Sergei V. Dzyadevych

Development and optimisation of biosensors based on pH-sensitive field effect transistors and cholinesterases for sensitive detection of solanaceous glycoalkaloids

Highly sensitive biosensors based on pH-sensitive field effect transistors and cholinesterases for detection of solanaceous glycoalkaloids have been developed, characterised and optimised. The main analytical characteristics of the biosensors developed have been studied under different conditions and an optimal experimental protocol for glycoalkaloids determination in model solution has been proposed. Using such a biosensor and an enzyme reversible inhibition effect, the total potato glycoalkaloids content can be determined within the range of 0.2-100 microM depending on the type of alkaloid, with lowest detection limits of 0.2 microM for alpha-chaconine, 0.5 microM for alpha-solanine and 1 microM for solanidine. The dynamic ranges for the compounds examined show that such biosensors are suitable for a quantitative detection of glycoalkaloids in real potato samples. High reproducibility, operational and storage stability of the biosensor developed have been shown.

Analysis of the potato glycoalkaloids by using of enzyme biosensor based on pH-ISFETs

The applicability of an enzyme biosensor based on pH-ISFETs for direct determination of total glycoalkaloids content in real potato samples, without any pre-treatment, is shown. The results of determination of the total glycoalkaloids concentrations in potato samples from different experimental varieties obtained by the biosensor are well correlated with the analogous data obtained by the HPLC method with standard complex sample pre-treatment procedure. The detection of total glycoalkaloids content by biosensors is reproducible, the relative standard deviation was around 3%. The dependence of total glycoalkaloids content on various parts of the potato tuber and their size, different growing area has been shown using the biosensor developed. The method based on biosensors is cheap, easy to operate and requires a shorter analysis time than the one needed using traditional methods for glycoalkaloids determination. The biosensor can operate directly on potato juice, or even directly on a suspension of potato or plant material. It can provide a way to save time and costs, with a possibility of taking rapid assessment of total glycoalkaloids content in a wide variety of potato cultivars. Furthermore the operational and storage stability of this biosensor are quite good with a drift lower than 1% per day and response being stable for more than 3 months.

Enzyme Biosensor for Tomatine Detection in Tomatoes

Abstract A biosensor for detection of tomatine in tomatoes has been developed using pH‐sensitive field effect transistor as transducer and immobilised enzyme butyryl cholinesterase (BuChE) as a biorecognition element. The main analytical characteristics of the biosensor developed were studied for different conditions. The possibility to optimise these working parameters was investigated. By using this biosensor and enzyme inhibition effect, the tomatine can be measured in the concentration range of 0.5–50 µM with a detection limit of 0.2 µM. Tomatine concentrations in different tomato juice samples were determined by such a biosensor, and a good correlation with the known real content was revealed. A high reproducibility and operational stability of the biosensor developed were shown.