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Bio-mimetic sensors design for food-borne Pathogens Detection: A mixed computational and experimental approach

Final Activity Report Summary - CEA (Bio-mimetic sensors design for food-borne Pathogens Detection: A mixed computational and experimental approach)

The key points of the project were the following:
- rationally designing and binding simulation of the biomimetic receptors starting from biological data;
- testing the affinity of receptor libraries towards the target using fast screening technology like high density colorimetric array technology;
- developing bio-mimicking receptors to be incorporated in affinity media for detecting pathogens;
- demonstrating the ability of these new receptors' generation to detect the target analyte with the same potentiality of antibodies preserving robustness and shelf-life;
- testing a set of label free piezoelectric biomimetic sensors, for fast, qualitative and direct detection of pathogens (regeneration, sensitivity, repeatability, nonspecific binding and cross-reactivity).
All milestones were reached.

The reasons to work with a biomimetic approach is the possibility to work in polar and non-polar solvents; Increasing the shelf-life of devices (in stability and reproducibility); the extreme difficulty to produce antibody for some xenobiotics; the affinity media are easier to prepare, more robust towards elution conditions; the biomimetic receptors are less expensive than immunoaffinity classical devices and can be avoided the use of animals for bio-molecules production.

As reported in the project objectives, a computational strategy was carried out for reducing experimental procedures (avoiding trial and error methods). The main advantage of this procedure was a drastic reduction of the number of structures to be tested.

The main objective of the project was to produce a strategy to obtain biomimetic sensors for pathogens consequently Listeria bacterium was selected as the prototype model suitable for working laboratory. Two main reasons encouraged this choice:
1) large amount of X ray and NMR structures associated to that pathogen available from the literature;
2) the possibility to work in laboratory with a 2nd class pathogen and as negative control Listeria Innocua a species of Listeria typically non-hemolytic.

Experiments were carried out using, as screening tool, colorimetric microarray based technology. For producing label free biomimetic sensors, the piezoelectric system was chosen according with the proposal objectives.

The Listeria bacterium was clearly determined up to 1e07 cell/ml. Cross reactivity using similar bacteria were tested obtaining a ratio positive/negative up to seven times demonstrating a good correlation between experimental and simulated results. Using multivariate analysis the sample LM was clearly discriminated supporting the idea of signals semi-selectivity cooperation by obtaining the some results of the biological molecules.