Peptide Assembly of Al/CuO Nanothermite for Enhanced Reactivity of Nanoaluminum Particles.

Biological self-assembly procedures, which are generally carried out in an aqueous solution, have been found to be the most promising method for directing the fabrication of diverse nanothermites, including Al/CuO nanothermite. However, the aqueous environment in which Al nanoparticles self-assemble has an impact on their stability. We show that using a peptide to self-assemble Al or CuO nanoparticles considerably improves their durability in phosphate buffer aqueous solution, with Al and CuO nanoparticles remaining intact in aqueous solution for over 2 weeks with minimal changes in the structure. When peptide-assembled Al/CuO nanothermite was compared with a physically mixed sample in phosphate buffer for 30 min, the energy release of the former was higher by 26%. Furthermore, the energy release of peptide-assembled Al/CuO nanocomposite in phosphate buffer showed a 6% reduction by Day 7, while that of the peptide-assembled Al/CuO nanocomposite in ultrapure water was reduced by 75%. Taken together, our study provides an easy method for keeping the thermal activity of Al/CuO nanothermite assembled in aqueous solution.

Conventional and microfluidic methods: Design and optimization of lipid-polymeric hybrid nanoparticles for gene therapy.

Gene therapy holds significant promise as a therapeutic approach for addressing a diverse range of diseases through the suppression of overexpressed proteins and the restoration of impaired cell functions. Developing a nanocarrier that can efficiently load and release genetic material into cells remains a challenge. The primary goal of this study is to develop formulations aimed to enhance the therapeutic potential of GapmeRs through technological approaches. To this end, lipid-polymeric hybrid nanoparticles (LPHNPs) with PLGA, DC-cholesterol, and DOPE-mPEG2000 were produced by conventional single-step nanoprecipitation (SSN) and microfluidic (MF) methods. The optimized nanoparticles by SSN have a size of 149.9 ± 18.07 nm, a polydispersity index (PdI) of 0.23 ± 0.02, and a zeta potential of (ZP) of 29.34 ± 2.44 mV, while by MF the size was 179.8 ± 6.3, a PdI of 0.24 ± 0.01, and a ZP of 32.25 ± 1.36 mV. Furthermore, LPHNPs prepared with GapmeR-protamine by both methods exhibit a high encapsulation efficiency of approximately 90%. The encapsulated GapmeR is completely released in 24 h. The LPHNP suspensions are stable for up to 6 h in 10% FBS at pH 5.4 and 7.4. By contrast, LPHNPs remain stable in suspension in 4.5% albumin at pH 7.4 for 24 h. Additionally, LPHNPs were successfully freeze-dried using trehalose in the range of 2.5-5% as cryoprotectant The LPHNPs produced by MF and SSN increase, 6 and 12 fold respectively, GapmeR cell uptake, and both of them reduce by 60-70% expression of Tob1 in 48 h.Our study demonstrates the efficacy of the developed LPHNPs as carriers for oligonucleotide delivery, offering valuable insights for their scale up production from a conventional bulk methodology to a high-throughput microfluidic technology.

Ozonation/UV irradiation of dispersed Ag/AgI nanoparticles in water resources: stability and aggregation.

Proliferation of nanoparticles (NPs) as aqueous pollutants is a matter of growing concern today. The aggregation kinetics of colloidal bare silver (Ag, 20.5 nm) and silver iodide (AgI, 15.3 nm) NPs were investigated during ozone/ultraviolet (O3/UV) oxidation. Dynamic light scattering was applied to monitor the aggregation of NPs, and the z-average of treated samples was considered aggregate diameter. The effect of temperature, pH, and initial concentration of NPs was investigated on the aggregation rate constant and stability ratio. At a short oxidation period of approximately 1 min, the lower stability ratio was achieved for Ag NPs (< 50) than AgI NPs (> 100). Under acidic conditions, the negative surface charge of both NPs was neutralized that resulted in faster aggregation. In contrast, the impact of temperature and initial concentration of NPs on the aggregation rate was different for both NPs, which was due to the type of O3/UV interaction with the surface of NPs and the thickness of the electrical double layer surrounding the NPs. The aggregation behavior of Ag NPs obeyed diffusion-limited regime, while an intermediate regime between diffusion- and reaction-limited was observed for AgI NP aggregation. The resulting aggregate morphologies showed that the clusters were ramified for Ag and compressed for AgI NPs. Applying the O3/UV oxidation process for water treatment purposes leads to a significant reduction in aggregation time for inherently unstable Ag and stable AgI toxic NPs from several hours or days to several minutes.

High Salinity and High Temperature Stable Colloidal Silica Nanoparticles with Wettability Alteration Ability for EOR Applications.

