Ultrasensitive Surface-Enhanced Raman Spectroscopy Detection by Porous Silver Supraparticles from Self-Lubricating Drop Evaporation

This work demonstrates an original and ultrasensitive approach for surface-enhanced Raman spectroscopy (SERS) detection based on evaporation of self-lubricating drops containing silver supraparticles. The developed method detects an extremely low concentration of analyte that is enriched and concentrated on sensitive SERS sites of the compact supraparticles formed from drop evaporation. A low limit of detection of 10^-16 M is achieved for a model hydrophobic compound rhodamine 6G (R6G). The quantitative analysis of R6G concentration is obtained from 10^-5 to 10^-11 M. In addition, for a model micro-pollutant in water triclosan, the detection limit of 10^-6 M is achieved by using microliter sample solutions. The intensity of SERS detection in this approach is robust to the dispersity of the nanoparticles in the drop but became stronger after a longer drying time. The ultrasensitive detection mechanism is the sequential process of concentration, extraction, and absorption of the analyte during evaporation of self-lubrication drop and hot spot generation for intensification of SERS signals. This novel approach for sample preparation in ultrasensitive SERS detection can be applied to the detection of chemical and biological signatures in areas such as environment monitoring, food safety, and biomedical diagnostics.Comment: 25 Pages, 12 Figure

Protective effect of eugenol from Mesua ferrea on the oxidative damages caused by 5-fluorouracil in PBMC cells

78-855-Fluorouracil (5-FU), a pyrimidine analogue with fluorine at C5 position, is one of the chemotherapy drugs used to treat various cancers. Though 5-FU is a very promising anticancer drug, it can cause side effects such as coronary thrombosis, intestinal mucositis, cognitive impairment, and anaemia through the generation of free radicals, damages the normal cells and also leads to apoptosis. To overcome such toxic effects of 5-FU, in the present work we have explored the cytoprotective potential of eugenol, the antioxidant active compound available in ethanolic extract of an Indian herbal drug Mesua ferrea. Aim of the present study was to evaluate the cytoprotective effect of eugenol against 5-FU toxicity in peripheral blood mononuclear cells (PBMC). Based on MTT assay, it is noticed that eugenol significantly prevents the toxicity of 5-FU (73%) in PBMC cells. Eugenol has lowered the generation of intra-cellular ROS (20035.5 AU) when compared to 5-FU treated cells (58918.5 AU). Eugenol exhibited remarkable inhibition of lipid peroxidation (43%) and cell membrane damage (LDH release: 488.02 IU/L). Thus, eugenol prevents apoptosis-induced cell death when compared with 5-FU in PBMC cells and hence it can be used to overcome the cytotoxicity caused by 5-FU and it warrants further study

Development of Sustainable Rapid Microwave Assisted Process for Extracting Nanoporous Si from Earth Abundant Agricultural Residues and Their Carbon-based Nanohybrids for Lithium Energy Storage

Bamboo culm (BC), rice husk (RH), and sugarcane bagasse (SB) are the most earth abundant, low-cost, and eco-friendly agricultural residues that contain a substantial amount of biogenic silica (SiO₂) in the form of amorphous hydrated silica grains. In this study, we successfully extracted SiO₂ from various agricultural residues such as BC, RH, and SB via rapid microwave assisted solid-state ashing (MW-SS), followed by microwave assisted magnesiothermic reduction (MW-MR) of SiO₂ into crystalline silicon (Si) at <650 °C for 30 min without the need for a reducing gas atmosphere. The MW-MR process further supports the development of an interconnected three-dimensional porous Si network with a pore diameter of 50–80 nm and wall thickness of ∼23 nm. The obtained Si is further decorated with dimensionally modulated carbon-based materials such as carbon (C), graphene nanosheets (GNS), and multiwall carbon nanotubes (MWCNT), which can offer higher delithiation capacities (1997, 1290, and 1166 mAh g^–1, respectively) compared to pristine Si (956 mAh g^–1) extracted from RH at C/5 rate after 200 cycles. These results suggest that the earth-abundant BC, RH, and SB could be sustainable resources for large-scale production of nanoporous crystalline Si, which has been extracted via an energy efficient, low-cost microwave assisted sustainable process for lithium ion battery anodes

