Analyst Blog

Scientists in the US have developed a mouthguard sensor that could be used to monitor metabolites in saliva to provide real-time information on the health status of the wearer.

Real-time health monitoring is an attractive goal for biomedical, sport and military fields. A range of sensors have been developed that monitor physical signs such as heart rate, but recently interest has moved to detecting biomarkers non-invasively in body fluids to obtain more detailed information.

Saliva is an easily obtainable body fluid and contains analytes that closely correlate to those of blood, providing a good indication of metabolism and hormone levels. Previous saliva sensors have included dental tattoos and dentures but the new mouthguard sensor from Joseph Wang and colleagues at the University of California, San Diego, is much less invasive.

To read the full article by Harriet Brewerton, please go to Chemistry World.

Non-invasive mouthguard biosensor for continuous salivary monitoring of metabolites
Jayoung Kim, Gabriela Valdés-Ramírez, Amay J. Bandodkar, Wenzhao Jia, Alexandra G. Martinez, Julian Ramírez, Patrick Mercier and Joseph Wang
Analyst, 2014, Advance Article
DOI: 10.1039/C3AN02359A, Paper

Scientists in the US have unveiled details of a colorimetric assay that could provide an initial indication of a suspect’s gender during the on-scene stages of a forensic investigation.

Narrowing the pool of potential suspects early on in their investigations can give the police the upper hand. However, traditional DNA analysis requires laboratory conditions, sophisticated equipment and time. Rapid, simple, on-site analysis of blood left behind at a crime scene may provide investigators with a head start to quickly identify a group of possible suspects or rule out others.

Complementing their previous work, which used the enzyme biomarkers of creatine kinase (CK) and lactate dehydrogenase (LDH) to differentiate between blood samples from different ethnicities, Evgeny Katz at Clarkson University, Potsdam, and Jan Halámek at the University at Albany, State University of New York, have combined analysis of CK with another biomarker, alanine transaminase (ALT), to distinguish between male and female human serum samples. The levels of CK and ALT in the blood of males and females are known to show a small but significant difference. Using a multi-enzyme/multistep biocatalytic cascade, this small difference can be amplified and with the final step involving a coloured compound, a visual identification of gender can be made.

To read the full article, please go to Chemistry World.

Biocatalytic analysis of biomarkers for forensic identification of gender
Saira Bakshi, Lenka Halámková, Jan Halámek and Evgeny Katz
Analyst, 2014,139, 559-563
DOI: 10.1039/C3AN02055J, Communication

Mass differences between bovine sperm bearing X or Y chromosomes have been measured by researchers in Italy. The findings could be used to develop a gentle sperm sexing technique.

The livestock industry relies on sperm sorting to select the right candidates for artificial insemination. Flow cytometry, the current technique used to sort sperm, involves labelling sperm with a fluorescent dye and capturing the labelled sperm in single droplets before exciting the dye. The strength of the dye’s fluorescence indicates the presence of X or Y chromosomes. However, in this intrusive process the sperm become stressed – the extent of the damage this causes is still under debate.

A microbridge sensor developed by Marco Mauro and his team at Novaetech, Napoli, in collaboration with the Italian Experimental Institute, Lazarro Spallanzani in Cremona, is a non-invasive alternative for sorting live sperm cells.

To read the full article, please visit Chemistry World.

Experimental evidence of a buoyant mass difference between bovine spermatozoa bearing X- and Y-chromosomes using a micromechanical resonator
Marco Mauro, Raffaele Battaglia, Gianluca Ferrini, Roberto Puglisi, Donatella Balduzzi and Andrea Galli
Analyst, 2014, Advance Article
DOI: 10.1039/C3AN01979A, Paper

Scientists in the US have designed a biosensor that could be used to study the metabolism of free-flying birds in real time.

There is still much we could learn about wild bird species to help us understand their behaviour, biology and evolution. The fast metabolism of birds makes them very responsive to environmental changes so bird studies are also very useful in ecology research.

Researchers have tracked migration patterns using radio tags and data loggers, but physiological states are mainly assessed by capturing the birds and taking blood samples. Such samples will only provide information of a bird’s current state, which will vary widely depending on the time of year, breeding, migration and so on. A device that tracks a bird whilst monitoring its physiological state would provide in depth information, particularly on migrating birds that travel thousands of kilometres.

Abdurrahman Gumus and colleagues at Cornell University have designed a sensor that could be used to track a bird whilst monitoring its physiology. Gumus says ‘although we have the ability to track the position of birds and, to some degree, correlate their behaviour with environmental conditions, the ability to actually directly link this with the physiological state opens up an entirely new way of conducting ornithological research’.

To read the full article, please visit Chemistry World.

Real-time in vivo uric acid biosensor system for biophysical monitoring of birds
A. Gumus, S. Lee, K. Karlsson, R. Gabrielson, D. W. Winkler and D. Erickson
Analyst, 2014,139, 742-748
DOI: 10.1039/C3AN01787G, Paper

Scientists in the US have devised an enzymatic logic system that could be used for releasing drugs. This is the first report of a man-made biomolecular system that can process a series of physiological signals, without the use of electronics.

Biocomputer-based logic systems that process biomolecular signals could revolutionise drug administration. By harnessing signal-responsive electrode surfaces that respond to biochemical signals, widespread personalised medicine takes a step closer to reality.

Historically, drug-release systems have been plagued by slow and uncontrolled release. Various external triggers, including temperature, pH and biochemical species, have been used to stimulate drug release. Systems activated by biochemical signals are often complicated and limited, combining both the receptor and the release system. Physical separation of these two components on individual electrodes would simplify the process.

Expanding on their recent work with glucose sensing electrodes, Evgeny Katz and Shay Mailloux at Clarkson University, in collaboration with Jan Halámek from the State University of New York at Albany, have developed a logical biomolecule release system. An electrode covered by a redox-active, iron(III)-cross-linked alginate polymer film with physically entrapped biomolecules serves as the substance-releasing component and a pyrroloquinoline quinone (PQQ)-modified electrode serves as the biocatalytic electrode.

To read the full article, please visit Chemistry World

A model system for targeted drug release triggered by biomolecular signals logically processed through enzyme logic networks
Shay Mailloux, Jan Halámek and Evgeny Katz
Analyst, 2014, Advance Article
DOI: 10.1039/C3AN02162A, Communication