Assessment of dosimetric sensitivity enhancement of xylenol orange Fricke gel by AuNPs: optical and MR imaging investigation.

Metallic nanoparticles, such as gold (Au, Z = 79) and silver (Ag, Z = 47) nanoparticles (AuNPs and AgNPs, respectively), possess strong surface plasmonic resonance (SPR) and high atomic number, which makes them ideal candidates for enhancing dosimeter sensitivity. In this study, we have inserted different mass percentages (from 0 to 0.015 wt%) of AuNPs into a gelatinous Fricke-xylenol-orange (FXO-f) gel matrix and irradiated it with doses ranging from 2 to 32 Gy, using a source of x-ray of low energy with an effective energy of 42 keV. Optical absorption increased significantly; sensitivity gains of up to 50% were achieved for the FXO-f gel matrix containing 0.011 wt% AuNPs. To elucidate the mechanism underlying this increased sensitivity, we also evaluated FXO-f gel matrixes containing AgNPs. AgNPs insertion into the FXO-f gel matrix did not enhance sensitivity, which suggested that the AgNPs plasmonic absorption band and the FXO-f gel matrix absorption band at 441 nm overlapped, to increase absorption even after the gel matrix was irradiated. To visualize the dose distribution, we recorded optical tomography and acquired 3D reconstruction maps. In addition, we analyzed the dose enhancement factor (DEF) by using magnetic resonance images. AuNPs insertion into the FXO-f gel matrix resulted in a DEF gain of 1.37, associated with the photoelectric effect originating from the increased number of free radicals.

Selection and Control of Process Conditions Enable the Preparation of Curcumin-Loaded Poly(lactic-co-glycolic acid) Nanoparticles of Superior Performance.

Curcumin (CUR) is one natural bioactive compound acknowledged for diverse therapeutic activities, but its use is hindered by its poor bioavailability, fast metabolism, and susceptibility to pH variations and light exposure. Thus, the encapsulation in poly(lactic-co-glycolic acid), or PLGA, has been successfully used to protect and enhance CUR absorption in the organism, making CUR-loaded PLGA nanoparticles (NPs) promising drug delivery systems. However, few studies have focused beyond CUR bioavailability, on the environmental variables involved in the encapsulation process, and whether they could help obtain NPs of superior performance. Our study evaluated pH (3.0 or 7.0), temperature (15 or 35 °C), light exposure, and inert atmosphere (N2) incidence in the encapsulation of CUR. The best outcome was at pH 3.0, 15 °C, without light incidence, and without N2 usage. This best nanoformulation showed NP size, zeta potential, and encapsulation efficiency (EE) of 297 nm, -21 mV, and 72%, respectively. Moreover, the CUR in vitro release at pH values 5.5 and 7.4 suggested different potential applications for these NPs, one of which was demonstrated by the effective inhibition of multiple bacteria (i.e., Gram-negative, Gram-positive, and multi-resistant) in the minimal inhibition concentration assay. Besides, statistical analyses confirmed a significant impact of temperature on the NP size; in addition, temperature, light, and N2 affected the EE of CUR. Thus, the selection and control of process variables resulted in higher CUR encapsulation and customizable outcomes, ultimately enabling more economical processes and providing future scale-up guidelines.

Antimicrobial active edible coating of alginate and chitosan add ZnO nanoparticles applied in guavas (Psidium guajava L.).

Nanostructured coatings made with chitosan (100%Q), alginate (100%A) and blends of 50%Q-50%A; 90%Q-10%A and 90%A-10%Q, were added with (1%v/vgel) of nanoZnO and applied to guavas (Psidium guajava L.). After the coating application, fruits were stored for 15 days at 21 ±â€¯1 °C and 80 ±â€¯2% RH. To determine the effect on ripening process, fruits were submitted to water loss, texture, color, rot index, and physic-chemical assays. The results showed that coatings are able to prevent rot appearance in every sample, corroborating with the antibacterial action of nanoZnO. Coatings made with alginate and 90%A did not delay the maturation process, however, chitosan matrices (100%Q or 90%Q) protected fruits against excessive mass loss and retarded physic-chemical changes related to maturation. The experiment or study showed that it is possible to extend guava shelf life with ZnO nanostructured coatings with 100%Q or 90%Q-10%A for up to twenty days versus seven days of uncoated fruits.