University of Madeira

About: University of Madeira is a education organization based out in Funchal, Portugal. It is known for research contribution in the topics: Population & Dendrimer. The organization has 1014 authors who have published 2759 publications receiving 59457 citations.

UTMD-Promoted Co-Delivery of Gemcitabine and miR-21 Inhibitor by Dendrimer-Entrapped Gold Nanoparticles for Pancreatic Cancer Therapy.

Abstract: Conventional chemotherapy of pancreatic cancer (PaCa) suffers the problems of low drug permeability and inherent or acquired drug resistance. Development of new strategies for enhanced therapy still remains a great challenge. Herein, we report a new ultrasound-targeted microbubble destruction (UTMD)-promoted delivery system based on dendrimer-entrapped gold nanoparticles (Au DENPs) for co-delivery of gemcitabine (Gem) and miR-21 inhibitor (miR-21i). Methods: In this study, Gem-Au DENPs/miR-21i was designed and synthesized. The designed polyplexes were characterized via transmission electron microscopy (TEM), Gel retardation assay and dynamic light scattering (DLS). Then, the optimum exposure parameters were examined by an ultrasound exposure platform. The cellular uptake, cytotoxicity and anticancer effects in vitro were analyzed by confocal laser microscopy, spectra microplate reader, flow cytometry and a chemiluminescence imaging system. Lastly, the anticancer effects in vivo were evaluated by contrast-enhanced ultrasound (CEUS), hematoxylin and eosin (H&E) staining, TUNEL staining and comparison of tumor volume. Results: The results showed that the Gem-Au DENPs/miR-21i can be uptake by cancer cells and the cellular uptake was further facilitated by UTMD with an ultrasound power of 0.4 W/cm2 to enhance the cell permeability. Further, the co-delivery of Gem and miR-21i with or without UTMD treatment displayed 82-fold and 13-fold lower IC50 values than the free Gem, respectively. The UTMD-promoted co-delivery of Gem and miR-21i was further validated by in vivo treatment and showed a significant tumor volume reduction and an increase in blood perfusion of xenografted pancreatic tumors. Conclusion: The co-delivery of Gem and miR-21i using Au DENPs can be significantly promoted by UTMD technology, hence providing a promising strategy for effective pancreatic cancer treatments.

Simultaneous Measurement for Strain and Temperature Based on a Long-Period Grating Combined With a High-Birefringence Fiber Loop Mirror

Abstract: This work presents an alternative solution for simultaneous measurement of strain and temperature. The sensing head is formed by a long-period fiber grating combined with a high-birefringence fiber loop mirror resulting in a configuration capable of temperature and strain discrimination. These optical devices have opposite sensitivity responses when a variation of temperature and/or strain is applied. Maximum errors of plusmn0.8degC and plusmn21muepsiv are reported over 60 degC and 700-muepsiv measurement ranges, respectively

Facile one-pot preparation, surface functionalization, and toxicity assay of APTS-coated iron oxide nanoparticles.

Abstract: We report a facile approach to synthesizing 3-aminopropyltrimethoxysilane (APTS)-coated magnetic iron oxide (Fe3O4@APTS) nanoparticles (NPs) with tunable surface functional groups for potential biomedical applications. The Fe3O4 NPs with a mean diameter of 6.5 nm were synthesized by a hydrothermal route in the presence of APTS. The formed amine-surfaced Fe3O4@APTS NPs were further chemically modified with acetic anhydride and succinic anhydride to generate neutral (Fe3O4@APTS⋅Ac) and negatively charged (Fe3O4@APTS⋅SAH) NPs. These differently functionalized NPs were extensively characterized by x-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetry analysis, zeta potential measurements, and T2 relaxometry. The cytotoxicity of the particles was evaluated by in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric viability assay of cells along with microscopic observation of cell morphology. The hemocompatibility of the particles was assessed by in vitro hemolysis assay. We show that the hydrothermal approach enables an efficient modification of APTS onto the Fe3O4 NP surfaces and the formed NPs with different surface charge polarities are water-dispersible and colloidally stable. The acetylated Fe3O4@APTS⋅Ac NPs displayed good biocompatibility and hemocompatibility in the concentration range of 0–100 µg ml−1, while the pristine Fe3O4@APTS and Fe3O4@APTS⋅SAH particles started to display slight cytotoxicity at a concentration of 10 µg ml−1. The findings from this study suggest that the Fe3O4@APTS NPs synthesized by the one-pot hydrothermal route can be surface modified for various potential biomedical applications.

Thermo/redox/pH-triple sensitive poly(N-isopropylacrylamide-co-acrylic acid) nanogels for anticancer drug delivery.

Abstract: The clinical application of doxorubicin (DOX), like other anticancer drugs, is limited by insufficient cellular uptake and the numerous drug resistance mechanisms existing in cells. The development of smart nanomaterials capable of carrying the drugs into the cells and of releasing them under the control of the microenvironment is an interesting approach that may increase the success of the anticancer drugs currently in use. Herein, we report an easy process to prepare biocompatible nanogels (NGs) with thermo/redox/pH-triple sensitivity, which are highly effective in the intracellular delivery of DOX. Redox-sensitive/degradable NGs (PNA-BAC) and nondegradable NGs (PNA-MBA) were prepared through in situ polymerization of N-isopropylacrylamide (NIPAM) and acrylic acid (AA) in the presence of sodium dodecyl sulfate (SDS) as a surfactant, using N,N′-bis(acryloyl)cystamine (BAC) as a biodegradable crosslinker or N,N′-methylene bisacrylamide (MBA) as a nondegradable crosslinker, respectively. After that, the cationic DOX drug was loaded into the NGs through electrostatic interactions, by simply mixing them in aqueous solution. Compared to nondegradable PNA-MBA NGs, PNA-BAC NGs not only presented a higher DOX drug loading capacity, but also allowed a more sustainable drug release behavior under physiological conditions. More importantly, PNA-BAC NGs displayed thermo-induced drug release properties and an in vitro accelerated release of DOX under conditions that mimic intracellular reductive conditions and acidic tumor microenvironments. The thermo/redox/pH multi-sensitive NGs can quickly be taken up by CAL-72 cells (an osteosarcoma cell line), resulting in a high DOX intracellular accumulation and an improved cytotoxicity when compared with free DOX and DOX-loaded nondegradable PNA-MBA NGs. The developed NGs can be possibly used as an effective platform for the delivery of cationic therapeutic agents for biomedical applications.