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Biosensing

While “Biosensors” are analytical devices incorporating a biological sensing element, “Biosensing” covers the use of any sensor to monitor a living system and includes chemical sensors, such as gas sensors and ion-selective electrodes, as well as Biosensors. A wide range of activities at Linköping University fall into this category with extensive work on gas sensors, FET’s and lab-on-a-chip devices being carried out by our colleagues in Applied Physics and being applied by clinical colleagues in Linköping Health University on our Hospital Campus. 

Examples of Biosensing projects within the Biosensors and Bioelectronics Centre that are not covered elsewhere on this site include:

Registration of nanoparticle-microelectrode collisions: electroanalysis for nanomaterial characterisation and environmental monitoring

Martin Mak and Mikhail Vagin are developing a new platform for nanoparticle (NP) characterisation, which will explore the electrochemical behaviour of nanoparticles and their application, thus enhancing two ongoing PhD projects: Alina Sekretaryova (electrochemical detection of nanoparticles) and Onur Parlak (nanomaterial biosensors).

Polypyrrole-based biosensors

Valerio Beni and Edwin Jager continued to explore the use of polypyrrole for the development of novel chemi/biosensors. As part of her master thesis, Laurence Padiolleau developed a highly specific chemical sensor for dopamine based on over-oxidised polypyrrole doped with a specific ligand. Mohsen Golabi and Elham Sheikhzadeh investigated the use of functional dopants and/or modified pyrrole monomers for modulating the adhesion of bacteria onto surfaces and for the development of bacteria biosensors, following functionalisation of the polypyrrole film with aptamers. 

Skin Emissions studies for Bed Sore Prevention

Pressure ulcers are a major problem for bed-ridden patients, causing pain and intense suffering for the individual. Furthermore, treatment is very costly and labour intensive. A lot can be gained therefore if early precursors of pressure ulcers can be spotted and measures taken before an ulcer occurs. In collaboration with researchers at the Health University in Linköping and at the University of Rome “Tor Vergata”, Prof Lundström’s team have performed an initial study to find out if there is a difference in the emissions from the skin of compressed tissue compared with uncompressed tissue. The experiments were performed on hospitalised patients in an intensive care unit and on healthy volunteers. This GC-MS study indicates that difference in general emission patterns are seen between hospitalised and healthy people, respectively. Furthermore within each group it was possible to differentiate between compressed and uncompressed tissue. This lays the foundation for the development of smart technology to prevent this costly and damaging trauma. 

Artificial Olfaction

A further collaboration with the University of Rome “Tor Vergata” in the area of artificial olfaction and colour indicators for volatile organic compounds has resulted in improved modeling of the olfactory system based on optical chemical sensing, where each pixel in a response image is regarded as an olfactory receptor neuron. Our results indicate that the average firing rate of the output spike sequences shows the best separation among the experienced vapours, however the latency code is able in a shorter time to correctly discriminate all the tested volatile compounds. This behavior is qualitatively similar to those recently found in natural olfaction, and in particular it provides a practical route to tailor the measurement conditions of artificial olfactory systems, defining for each specific case a proper measurement time.

Stess-O-meter

A pilot study on the associations between sAA, psychosocial factors, self-rated health and inflammation markers has been conducted in cooperation with researchers at the Health University having a saliva bank within a study called Life conditions, Stress and Health. Levels of sAA just after awakening were positively associated with depression scores and level of ongoing inflammation, and negatively associated with self-rated health. Levels of sAA 30 minutes after awakening and just before going to bed point in the same direction, but may be influenced by recent daily activity to a higher extent. The findings support the hypothesis that sAA might be a reliable marker of ANS activity in saliva.Reaction kinetics due to amylase activity can be measured with simple instrumentation using a light source (LED) and a detector (phototransistor) or with a disposable plastic electrochemical strip. Preliminary comparison with an established method for determination of saliva amylase activity is shown below. Pink triangles = measurements on diluted saliva, blue = standard method.

Over-oxidised polypyrrole electrodes for dopamine detection.

Dopamine is a neurotransmitter involved in several processes in the brain including addiction, cravings and symptoms connected to drug withdrawal. In the last year the Centre has been working, in collaboration with Dr. Susanne Hilke at IKE, on the development of a biosensing platform, based on over-oxidised polypyrrole doped with dopamine specific ligand, for the detection of dopamine in brain fluids.

Preliminary results indicate that the developed sensor can detect dopamine with high specificity.

Long term goal of the project is to integrate the developed sensor within micro-dialysis system for real time in-line monitoring of dopamine.

Electronic Tongue

The use of multivariate analysis in combination with gas-sensor arrays has spawned the so called “Electronic Nose”, by analogy to olfactory sensing. Similar techniques can be applied to sensor arrays used in aqueous solution and we are exploring the “Electronic Tongue” in a variety of configurations to serve as early-warning systems to detect, for example, incidents of water contamination.   Simple noble metal electrode arrays offer advantages by being robust, amenable to various cleaning strategies to remove fouling and offer long operational lifetimes. These relatively simple systems have proved to be surprisingly effective and we are now working to improve both the electrochemical performance, exploring for example the use of microelectrode arrays, and the selectivity of the sensing performance with the use of tailored polymers.

 

Insect Detection

Insect attacks will often lead to serious damage of growing crops, and is controlled by the use of insecticides, which often are used for preventive purposes or too late. Obviously there is a need for a system that can detect insect attacks. The BugIT project, supported by grants from the Swedish Farmers Foundation for Agricultural Research, aims to develop a system for monitoring and identification of insects in the field, which will help the farmers to optimise insect control.

The system is based on an electrical detector, using 1.5 kV between two conductors, and when the insect passes them, an electrical shock is generated that knocks the insect and can be registered. The first detector was developed for the monitoring of pollen beetles, and to attract these, the detector was coloured yellow and contained a chemical attractant. The detector was connected to a microcontroller for measurements, data treatment and storage. To the system also sensors for air humidity, temperature, sun intensity and battery voltage were connected.


Responsible for this page: Martin Wing Cheung Mak
Last updated: 05/04/15