Polymer functionalized gold nanoparticles as non-viral gene delivery reagents.

Background: In this study we investigated the ability of PEG functionalized gold nanoparticles as non-viral vectors in the transfection of different cell lines, comparing them with commercial lipoplexes. Methods: Positively charged gold nanoparticles were synthesized using PEI as reducing and stabilizer agent and its cytotoxicity reduced by its functionalization with PEG. We bound the nanoparticles to three plasmids with different sizes (4-40 kpb). The vector internalization was evaluated by confocal and electronic microscopy. Its transfection efficacy was studied by fluorescence microscopy and flow cytometry. The application of the resulting vector in gene therapy was indirectly evaluated using ganciclovir in HeLa cells transfected to express the herpes virus thymidine kinase. Results: An appropriate ratio between the nitrogen from the PEI and the phosphorous from the phosphate groups of the DNA together with a reduced size and an elevated electrokinetic potential are responsible for an increased nanoparticle internalization and enhanced protein expression when carrying plasmids of up to 40kbp (plasmid size close to the limit of the DNA carrying capacity of viral vectors). Compared to a commercial transfection reagent, an equal or even higher expression of reporter genes (on HeLa and HEK 293T) and suicide effect on HeLa cells transfected with the herpes virus thymidine kinase gene were observed when using this novel nanoparticulated vector. Conclusions: Non-viral vectors based on gold nanoparticles covalently coupled with polyethylene glycol (PEG) and Polyethylenimine (PEI) can be used as efficient transfection reagents showing expression levels same or greater than the ones obtained with commercially available lipoplexes.pre-print3905 K

The effect of hollow gold nanoparticles on stem cell migration. Potencial application in tissue regeneration.

Every year trauma together with bone, joints and cartilage-associated diseases usually involve structural damage, resulting in a severe pain and disability for millions of people worldwide[1]. In regenerative medicine, cellular, tissue and organ-based approaches are developed to restore biological functions that have been lost[2],[3]. Therefore, tissue repair and regenerative medicine have attracted the interest of the scientific community, providing promising results in preclinical models and clinical pilot studies.pre-print3341 K

Cancer-derived exosomes loaded with ultrathin palladium nanosheets for targeted bioorthogonal catalysis

The transformational impact of bioorthogonal chemistries has inspired new strategies for the in vivo synthesis of bioactive agents through non-natural means. Among these, Pd catalysts have played a prominent role in the growing subfield of bioorthogonal catalysis by producing xenobiotics and uncaging biomolecules in living systems. However, delivering catalysts selectively to specific cell types still lags behind catalyst development. Here, we have developed a bioartificial device comprising cancer-derived exosomes that are loaded with Pd catalysts by a method that enables the controlled assembly of Pd nanosheets directly inside the vesicles. This hybrid system mediates Pd-triggered dealkylation reactions in vitro and inside cells, and displays preferential tropism for their progenitor cells. The use of Trojan exosomes to deliver abiotic catalysts into designated cancer cells creates the opportunity for a new targeted therapy modality; that is, exosome-directed catalyst prodrug therapy, whose first steps are presented herein with the cell-specific release of the anticancer drug panobinostat

Selective delivery of photothermal nanoparticles to tumors using mesenchymal stem cells as Trojan horses

The main challenge of cancer treatment is to avoid or minimize systemic side effects in off-target tissues. Mesenchymal stem cells (MSCs) can be used as therapeutical carriers because of their ability to migrate and incorporate into inflammation areas including tumors. Here, this homing ability is exploited by carrying therapeutic nanoparticles (Hollow Gold Nanoparticles (HGNs)) following a “Trojan-horse” strategy. Amongst the different nanoparticles to be employed, HGNs have the capacity to resonate in the near infrared region when irradiated by an appropriated laser (808 nm). By transforming this absorbed energy into heat, they are capable to produce locally induced hyperthermia. At this wavelength healthy tissues have a minimal light absorption being the effect restricted to the tissues containing HGNs. By placing HGNs inside MSCs, the recognition, excretion and immune response are minimized. We demonstrate that MSCs internalize HGNs and reach the tumors still containing HGNs. After laser treatment this loaded cells are able to eradicate tumoral cells in vitro and in vivo without significant toxicity. Also Ki67 expression, which is usually correlated with proliferation, is reduced after treatment. This approach enhances the effectiveness of the treatment when compared to just the enhanced permeation and retention effect (EPR) of the HGNs by themselves

