Analytical Methods Blog

Synthesis of gold-antibody nanocomposite and AFP immunoassay

The construction of successful biosensors is often hampered by the difficulty of immobilising biomolecules onto the desired surface in an orderly fashion. As a support medium, nanoparticles display a particularly large surface-to-volume ratio and their physical properties can be adjusted to match requirements.

Researchers led by Zhihui Dai from the Nanjing Normal University, China, have used a liquid-liquid interface technique to immobilise Ab₁ antibodies onto gold nanoparticles, characterising the material using energy dispersive spectroscopy (EDS).

Detection of abnormal levels of alpha-fetoprotein (AFP) can indicate the presence of cancerous cells. In this work, a sandwich immunoassay was used to test the sensitivity of the Au-Ab₁ nanocomposite towards AFP, demonstrating good selectivity, stability and reproducibility of the sensor. In clinical samples, the gold-based sensor performed well against the current enzyme-linked immunosorbant assay (ELISA) method of testing.

Do you want to know more about this research? Click on the link below, this article will be free to read until April 19th:

Gold–antibody nanocomposite thin film fabricated by a liquid–liquid interface technique and its application for the sensitive immunoassay of alpha-fetoprotein
Kun Wang ,  Tianxiang Wei ,  Wenwen Tu ,  Min Han and Zhihui Dai
Anal. Methods, 2013,5, 1909-1914
DOI: 10.1039/C3AY26541B

Drug discovery, development, and manufacturing widely make use of high performance liquid chromatography (HPLC) to separate compound mixtures for identification, quantification, and purification of individual components. Hence, the quest for the “next generation” of HPLC instruments is in high demand for improved analysis. Monica Yang and colleagues from Merck and Eksigent corporations have tested the performance of Eksigent Express LC Ultra micro high pressure liquid chromatography for real-world pharmaceutical application. By combining the capability of microflow HPLC, and the function to separate under high pressures, the new instrument enables fast separation efficiency, cost reduction and high system reproducibility.

Mixture Separation Using Eksigent ExpressLC Ultra HPLC

Find out more about this recent advancement by accessing the link below:

Evaluation of micro ultra high pressure liquid chromatography for pharmaceutical analysis
Monica (Mei) Yang ,  Xiaoyi Gong ,  Wes Schafer ,  Don Arnold and Christopher J. Welch
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C3AY26435A

Take a look at our selected HOT articles free for you to enjoy until April 4^th. Papers include innovative research such as the characterisation of grape seed residues from ethanol-distillation industry, the development of a camera phone-based platform for fluorescence sensing and a new method for analysis of low-levels of asbestos in soil. To read the full papers, please click on the links below:

Grape seeds characterisation

A proof-of-concept fluorescent strategy for highly selective detection of Cr(VI) based on inner filter effect using a hydrophilic ionic chemosensor
Dawei Zhang ,  Zhiyun Dong ,  Xiaozhi Jiang ,  Meiyun Feng ,  Wen Li and Guohua Gao
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C3AY26555B

Evaluation of a fluidized bed asbestos segregator preparation method for the analysis of low-levels of asbestos in soil and other solid media
J. Januch ,  W. Brattin ,  L. Woodbury and D. Berry
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C3AY26254

A camera phone-based platform for fluorescence sensing

Characterization of grape seed residues from the ethanol-distillation industry

Ángela Peralbo-Molina ,  Feliciano Priego-Capote and María Dolores Luque de Castro
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C3AY00008G

A novel camera phone-based platform for quantitative fluorescence sensing
Stephen O’Driscoll ,  Brian D. MacCraith and Conor S. Burke
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C3AY40116B

A non-enzymatic glucose sensor

Detecting glucose is not only important in the diagnosis and monitoring of diabetes; it has also wide applications in food analysis and waste water treatment. Traditional glucose sensors are based on an enzymatic method, employing glucose oxidase. Although this makes for a highly selective electrode, enzymes are easily affected by environmental factors such as temperature, humidity and pH.

Researchers led by Yongqing Zhao and Cailing Xu at Lanzhou University, China, have designed and created a new glucose sensor which is non-enzymatic and uses a 3D electrode architecture to increase the surface area in contact with the electrolyte. The porous nickel foam scaffold is loaded with nickel oxide, which has fast redox kinetics and better stability towards air and water than nickel metal.

The sensor has been evaluated against traditional methods by measuring glucose levels in blood serum samples and was found to perform well, with excellent response times, high selectivity, a low detection limit and good electrocatalytic activity.

To know more about this research, please access the link below. This paper will be free to read until April 2^nd.

Non-enzymatic glucose sensor based on three dimensional nickel oxide for enhanced sensitivity
Chunyan Guo,  Yinmei Wang,  Yongqing Zhao and Cailing Xu
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C3AY00067B

Trace amounts of some metals can have highly toxic effects on diverse life forms. Furthermore, over accumulation of other metals can give rise to various diseases. Quantitative imaging techniques such as laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) can help identify changes in metal content in biological materials. The versatility of LA-ICP-MS however, is somewhat limited as calibration accuracy and precision are largely dependent on the sample matrix used. Hence, acquiring reliable data can be a challenge due to the lack of well characterized reference standards.

Calibration Procedure Using LA-ICP-MS

To address this issue, Philip Doble and colleagues from the University of Melbourne, Australia, have developed a “general guide” to creating matrix-matched standards to monitor trace metals in brain tissue.

Learn more about this research by accessing the link below. This paper will be free to read until April 2^nd.

Protocol for production of matrix-matched brain tissue standards for imaging by laser ablation-inductively coupled plasma-mass spectrometry
Dominic J. Hare ,  Jessica Lear ,  David Bishop ,  Alison Beavis and Philip A. Doble
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C3AY26248K

Analysis of gas and liquid phase photoreduction products

Carbon dioxide produced by combustion of fossil fuels can potentially be removed from the atmosphere using an abundant carbon-neutral form of energy: sunlight. Photocatalytic reduction is a promising strategy for CO₂ conversion, but controlling the reaction pathways can be difficult. Identification and isolation of the range of reduction products provides a way of evaluating the efficiency of different photocatalysts.

In this minireview, Rong Xu and researchers at the Nanyang Technological University examine different analytical methods for these conversion products.  They compare a range of GC, HPLC and other chromatographic systems for separation of compounds including alcohols, aldehydes, carboxylic acids and small hydrocarbons. Moreover, they apply their findings to a new set of techniques for accurate detection of CO₂ reduction products with low detection limits, employing a combination of GC and HPLC.

In a useful addition to the study, the authors also investigated the effects of organic additives such as solvents and photosensitisers on these analytical methods.

Photocatalytic reduction of CO₂: a brief review on product analysis and systematic methods
Jindui Hong, Wei Zhang, Jia Ren and Rong Xu
Anal. Methods, 2013,5, 1086-1097
DOI: 10.1039/C2AY26270C