Optical portable biosensors based on stabilized lipid membrane for the rapid detection of doping materials in human urine

This work reports a technique for the construction of portable devices that are based on stabilized lipid membrane with an incorporated artificial receptor that can be used for the rapid optical detection of doping materials in human urine. The artificial receptors are incorporated within the lipid mixture prior to polymerization. Microporous filters composed of glass fibers were used as supports for the stabilization of these sensors. The lipid film was formed on the filter by polymerization using UV irradiation prior its use. Methacrylic acid was the functional monomer, ethylene glycol dimethacrylate was the crosslinker and 2,2′-azobis-(2-methylpropionitrile) was the initiator. The polymerization is completed within 4 h and the artificial receptors retain their activity. These devices can be used as portable sensors because they provided a simple screening sensitive spot optical test for the rapid one-shot detection of dopamine and ephedrine in human urine. It was now possible to have quantitative data based on a calibration graph. A quantitative method for the detection of dopamine or ephedrine in real samples of urine that can be complimentary to HPLC methods is provided in the present paper. An investigation of the mechanism of signal generation for the “switch on” and “switch off” the fluorescence signal is made herein. The construction of these devices will allow the practical use of the techniques for chemical sensing based on lipid membranes to prepare portable chips/biosensors for the detection of toxicants in foods or pollutants in the field and commercialization of these devices.