Interfacial electron-shuttling processes across KolliphorEL monolayer grafted electrodes

PEGylation of zinc nanoparticles amplifies their ability to enhance olfactory responses to odorant

Olfactory responses are intensely enhanced with the addition of endogenous and engineered primarily-elemental small zinc nanoparticles (NPs). With aging, oxidation of these Zn nanoparticles eliminated the observed enhancement. The design of a polyethylene glycol coating to meet storage requirements of engineered zinc nanoparticles is evaluated to achieve maximal olfactory benefit. The zinc nanoparticles were covered with 1000 g/mol or 400 g/mol molecular weight polyethylene glycol (PEG). Non-PEGylated and PEGylated zinc nanoparticles were tested by electroolfactogram with isolated rat olfactory epithelium and odorant responses evoked by the mixture of eugenol, ethyl butyrate and (±) carvone after storage at 278 K (5 ^oC), 303 K (30 ^oC) and 323 K (50 ^oC). The particles were analyzed by atomic force microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and laser Doppler velocimetry. Our data indicate that stored ZnPEG400 nanoparticles maintain physiologically-consistent olfactory enhancement for over 300 days. These engineered Nanoparticles support future applications in olfactory research, sensitive detection, and medicine.

A nanostructured Fc(COCH3)2 film prepared using silica monolayer colloidal crystal templates and its electrochromic properties

Since oxidation and reduction reactions mainly take place on surfaces, enlarging the specific surface of redox materials is the key to achieving excellent electrochemical performance. In this work, by using silica monolayer colloidal crystal templates (MCCTs), a nanostructured Fc(COCH₃)₂ film is prepared successfully, and such a nanostructure could exhibit the following unique electrochemical properties: the MCCTs could impede the aggregation tendency of Fc(COCH₃)₂ and possess high electrochemical activity; Fc(COCH₃)₂ enlarges the contact area and offers more active sites and faster electronic transmission channels. The structure, optical and electrochemical properties of the nanostructured Fc(COCH₃)₂ were tested and then compared with those of compact Fc(COCH₃)₂ films to evaluate the role of the nanoarchitecture. The unique structure design of the Fc(COCH₃)₂ film enables outstanding performance, showing a large transmittance change (ΔT) of 37% at 550 nm when switched between 0.5 V and -2.5 V, which is approximately ninefold higher than that of the compact Fc(COCH₃)₂ film (approximately 4%). Response times of coloration and bleaching are found to be only 16.15 s and 5.56 s. Furthermore, the nanostructured Fc(COCH₃)₂ film shows much better cycling stability than the compact one. The results indicate that the nanostructure could significantly improve the electrochemical performance of the Fc(COCH₃)₂ film due to the increase in electrochemical active sites and the enhancement of the "D-to-A" redox switch of ferrocene.