protected the Fe cores from oxidations, and the core/shell NPs had higher Ms. than
ferrite NPs. It was reported that Ms. of Fe@MnFe 2 O 4 NPs was highest. Thus the
development of multifunctional MNPs from such heterostructured MNPs can be
used for designing multimodal MRSw-based nanosensors (Zhang et al. 2017b).
These magnetic NPs can be conjugated with biorecognitive molecules (enzymes,
DNA, etc.), and can be used for enrichment for the target analyte. Hence, these
sensors can be applied to improve sensor sensitivity (Jianrong et al. 2004). Chemla
et al. (2000) used magnetic NPs labelled with antibodies for sensing biological
targets. They used sensitive SQUID technique which is highly sensitive and specific
for detection of labelled magnetic NPs. Antibodies functionalized magnetic NPs can
also be applied for detection of toxins from environmental samples.
5.3.2.3 Bio-Nanomaterials and Polymeric Nanomaterials
Bio-nanomaterials and polymeric nanomaterials possess excellent thermal, mechanical, catalytic, physical and electrical properties. Hence these types of nanomaterials
can be used for fabrication of highly selective and responsive nanobiosensors and
electrochemical sensors (Yang et al. 2016). These nanomaterials can be combined
with novel scientific and analytical techniques for application as electrochemical
sensors (Wang et al. 2016).
Bio-nanomaterials based sensors: a large number of nanosensors have been
fabricated by combining the unique features of nanomaterials with the catalytic
activity of biomolecules. Biomolecules, through self-organization can result in the
formation of proper nanostructures with biomaterials. Sabela et al., designed
electrochemical biosensor for capsaicin, using nanobiocomposites of enzyme Lphenylaniline ammonia-lyase and MWCNTs (Sabela et al. 2016). Li et al., developed portable biosensor for E. coli O157:H7 using self-assembled monolayers
(SAMs) method (Li et al. 2015b).
Polymer-based nanomaterials: Polymeric nanomaterials have been combined
with various sensing technologies for the sensing of gaseous and liquid environmental pollutants and food contaminants (Rother et al. 2016). The electrochemical
sensing properties of polymer-based nanomaterials can be improved by integration of graphene, CNTs, metal and metal oxide NPs, etc. (Villalonga et al. 2012;
Dai et al. 2016).
The selectivity and sensitivity and biocompatibility of nanosensors can be
enhanced by combination of nanofillers and matrix. Navele et al. reported the
room temperature sensing of reducing (NH 3 , H 2 S, C 2 H 5 OH, CH 3 OH) and oxidizing
(Cl 2 and NO 2 ) gases using nanocomposite of polypyrrole (PPy)/a-Fe 2 O 3 (Navale
et al. 2014). Pramanik reported gas sensor for toxic gases like toluene, ethanol,
benzene and acetone using bentonite nanohybrid modified polyaniline (PANI)
nanofibers (Pramanik et al. 2013).
5.3.2.4 Metal Oxide (MOX)-Based Nanomaterials
Metal oxide nanoparticles (NPs) and thin films are cost-effective ceramic-based
nanomaterials with high surface area and unique properties. These materials have
been well-explored for highly efficient nanosensors for various environmental
110
U. Chakraborty et al.
ferrite NPs. It was reported that Ms. of Fe@MnFe 2 O 4 NPs was highest. Thus the
development of multifunctional MNPs from such heterostructured MNPs can be
used for designing multimodal MRSw-based nanosensors (Zhang et al. 2017b).
These magnetic NPs can be conjugated with biorecognitive molecules (enzymes,
DNA, etc.), and can be used for enrichment for the target analyte. Hence, these
sensors can be applied to improve sensor sensitivity (Jianrong et al. 2004). Chemla
et al. (2000) used magnetic NPs labelled with antibodies for sensing biological
targets. They used sensitive SQUID technique which is highly sensitive and specific
for detection of labelled magnetic NPs. Antibodies functionalized magnetic NPs can
also be applied for detection of toxins from environmental samples.
5.3.2.3 Bio-Nanomaterials and Polymeric Nanomaterials
Bio-nanomaterials and polymeric nanomaterials possess excellent thermal, mechanical, catalytic, physical and electrical properties. Hence these types of nanomaterials
can be used for fabrication of highly selective and responsive nanobiosensors and
electrochemical sensors (Yang et al. 2016). These nanomaterials can be combined
with novel scientific and analytical techniques for application as electrochemical
sensors (Wang et al. 2016).
Bio-nanomaterials based sensors: a large number of nanosensors have been
fabricated by combining the unique features of nanomaterials with the catalytic
activity of biomolecules. Biomolecules, through self-organization can result in the
formation of proper nanostructures with biomaterials. Sabela et al., designed
electrochemical biosensor for capsaicin, using nanobiocomposites of enzyme Lphenylaniline ammonia-lyase and MWCNTs (Sabela et al. 2016). Li et al., developed portable biosensor for E. coli O157:H7 using self-assembled monolayers
(SAMs) method (Li et al. 2015b).
Polymer-based nanomaterials: Polymeric nanomaterials have been combined
with various sensing technologies for the sensing of gaseous and liquid environmental pollutants and food contaminants (Rother et al. 2016). The electrochemical
sensing properties of polymer-based nanomaterials can be improved by integration of graphene, CNTs, metal and metal oxide NPs, etc. (Villalonga et al. 2012;
Dai et al. 2016).
The selectivity and sensitivity and biocompatibility of nanosensors can be
enhanced by combination of nanofillers and matrix. Navele et al. reported the
room temperature sensing of reducing (NH 3 , H 2 S, C 2 H 5 OH, CH 3 OH) and oxidizing
(Cl 2 and NO 2 ) gases using nanocomposite of polypyrrole (PPy)/a-Fe 2 O 3 (Navale
et al. 2014). Pramanik reported gas sensor for toxic gases like toluene, ethanol,
benzene and acetone using bentonite nanohybrid modified polyaniline (PANI)
nanofibers (Pramanik et al. 2013).
5.3.2.4 Metal Oxide (MOX)-Based Nanomaterials
Metal oxide nanoparticles (NPs) and thin films are cost-effective ceramic-based
nanomaterials with high surface area and unique properties. These materials have
been well-explored for highly efficient nanosensors for various environmental
110
U. Chakraborty et al.