ATR-FTIR Characterization of Janus Nanoparticles-Part II: Follow-Up Skin Application

Biogenic selenium nanoparticles: trace element with promising anti-toxoplasma effect

Toxoplasmosis is an opportunistic infection caused by the coccidian Toxoplasma gondii which represents a food and water contaminant. The available chemotherapeutic agents for toxoplasmosis are limited and the choice is difficult when considering the side effects. Selenium is an essential trace element. It is naturally found in dietary sources, especially seafood, and cereals. Selenium and selenocompounds showed anti-parasitic effects through antioxidant, immunomodulatory, and anti-inflammatory mechanisms. The present study evaluated the potential efficacy of environmentally benign selenium nanoparticles (SeNPs) against acute toxoplasmosis in a mouse model. SeNPs were fabricated by nanobiofactory Streptomyces fulvissimus and characterized by different analytical techniques including, UV-spectrophotometry, transmission electron microscopy, EDX, and XRD. Swiss albino mice were infected with Toxoplasma RH strain in a dose of 3500 tachyzoites in 100 μl saline to induce acute toxoplasmosis. Mice were divided into five groups. Group I: non-infected, non-treated, group II: infected, non-treated, group III: non-infected, treated with SeNPs, group IV: infected, treated with co-trimoxazole (sulfamethoxazole/trimethoprim) and group V: infected, treated with SeNPs. There was a significant increase in survival time in the SeNPs-treated group and minimum parasite count was observed compared to untreated mice in hepatic and splenic impression smears. Scanning electron microscopy showed tachyzoites deformity with multiple depressions and protrusions, while transmission electron microscopy showed excessive vacuolization and lysis of the cytoplasm, especially in the area around the nucleus and the apical complex, together with irregular cell boundary and poorly demarcated cell organelles. The present study demonstrated that the biologically synthesized SeNPs can be a potential natural anti-Toxoplasma agent in vivo.

Nanoscale investigation of human skin and study of skin penetration of Janus nanoparticles

Janus nanoparticles (JNP) are innovative nanocarriers with an interesting pharmaceutical and cosmetic potential. They are characterized by the presence of a lipid compartment associated with an aqueous compartment delimited by a phospholipid bilayer containing phospholipids and non-ionic surfactants. The hydrodynamic diameter of JNP varies between 150 and 300 nm. The purpose of this study was to answer the following questions: after cutaneous application, are JNP penetrating? If so, how deep? And in which state, intact or degraded? It was essential to understand these phenomena in order to control the rate and kinetics of diffusion of active ingredients, which can be encapsulated in this vehicle for pharmaceutical or cosmetic purposes. An innovative technique called AFM-IR, was used to elucidate the behavior of JNP after cutaneous application. This instrument, coupling atomic force microscopy and IR spectroscopy, allowing to perform chemical analysis at the nanometer scale thanks to local absorption measurements. The identification of organic molecules at the nanoscale is possible without any labelling. Before cutaneous application of JNP, the nano-structure of untreated human skin was investigated with AFM-IR. Then, in vitro human skin penetration of JNP was studied using Franz cells, and AFM-IR allowed us to perform ultra-local information investigations.