extracts from patients, we also demonstrate that colorimetric LAMP is a quantitative method comparable in diagnostic performance to RT-qPCR. We envision that LAMP may greatly enhance the capabilities for COVID-19 testing in situations where RT-qPCR is not feasible or is unavailable. Moreover, the portability, ease of use, and reproducibility of this strategy make it a reliable alternative for deployment of point-of-care SARS-CoV-2 detection efforts during the pandemics.
