Sustained release of alpha-methylacyl-CoA racemase (AMACR) antibody-conjugated and free doxorubicin from silica nanoparticles for prostate cancer cell growth inhibition.

This article presents silica nanoparticles for the sustained release of AMACR antibody-conjugated and free doxorubicin (DOX) for the inhibition of prostate cancer cell growth. Inorganic MCM-41 silica nanoparticles were synthesized, functionalized with phenylboronic acid groups (MCM-B), and capped with dextran (MCM-B-D). The nanoparticles were then characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, zeta potential analysis, nitrogen sorption, X-ray diffraction, and thermogravimetric analysis, before exploring their potential for drug loading and controlled drug release. This was done using a model prostate cancer drug, DOX, and a targeted prostate cancer drug, α-Methyl Acyl-CoA racemase (AMACR) antibody-conjugated DOX, which attaches specifically to AMACR proteins that are overexpressed on the surfaces of prostate cancer cells. The kinetics of sustained drug release over 30 days was then studied using zeroth order, first order, second order, Higuchi, and the Korsmeyer-Peppas models, while the thermodynamics of drug release was elucidated by determining the entropy and enthalpy changes. The flux of the released DOX was also simulated using the COMSOL Multiphysics software package. Generally, the AMACR antibody-conjugated DOX drug-loaded nanoparticles were more effective than the free DOX drug-loaded formulations in inhibiting the growth of prostate cancer cells in vitro over a 96 h period. The implications of the results are then discussed for the development of drug-eluting structures for the localized and targeted treatment of prostate cancer.

Electrochemical Nitrogen Reduction to Ammonia Under Ambient Conditions: Stakes and Challenges.

Aqueous electrochemical nitrogen reduction (ENR) to ammonia (NH3 ) under ambient conditions is considered as an alternative to the energy-intensive Haber-Bosch process for ammonia production. Many metal, non-metal, carbon-based materials along with metal-chalcogenides, metal-nitrides have been explored for their ENR activity. The reported NH3 production through ENR is still in the micro-gram level and often falls in the range of NH3 and NOx contaminations from the surrounding. The quantification of NH3 at very low concentration possess enormous challenge in this field and thus many reported ENR electrocatalysts suffer from reproducibility issue. This review highlights in detail the challenges associated with ENR in aqueous medium and necessitates standardization of protocols to quantify the low concentration of NH3 free of false-positives. It concludes the prospects of electrochemical NH3 production through lithium-mediated N2 reduction.

Facts or Artifacts: Pitfalls in Quantifying Sub-ppm Levels of Ammonia Produced from Electrochemical Nitrogen Reduction.

Synthesis of ammonia through electrochemical nitrogen reduction (ENR) is emerging as one of the attractive research areas in recent years, notwithstanding the enormous challenges it faces in quantification of ammonia at very low concentrations. Several reports claiming high production rate are unwittingly compromised by the accuracy of analyzing a very low concentration (<1 ppm) of ammonia in the electrolyte post-ENR reaction using the indophenol method. Therefore, in this work, we have highlighted the significance of selecting and standardizing a right protocol encompassing admissible levels of oxidants and a complexing agent, citrate (to mitigate the effect of interfering metal ions), through elaborate control experiments. In addition, the importance of setting the lowest limit of ammonia concentration that can be accurately quantified by the indophenol method is also justified. Further, the experimental observations were summarized into a protocol, which was followed to re-evaluate the performance of two well-claimed electrocatalysts for ENR reported recently in the literature.