In recent years, the application of dendrimers in biomedicine attracted much attention from scientists. Dendrimers are interesting for biomedical applications because of their characteristics, including: a hyperbranching, well-defined globular structures, excellent structural uniformity, multivalency, variable chemical composition, and high biological compatibility. In particular, the three-dimensional architecture of dendrimers can incorporate a variety of biologically active agents to form biologically active conjugates. This review of dendrimers focuses on their use as protein mimics, drug delivery agents, anticancer and antiviral therapeutics, and in biomedical diagnostic applications such as chemically modified electrodes.

A novel family of metallopentacycles was constructed by the facile self-assembly of a bis(terpyridine)-carbazole monomer utilizing terpyridine-metal(II)-terpyridine connectivity; its photophysical properties were investigated.

An electro-Fenton-based method was used to promote the regeneration of granular activated carbon (GAC) previously adsorbed with toluene. Electrochemical regeneration experiments were carried out using a standard laboratory electrochemical cell with carbon paste electrodes and a batch electrochemical reactor. For each system, a comparison was made using FeSO4 as a precursor salt in solution (homogeneous system) and an Fe-loaded ion-exchange resin (Purolite C-100, heterogeneous system), both in combination with electrogenerated H2O2 at the GAC cathode. In the two cases, high regeneration efficiencies were obtained in the presence of iron using appropriate conditions of applied potential and adsorption-polarization time. Consecutive loading and regeneration cycles of GAC were performed in the reactor without great loss of the adsorption properties, only reducing the regeneration efficiency by 1% per cycle during 10 cycles of treatment. Considering that, in the proposed resin-containing process, the use of Fe salts is avoided and that GAC cathodic polarization results in efficient cleaning and regeneration of the adsorbent material, this novel electro-Fenton approach could constitute an excellent alternative for regenerating activated carbon when compared to conventional methods.

Gold bead electrodes were modified with submonolayers of 3-mercaptopropionic acid or 2-aminoethanethiol and further reacted with poly(amidoamine) (PAMAM) dendrimers (generation 4.0 and 3.5, respectively) to obtain films on which Prussian Blue (PB) was later absorbed to afford mixed and stable electrocatalytic layers. Experiments carried out with these novel materials not only showed an improved surface coverage of PB on the dendrimer modified electrodes as compared to PB modified gold electrodes prepared under acidic conditions, but also showed an increased stability at neutral pH values for one of the dendrimer containing substrates where the PB film on a bare gold electrode is simply not formed. The dendrimer modified electrodes were also tested as electrocatalytic substrates for the electroxidation of L(+)-ascorbic acid (AA), and it was found that their sensitivity as well as the corresponding detection limits were improved as compared to the voltammetric response of a Au-PB modified electrode. On the basis of UV-visible (UV-vis) spectroscopy and electrochemical experiments, it is suggested that the PB molecules are located within the dendritic structure of the surface attached PAMAM dendrimers.

After intense years of great development, the electrochemical technologies have become very suitable alternatives in niche markets like industrial wastewater reclamation and soil remediation. A key role to achieve a high efficiency in such treatments is played by the characteristics of the coating of the electrodes employed. This paper compares three techniques, namely immersion, painting and electrophoresis, for the preparation of IrO2-Ta2O5ǀTi, so-called dimensionally stable anodes (DSA(®)). The quality of the coatings has been investigated by means of surface and electrochemical analysis. Their ability to generate hydroxyl radicals and degrade aqueous solutions of hydrocarbons like phenanthrene, naphthalene and fluoranthene has been thoroughly assessed. Among the synthesis techniques, electrophoretic deposition yielded the best results, with DSA(®) electrodes exhibiting a homogeneous surface coverage that led to a good distribution of active sites, thus producing hydroxyl radicals that were able to accelerate the degradation of hydrocarbons.

IrO 2-Ta 2 O 5 |Ti electrodes prepared by electrodeposition from different Ir:Ta ratios for the degradation of polycyclic aromatic hydrocarbons,

The hydroxyl radical (•OH) is one of the most attractive reactive oxygen species due to its high oxidation power and its clean (photo)­(electro)­generation from water, leaving no residues and creating new prospects for efficient wastewater treatment and electrosynthesis. Unfortunately, in situ detection of •OH is challenging due to its short lifetime (few ns). Using lifetime-extending spin traps, such as 5,5-dimethyl-1-pyrroline N-oxide (DMPO) to generate the [DMPO–OH]• adduct in combination with electron spin resonance (ESR), allows unambiguous determination of its presence in solution. However, this method is cumbersome and lacks the necessary sensitivity and versatility to explore and quantify •OH generation dynamics at electrode surfaces in real time. Here, we identify that [DMPO–OH]• is redox-active with E 0 = 0.85 V vs Ag|AgCl and can be conveniently detected on Au and C ultramicroelectrodes. Using scanning electrochemical microscopy (SECM), a four-electrode technique capable of collecting the freshly generated [DMPO–OH]• from near the electrode surface, we detected its generation in real time from operating electrodes. We also generated images of [DMPO–OH]• production and estimated and compared its generation efficiency at various electrodes (boron-doped diamond, tin oxide, titanium foil, glassy carbon, platinum, and lead oxide). Density functional calculations, ESR measurements, and bulk calibration using the Fenton reaction helped us unambiguously identify [DMPO–OH]• as the source of redox activity. We hope these findings will encourage the rapid, inexpensive, and quantitative detection of •OH for conducting informed explorations of its role in mediated oxidation processes at electrode surfaces for energy, environmental, and synthetic applications.

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