Molecularly imprinted polymer (MIP) particles offer many advantages as recognition objects. Therefore, we examd. thoroughly the effect of various exptl. parameters including cross-linker concn., nature of solvent, type of template and its concn., reaction vol. and temp. on the formation of particulate MIPs using pptn. polymn. The particles were characterized by various methods, such as XHR-SEM, HR-TEM and BET. Statistical calcns. were carried out using ImageJ software over population of at least 200 particles in each expt. The reproducibility of MIP synthesis was examd. and the SD was better than 10%. MIP particles were imprinted with different Sudan dye derivs. (Sudan II, III, IV and Sudan orange G). Raman and FTIR spectroscopies were used to prove the successful imprinting. Reuptake measurements were carefully compared between non-imprinted molecularly polymer (NIP) and MIP particles employing the same quantity and similar diam. and polydispersity of NIP and MIP, as never reported before. The results showed that MIP particles imprinted by Sudan IV showed higher selectivity toward this specific dye as compared with MIPs imprinted by other Sudan dyes and NIPs. [on SciFinder(R)]

This study extends the concept of nanoparticle imprinted matrixes (NAIMs) to systems, in which template nanoparticles (NPs) are immobilized on a conducting surface and a polymer matrix is built around them before the release of the template NPs. Specifically, citrate-stabilized AuNPs, 40 nm in diam., were bound to a 3-aminopropyltriethoxysilane (APTES)-modified indium tin oxide (ITO) electrode at pH 5. Subsequently, a polymer matrix was generated by electropolymn. of self-inhibiting poly(phenol) (PPh) layer. The template AuNPs were removed either by electrooxidn. of the Au core during linear sweep voltammetry (LSV) in Cl–contg. aq. soln. or by chem. oxidn. in aq. KCN soln. After template removal, nanocavities were left behind, which showed size-selective in the competitive reuptake of analyte NPs demonstrated by the preference for citrate-stabilized silver nanoparticles (AgNPs) with 20 nm diam. over AuNPs with 50 nm diam. The remaining nanocavities and their size-recognition ability were examd. by SEM and LSV. Complementing studies by X ray photoelectron spectroscopy and scanning force microscopy corroborated the template embedding, template release and analyte NP uptake. [on SciFinder(R)]

Measuring and monitoring of protein oxidn. modifications is important for biopharmaceutical process development and stability assessment during long-term storage. Currently available methods for biomols. oxidn. anal. use time-consuming peptide mapping anal. Therefore, it is desirable to develop high-throughput methods for advanced process control of protein oxidn. Here, we present a novel approach by which oxidative protein modifications are monitored by an indirect potentiometric method. The method is based on adding an electron mediator, which enhances electron transfer (ET) between all redox species and the electrode surface. Specifically, the procedure involves measuring the sharp change in the open circuit potential (OCP) for the mediator system (redox couple) as a result of its interaction with the oxidized protein species in the soln. Application of Pt and Ag/AgCl microelectrodes allowed for a high-sensitivity protein oxidn. anal. We found that the Ru(NH3)2+/3+6 redox couple is suitable for measuring the total oxidn. of a wide range of therapeutic proteins between 1.1 and 13.6%. Accuracy detd. by comparing with the known percentage oxidn. of the ref. std. showed that percentage oxidn. detd. for each sample was within ±20% of the expected percentage oxidn. detd. by mass spectrometry. [on SciFinder(R)]

VO2 has garnered much attention in recent years as a promising candidate for thermochromic window applications due to rising awareness about energy conservation. However, the trade-off between improving the luminous transmittance (Tlum) and solar modulation ability (ΔTsol) limits the commercialization of VO2-based smart windows. Four major nanostructuring approaches were implemented to enhance both Tlum and ΔTsol, namely nanocomposites, nanoporous films, biomimetic moth-eye structures and anti-reflection coating (ARC) multilayers. This work demonstrates a novel approach that fabricates periodic, micro-patterned structures of VO2 using a facile screen printing method. The micro-patterned structure is able to favorably transmit visible light without sacrificing high near-IR modulation, and the patterned film shows improved Tlum (67% vs. 60%) and ΔTsol (8.8% vs. 6.9%) compared with continuous films. By varying the thickness, periodicity and solid concn., this approach can give a ΔTsol of 14.9% combined with a Tlum of 43.3%, which is comparable, if not superior to, some of the best reported results found using other approaches. [on SciFinder(R)]

The toxicity of nanoparticles is not only a function of the constituting material but depends largely on their size, shape and stabilizing shell. Hence, the speciation of nanoscale objects, namely, their detection and sepn. based on the different species, similarly to heavy metals, is of outmost importance. Here we demonstrate the speciation of gold nanoparticles (AuNPs) and their electrochem. detection using the concept of "nanoparticles imprinted matrixes" (NAIM). Neg. charged AuNPs are adsorbed as templates on a conducting surface previously modified with polyethylenimine (PEI). The selective matrix is formed by the adsorption of either oleic acid (OA) or poly(acrylic acid) (PAA) on the non-occupied areas. The AuNPs are removed by electrooxidn. to form complementary voids. These voids are able to recognize the AuNPs selectively based on their size. Furthermore, the selectivity could be improved by adsorbing an addnl. layer of 1-hexadecylamine, which deepened the voids. Interestingly, silver nanoparticles (AgNPs) were also recognized if their size matched those of the template AuNPs. The steps in assembling the NAIMs and the reuptake of the nanoparticles were characterized carefully. The prospects for the anal. use of NAIMs, which are simple, of small dimension, cost-efficient and portable, are in the sensing and sepn. of nanoobjects. [on SciFinder(R)]

