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Tomasz Kostrzewa,1 Izabela Nowak,2 Agnieszka Feliczak-Guzik,2 Joanna Drzeżdżon,3 Dagmara Jacewicz,3 Magdalena Górska-Ponikowska,1,4,5 Alicja Kuban-Jankowska1 1Department of Medical Chemistry, Faculty of Medicine, Medical University of Gdansk, Gdansk, 80-211, Poland; 2Department of Applied Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Poznań, 61-614, Poland; 3Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, Gdansk, 80-308, Poland; 4IEMEST Istituto Euro-Mediterraneo di Scienza e Tecnologia, Palermo, 90127, Italy; 5Department of Biophysics, Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, 70174, GermanyCorrespondence: Tomasz Kostrzewa; Alicja Kuban-Jankowska, Department of Medical Chemistry, Faculty of Medicine, Medical University of Gdansk, Gdansk, 80-211, Poland, Tel +48 58 349 14 50, Fax +48 58 349 14 56, Email tomasz.kostrzewa@gumed.edu.pl; alicja.kuban-jankowska@gumed.edu.plIntroduction: Solid lipid nanoparticles (SLN) have been considered lately as promising drug delivery system in treatment of many human diseases including cancers. We previously studied potential drug compounds that were effective inhibitors of PTP1B phosphatase – possible target for breast cancer treatment. Based on our studies, two complexes were selected for encapsulation into the SLNs, the compound 1 ([VO(dipic)(dmbipy)] · 2 H2O) and compound 2 ([VOO(dipic)](2-phepyH) · H2O). Here, we investigate the effect of encapsulation of those compounds on cell cytotoxicity against MDA-MB-231 breast cancer cell line. The study also included the stability evaluation of the obtained nanocarriers with incorporated active substances and characterization of their lipid matrix. Moreover, the cell cytotoxicity studies against the MDA-MB-231 breast cancer cell line in comparison and in combination with vincristine have been performed. Wound healing assay was carried out to observe cell migration rate.Methods: The properties of the SLNs such as particle size, zeta potential (ZP), and polydispersity index (PDI) were investigated. The morphology of SLNs was observed by scanning electron microscopy (SEM), while the crystallinity of the lipid particles was analyzed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The cell cytotoxicity of complexes and their encapsulated forms was carried out against MDA-MB-231 breast cancer cell line using standard MTT protocols. The wound healing assay was performed using live imaging microscopy.Results: SLNs with a mean size of 160 ± 25 nm, a ZP of − 34.00 ± 0.5, and a polydispersity index of 30 ± 5% were obtained. Encapsulated forms of compounds showed significantly higher cytotoxicity also in co-incubation with vincristine. Moreover, our research shows that the best compound was complex 2 encapsulated into lipid nanoparticles.Conclusion: We observed that encapsulation of studied complexes into SLNs increases their cell cytotoxicity against MDA-MB-231 cell line and enhanced the effect of vincristine.Keywords: solid lipid nanoparticles, stability of nanoparticles, oxovanadium(IV) and dioxovanadium(V) complexes, triple-negative MDA-MB-231 breast cancer cell line, live imaging microscopy

The stability of nanoparticles in the aqueous phase is a major challenge in the application of nanoparticles in Enhanced Oil Recovery (Nano-EOR) processes. Previous studies evaluated the performance of nanoparticles for EOR purposes; either deionized water or water at very low ionic strength was used. Nanoparticles can be easily dispersed in the deionized or low salinity water, whereas they are extremely unstable in high salinity seawater or formation water. Typically, seawater or formation brine is injected for water-flooding and EOR purposes. If we want to change the fluid–fluid or fluid-rock properties by injecting nanoparticle enhanced water, then, the stability of the nanoparticles in high salinity water is extremely important. In this work, a novel and simple method to stabilize silica nanoparticles in seawater is proposed. First, the aggregation of silica nanoparticles in the presence of different ions is investigated. The results show that the presence of positive multivalent ions in the electrical double layer around nanoparticles can destabilize silica nanoparticles. In order to reduce the concentration of positive multivalent ions around silica nanoparticles, a theory based on “H + protection” is proposed and its effectiveness is tested by particle size, turbidity, zeta-potential, and pH measurements. The effect of the concentrations of nanoparticles and HCl on the stability of silica nanoparticles in seawater is evaluated. Experimental results show that H + protection, which can be obtained by adding HCl to the solution, can effectively stabilize silica nanoparticles in seawater. The experiments show that the size of nanoparticles in the seawater directly depends on the concentration of nanoparticles and inversely to the HCl concentration. [ABSTRACT FROM AUTHOR]

The optimisation of new particle based products with respect to their stability and physico-chemical behaviour requires the characterisation of the interfacial properties. Such a characterisation may be achieved by means of the zeta potential, which is related to the surface charge and electric double layer (EDL) of colloidal particles. Furthermore, the zeta potential is a powerful parameter of the EDL and an appropriate way of predicting the suspension stability. This study discusses the performance of two techniques for the measurement of zeta potential value and its comparability of zeta potential values for pyrogenic materials. This measurement encounters several experimental challenges, because each measurement technique possesses specific limits with regard to particle size, concentration and morphology. Furthermore, this study examines the comparability of zeta potential measurements by variation of mentioned specific limits taking the conservation of the chemical equilibrium into account and also understanding the impact of aggregate morphology on the electrokinetic mobility. [ABSTRACT FROM AUTHOR]

Highlights: [•] BaSO4 nanoparticles were produced by wet grinding in stirred media mill. [•] The primary particle size was less than 50nm as measured by TEM and XRD. [•] The stability of nanoparticles suspension was improved by the use of dispersant. [•] Structural changes caused by grinding were evidenced from XRD, FTIR and TGA. [ABSTRACT FROM AUTHOR]

In this study, silver nanoparticles were prepared using silver nitrate as the metal precursor, starch as protecting agent, and sodium borohydride (NaBH4) as a reducing agent by the chemical reduction method. The formation of the silver nanoparticles was monitored using ultraviolet-visible absorption spectroscopy, cyclic voltammetry, and particle size analyzer and characterized by transmission electron microscopy (TEM) and x-ray diffraction (XRD). Synthesis of nanoparticles were carried out by varying different parameters, such as reaction temperature, concentration of reducing agent, concentration of silver ion in feed solution, type and concentration of the stabilizing agent, and stirrer speed expressed in terms of particle size and size distribution. Dispersion destabilization of colloidal nanoparticles was detected by Turbiscan. It was observed that size of the starch stabilized silver nanoparticles were lower than 10 nm. The microbial activity of synthesized silver nanoparticles was examined by modified Kirby-Bauer disk diffusion method. Silver nanoparticles were tested for their antibacterial activity against Gram negative bacteria such as Escherichia coli, Pseudomonas aeruginosa, and Gram positive bacteria such as Staphylococcus aureus and Staphylococcus epidermidis. High bacterial activity was observed at very low concentrations of silver (below 1.39 μg/ml). The antifungal activity of silver nanoparticles has been assayed against Candida albicans. [ABSTRACT FROM AUTHOR]