Aptamer-based field-effect biosensor for tenofovir detection

During medical treatment it is critical to maintain the circulatory concentration of drugs within their therapeutic range. A novel biosensor is presented in this work to address the lack of a reliable point-of-care drug monitoring system in the market. The biosensor incorporates high selectivity and sensitivity by integrating aptamers as the recognition element and field-effect transistors as the signal transducer. The drug tenofovir was used as a model small molecule. The biointerface of the sensor is a binary self-assembled monolayer of specific thiolated aptamer and 6-mercapto-1-hexanol (MCH), whose ratio was optimized by electrochemical impedance spectroscopy measurements to enhance the sensitivity towards the specific target. Surface plasmon resonance, performed under different buffer conditions, shows optimum specific and little non-specific binding in phosphate buffered saline. The dose-response behavior of the field-effect biosensor presents a linear range between 1 nM and 100 nM of tenofovir and a limit of detection of 1.2 nM. Two non-specific drugs and one non-specific aptamer, tested as stringent control candidates, caused negligible responses. The applications were successfully extended to the detection of the drug in human serum. As demonstrated by impedance measurements, the aptamer-based sensors can be used for real-time drug monitoring

Environmental Applications of Boron‐Doped Diamond Electrodes: 2. Soil Remediation and Sensing Applications

The chemical stability and electrocatalytic properties of borondoped diamond (BDD) electrodes give rise to various applications. While wastewater treatment is the most widely studied field, the use of BDD for soil remediation and environmental sensing is currently investigated more and more. With regards to soil remediation, promising results have been reported for the treatment of soil washing solutions. Anodic oxidation using BDD at high current density allows high mineralization rates of biorefractory soil pollutants and extracting agents to be reached. At low current density, selective degradation of target pollutants has been achieved, thus allowing the reuse of extracting agents for further soil washing steps. BDD-based electrochemical sensors have been studied for chemical oxygen demand determination, pesticide/pharmaceutical detection as well as other applications such as pH, O2 and analysis of various organic and inorganic compounds. Low detection limits, wide linear ranges and low standard deviations have been achieved. The main reasons behind the superiority of BDD sensors are the chemical stability, wide applicability and resistance of BDD towards biofouling. The beauty of BDD sensing is that it can work for a variety of organic and inorganic compounds under many physicochemical parameter