The toxicity of nanoparticles is not only a function of the constituting material but depends largely on their size, shape and stabilizing shell. Hence, the speciation of nanoscale objects, namely, their detection and sepn. based on the different species, similarly to heavy metals, is of outmost importance. Here we demonstrate the speciation of gold nanoparticles (AuNPs) and their electrochem. detection using the concept of "nanoparticles imprinted matrixes" (NAIM). Neg. charged AuNPs are adsorbed as templates on a conducting surface previously modified with polyethylenimine (PEI). The selective matrix is formed by the adsorption of either oleic acid (OA) or poly(acrylic acid) (PAA) on the non-occupied areas. The AuNPs are removed by electrooxidn. to form complementary voids. These voids are able to recognize the AuNPs selectively based on their size. Furthermore, the selectivity could be improved by adsorbing an addnl. layer of 1-hexadecylamine, which deepened the voids. Interestingly, silver nanoparticles (AgNPs) were also recognized if their size matched those of the template AuNPs. The steps in assembling the NAIMs and the reuptake of the nanoparticles were characterized carefully. The prospects for the anal. use of NAIMs, which are simple, of small dimension, cost-efficient and portable, are in the sensing and sepn. of nanoobjects. [on SciFinder(R)]

The present invention relates to electrochem. initiated bioadhesive compns. comprising biocompatible polymers contg. derivs. of diazonium, arylsulfonium, or diaryliodonium in general, and to their use in tissue fixation, in particular. [on SciFinder(R)]

Sol-gel/carbon nanotube (CNT) nano-composite films were electrochem. deposited by applying a neg. potential to a conducting substrate, i.e. indium tin oxide (ITO) and an Ag grid printed on polyethylene terephthalate (PET). The deposition is driven by the local pH rise on the cathode that catalyzes the formation of sol-gel films. The latter serve as a binder and trap for CNTs. The deposition can be well manipulated by the deposition potential and time, and the film can be selectively electrodeposited on the conductive parts of Ag grids printed on PET from an optimized dispersion. The thickness, transmittance, morphol. and hydrophilicity of the films are characterized by profilometry, spectrophotometry, SEM (SEM) and water contact angle, resp. It is further revealed that the electrodeposited sol-gel/CNT composite films have non-linear optical properties and exhibit pronounced antireflective performance (specular reflection < 0.5%) over a visible to long-wave IR range, allowing their potential application as optical materials. [on SciFinder(R)]

The electrochemical detection of mercury in aqueous solutions was studied at glassy carbon (GC) and indium-tin oxide (ITO) electrodes modified by gold nanoparticles (Au NPs). Two methods of modification were used: electrochemical reduction of HAuCl4 and electrostatic adsorption of Au NPs stabilized by citrate. We found that the Au NPs modified surfaces yielded higher sensitivity and sharper and more reproducible stripping peaks of Hg as compared with the bare electrodes. The effect of the modification by Au NPs on the stripping potential was examined. Interestingly, the stripping of Hg on GC and ITO modified by Au NPs occurred at the same potential as on bare GC and ITO, respectively. Only the full coverage of ITO by either electrochemically deposited Au for a long time or by vapor deposition, shifted the stripping potential more positive by ca. 0.4 V to that observed on a bare Au electrode. These and further experiments led us to conclude that the Au NPs served as nucleation sites for the deposition of Hg, whereas the GC or ITO are superior for the stripping of mercury. Hence, a combination of well-defined Au NPs on ITO or GC were found ideal for the electrochemical detection of Hg. Indeed, we achieved a remarkable detection limit of 1 μm·L(-1) of Hg using an ITO surface modified by electrostatically adsorbed Au NPs.[on SciFinder (R)]

The units of concn. of mercury noted as "μm L-1" should read as "ng L-1.". [on SciFinder(R)]

The electrochem. detection of Hg in aq. solns. was studied at glassy C (GC) and In-Sn oxide (ITO) electrodes modified by Au nanoparticles (Au NPs). Two methods of modification were used: electrochem. redn. of HAuCl4 and electrostatic adsorption of Au NPs stabilized by citrate. We found that the Au NPs modified surfaces yielded higher sensitivity and sharper and more reproducible stripping peaks of Hg as compared with the bare electrodes. The effect of the modification by Au NPs on the stripping potential was examd. Interestingly, the stripping of Hg on GC and ITO modified by Au NPs occurred at the same potential as on bare GC and ITO, resp. Only the full coverage of ITO by either electrochem. deposited Au for a long time or by vapor deposition, shifted the stripping potential more pos. by \~0.4 V to that obsd. on a bare Au electrode. These and further expts. led us to conclude that the Au NPs served as nucleation sites for the deposition of Hg, whereas the GC or ITO are superior for the stripping of Hg. Hence, a combination of well-defined Au NPs on ITO or GC were found ideal for the electrochem. detection of Hg. We achieved a remarkable detection limit of 1 μm/L of Hg using an ITO surface modified by electrostatically adsorbed Au NPs. [on SciFinder(R)]