3.1.1 Antibiotics
Chloramphenicol is an effective broad-spectrum antibiotic used in the treatment of
infectious diseases. Due to its potential lethal side effects it was defined that
chloramphenicol in any concentration is a health risk. To ensure food safety, the
European Commission set a minimum required performance limit (MRPL) value,
defining the lowest detectable concentration of the analysis method [74]. Currently,
the detection of chloramphenicol is based on gas chromatography, high performance
liquid chromatography, and mass spectrometry, which are very sensitive, but are
expensive, time-consuming, and require highly trained personnel. Pilehvar et al.
developed a simple low-cost aptamer-based impedimetric biosensor with an approximate assay time of 5 h and a detection limit of 1.76 nM (0.6 μg/l), which approaches
the MRPL value of 0.3 μg/kg [68].
3.1.2 Anthracycline
Doxorubicin belongs to the group of anthracycline antibiotics and is used as
chemotherapeutics in cancer therapy. By incomplete degradation in wastewater,
this drug residue reaches our tap water. Due to its cardiotoxicity, it contaminates
nature and threatens humans and the environment. An aptamer-based biosensor for
detection of doxorubicin by electrochemical impedance spectroscopy was developed
by Bahner et al. [69]. The developed sensor was able to reach a detection limit of
28 nM in buffer and thus a lower detection limit as previously reported by Erdem
et al. (128 nM) [70].
3.1.3 Hormones
Hormones can also be detected with aptasensors. The hormone estradiol is one of the
most important active ingredients for contraception and hormone treatment. When
ingested by humans, it can enter the sewage system. Zhu et al. developed a sensitive
impedimetric aptasensor for the detection of 17ß-estradiol with a detection limit of
1 fM [71]. They successfully detected estradiol in spiked biologically complex
human urine samples as well as spiked untreated tap water samples and obtained
Table 6 List of impedimetric
aptasensors for the detection
of drug residues
Drug residue
Detection limit (M)
Reference
Chloramphenicol
1.76 Â 10
À9
[68]
Doxorubicin
2.80 Â 10
À8
[69]
1.28 Â 10
À7
[70]
17ß-estradiol
1.00 Â 10
À15
[71]
2.00 Â 10
À12
[72]
Progesterone
3.00 Â 10
À9
[73]
Impedimetric Aptamer-Based Biosensors: Applications
63
Chloramphenicol is an effective broad-spectrum antibiotic used in the treatment of
infectious diseases. Due to its potential lethal side effects it was defined that
chloramphenicol in any concentration is a health risk. To ensure food safety, the
European Commission set a minimum required performance limit (MRPL) value,
defining the lowest detectable concentration of the analysis method [74]. Currently,
the detection of chloramphenicol is based on gas chromatography, high performance
liquid chromatography, and mass spectrometry, which are very sensitive, but are
expensive, time-consuming, and require highly trained personnel. Pilehvar et al.
developed a simple low-cost aptamer-based impedimetric biosensor with an approximate assay time of 5 h and a detection limit of 1.76 nM (0.6 μg/l), which approaches
the MRPL value of 0.3 μg/kg [68].
3.1.2 Anthracycline
Doxorubicin belongs to the group of anthracycline antibiotics and is used as
chemotherapeutics in cancer therapy. By incomplete degradation in wastewater,
this drug residue reaches our tap water. Due to its cardiotoxicity, it contaminates
nature and threatens humans and the environment. An aptamer-based biosensor for
detection of doxorubicin by electrochemical impedance spectroscopy was developed
by Bahner et al. [69]. The developed sensor was able to reach a detection limit of
28 nM in buffer and thus a lower detection limit as previously reported by Erdem
et al. (128 nM) [70].
3.1.3 Hormones
Hormones can also be detected with aptasensors. The hormone estradiol is one of the
most important active ingredients for contraception and hormone treatment. When
ingested by humans, it can enter the sewage system. Zhu et al. developed a sensitive
impedimetric aptasensor for the detection of 17ß-estradiol with a detection limit of
1 fM [71]. They successfully detected estradiol in spiked biologically complex
human urine samples as well as spiked untreated tap water samples and obtained
Table 6 List of impedimetric
aptasensors for the detection
of drug residues
Drug residue
Detection limit (M)
Reference
Chloramphenicol
1.76 Â 10
À9
[68]
Doxorubicin
2.80 Â 10
À8
[69]
1.28 Â 10
À7
[70]
17ß-estradiol
1.00 Â 10
À15
[71]
2.00 Â 10
À12
[72]
Progesterone
3.00 Â 10
À9
[73]
Impedimetric Aptamer-Based Biosensors: Applications
63