Enhanced growth of tellurium nanowires under conditions of macromolecular crowding.

An unprecedented rate enhancement was observed in the wet-chemical synthesis of tellurium nanowires under crowded conditions of inert macromolecules. The synthesis was carried out at 105 °C using solutions of sodium tellurite (Na2TeO3) as a precursor, hydrazine (N2H4) as a reducing agent, and polyvinylpyrrolidone (PVP) as both a stabilizing and crowding agent. The PVP concentration was systematically varied between the dilute and crowding regimes up to 166 g l-1. The growth of the nanowires was monitored by measuring their size-dependent optical properties in the UV-Vis spectrum characterizing the size and morphology evolution of the nanowires and a coexisting phase of amorphous tellurium nanoparticles. The observed growth characteristics were interpreted in terms of non-specific structural organization of the crowded media due to the entropic-driven effects of space compartmentalization.

Innovative Approach to Producing Palladium-103 for Auger-Emitting Radionuclide Therapy: A Proof-of-Concept Study.

Auger-emitting radionuclides, exemplified by Pd-103, exhibit considerable therapeutic potential in cancer treatment due to their high cytotoxicity and localized biological impact. Despite these advantages, the separation of such radionuclides presents a complicated challenge, requiring intricate and time-intensive "wet chemistry" methods attributed to the exceptional chemical inertness of the associated metals. This study proposes an innovative solution to this separation challenge through the design and implementation of a piece of radionuclide separation equipment (RSE). The equipment employs a dry distillation approach, capitalizing on differences in partial vapor pressures between irradiated and resulting radioactive metals, with a diffusion-driven extraction method applied to separate Pd-103 radionuclides generated via the proton irradiation of Rh-103 at cyclotron. Our optimization endeavors focused on determining the optimal temperature for effective metal separation and adjusting the diffusion, evaporation, and deposition rates, as well as addressing chemical impurities. The calculations indicate 17% ± 2% separation efficiency with our RSE. Approximately 77 ± 2% and 49 ± 2% of the deposited Pd-103 were isolated on substrates of Nb foil and ZnO-covered W disc, respectively. The proposed innovative dry distillation method that has been experimentally tested offers a promising alternative to conventional separation techniques, enabling enhanced purity and cost-efficient cancer treatment strategies.

Electrosprayed calcium silicate nanoparticle-coated titanium implant with improved antibacterial activity and osteogenesis.

To ensure clinical success, the implant and the surrounding bone tissue must not only be integrated, but also must not be suspected of infection. In this work, an antibacterial and bioactive nanostructured calcium silicate (CaSi) layer on titanium substrate by an electrospray deposition method was prepared, followed by annealing at 700, 750 and 800 °C to improve the bonding strength of the CaSi coating. The phase composition, microstructure and bonding strength of the CaSi coatings were examined. Human mesenchymal stem cells (hMSCs), Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) species were used to analyze the osteogenic and antibacterial activity of the coatings, respectively. Experimental results showed that the as-prepared CaSi coating was mainly composted of ß-dicalcium silicate phase with a particle size of about 300 nm. After annealing, the thickness of the oxidation reaction layer increased obviously from 0.3 µm to 1 µm with increase in temperature, which was confirmed by the cross-sectional morphology and element depth profile. The bonding strength of the coating annealed at 750 °C (19.0 MPa) was significantly higher (p < 0.05) than that of the as-prepared coating (4.4 MPa) and the ISO 13,779 standard (15 MPa). The results of antibacterial efficacy and stem cell osteogenesis consistently elaborated that the 750 °C-annealed coating had higher activity than the as-prepared coating and the Ti control. It is concluded that after annealing at 750 °C, the CaSi nanoparticle-coated Ti implant had good bond strength, osteogenic and antibacterial activity.

Calcium silicate layer on titanium fabricated by electrospray deposition.

Titanium and its alloys have been used as implant materials. Non-ideal osseointegration of the implant materials has facilitated the development of the bioactive coatings on the implant surfaces. In this work, the bioactive calcium silicate (CaSi) powder prepared in a green synthesis route was used to cover the surface of Ti implants by a facile electrospray deposition method. Post annealing in air was also applied to form the oxidation layer on the Ti surface with the aim of increasing the bond strength between the CaSi coating layer and Ti substrate. For the characterization of the coatings several analytical methods such as X-ray diffraction, scanning electron microscopy, secondary neutral mass spectrometry, and Raman-spectroscopy were used, in addition to the measurement of bond strength and corrosion resistance. The results indicated a uniform CaSi layer with a thickness of about 1 µm deposited on the Ti substrate. Annealing in the range of 700-900 °C in air resulted in the formation of rutile phase of TiO2; more importantly, annealing at 800 °C did not significantly affect the composition of the CaSi layer consisting of ß-Ca2SiO4. The bond strength between the coating layer and Ti substrate can be remarkably enhanced at an annealing temperature of 700 or 800 °C compared with the as-prepared coating without annealing. The annealed coatings had a better corrosion resistance than the as-prepared coating. It is concluded that the electrospray method associated with the post-annealing can be successfully used for the deposition of a CaSi layer with a defined structure and composition on titanium implants.