Electrochemical studies of poly (3,4-ethylenedioxythiophene) PEDOT/VS<SUB>2</SUB> nanocomposite as a cathode material for rechargeable lithium batteries

Here, we demonstrate the electrochemical characterization of a new type of layered poly (3,4-ethylenedioxythiophene) PEDOT/ VS<SUB>2</SUB> nanocomposite. It has been prepared via flocculation of delaminated VS<SUB>2</SUB> with subsequent in situ oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) with VS<SUB>2</SUB> as a host material in the presence of an external oxidizing agent. The interlayer spacing of VS<SUB>2</SUB> expands from 5.71 to 14.01 &#197; and this interlayer separation is consistent with the existence of a monolayer of PEDOT in the VS<SUB>2</SUB> framework. X-ray diffraction, XPS and TEM studies have been shown the change in interlayer separation is consistent with the existence of two phases of organic and inorganic species in the nanocomposites corresponding to the intercalation of PEDOT in the VS<SUB>2</SUB> framework. The application potential of the nanocomposite as a cathode material for rechargeable lithium batteries is also demonstrated by the electrochemical intercalation of lithium into the PEDOT/VS<SUB>2</SUB> nanocomposite, where a significant enhancement in the discharge capacity is observed (~130 mAh/g) compared to that (80 mAh/g) for pristine VS<SUB>2</SUB>

Cyclic voltammetry, electrochemical impedance and ex situ X-ray diffraction studies of electrochemical insertion and deinsertion of lithium ion into nanostructured organic-inorganic poly(3,4-ethylenedioxythiophene) based hybrids

10.1016/j.jelechem.2007.02.013Journal of Electroanalytical Chemistry6032287-296JECH

Highly efficient organic-inorganic poly(3,4-ethylenedioxythiophene)-molybdenum trioxide nanocomposite electrodes for electrochemical supercapacitor

In this paper, we report a highly efficient organic-inorganic nanocomposite electrode with enhanced double layer capacitance, which has been synthesized using 3,4-ethylenedioxythiophene and crystalline molybdenum trioxide (MoO<SUB>3</SUB>) in the presence of an external oxidizing agent. The interlayer spacing of MoO<SUB>3</SUB> upon intercalation expands from 6.93 to 13.46 Å and is followed by an exfoliation and restacking process. The resulting nanocomposite is characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and four probe conductivity measurements. The application potential of this nanocomposite as an electrode material for electrochemical supercapacitors has been investigated, highlighting the unusual enhancement of double layer capacitance of poly(3,4-ethylenedioxythiphene) (PEDOT-MoO<SUB>3</SUB>) nanocomposites ( ~300 F g<SUP>−1</SUP>) compared to that of pristine MoO<SUB>3</SUB> (~40 mF g<SUP>−1</SUP>). The improved electrochemical performance is attributed to the intercalation of electronically conducting PEDOT between MoO<SUB>3</SUB> layers with enhanced bidimensionality and an increase in the surface area

Protective effect of eugenol from Mesua ferrea on the oxidative damages caused by 5-fluorouracil in PBMC cells

5-Fluorouracil (5-FU), a pyrimidine analogue with fluorine at C5 position, is one of the chemotherapy drugs used to treat various cancers. Though 5-FU is a very promising anticancer drug, it can cause side effects such as coronary thrombosis, intestinal mucositis, cognitive impairment, and anaemia through the generation of free radicals, damages the normal cells and also leads to apoptosis. To overcome such toxic effects of 5-FU, in the present work we have explored the cytoprotective potential of eugenol, the antioxidant active compound available in ethanolic extract of an Indian herbal drug Mesua ferrea. Aim of the present study was to evaluate the cytoprotective effect of eugenol against 5-FU toxicity in peripheral blood mononuclear cells (PBMC). Based on MTT assay, it is noticed that eugenol significantly prevents the toxicity of 5-FU (73%) in PBMC cells. Eugenol has lowered the generation of intra-cellular ROS (20035.5 AU) when compared to 5-FU treated cells (58918.5 AU). Eugenol exhibited remarkable inhibition of lipid peroxidation (43%) and cell membrane damage (LDH release: 488.02 IU/L). Thus, eugenol prevents apoptosis-induced cell death when compared with 5-FU in PBMC cells and hence it can be used to overcome the cytotoxicity caused by 5-FU and it warrants further study