emitting carbon nanodots. Appreciable limit of detection (LOD) value of
5 Â 10
À5 M was obtained by visual detection and 0.127 μM by fluorescence
measurements (Ren et al. 2018). Yan et al., reported specific electrocatalytic sensing
of endocrine disrupting chemical bisphenol A (BPA) using graphitic carbon nitride
modified with molecular imprinted polymer (Yan et al. 2018). Chiu et al. designed
screen-printed carbon electrode sensor using conducting polymer (melamine)
modified MWCNTs, based on the high stability and large surface area of CNTs.
This sensor was efficiently used for electrochemical sensing of nitro furans in milk
and lake water samples (Chiu et al. 2018). Detection of bacterial pathogens and
viruses has also been done using carbon-based nanomaterials modified sensors.
Carbon-based nanomaterials modified pyrolytic graphite electrode (Banks and
Compton 2005) and glassy carbon electrode (Dekanski et al. 2001) have been
successfully explored for this purpose. Sensing of pathogens is facilitated by high
sensitivity and selectivity of carbon nanomaterials based nanobiosensors. Bharadwaj
et al., proposed antibody-conjugated SWCNTs for electrochemical immunosensing
of S. aureus (Bhardwaj et al. 2017). Carbon-nanomaterials-based sensors have been
applied for detection of harmful heavy metal ions. Zhou et al., reviewed the recent
progress in detection of heavy metal ions using biosensors prepared by
nanostructures modified with DNAzymes/DNA (Zhou et al. 2016). The use of
carbon-based nanomaterials for detection of different organic, inorganic and
biological pollutants has been listed in Table 5.2.
Carbon-based nanomaterials also exhibit excellent optical properties and these
materials have also been used for developing optical nanosensors. Zhang et al.
reported ultrasensitive glucose and hydrogen peroxide (H 2 O 2 ) detection using
FRET between polyaniline and carbon quantum dots (Zhang et al. 2015b). Recently,
Bhaisare et al., reported the fluorescent sensing of urine sample with pathogenic
bacteria (Escherichia coli (E. Coli) and Staphylococcus aureus (S. aureus)), based
on their strong adhesion over carbon dots decorated magnetic nanoparticles
functionalized with amine group (Bhaisare et al. 2016).
5.3.2.2 Magnetic Nanoparticles
Magnetic nanoparticles also find significant use in important nanosensors
applications. They can be fabricated with many forms like different types of ferrites
(MeO.Fe 2 O 3 , Me ¼ Mn, Mg, Co, Ni, Zn, etc.), maghemite (γ-Fe 2 O 3 ), greigite
(Fe 3 S 4 ), superparamagnetic magnetite (Fe 3 O 4 ), etc. (Šafařik and Šafaříková 2002).
Magnetization of the MNPs can be enhanced by introduction of chemical dopants
like Co
2+ , Mn
2+ , Ni
2+ , Zn
2+ which have higher magnetic moment (Cheon and Lee
2008; Jang et al. 2009). Magnetic properties can also be enhanced by fabricating
core/shell MNPs with both the core and shell having high Ms. Magnetic moment
possessed by Fe, Ni and Co NPs is stronger than iron oxide NPs, but these NPs are
highly reactive in the aqueous medium making their direct application difficult.
Designing core/shell NPs with these NPs as core and iron oxide or other metals as
shell results in preserving the large magnetic moment of the cores and also gives
them higher colloidal stability. For instance, different core-shell NPs Fe@MnFe 2 O 4 ,
Fe@Fe 3 O 4 , Fe@CoFe 2 O 4 with Fe core were reported (Lee et al. 2011). The shells
5 Development of Environmental Nanosensors for Detection Monitoring. . .
107
5 Â 10
À5 M was obtained by visual detection and 0.127 μM by fluorescence
measurements (Ren et al. 2018). Yan et al., reported specific electrocatalytic sensing
of endocrine disrupting chemical bisphenol A (BPA) using graphitic carbon nitride
modified with molecular imprinted polymer (Yan et al. 2018). Chiu et al. designed
screen-printed carbon electrode sensor using conducting polymer (melamine)
modified MWCNTs, based on the high stability and large surface area of CNTs.
This sensor was efficiently used for electrochemical sensing of nitro furans in milk
and lake water samples (Chiu et al. 2018). Detection of bacterial pathogens and
viruses has also been done using carbon-based nanomaterials modified sensors.
Carbon-based nanomaterials modified pyrolytic graphite electrode (Banks and
Compton 2005) and glassy carbon electrode (Dekanski et al. 2001) have been
successfully explored for this purpose. Sensing of pathogens is facilitated by high
sensitivity and selectivity of carbon nanomaterials based nanobiosensors. Bharadwaj
et al., proposed antibody-conjugated SWCNTs for electrochemical immunosensing
of S. aureus (Bhardwaj et al. 2017). Carbon-nanomaterials-based sensors have been
applied for detection of harmful heavy metal ions. Zhou et al., reviewed the recent
progress in detection of heavy metal ions using biosensors prepared by
nanostructures modified with DNAzymes/DNA (Zhou et al. 2016). The use of
carbon-based nanomaterials for detection of different organic, inorganic and
biological pollutants has been listed in Table 5.2.
Carbon-based nanomaterials also exhibit excellent optical properties and these
materials have also been used for developing optical nanosensors. Zhang et al.
reported ultrasensitive glucose and hydrogen peroxide (H 2 O 2 ) detection using
FRET between polyaniline and carbon quantum dots (Zhang et al. 2015b). Recently,
Bhaisare et al., reported the fluorescent sensing of urine sample with pathogenic
bacteria (Escherichia coli (E. Coli) and Staphylococcus aureus (S. aureus)), based
on their strong adhesion over carbon dots decorated magnetic nanoparticles
functionalized with amine group (Bhaisare et al. 2016).
5.3.2.2 Magnetic Nanoparticles
Magnetic nanoparticles also find significant use in important nanosensors
applications. They can be fabricated with many forms like different types of ferrites
(MeO.Fe 2 O 3 , Me ¼ Mn, Mg, Co, Ni, Zn, etc.), maghemite (γ-Fe 2 O 3 ), greigite
(Fe 3 S 4 ), superparamagnetic magnetite (Fe 3 O 4 ), etc. (Šafařik and Šafaříková 2002).
Magnetization of the MNPs can be enhanced by introduction of chemical dopants
like Co
2+ , Mn
2+ , Ni
2+ , Zn
2+ which have higher magnetic moment (Cheon and Lee
2008; Jang et al. 2009). Magnetic properties can also be enhanced by fabricating
core/shell MNPs with both the core and shell having high Ms. Magnetic moment
possessed by Fe, Ni and Co NPs is stronger than iron oxide NPs, but these NPs are
highly reactive in the aqueous medium making their direct application difficult.
Designing core/shell NPs with these NPs as core and iron oxide or other metals as
shell results in preserving the large magnetic moment of the cores and also gives
them higher colloidal stability. For instance, different core-shell NPs Fe@MnFe 2 O 4 ,
Fe@Fe 3 O 4 , Fe@CoFe 2 O 4 with Fe core were reported (Lee et al. 2011). The shells
5 Development of Environmental Nanosensors for Detection Monitoring. . .
107