SERS-based monitoring of the intracellular pH in endothelial cells:the influence of the extracellular environment and tumour necrosis factor-alpha

The intracellular pH plays an important role in various cellular processes. In this work, we describe a method for monitoring of the intracellular pH in endothelial cells by using surface enhanced Raman spectroscopy (SERS) and 4-mercaptobenzoic acid (MBA) anchored to gold nanoparticles as pH-sensitive probes. Using the Raman microimaging technique, we analysed changes in intracellular pH induced by buffers with acid or alkaline pH, as well as in endothelial inflammation induced by tumour necrosis factor-alpha (TNF alpha). The targeted nanosensor enabled spatial pH measurements revealing distinct changes of the intracellular pH in endosomal compartments of the endothelium. Altogether, SERS-based analysis of intracellular pH proves to be a promising technique for a better understanding of intracellular pH regulation in various subcellular compartments.This work was supported by the National Center of Science (grant PRELUDIUM DEC-2012/05/N/ST4/00218) and by the European Union from the resources of the European Regional Development Fund under the Innovative Economy Programme (grant coordinated by JCET-UJ, no. POIG.01.01.02-00-069/09). We also thank the University of Edinburgh School of Chemistry for the Neil Campbell Travel Award for supporting LJ. We also thank Joanna Jalmuzna from the Department of Mathematics and Computer Sciences, Jagiellonian University in Krakow for fitting the calibration curve using Gnuplot software

Present and Future of Surface-Enhanced Raman Scattering.

The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article

Vibrational spectroscopy, potential energy surfaces, and conformations of four H-pyran, cyclohexene, five, six-Dihydro-four H-thiopyran, and cyclopentanone

Vita.ADD ABSTRAC

FAR-INFRARED SPECTRA AND TWO-DIMENSIONAL POTENTIAL ENERGY SURFCES FOR THE OUT-OF-PLANE RING VIBRATIONS OF CYCLOPENTANONE IN ITS S0S_{0} AND S1(n,π∗)S_{1} (n,\pi^{*}) ELECTRONIC STATES

Author Institution: Department of Chemistry, Texas A\&M UniversityThe far-infrared spectra of cyclopentanone has been reexamined. In addition to the ring bending series previously observed in the $80-100 cm^{-1}$ region, ring-twisting bands ($200-240 cm^{-1}$), bend-twist sum bands ($305-335 cm^{-1})$, and bend-twist difference bands were also detected for the first time. From this data a two dimensional potential energy surface with a barrier to planarity of $1408 cm^{-1}$ and a barrier to pseudorotation of 1$358 cm^{-1}$ was determined. This same surface yields calculated frequencies in good agreement for not only the undeuterated cyclopentanone, but also for four isotopomers. In addition to determining the potential energy surface for the $S_{0}$ electronic ground state, we have also utilized our previously reported fluorescence excitation spectra to determine the corresponding potential energy surface of the $S_{1}(n,\Pi^{*})$ electronic excited state. The barrier to planarity in the $S_{1}$ stated is $1273 cm^{-1}$ while the barrier to pseudorotation has been reduced substantially to $850 cm^{-1}$

Nanomaterial-assisted aptamers for optical sensing

Aptamers are single-strand DNA or RNA selected in vitro that bind specifically with a broad range of targets from metal ions, organic molecules, to proteins, cells and microorganisms. As an emerging class of recognition elements, aptamers offer remarkable convenience in the design and modification of their structures, which has motivated them to generate a great variety of aptamer sensors (aptasensors) that exhibit high sensitivity as well as specificity. On the other hand, the development of nanoscience and nanotechnology has generated nanomaterials with novel properties compared with their counterparts in macroscale. By integrating their strengths of both fields, recently, versatile aptamers coupling with novel nanomaterials for designing nanomaterial-assisted aptasensors (NAAs) make the combinations universal strategies for sensitive optical sensing. NAAs have been considered as an excellent sensing platform and found wide applications in analytical community. In this review, we summarize recent advances in the development of various optical NAAs, employing various detection techniques including colorimetry, fluorometry, surface-enhanced Raman scattering (SERS), magnetic resonance imaging (MRI) and surface plasmon resonance (SPR). (c) 2009 Elsevier B.V. All rights reserved.Aptamers are single-strand DNA or RNA selected in vitro that bind specifically with a broad range of targets from metal ions, organic molecules, to proteins, cells and microorganisms. As an emerging class of recognition elements, aptamers offer remarkable convenience in the design and modification of their structures, which has motivated them to generate a great variety of aptamer sensors (aptasensors) that exhibit high sensitivity as well as specificity. On the other hand, the development of nanoscience and nanotechnology has generated nanomaterials with novel properties compared with their counterparts in macroscale. By integrating their strengths of both fields, recently, versatile aptamers coupling with novel nanomaterials for designing nanomaterial-assisted aptasensors (NAAs) make the combinations universal strategies for sensitive optical sensing. NAAs have been considered as an excellent sensing platform and found wide applications in analytical community. In this review, we summarize recent advances in the development of various optical NAAs, employing various detection techniques including colorimetry, fluorometry, surface-enhanced Raman scattering (SERS), magnetic resonance imaging (MRI) and surface plasmon resonance (SPR). (c) 2009 Elsevier B.V. All rights reserved

Effect of LiCoO2 Cathode Nanoparticle Size on High Rate Performance for Li-Ion Batteries

The effect of LiCoO2 cathode nanoparticle size on high-rate performance in Li-ion batteries was investigated using hydrothermally prepared oleylamine-capped LiCoO2 nanoparticles with a particle size of 50 nm obtained at 200 degrees C. Upon annealing as-prepared LiCoO2 at 500, 700, and 900 degrees C, the particle size increased to 100 nm, 300 nm, and 1 mu m, respectively. Ex situ transmission electron microscopy and X-ray diffraction results indicated that the thickness of the solid electrolyte interface (SEI) affected the particle's electrochemical properties at high rates. A LiCoO2 cathode with a smaller particle size had a thicker SEI layer, which acted as a barrier for Li-ion diffusion, resulting in deteriorated rate capabilities at higher C rates. However, irrespective of the particle size, there was no structural degradation after cycling. Rate capability tests were performed under two different electrode densities (3.4 and 2.8 g/cm(3)), and LiCoO2 with a particle size of 300 nm demonstrated the best rate capability at higher C rates. Upon extended cycling at the 7 C rate, LiCoO2 with a particle size of 300 nm exhibited 87 and 150 mAh/g under 3.4 and 2.8 g/cm(3), respectively.close504