Semiconductor Nanocomposites-Based Photoelectrochemical Aptamer Sensors for Pharmaceuticals Detection

Semiconductor Nanocomposites-Based Photoelectrochemical Aptamer Sensors for Pharmaceuticals Detection

Kevin Otieno Okoth (Tom Mboya University College, Kenya), Ruth Nduta Wanjau (Kenyatta University, Kenya) and Maurice Otieno Odago (State University of New York at Oneonta, USA)
DOI: 10.4018/978-1-7998-1871-7.ch007


Development of sensors for pharmaceuticals has become very essential. This is due to the need to monitor the release and toxicological effects of pharmaceuticals into the environment. In this work, the authors explored bismuth sulphide (Bi2S3) nanorods and graphene as photoactive material for constructing a photoelectrochemical (PEC) aptasensor for sulfadimethoxine (SDM) detection, exhibiting high sensitivity, stability, and reproducibility. In another experiment, Mo-doped BiVO4 (Mo-BiVO4) and graphene nanocomposites were explored as photoactive material to construct a visible light-driven photoelectrochemical biosensor. Graphene in the nanocomposites was very essential in immobilizing streptomycin aptamer through π-π stacking interaction. Finally, graphene doped CdS (GR-CdS) synthesized via one pot hydrothermal technique and gold nanoparticles (Au NPs) were employed to construct a PEC aptasensor for diclofenac (DCF).
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Over the past few decades, a number of organic compounds that have been found to resist biodegradation, bioaccumulate in organisms and therefore possess the potential to adversely affect the environment and human health have been identified. Amongst these chemicals, antibiotics play an important role in treatment and prevention of bacterial infection in human and animals as well as serving as growth promoters. Development of reliable analytical techniques has led to knowledge on their toxicities levels. However, monitoring these chemicals still remains a big challenge since most are not covered by standard monitoring techniques. Despite the great efforts aimed at developing reliable analytical techniques to identify and quantify the emerging pollutants in the environment, serious challenges such as existence of a number of isomers, occurance in very low concentrations and existence of the compounds in very complex environments still remain. So far, techniques such as chromatography, spectroscopy, colorimetric methods, enzyme linked immunosorbent assay (ELISA) and electrophoresis have been applied to the determination of these pollutants and exhibited high sensitivity and accuracy. Unfortunately, applications of some of these techniques have been constrained by the sophisticated instruments involved, long preparation time, complicated procedures that require skilled manpower and high detection cost. In addition, some of these techniques are plagued by low detection levels while some electrochemical techniques lack specificity. However, with the ever increasing demand for sensitive and selective detection, great efforts have been made towards development of modern electrochemical and photoelectrochemical sensors that are applicable not only in laboratories but in a variety of other settings.

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