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Lenart V.M.,State University of Ponta Grossa | Turchiello R.F.,Federal University of Technology of Parana | Goya G.F.,Aragon Institute of Nanoscience | Gomez S.L.,State University of Ponta Grossa
Brazilian Journal of Physics | Year: 2015

This work presents an experimental study of the thermal lens effect in Au nanoparticles-doped lyotropic liquid crystals under cw 532 nm optical excitation. Spherical Au nanoparticles of about 12 nm were prepared by Turkevich’s method, and the lyotropic liquid crystal was a ternary mixture of SDS, 1-DeOH, and water that exhibits an isotropic phase at room temperature. The lyotropic matrix induces aggregation of the nanoparticles, leading to a broad and a red-shifted surface plasmon resonance. The thermal nonlinear optical refraction coefficient n2 increases as a power of number density of nanoparticles, being possible to address this behavior to nanoparticle clustering. © 2015, Sociedade Brasileira de Física. Source

Smith C.-A.M.,University of Glasgow | Fuente J.D.L.,Aragon Institute of Nanoscience | Pelaz B.,Aragon Institute of Nanoscience | Furlani E.P.,State University of New York at Buffalo | And 2 more authors.
Biomaterials | Year: 2010

Magnetic nanoparticles are widely used in bioapplications such as imaging (MRI), targeted delivery (drugs/genes) and cell transfection (magnetofection). Historically, the impermeable nature of both the plasma and nuclear membranes hinder potential. Researchers combat this by developing techniques to enhance cellular and nuclear uptake. Two current popular methods are using external magnetic fields to remotely control particle direction or functionalising the nanoparticles with a cell penetrating peptide (e.g. tat); both of which facilitate cell entry. This paper compares the success of both methods in terms of nanoparticle uptake, analysing the type of magnetic forces the particles experience, and determines gross cell response in terms of morphology and structure and changes at the gene level via microarray analysis. Results indicated that both methods enhanced uptake via a caveolin dependent manner, with tat peptide being the more efficient and achieving nuclear uptake. On comparison to control cells, many groups of gene changes were observed in response to the particles. Importantly, the magnetic field also caused many change in gene expression, regardless of the nanoparticles, and appeared to cause F-actin alignment in the cells. Results suggest that static fields should be modelled and analysed prior to application in culture as cells clearly respond appropriately. Furthermore, the use of cell penetrating peptides may prove more beneficial in terms of enhancing uptake and maintaining cell homeostasis than a magnetic field. © 2010 Elsevier Ltd. Source

Child H.W.,University of Glasgow | Del Pino P.A.,Aragon Institute of Nanoscience | De La Fuente J.M.,Aragon Institute of Nanoscience | Hursthouse A.S.,University of West of Scotland | And 6 more authors.
ACS Nano | Year: 2011

Nanoparticles (NPs) are currently being developed as vehicles for in vivo drug delivery. Two of the biggest barriers facing this therapy are the site-specific targeting and consequent cellular uptake of drug-loaded NPs 1. In vitro studies in 2D cell cultures have shown that an external magnetic field (MF) and functionalization with cell-penetrating peptides (CPPs) have the capacity to overcome these barriers. This study aimed to investigate if the potential of these techniques, which has been reported in 2D, can be successfully applied to cells growing in a 3D environment. As such, this study provides a more realistic assessment of how these techniques might perform in future clinical settings. The effect of a MF and/or penetratin attachment on the uptake of 100 and 200 nm fluorescent iron oxide magnetic NPs (mNPs) into a fibroblast-seeded 3D collagen gel was quantified by inductively coupled plasma mass spectrometry. The most suitable mNP species was further investigated by fluorescence microscopy, histology, confocal microscopy, and TEM. Results show that gel mNP uptake occurred on average twice as fast in the presence of a MF and up to three times faster with penetratin attachment. In addition, a MF increased the distance of mNP travel through the gel, while penetratin increased mNP cell localization. This work is one of the first to demonstrate that MFs and CPPs can be effectively translated for use in 3D systems and, if applied together, will make excellent partners to achieve therapeutic drug delivery in vivo. © 2011 American Chemical Society. Source

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