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Further sensitivity enhancement of HFF-QCM immunosensors for pesticides

Authors: C. March, J.V. García, R. Fernández, Y.Jiménez, A. Arnau. A.Montoya

Event: 4th International Conference on Biosensing Technology, Lisbon (2015)

Recently, High Fundamental Frequency Quartz Crystal Microbalance (HFF-QCM) immunosensors have succesfully been developed. Therefore, sensitivity of QCM biosensors is no longer a drawback. Taking advantage of this previous work, we have developed a renewed highly sensitive HFF piezoelectric immunosensor using carbaryl insecticide as a model analyte for pesticide detection. To this purpose, 100 MHz quartz crystal sensors were used as the transducer elements of the biosensor and a monoclonal antibody-based competitive immunoassay was integrated as the sensing specific bio-recognition event. The biosensing interface was improved by employing mixed self-assembled monolayers (mSAMs) of alkane thiols as intermediate layers for surface functionalization. This approach allowed the covalent attachment of the assay conjugate (20.0 µg mL-¹ of BSA-CNH conjugate) onto the gold electrode surface in a more orderly and stable way than with simple SAMs. A very low concentration (1.0 µg mL-¹) of LIB-CNH45 monoclonal antibody was used for the competitive immunoassays. All immunosensor assays were performed in the AWS-A10 test platform from AWSensors. In terms of analytical performance, the new carbaryl HFF-QCM immunosensor showed higher sensitivity than the previously developed one, with analytical parameters very close to those of the most sensitive reported ELISA for carbaryl.

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Comparison between High Fundamental Frequency Quartz Crystal Microbalance and Love Mode Surface Acoustic Wave devices in the detection of Carbaryl pesticide

Authors: J.V. García, M.I. Rocha, C. March, P. García, L.A. Francis, A. Montoya, A. Arnau, Y. Jiménez

Event: Acoustic Sensors in analytical and Biophysical Studies, 29-30 August 2013, IMBB-FORTH, Heraklion, Crete.

 

In this work two acoustic technologies: High Fundamental Frequency Quartz Crystal Microbalance (HFF-QCM) and Love Mode Surface Acoustic Wave (LM-SAW) have been compared for the detection of Low Molecular Weight (LMW) compounds in terms of Sensitivity and LOD. The results have also been compared with those obtained with other techniques: Traditional QCM, Surface Plasmon Resonance (SPR) and Enzyme-Linked ImmunoSorbent Assay (ELISA). Carbaryl pesticide was chosen as model analyte because it had been used as a reference LMW compound by those mentioned techniques.

AWS-A10 research platform (AWSensors, Spain) was used to perform the experiments. This platform allowed for a comparison of both devices measured by the same characterization system under similar experimental conditions.

The results achieved with LM-SAW and 100Mhz HFF-QCM were in the same order of magnitude. The achieved value sensitivity (I50 value) and LOD (I90 ) were around 0.31 µ/L and 0.09 µ/L, respectively, for LM-SAW device, and around 0’66 µ/L and 0’14 µ/L, respectively, for HFF-QCM device. Sensitivities and LODs with these novel developments on acoustic technologies improve SPR and traditional QCM technologies, and approach ELISA’s ones.

Review the poster about this experiment by clicking here:

Póster about AWS-HFF sensors for detection of Carbaryl pesticide showed at Crete 2013