Optimizing Aerosol Jet Printing Process of Platinum Ink for High-Resolution Conductive Microstructures on Ceramic and Polymer Substrates

Printing nano-ink with platinum nanoparticles to generate conductive microstructures for electronics on different types of substrates has gained increasing interest in recent years. To solve the problem of the low conductivity of platinum (Pt) nano-ink, we synthesized chemically pure Pt nanoparticles with sizes of 18.2 ± 9.0 nm by spark discharge method. A low toxic solvent, ethylene glycol with water, was used to ensure the aggregation stability of Pt nanoparticles. Polyvinylpyrrolidone was used as an adhesive additive and binder in the nano-ink. Narrow and conductive Pt lines were generated by aerosol jet printing technology. The resistivity of the Pt lines sintered at 750 °C on alumina substrate was found to exceed the bulk Pt by about 13%. Moreover, the Pt film fabricated on polymer substrates has demonstrated excellent mechanical flexibility in terms of twisting tests.

Novel four-disulfide insulin analog with high aggregation stability and potency

A novel four-disulfide insulin analog was designed with retained bioactivity and increased fibrillation stability.

Aggregation stability of nanoparticles based on rare-earth elements in different microenvironment and biological media

Background: Development of new pharmacological forms able to increase the therapeutic effectiveness of already known drugs, to reduce side effects, and to increase the comfort of treatment for the patient is an actual task of modern medicine and pharmacy. To solve the problem, one of the most promising directions in this field is the use of various nanomaterials, among which in recent years the main attention was drawn to nanomaterials based on rare earth elements (REEs). At the same time, the question of the relation between the biological activity of nanomaterials and their physical and chemical properties, as well as the features of interaction with microenvironments in biosystems, remain controversial. Objectives: Estimation of the aggregation stability of REE-based nanoparticles (NPs) in incubation media of different compositions and of the role of certain factors in stabilizing NPs in the biological microenvironment. Materials and methods: Aggregation stability of GdYVO4:Eu3+, LaVO4: Eu3+, CeO2, GdVO4:Eu3+ NPs was studied using dynamic and electrophoretic light scattering techniques. NPs were incubated in 5% glucose or buffers: 50 mM Tris buffer (with different pH within of physiological values); Igla МЕМ medium; Krebs-Ringer buffer pH 7.4; HBSS-buffer (HEPES-buffered saline-solution) pH 7.4, in the absence or presence of 0.2% BSA, for 30 minutes and 24 hours. The effect of oxidized and reduced glutathione on the stability of solutions of NPs in Tris buffer at various pH values was also determined. Results: The results have shown that in contrast to the stabilizing effect of 5% glucose solution significant aggregation of NPs is observed in saline systems. The highest degree of aggregation was observed in the Igla МЕМ and Krebs-Ringer buffer environment. Addition of 0.2% of albumin to all media prevented aggregation. Interaction of immunoglobulin with NPs leads to increase in hydrodynamic diameter, especially for some types of NPs, already at the smallest of the used protein concentrations. Oxidized but not recovered glutathione promoted aggregation of all types of orthovanadate NPs in acidic medium (Tris buffer pH=6.7). Conclusions: The aggregative stability of NPs in the salt media increases significantly in the presence of serum albumin due to changes in the ratio of the electrostatic and steric components of the interaction of NPs with the microenvironment.

Control of Natural Zeolite Properties by Mechanical Activation in Stirred Media Mill

Due to the special characteristics of zeolites, they can be applied in a very wide range of industries, i.e. agricultural, environmental or water treatment purposes. Generally, high added value zeolite products are manufactured by micro- or nanogrinding. However, these processes require high energy input and cause significant wearing of the mill parts. Therefore, the optimization of zeolite grinding, as well as the control of its properties are of a great importance. In the present paper a Hungarian natural zeolite was mechanically activated in stirred media mill for various residence times in distilled water, meanwhile the particle size distribution and the grinding energy were measured. Additionally, on-line tube rheometer was used to study the rheology of the suspension during the grinding process. The particle interaction and the suspension aggregation stability were detected by zeta-potential measurements. Structural changes due to the mechanical activation process were monitored by FTIR. It was found that the material structure of the zeolite, as well as the rheological behaviour of the zeolite suspension and its aggregation stability had been altered due to the mechanical activation in the stirred media mill. It can be concluded that the zeolite product properties can be modified by mechanical activation in order to produce a high added value tailored material.