High-Precision Photothermal Ablation using Biocompatible Palladium Nanoparticles and Laser Scanning Microscopy

Herein, we report a straightforward method for the scalable preparation of Pd nanoparticles (Pd-NPs) with reduced inherent cytotoxicity and high photothermal conversion capacity. These Pd-NPs are rapidly taken up by cells and able to kill labeled cancer cells upon short exposure to near-infrared (NIR) light. Following cell treatment with Pd-NPs, ablated areas were patterned with high precision by laser scanning microscopy, allowing one to perform cell migration assays with unprecedented accuracy. Using coherent Raman microscopy, cells containing Pd-NPs were simultaneously ablated and imaged. This novel methodology was combined with intravital imaging to mediate microablation of cancerous tissue in tumor xenografts in mice

A simple approach to obtain hybrid Au-loaded polymeric nanoparticles with a tunable metal load

A new strategy to nanoengineer multi-functional polymer–metal hybrid nanostructures is reported. By using this protocol the hurdles of most of the current developments concerning covalent and noncovalent attachment of polymers to preformed inorganic nanoparticles (NPs) are overcome. The strategy is based on the in situ reduction of metal precursors using the polymeric nanoparticle as a nanoreactor. Gold nanoparticles and poly(DL-lactic-co-glycolic acid), PLGA, are located in the core and shell, respectively. This novel technique enables the production of PLGA NPs smaller than 200 nm that bear either a single encapsulated Au NP or several smaller NPs with tunable sizes and a 100% loading efficiency. In situ reduction of Au ions inside the polymeric NPs was achieved on demand by using heat to activate the reductive effect of citrate ions. In addition, we show that the loading of the resulting Au NPs inside the PLGA NPs is highly dependent on the surfactant used. Electron microscopy, laser irradiation, UV-Vis and fluorescence spectroscopy characterization techniques confirm the location of Au nanoparticles. These promising results indicate that these hybrid nanomaterials could be used in theranostic applications or as contrast agents in dark-field imaging and computed tomograph

Potentiation of 5-fluorouracil encapsulated in zeolites as drug delivery systems for in vitro models of colorectal carcinoma

The studies of potentiation of 5-fluorouracil (5-FU), a traditional drug used in the treatment of several cancers, including colorectal (CRC), were carried out with zeolites Faujasite in the sodium form, with different particle sizes (NaY, 700nm and nanoNaY, 150nm) and Linde type L in the potassium form (LTL) with a particle size of 80nm. 5-FU was loaded into zeolites by liquid-phase adsorption. Characterization by spectroscopic techniques (FTIR, 1H NMR and 13C and 27Al solid-state MAS NMR), chemical analysis, thermal analysis (TGA), nitrogen adsorption isotherms and scanning electron microscopy (SEM), demonstrated the successful loading of 5-FU into the zeolite hosts. In vitro drug release studies (PBS buffer pH 7.4, 37°C) revealed the release of 80-90% of 5-FU in the first 10min. To ascertain the drug release kinetics, the release profiles were fitted to zero-order, first-order, Higuchi, Hixson-Crowell, Korsmeyer-Peppas and Weibull kinetic models. The in vitro dissolution from the drug delivery systems (DDS) was explained by the Weibull model. The DDS efficacy was evaluated using two human colorectal carcinoma cell lines, HCT-15 and RKO. Unloaded zeolites presented no toxicity to both cancer cells, while all DDS allowed an important potentiation of the 5-FU effect on the cell viability. Immunofluorescence studies provided evidence for zeolite-cell internalization.RA is recipient of fellowship SFRH/BI/51118/2010 from Fundacao para a Ciencia e a Tecnologia (FCT, Portugal). This work was supported by the FCT projects refs. PEst-C/QUI/UI0686/2011 and PEst-C/CTM/LA0011/2011 and the Centre of Chemistry and Life and Health Sciences Research Institute (University of Minho, Portugal). The NMR spectrometer is part of the National NMR Network (RNRMN), supported with funds from FCT/QREN (Quadro de Referencia Estrategico Nacional)

