Introduction

In recent times, the intensive use of highly toxic pesticides in agriculture worldwide has contributed significantly to the considerable problem of water and soil pollution. The need for methods and devices that detect the presence of pesticides and other environmental contaminants, especially photosynthetic herbicides (chemical compounds that block the photosynthetic process), grew extensively in the industry. Thus, the making of a new, simple, economical, environmentally sustainable electrochemical biosensor with high stability and sensitivity, is highly desirable.

Technical features

The main disadvantages in assembling state-of-the art biosensors remain the use of organic solvents and expensive binding agents to immobilize the biological recognition element on the electrochemical transduction element. The alternative to the proposed state-of-the art, is an electrochemical biosensor that allows to detect photosynthetic herbicides and other contaminants with high sensitivity and reproducibility by means of amperometric measurements, that can be produced in an extremely simple way. It is composed of a carbon paper support, in which a work surface is delimited, on which the thylakoidal membranes are deposited (site of photosynthetic reactions in plants containing photosystems I and II). The end is coated with a conductive material, the remaining part is coated with an insulator, except for the working surface. The present biosensor can also include several working electrodes, for example N electrodes each sensitive to a specific contaminant, thanks to the use on different modified tilacoid electrodes, thus realizing a multi-detection systemelectrode, to detect in parallel N different contaminants (Fig.2). TRL=4.

Possible Applications

• Detection in environmental samples of contaminants inhibiting electron transport at the level of photosystem I (PSI) or photosystem II (PSII) in oxygenic photosynthetic organisms. Examples of photosynthetic contaminants are: heavy metals, explosives and ionizing radiations.

Advantages

• Easy, economical and sustainable to prepare: the preparation excludes the use of organic solvents, heavy metal salts, and other reagents that could adversely affect the environment and health
• Extremely sensitive and optimally preserves the catalytic activity of PSII of immobilized tilacoids and stable for a long time even at room temperature