Evaluation of Metal Oxide Surface Catalysts for the Electrochemical Activation of Amino Acids.

Electrochemical detection of amino acids is important due to their correlation with certain diseases; however, most amino acids require a catalyst to electrochemically activate. One common catalyst for electrochemical detection of amino acids are metal oxides. Metal oxide nanoparticles were electrodeposited onto glassy carbon and platinum working electrodes. Cyclic voltammetry (CV) experiments in a flow cell were performed to evaluate the sensors' ability to detect arginine, alanine, serine, and valine at micromolar and nanomolar concentrations as high as 4 mM. Solutions were prepared in phosphate buffer saline (PBS) and then 100 mM NaOH. Specifically, NiO surfaces were responsive to amino acids but variable, especially when exposed to arginine. Polarization resistance experiments and scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) data indicated that arginine accelerated the corrosion of the NiO catalyst through the formation of a Schiff base complex.

Porphyrin-Cored Polymer Nanoparticles: Macromolecular Models for Heme Iron Coordination.

Porphyrin-cored polymer nanoparticles (PCPNs) were synthesized and characterized to investigate their utility as heme protein models. Created using collapsible heme-centered star polymers containing photodimerizable anthracene units, these systems afford model heme cofactors buried within hydrophobic, macromolecular environments. Spectroscopic interrogations demonstrate that PCPNs display redox and ligand-binding reactivity similar to that of native systems and thus are potential candidates for modeling biological heme iron coordination.