Controlled Release of Doxorubicin Loaded within Magnetic Thermo-responsive Nanocarriers under Magnetic and Thermal Actuation in a Microfluidic Channel

We report a procedure to grow thermo-responsive polymer shells at the surface of magnetic nanocarriers made of multiple iron oxide superparamagnetic nanoparticles embedded in poly(maleic anhydride-alt-1-ocatadecene) polymer nanobeads. Depending on the comonomers and on their relative composition, tunable phase transition temperatures in the range between 26 and 47 °C under physiological conditions could be achieved. Using a suitable microfluidic platform combining magnetic nanostructures and channels mimicking capillaries of the circulatory system, we demonstrate that thermo-responsive nanobeads are suitable for localized drug delivery with combined thermal and magnetic activation. Below the critical temperature nanobeads are stable in suspension, retain their cargo, and cannot be easily trapped by magnetic fields. Increasing the temperature above the critical temperature causes the aggregation of nanobeads, forming clusters with a magnetic moment high enough to permit their capture by suitable magnetic g..

Selective delivery of photothermal nanoparticles to tumors using mesenchymal stem cells as Trojan horses

et al.The main challenge of cancer treatment is to avoid or minimize systemic side effects in off-target tissues. Mesenchymal stem cells (MSCs) can be used as therapeutical carriers because of their ability to migrate and incorporate into inflammation areas including tumors. Here, this homing ability is exploited by carrying therapeutic nanoparticles (Hollow Gold Nanoparticles (HGNs)) following a >Trojan-horse> strategy. Amongst the different nanoparticles to be employed, HGNs have the capacity to resonate in the near infrared region when irradiated by an appropriated laser (808 nm). By transforming this absorbed energy into heat, they are capable to produce locally induced hyperthermia. At this wavelength healthy tissues have a minimal light absorption being the effect restricted to the tissues containing HGNs. By placing HGNs inside MSCs, the recognition, excretion and immune response are minimized. We demonstrate that MSCs internalize HGNs and reach the tumors still containing HGNs. After laser treatment this loaded cells are able to eradicate tumoral cells in vitro and in vivo without significant toxicity. Also Ki67 expression, which is usually correlated with proliferation, is reduced after treatment. This approach enhances the effectiveness of the treatment when compared to just the enhanced permeation and retention effect (EPR) of the HGNs by themselves.Financial support from the EU thanks to the ERC Consolidator Grant program (ERC-2013-CoG-614715, NANOHEDONISM) is gratefully acknowledged.Peer Reviewe

Advances in draw solutes for forward osmosis: Hybrid organic-inorganic nanoparticles and conventional solutes

Forward osmosis (FO) is one of the emerging membrane technologies which has gained interest in the last decade for being a low energy desalination process. The most important factors controlling FO processes are performance, recyclability and cost of the draw solution (DS) used together with the FO membrane itself because they play a crucial role on the feasibility of this technology. Consequently, the selection of an appropriate DS is vital for the process efficiency, besides the required selectivity and permeance of the membrane and the efficient DS regeneration process. A wide variety of DS have been tested so far and this paper aims to review recent advances in the synthesis and selection of an appropriate DS. It provides valuable information on a new type of draw solutes based on hybrid organic-inorganic nanosystems which, at a certain extent, show synergistic properties that face some of the technology shortcomings. Magnetic nanoparticles (MNPs) are the most promising nanosystems intended for desalination because they can be readily recovered applying a magnetic field or by conventional membrane processes. This review also deals with the most important characteristics of DS based on nanoparticles (NPs) and how they affect the performance of the overall processes. Finally, this review also highlights future research directions, where nanosystems will mitigate inverse diffusion and concentration polarization phenomena widely reported as limiting factors in FO processes.Abengoa Research, the People Program (CIG-Marie Curie Actions, REA grant agreement no. 321642), the Government of Aragon and the European Social Fund are gratefully acknowledged. CIBER-BBN is an initiative funded by the VI National R&D&i Plan 2008–2011 financed by the Instituto de Salud Carlos III with the assistance of the European Regional Development Fund.Peer reviewe