|Dr Alessandra Bonanni||Biosensor technologies
Biosensors are analytical tools which combine a biorecognition agent which provides selectivity and a transducer that confers sensitivity and can convert the biorecognition event into a measurable electronic signal. The advantage of using biosensor over traditional techniques is represented by their low costs, small dimensions, portability, and fast response. The different areas for potential biosensor applications are mainly medical diagnosis, environmental monitoring and food analysis.
DNA analysis is of extreme importance to solve problems of different nature such as investigation on genetic diseases, detection of food and water contamination by microorganism, studies on breeding origins or tissue matching, and solution of forensic issues. The techniques for genome identification are nowadays mainly based on DNA sequencing by using fluorescent labels and optical detectors. They require a few days for the analysis to be completed and the costs are prohibitive to the general public. Demand has never been greater for innovative technologies which can provide fast, inexpensive and reliable genome information.
The focus of my research is on the development of analytical tools (biosensors) for the rapid, reliable and low cost identification of DNA sequences. In order to achieve that, different electrochemical techniques are used for the detection of the analytical signal. The developed biosensors are based on various platforms (such as gold, carbon and silicon) and different nanomaterials (i.e. gold nanoparticles, graphene nanoplatelets and several quantum dots) are employed for the amplification of the obtained signal and the improvement of detection limit.
The final step of this work is the application of the developed genosensor to real sample analysis. Once this second part is successfully accomplished, the analytical tool could be eventually integrated into a DNA amplification process, resulting in a portable device for point-of-care diagnostic tests and for very sensitive detection of SNPs correlated to different diseases.
This field includes research in the two following areas:
- Application of DNA genosensors to identify of DNA sequences correlated to bacteria involved in food contamination (i.e. Salmonella spp, Listeria monocytogenes, Escherichia coli)
- Development of electrochemical biosensors for the detection of antioxidant capacity of food and beverages
|Prof Bo Gunnar Liedberg||The research interests of Prof. Bo Liedberg can be divided into three main areas
Surface Chemistry and Self Assembled Monolayers
This part of the research concerns fundamental studies of adsorbates and ultrathin molecular architectures, like Self-Assembled Monolayers (SAMs), on solid supports. The group was very early in studying self-assembly of substituted alkylthiols on gold substrates. A key activity has been to study temperature driven phenomena occurring in such assemblies as well as in adsorbed layers on top such SAMs. Oligo(ethylene glycol) and oligosaccharide SAMs have attracted considerable attention, both experimentally and theoretically, because of their structural characteristics and advantageous properties in contact with biofluids. Another area concerns interfacial water and ice. Temperature programmed studies have been undertaken to improve the understanding of the nucleation and microscopic wetting behavior of water/ice. The complexity of the SAMs has increased over the years and we are today focusing on architectures based on SAMs bearing multivalent chelator heads, helix-loop-helix polypeptides and receptor functions.
Bioinspired and Biomimetic Nanoscience
This research concerns the development of nanoscale architectures fabricated using either top-down or bottom-up protocols (or a combination of both). We are, for example, developing plasmonic arrays based on 100 nm gold nano dots on silicon and glass surface for amplification of optical fluorescence signals, so-called metal enhanced fluorescence (MEF). We are also developing composite materials based on a combination of de novo designed peptide scaffolds, planar surfaces and nanoparticles of controlled size and shape. A novel concept based on peptide folding has been used for controlled assembly of gold nanoparticles. The group is also involved in the development of Dip Pen Nanolithography (DPN) for patterning of surfaces on the 30-100 nm length scale. This work is performed jointly with a previous student of the group who nowadays is setting up a nanolaboratory at the Institute of Physics, Vilnius. We are also involved in several EC projects where different types of micro- and nanoscale patterning tools are employed for production of coatings for biofouling, sensing and biomedical applications.
Optical Biosensors, micro- and nanoarrays
The group has a long experience in developing optical transducers for biosensing application. We were the first to demonstrate the use of surface plasmon resonance for studies of bioaffinity interactions at surfaces, a technology that today form the backbone in SPR/Biacore instruments developed for biospecific interaction analysis (BIA). We are today using it in combination with ellipsometric interrogation and imaging optics for microarraying, and in combination with nanoparticle for studies optical enhancement phenomena. This includes, for example, microarray chips for protein multiplexing. The group is also working on the development of generic biochips for studies of ligand-receptor binding. Besides working on microarray fabrication for protein detection and analysis we are also developing biochips for the safety and security area.
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2. Aili, D., Enander, K., Tai, F-I., Baltzer, L., Liedberg, B., Angew. Chem., 120, 5636-5638 (2008).
3. Aili, D., Enander, K., Baltzer, L., Liedberg, B., Nano Letters, 8, 2473-2478 (2008).
4. Andersson, O., Ulrich, C., Björefors, F., Liedberg, B., Sensors&Actuators B: Chemical, 134, 545-550 (2008).
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6. Aili, D., Selegård. R., Baltzer, L., Enander, K., Liedberg, Small, 5, 2445-2452 (2009).
7. Lee, H.-H., Ruzele, Z., Malysheva, L., Onipko, A., Gutes, A., Björefors, F., Valiokas, R., Liedberg, B., Langmuir, 25(24), 13959–71 (2009).