Nanocrystalline Cubic Phase Scandium-Stabilized Zirconia Thin Films.

The cubic zirconia (ZrO2) is attractive for a broad range of applications. However, at room temperature, the cubic phase needs to be stabilized. The most studied stabilization method is the addition of the oxides of trivalent metals, such as Sc2O3. Another method is the stabilization of the cubic phase in nanostructures-nanopowders or nanocrystallites of pure zirconia. We studied the relationship between the size factor and the dopant concentration range for the formation and stabilization of the cubic phase in scandium-stabilized zirconia (ScSZ) films. The thin films of (ZrO2)1-x(Sc2O3)x, with x from 0 to 0.2, were deposited on room-temperature substrates by reactive direct current magnetron co-sputtering. The crystal structure of films with an average crystallite size of 85 Å was cubic at Sc2O3 content from 6.5 to 17.5 mol%, which is much broader than the range of 8-12 mol.% of the conventional deposition methods. The sputtering of ScSZ films on hot substrates resulted in a doubling of crystallite size and a decrease in the cubic phase range to 7.4-11 mol% of Sc2O3 content. This confirmed that the size of crystallites is one of the determining factors for expanding the concentration range for forming and stabilizing the cubic phase of ScSZ films.

Targeting phenylalanine assemblies as a prospective disease-modifying therapy for phenylketonuria.

Phenylketonuria is characterized by the accumulation of phenylalanine, resulting in severe cognitive and neurological disorders if not treated by a remarkably strict diet. There are two approved drugs today, yet both provide only a partial solution. We have previously demonstrated the formation of amyloid-like toxic assemblies by aggregation of phenylalanine, suggesting a new therapeutic target to be further pursued. Moreover, we showed that compounds that halt the formation of these assemblies also prevent their resulting toxicity. Here, we performed high-throughput screening, searching for compounds with inhibitory effects on phenylalanine aggregation. Morin hydrate, one of the most promising hits revealed during the screen, was chosen to be tested in vivo using a phenylketonuria mouse model. Morin hydrate significantly improved cognitive and motor function with a reduction in the number of phenylalanine brain deposits. Moreover, while phenylalanine levels remained high, we observed a recovery in dopaminergic, adrenergic, and neuronal markers. To conclude, the ability of Morin hydrate to halt phenylalanine aggregation without reducing phenylalanine levels implies the toxic role of the phenylalanine assemblies in phenylketonuria and opens new avenues for disease-modifying treatment.

Antibacterial Properties of Rose Bengal Conjugated to Hyaluronic Acid.

Dental diseases, including conditions affecting oral structures, have become more common due to unhealthy lifestyle choices. Traditional antibiotic treatments face challenges related to the development of antibiotic resistance in bacteria. Photodynamic antibacterial chemotherapy is emerging as a promising alternative using photosensitizers to generate reactive oxygen species upon exposure to light. This article examines the photosensitizer Rose Bengal (RB) immobilized in hyaluronic acid (HA) for prolonged antibacterial action. The RB-HA conjugate demonstrated a molar ratio of approximately three RB residues to each of the ten units of HA. RB-HA exhibited a high singlet oxygen quantum yield (ΔΦ = 0.90), suggesting its efficacy in photodynamic treatment. A photostability analysis revealed slower photobleaching of RB-HA, which is essential for prolonged application. Under visible light and ultrasonic treatment, RB-HA exhibited effective antibacterial activity against Gram-positive S. aureus and Gram-negative E. coli bacteria for at least 80 days. The gradual release of RB ensured sustained bactericidal concentration. The study establishes RB-HA as a promising candidate for antimicrobial photodynamic and sonodynamic therapy in dental and other medical fields, providing enhanced stability and prolonged antibacterial efficacy.