Electron biologically important entities

The transfer of a single electron between two chemical entities is the simplest of oxidation-reduction processes, but it is of central importance in vast areas of chemistry. Electron transfer processes constitute the fundamental steps in biological utilization of oxygen, in electrical conductivity, in oxidation reduction reactions of organic and inorganic substrates, in many catalytic processes, in the transduction of the sun s energy by plants and by synthetic solar cells, and so on. The breadth and complexity of the subject is evident from the five volume handbook Electron Transfer in Chemistry (V. Balzani, Ed.), published in 2001. The most fimdamental principles that govern the efficiencies, the yields or the rates of electron-transfer processes are independent of the nature of the substrates. The properties of the substrates do dictate the conditions for apphcability of those fimdamental... 

A.7.6 Electrons and protons are the most important biological entities that require quanmm treatment on a routine basis. 

Ions are very important in biological processes because they represent the charge carriers in biological organisms. In the chemical soup inside biological entities, electrical current is carried by ions rather than by solitary electrons. 

One of the most important aspects of nanoparticles in biomedical applications is their surface functionalization in order to improve their biocompatibility with biological entities, and Fourier infrared spectroscopy (FTIR) is very useful technique that provides information about iron oxides in their ground electronic state, and when this material is bonding with a polymeric coating provides information about mechanism of functionalized magnetic nanopartides. This technique is widely used in characterization nanopartides due to its simplicity and availability. In magnetite structure it provides information about the excitation of vibration or rotation of the trivalent and divalent iron cations and allows knowing the occupied sites when the divalent iron is replaced with other cations. 

Idilayer formed by the lipid. In addition to vesicles and liposomes formed by biologically derived phospholipids, synthetic vesicles formed by surfactant derivatives such as dioctadecyl dimethyl ammonium chloride (DODAC) have been reported recently. Vesicles, unlike micelles are static entities and can accomodate a substantial number of guest molecules per aggregate. As in micelles, these systems can organise donors and acceptors, lower ionisation potentials and more importantly through their interfaces or electrical double layer allow for some kinetic control of electron transfers. 

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