Biosensors are analytical tools designed to detect chemical or physiological
changes in an environment through the integration of biological recognition parts with
physical transducers. They are widely used in clinical diagnostics, environmental
monitoring, food safety, and pharmaceutical analysis due to their rapid response times,
high sensitivity, and ease of operation. These devices offer a reliable and cost-effective
alternative to conventional analytical techniques. Herb-based biosensors, which use
bioactive phytochemicals including enzymes, flavonoids, terpenoids, and polyphenols
derived from plants, have emerged as a sustainable and ecologically friendly alternative
in recent years. These compounds interact with specific analytes through chemical
mechanisms such as redox reactions, hydrogen bonding, and catalytic oxidation,
enabling the detection of a wide range of targets, including drugs, hormones,
pesticides, and amino acids. Examples include the use of banana or asparagus pulp to
track pesticide residues and palm fruit fibers to detect adrenaline. Tissues from
broccoli, potato, and tomato have also been employed to detect phenolic compounds,
achieving detection limits in the micromolar range and performance comparable to
standard electrochemical methods. The chemical basis of these sensors lies in the
functional groups of herbal compounds, which contribute to signal generation through
electron transfer, pH-sensitive color change, or catalytic reactions, depending on the
transduction method used. These herb-derived materials are not only biocompatible and
biodegradable, but also available at low cost, making them attractive for green
analytical technologies. The chemistry of sensor-analyte interactions, manufacturing
techniques, and material design are highlighted in this chapter, which summarizes
thirty years of study in the creation of herb-based biosensors. Additionally, it examines
new developments that have the potential to revolutionize analytical science, including
polymeric encapsulation for stability, AI-assisted diagnostics, IoT-enabled real-time
monitoring, and nanomaterial-enhanced sensitivity.
Keywords: Biosensor, Enzymes, Electrochemical transducers, Herbs, Herbicide.
