3 Impedimetric Aptasensors for Environmental
Application (Gray Biotechnology)
In gray biotechnology, impedimetric aptasensors attracted attention in recent years
due to Guideline 2008/105/EG of the European Parliament and the Council of
16 December 2008. Gray biotechnology covers biotechnological applications in
the environment such as monitoring of drinking water quality and efficiency of
wastewater treatment and is therefore also called environmental biotechnology.
Impedimetric aptasensors were developed for various purposes in environmental
biotechnological applications with the main focus on the detection of pollutants in
water sources such as drug residues, bacteria, toxins, and pesticides.
The sources of pollution are versatile, as drug residues are introduced by medical
treatments while micropollutants are released into the environment through plastic
production. Toxins produced by microorganisms enter the environment during cell
death or through their metabolism and accumulate, for example, in shellfish. With
impedimetric aptasensors due to the in vitro synthesis of aptamers, it is possible to
detect not only proteins, but also toxins, whole cells, and small molecules such as
ethanolamine, which has a molecular weight of 61 g/mol and is released into the
environment by the textile, chemical, and pharmaceutical industries. In 2016, Liang
et al. developed an impedimetric aptasensor for ethanolamine with a detection limit
of 0.08 nM, thus more sensitive than currently used chromatographic methods
(0.4 μM) [67]. This chapter is intended to give an overview of environmental
application of impedimetric biosensors and compares them with classical analytical
methods.
3.1 Drug Residues
As mentioned above, drugs are important for medical treatment, but they have
significant side effects when they are released into the environment or accumulate
in animal products (like milk). The residues of drugs are continuously released into
the environment, especially into the water. They can intervene in the regulatory
mechanism of the organisms present there. They can be detected there unchanged,
since they are often difficult to degrade and mobile. In sewage treatment plants, these
can only be retained to a limited extent. Due to the low concentration, many drug
residues cannot be detected with the previous methods; therefore, numerous
impedimetric aptasensors have been developed for the detection of antibiotics such
as tetracycline and chloramphenicol, chemotherapeutics like doxorubicin and hormones such as 17ß-estradiol and progesterone (see Table 6). These drugs are used in
cancer therapy, hormone therapy, and animal breeding. With these sensors a faster,
simpler, and more sensitive measurement is possible.
62
J.-A. Preuß et al.
Application (Gray Biotechnology)
In gray biotechnology, impedimetric aptasensors attracted attention in recent years
due to Guideline 2008/105/EG of the European Parliament and the Council of
16 December 2008. Gray biotechnology covers biotechnological applications in
the environment such as monitoring of drinking water quality and efficiency of
wastewater treatment and is therefore also called environmental biotechnology.
Impedimetric aptasensors were developed for various purposes in environmental
biotechnological applications with the main focus on the detection of pollutants in
water sources such as drug residues, bacteria, toxins, and pesticides.
The sources of pollution are versatile, as drug residues are introduced by medical
treatments while micropollutants are released into the environment through plastic
production. Toxins produced by microorganisms enter the environment during cell
death or through their metabolism and accumulate, for example, in shellfish. With
impedimetric aptasensors due to the in vitro synthesis of aptamers, it is possible to
detect not only proteins, but also toxins, whole cells, and small molecules such as
ethanolamine, which has a molecular weight of 61 g/mol and is released into the
environment by the textile, chemical, and pharmaceutical industries. In 2016, Liang
et al. developed an impedimetric aptasensor for ethanolamine with a detection limit
of 0.08 nM, thus more sensitive than currently used chromatographic methods
(0.4 μM) [67]. This chapter is intended to give an overview of environmental
application of impedimetric biosensors and compares them with classical analytical
methods.
3.1 Drug Residues
As mentioned above, drugs are important for medical treatment, but they have
significant side effects when they are released into the environment or accumulate
in animal products (like milk). The residues of drugs are continuously released into
the environment, especially into the water. They can intervene in the regulatory
mechanism of the organisms present there. They can be detected there unchanged,
since they are often difficult to degrade and mobile. In sewage treatment plants, these
can only be retained to a limited extent. Due to the low concentration, many drug
residues cannot be detected with the previous methods; therefore, numerous
impedimetric aptasensors have been developed for the detection of antibiotics such
as tetracycline and chloramphenicol, chemotherapeutics like doxorubicin and hormones such as 17ß-estradiol and progesterone (see Table 6). These drugs are used in
cancer therapy, hormone therapy, and animal breeding. With these sensors a faster,
simpler, and more sensitive measurement is possible.
62
J.-A. Preuß et al.