Fabrication of biosensors with the bio Sample Clauses

Fabrication of biosensors with the bio receptors identified in Task 2.1 Sensors with antibodies to CRP physisorbed on both P3HT-COOH15 and P3HT were selected to evaluate the response to CRP. This immobilization strategy, suggested by VTT, reduces the number of activation steps needed to anchor the antibodies on P3HT. Moreover, this approach is compatible with printing techniques. After deposition of the anti-CRP, the organic semiconductor surface was post-treated with pTHMMAA polymer to reduce non-specific bindings. The sensor response to CRP was evaluated with solutions at concentrations ranging from 50 µg/ml to 0.1 µg/ml in PBS 10 mM. Devices fabricated with the organic semiconductor only treated with pTHMMAA or functionalized with the anti-hIgG (an antibody nonspecific for the CRP protein) and treated with pTHMMAA were used as reference (negative controls). A decrease of the drain current and a shift of the threshold voltage after exposure to CRP solutions at different concentrations were observed for biosensors functionalized with the anti-CRP antibody, while no change of the current occurred when the antibodies to CRP were not present on the P3HT surface, thus confirming the biosensor specificity. All the CRP calibration curves of the biosensors fabricated using the P3HT polymeric semiconductor are given in the Figure below. Note that a sub µM detection limit was also achieved with this biosensor.