Surface-Enhanced Raman Spectroscopy Using Gold-Coated Horizontally Aligned Carbon Nanotubes

Gold-coated horizontally aligned carbon nanotube (Au-HA-CNT) substrates were fabricated for surface-enhanced Raman spectroscopy (SERS). the Au-HA-CNT substrates, which are granular in nature, are easy-to-prepare with large SERS-active area. Enhancement factors (EFs) of ~10⁷ were achieved using the Au-HA-CNTs as substrates for rhodamine 6G (R6G) molecules. Maximum enhancement was found when the polarization direction (E-field) of the incident laser beam was parallel to the aligned direction of the HA-CNTs. Simulations using the finite-difference time-domain (FDTD) method were carried out for the granular Au-HA-CNT samples. Enhancement mechanisms and determination of EFs were analyzed. Biological samples, including ¹³C- and deuterium (D)-labeled fatty acids and Coccomyxa sp. c-169 microalgae cells, were also measured using this SERS substrate. the limits of detection (LODs) of D- and ¹³C-labeled fatty acids on the SERS substrate were measured to be around 10 nM and 20 nM, respectively. Significantly enhanced Raman signals from the microalgae cells were acquired using the SERS substrate

Re-negotiating reproductive technologies:the 'Public Foetus' revisited

In debates over abortion, the foetus and the woman have been continually positioned as antagonists. Given the stakes involved in such debates about personal integrity, individual responsibility, life and death, it is no wonder that many radical feminist authors have concentrated on refocusing the attention on women and away from the disembodied foetus. Such writers have worked hard to decode and deconstruct the public foetus in our midst and have mobilized interpretative tools such as cultural criticism to contextualize the production and consumption of foetal images. Barbara Duden's book, The Public Foetus, is an important and interesting contribution to this effort, which is still taken up by authors writing in this field. Duden's strategy is to seek to remind us (and in particular those who are involved in reproductive medicine) that pregnancy is concentrated in the embedded pregnant woman rather than the disembodied ‘public foetus’ and she attempts to retrieve the embodied woman as the site of pregnancy through what Michaels has termed a ‘fetal disappearing act’. While this may create as many problems for women as it resolves, I would argue that, while the ‘public foetus’ continues to loom large in the politics of abortion and women's positions in relation to the new reproductive technologies remain contested, Duden's work remains important in the continuing debate about how women's reproductive freedom can be continually re-negotiated and re-established

Laser Treated Carbon Nanotube Yarn Microelectrodes for Rapid and Sensitive Detection of Dopamine in Vivo

Carbon nanotube yarn microelectrodes (CNTYMEs) exhibit rapid and selective detection of dopamine with fast-scan cyclic voltammetry (FSCV); however, the sensitivity limits their application in vivo. In this study, we introduce laser treatment as a simple, reliable, and efficient approach to improve the sensitivity of CNTYMEs by threefold while maintaining high temporal resolution. The effect of laser treatment on the microelectrode surface was characterized by scanning electron microscopy, Raman spectroscopy, energy dispersion spectroscopy, and laser scanning confocal microscopy. Laser treatment increases the surface area and oxygen containing functional groups on the surface, which provides more adsorption sites for dopamine than at unmodified CNTYMEs. Moreover, similar to unmodified CNTYMEs, the dopamine signal at laser treated CNTYMEs is not dependent on scan repetition frequency, unlike the current at carbon fiber microelectrodes (CFMEs) which decreases with increasing scan repetition frequency. This frequency independence is caused by the significantly larger surface roughness which would trap dopamine-<i>o</i>-quinone and amplify the dopamine signal. CNTYMEs were applied as an in vivo sensor with FSCV for the first time, and laser treated CNTYMEs maintained high dopamine sensitivity compared to CFMEs with an increased scan repetition frequency of 50 Hz, which is 5-fold faster than the conventional frequency. CNTYMEs with laser treatment are advantageous because of their easy fabrication, high reproducibility, fast electron transfer kinetics, high sensitivity, and rapid in vivo measurement of dopamine and could be a potential alternative to CFMEs in the future