The stability of nanoparticles at reservoir conditions is a key for a successful application of nanofluids for any oilfield operations, e.g., enhanced oil recovery (EOR). It has, however, remained a challenge to stabilize nanoparticles under high salinity and high temperature conditions for longer duration (at least months). In this work, we report surface modification of commercial silica nanoparticles by combination of zwitterionic and hydrophilic silanes to improve its stability under high salinity and high temperature conditions. To evaluate thermal stability, static and accelerated stability analyses methods were employed to predict the long-term thermal stability of the nanoparticles in pH range of 4-7. The contact angle measurements were performed on aged sandstone and carbonate rock surfaces to evaluate the ability of the nanoparticles to alter the wettability of the rock surfaces. The results of static stability analysis showed excellent thermal stability in 3.5% NaCl brine and synthetic seawater (SSW) at 60 °C for 1 month. The accelerated stability analysis predicted that the modified nanoparticles could remain stable for at least 6 months. The results of contact angle measurements on neutral-wet Berea, Bentheimer, and Austin Chalk showed that the modified nanoparticles were able to adsorb on these rock surfaces and altered wettability to water-wet. A larger change in contact angle for carbonate surface than in sandstone surface showed that these particles could be more effective in carbonate reservoirs or reservoirs with high carbonate content and help improve oil recovery.

Enhancement of Magnetic Hyperthermia by Mixing Synthetic Inorganic and Biomimetic Magnetic Nanoparticles.

In this work we report on the synthesis and characterization of magnetic nanoparticles of two distinct origins, one inorganic (MNPs) and the other biomimetic (BMNPs), the latter based on a process of bacterial synthesis. Each of these two kinds of particles has its own advantages when used separately with biomedical purposes. Thus, BMNPs present an isoelectric point below neutrality (around pH 4.4), while MNPs show a zero-zeta potential at pH 7, and appear to be excellent agents for magnetic hyperthermia. This means that the biomimetic particles are better suited to be loaded with drug molecules positively charged at neutral pH (notably, doxorubicin, for instance) and releasing it at the acidic tumor environment. In turn, MNPs may provide their transport capabilities under a magnetic field. In this study it is proposed to use a mixture of both kinds of particles at two different concentrations, trying to get the best from each of them. We study which mixture performs better from different points of view, like stability and magnetic hyperthermia response, while keeping suitable drug transport capabilities. This composite system is proposed as a close to ideal drug vehicle with added enhanced hyperthermia response.

Development of expanded polytetrafluoroethylene cardiovascular graft platform based on immobilization of poly lactic-co-glycolic acid nanoparticles using a wet chemical modification technique.

Expanded polytetrafluoroethylene ePTFE grafts are mostly employed to replace damaged blood vessels and to restore normal blood flow. However, the dilemma of early thrombosis, inflammation, and development of biofilms after implantation limit ePTFE long-term patency and restrict the patient's life quality. In this study, poly lactic-co-glycolic acid (PLGA) nanoparticles were covalently immobilized on ePTFE surface for local therapeutic purposes. First, the ePTFE surface was primarily oxidized by H2O2/H2SO4 solution to create hydroxyl groups. Consequently, free amino groups were introduced onto ePTFE surface by an aminolyzation reaction of the activated hydroxyl groups using 3-aminopropyl triethoxysilane. The produced amino groups were further used as anchor sites for covalent immobilization of previously prepared PLGA nanoparticles. The functional groups originated on ePTFE surface were confirmed by FTIR analysis. Furthermore, the scanning electron microscopy visualization evidenced a homogeneous distribution pattern of the immobilized PLGA nanoparticles on the surface. The immobilized PLGA nanoparticles showed stability on ePTFE surface under blood flow mimetic conditions. Additionally, light microscopy observation confirmed the biocompatibility of mouse L929 fibroblasts on the nano-coated ePTFE graft. The cellular adhesion and growth did not reveal remarkable cytotoxicity in the tested modified ePTFE grafts.

Self-Functionalization Behind a Solution-Processed NiOx Film Used As Hole Transporting Layer for Efficient Perovskite Solar Cells.

Fabrication of solution-processed perovskite solar cells (PSCs) requires the deposition of high quality films from precursor inks. Frequently, buffer layers of PSCs are formed from dispersions of metal oxide nanoparticles (NPs). Therefore, the development of trustable methods for the preparation of stable colloidal NPs dispersions is crucial. In this work, a novel approach to form very compact semiconducting buffer layers with suitable optoelectronic properties is presented through a self-functionalization process of the nanocrystalline particles by their own amorphous phase and without adding any other inorganic or organic functionalization component or surfactant. Such interconnecting amorphous phase composed by residual nitrate, hydroxide, and sodium ions, proved to be fundamental to reach stable colloidal dispersions and contribute to assemble the separate crystalline nickel oxide NPs in the final film, resulting in a very homogeneous and compact layer. A proposed mechanism behind the great stabilization of the nanoparticles is exposed. At the end, the self-functionalized nickel oxide layer exhibited high optoelectronic properties enabling perovskite p-i-n solar cells as efficient as 16.6% demonstrating the pertinence of the presented strategy to obtain high quality buffer layers processed in solution at room temperature.

Stability of core-shell magnetite nanoparticles.

In the paper, we present three different types of magnetite nanoparticles which were prepared from co-percipitation of iron (II) and (III) chlorides in aqueous solution with and without SiO2 and from thermal decomposition of iron (III) acetylacetonate in nonaqeous solutions. The obtained core-shell nanoparticles were tested in respect of their stability in distilled water, 10% acetic acid, 0.01 M citric acid, 0.9% NaCl and commercial white wine (12% of alcohol). Changes of the nanoparticles were examined by infrared spectroscopy, atomic absorption spectroscopy, transmission electron microscopy, X-ray diffraction and differential scanning calorimetry methods. Modification of magnetic properties was measured by Mössbauer spectroscopy.