Modular Flow-Through Platform for Spectroelectrochemical Analysis.

A new type of flow platform for electrochemical and spectroelectrochemical measurements is presented. Finite element method simulations confirm that the hydrodynamic profile within the device is not turbulent and provides an analytical platform for the investigation of homogeneous kinetics, radical lifetimes, and reaction mechanisms. The modular "plug and play" configuration of the platform allows one to carry out electrochemistry and spectroscopy individually or simultaneously. Specific demonstrations of electroanalytical measurements using the flow system platform includes voltammetric analysis of organometallic compounds and quantitative analysis of ascorbic acid in commercial orange juice samples. Combined spectroelectrochemical demonstrations include electrochemical luminescence of ruthenium compounds and ligand exchange reactions of iron complexes using UV-vis spectroscopy.

Ferrocene-Modified Phospholipid: An Innovative Precursor for Redox-Triggered Drug Delivery Vesicles Selective to Cancer Cells.

Controlled payload release is one of the key elements in the creation of a reliable drug delivery system. We report the discovery of a drug delivery vessel able to transport chemotherapeutic agents to target cancer cells and selectively trigger their release using the electrochemical activity of a ferrocene-modified phospholipid. Supported by in vitro assays, the competitive advantages of this discovery are (i) the simple one step scalability of the synthetic process, (ii) the stable encapsulation of toxic drugs (doxorubicin) during transport, and (iii) the selective redox triggering of the liposomes to harness their cytotoxic payload at the cancer site. Specifically, the redox-modified giant unilamellar vesicle and liposomes were characterized using advanced methods such as scanning electrochemical microscopy (SECM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and fluorescent imaging.

Determination of low levels of cadmium ions by the under potential deposition on a self-assembled monolayer on gold electrode.

The electrochemical determination of low levels of Cd using a self-assembled monolayer (SAM) modified Au electrode is reported. Determination was based on the stripping of Cd, which was deposited by under potential deposition (UPD). A series of short alkanethiol SAMs bearing different end groups, i.e., sulfonate, carboxylate and ammonium, were examined. Lowest level of detection (ca. 50 ngL(-1)) was achieved with a 3-mercaptopropionic acid (MPA) monolayer using subtractive anodic square wave voltammetry (SASV). Additional surface methods, namely, reductive desorption and X-ray photoelectron spectroscopy, were applied to determine the interfacial structure of the electrodeposited Cd on the modified electrodes. We conclude that the deposited Cd forms a monoatomic layer, which bridges between the gold surface and the alkanethiol monolayer associating with both the gold and the sulfur atoms.

A new approach for measuring the redox state and redox capacity in milk.

Milk is one of the most fundamental ingredients in our diet. It is a complex biological fluid, which contains numerous substances, ranging from metal ions to enzymes. There is a constant search for an improved way of monitoring its quality and freshness. These are highly affected by the redox state of milk, which is governed by different species. In this study, we investigated the redox state and capacity of milk. Specifically, milk was potentiometrically titrated using different redox mediators, which enabled facilitation of electron transfer between different oxidizable species and the electrode. We found that the iodine/iodide redox couple was superior for measuring the redox capacity of milk. These measurements revealed that milk is not a well-poised system due to the presence of at least two different oxidizable species, one of which is hydrophobic while the other is hydrophilic and therefore could be separated by phase separation of milk.