Analyst Blog

Detection of E. coli in Ringer's solution

Sophisticated analytical tests producing a readout which can be interpreted by the naked eye, or by image editing software, are becoming increasingly popular.  They offer a low cost alternative to tests requiring expensive equipment and highly trained analysts. Jürgen Popp and colleagues from the Friedrich Schiller University and the Institute of Photonic Technology in Jena, Germany, have developed a new detection method for DNA which provides a distinctive colour change in the case of a positive result.

The bacterial contamination of intravenous fluids in hospitals is a significant concern in modern medicine, so Popp and his team chose the detection of E. Coli in Ringer’s solution as the first test for their assay. The technique uses surface-modified magnetic beads which can bind complementary target DNA by hybridisation. A silver deposition kit provides the visual colour change: for a positive result, silver nanoparticles are generated by enzymatic silver deposition, turning the sample black. As well as being an inexpensive and convenient qualitative test, a quantitative result can be found by analysing a digital photograph of the colour change in standard image editing software.

To read the full article, please cick on the link below. The paper will be free to read for the next three weeks.

Convenient detection of E. coli in Ringer’s solution
Martha Schwarz, Susanne Pahlow, Thomas Bocklitz, Carolin Steinbrücker, Dana Cialla, Karina Weber and Jürgen Popp
Analyst, 2013, Advance Article
DOI: 10.1039/C3AN01240A

BODIPY-Based Probe for HClO Imaging

Detection of suitable biomarkers of disease is critical for medical diagnosis. However, detection becomes a paradoxical challenge when the biomarker is naturally found in healthy individuals. This is the case for the biomarker hypochlorous acid (HClO), a reactive oxygen species that plays an essential role in maintaining a healthy immune system under normal conditions. Yet, when optimal levels of HClO cannot be maintained by the body, cellular functions become disrupted and this can result in diseases such as atherosclerosis, arthritis, and cancer. Consequently, HClO requires medical monitoring, particularly in the mitochondria where a high concentration tends to reside. To help distinguish between healthy and diseased states, the ideal biosensor must provide fast response, high selectivity, high sensitivity and mitochondrial permeability.

To address this challenge, Xiaojun Peng and colleagues from the Dalian University of Technology in China have created a fluorescent imaging probe to detect HClO by localizing to mitochondria in live cells. Their probe makes use of boron dipyrromethene (BODIPY) dye for its outstanding fluorescent properties. Incorporation of an oxime group onto the BODIPY scaffold allows the tuning of fluorescence to an on/off state depending on the presence/absence of HClO, respectively. Lastly, incorporation of a triphenylphosphine group onto BODIPY provides the localization signal to the mitochondria. Learn all the details of this exciting new discovery by accessing the link below:

A highly specific BODIPY-based probe localized in mitochondria for HClO imaging
Guanghui Cheng, Jiangli Fan, Wen Sun, Kun Sui, Xin Jin, Jingyun Wang and   Xiaojun Peng  
Analyst, 2013, Advance Article
DOI: 10.1039/C3AN01152F

This pap[er will be free to read for the next three weeks. Let us know what your thoughts are by leaving a comment!

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Rapid detection and identification of bacteria in sepsis

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To read the full paper, free for you for the next three weeks, please access the link below:

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