"The development of these biosensors could complement or replace classical analytical methods by simplifying or eliminating sample preparation and making identification of chemical foodborne contaminants easier and faster."

Portable biosensor for rapid and ultra-sensitive identification of organophoshorous foodborne contaminants

Investigator: Lia Stanciu

Project Report 2007 - 2008

» Download Project Report 2007 - 2008

Project Rationale

The overall goal of this project was to advance the field of pesticide detection in food by developing ultra-sensitive biosensors based on immobilized acetylcholinesterase (AChE). Over the past decades, AChE biosensors have emerged as a promising technique for food quality control. The development of these biosensors could complement or replace classical analytical methods by simplifying or eliminating sample preparation and making identification of chemical foodborne contaminants easier and faster, with significant decreases in analysis time and cost.

Project Objectives

  • Establish the optimum parameters for the immobilization of AChE and the need and feasibility of using an oxidation strategy for phosphorothionates.
  • Fabricate and characterize the AChE biosensor by immobilizing the enzyme onto the surface of single-use screen-printing electrodes (SPE). Study enzyme stability and leaching.
  • Detect pesticides. Obtain calibration plots of the inhibitory degree upon application of various concentrations of pesticides. Determine the detection limit (DL), response time (RT), and linear concentration range (LCR) for selected pesticides.
  • Assemble and test the biosensor prototype for the analysis of pesticides in food samples. Evaluate the matrix effects and establish whether an extraction step is needed.

Project Highlights

We have made significant progress toward establishing the optimum parameters for enzyme immobilization using two matrices (sol-gel and Ni-nanoparticles)) that enable preservation of enzymatic activity. The procedure involving attachment via affinity binding to Ni-nanoparticles is new and highly innovative and can be used to fabricate a new class of biosensors with enhanced characteristics. We are the first researchers to use this direct binding of enzymes onto Ni-NPs for this purpose. This accomplishment is important because site-specific orientation of enzymes onto electrode surfaces has numerous advantages over classical procedures. It is highly sensitive, avoids conformational changes, decreases sensor costs (due to a lower enzyme requirement), and entails a simple single fabrication step. This method has the potential to become a robust, commercially viable system.

Alternatively, the procedure combining sol-gel technology with screen-printing protocols is also potentially useful for biosensor fabrication. Moreover, the sol-gel method is a versatile and efficient technique for conserving enzyme activity in organic solvents. We expect that this matrix will enable functionality of the enzyme in the presence of organic solvents, if this medium is necessary to extract the pesticides from the food matrix.

Annual Reports

Investigator

  • Lia Stanciu