Doping Independent Work Function and Stable Band Gap of Spinel Ferrites with Tunable Plasmonic and Magnetic Properties

Tuning optical or magnetic properties of nanoparticles, by addition of impurities, for specific applications is usually achieved at the cost of band gap and work function reduction. Additionally, conventional strategies to develop nanoparticles with a large band gap also encounter problems of phase separation and poor crystallinity at high alloying degree. Addressing the aforementioned trade-offs, here we report Ni–Zn nanoferrites with energy band gap (Eg) of ≈3.20 eV and a work function of ≈5.88 eV. While changes in the magnetoplasmonic properties of the Ni–Zn ferrite were successfully achieved with the incorporation of bismuth ions at different concentrations, there was no alteration of the band gap and work function in the developed Ni–Zn ferrite. This suggests that with the addition of minute impurities to ferrites, independent of their changes in the band gap and work function, one can tune their magnetic and optical properties, which is desired in a wide range of applications such as nanobiosensing, nanoparticle based catalysis, and renewable energy generation using nanotechnology

Antileishmanial Activity of Pyrazolopyridine Derivatives and Their Potential as an Adjunct Therapy with Miltefosine

A series of pyrazolo­(dihydro)­pyridines was synthesized and evaluated for antileishmanial efficacy against experimental visceral leishmaniasis (VL). Among all compounds, <b>6d</b> and <b>6j</b> exhibited better activity than miltefosine against intracellular amastigotes. Compound <b>6j</b> (50 mg/kg/day) was further studied against Leishmania donovani/BALB/c mice via the intraperitoneal route for 5 days and displayed >91 and >93% clearance of splenic and liver parasitic burden, respectively. Combination treatment of <b>6j</b> with a subcurative dose of miltefosine (5 mg/kg) in BALB/c mice almost completely ameliorated the disease (>97% inhibition) by augmenting nitric oxide generation and shifting the immune response toward Th1. Furthermore, investigating the effect of <b>6j</b> on <i>Leishmania</i> promastigotes revealed that it induced molecular events, such as a loss in mitochondrial membrane potential, externalization of phosphatidylserine, and DNA fragmentation, that ultimately resulted in the programmed cell death of the parasite. These results along with pharmacokinetic studies suggest that <b>6j</b> could be a promising lead for treating VL as an adjunct therapy with miltefosine