the outmost layer of the particle. Depending on the growth history and the lifetime of
a nanoparticle, very complex compositions, possibly with complex mixtures of
adsorbates, have to be expected. In the typical history of a combustion nanoparticle,
for example, many different agents are prone to condensation on the particle, while
they cool down and are exposed to different ambient atmospheres (Singh et al.
2011). Complex surface chemical processes are to be expected and have been
identified only for a small number of particulate model systems. At the nanoparticle–
liquid interface, polyelectrolytes have been utilized to modify surface properties and
the interactions between particles and their environment. They have been used in a
wide range of technologies, including adhesion, lubrication, stabilization, and controlled flocculation of colloidal dispersions (Liufu et al. 2004).
3.6 Applications of Nanobiosensors
3.6.1 Antibiotic Residues
Nanobiosensors for the detection of antibiotic residues in milk by different biomolecules such as antibody, aptamer, enzymes, etc. are in conjugation with gold,
silver, or iron nanoparticles based on their change in SPR properties (LSPR,
localized surface plasmon resonance) reinforcing the signal by means of electronic
coupling of surface and the NP plasmons (Lyon et al. 1998). A gold nanoparticle
label is an ideal one in biotechnological systems due to its inherent advantages, such
as easy preparation, good biocompatibility, and so on (Sapsford et al. 2013). As far
back as the 1970s, colloidal gold particles were used as an immune-staining and
contrast agent for electron microscopy (Faulk and Taylor 1971). Nowadays, gold
nanoparticles have been extensively employed as the labels for different biological
receptors, e.g., enzyme, DNA, antigen/antibody, and other biomolecules (Ghosh
et al. 2008; Ambrosi et al. 2007). More significantly, gold nanoparticles can be also
used as catalysts in a number of chemical reactions. Yang and Tang (Tang et al.
2011) designed two types of ultrasensitive electrochemical immunoassay using
nanometer gold labels as catalysts. The catalytic properties mainly derived from
the catalytic reduction of 4-nitrophenol by gold nano-labels (Zhang et al. 2013).
Based on the characteristic of surface plasmon resonance absorption of gold
nanoparticles, Zhu et al. (2011) constructed an optical sensor for detection of
antibiotics by using UV–vis absorbance spectrometry.
Natan’s group was one of the first research teams demonstrating the potential of
nano-gold probes for signal enhancement. They employed secondary nano-gold
probes (anti-IgG coupled to AuNP) to detect human IgG in a sandwich format (Lyon
et al. 1998). Regarding low molecular weight analytes, few papers report signal
enhancement using 10–40 nm secondary nano-gold probes. The enhancement
allowed reducing the concentration of primary antibody (i.e., from 10 to 1 μg
mL
À1 ) and improved the detectability (i.e., LOD from 0.1 to 0.007 μg L
À1 for
benzaldehyde) (Yuan et al. 2007, 2008; Mitchell and Lowe 2009). Jiang et al.
3 Application of Nanobiosensors for Food Safety Monitoring
105
a nanoparticle, very complex compositions, possibly with complex mixtures of
adsorbates, have to be expected. In the typical history of a combustion nanoparticle,
for example, many different agents are prone to condensation on the particle, while
they cool down and are exposed to different ambient atmospheres (Singh et al.
2011). Complex surface chemical processes are to be expected and have been
identified only for a small number of particulate model systems. At the nanoparticle–
liquid interface, polyelectrolytes have been utilized to modify surface properties and
the interactions between particles and their environment. They have been used in a
wide range of technologies, including adhesion, lubrication, stabilization, and controlled flocculation of colloidal dispersions (Liufu et al. 2004).
3.6 Applications of Nanobiosensors
3.6.1 Antibiotic Residues
Nanobiosensors for the detection of antibiotic residues in milk by different biomolecules such as antibody, aptamer, enzymes, etc. are in conjugation with gold,
silver, or iron nanoparticles based on their change in SPR properties (LSPR,
localized surface plasmon resonance) reinforcing the signal by means of electronic
coupling of surface and the NP plasmons (Lyon et al. 1998). A gold nanoparticle
label is an ideal one in biotechnological systems due to its inherent advantages, such
as easy preparation, good biocompatibility, and so on (Sapsford et al. 2013). As far
back as the 1970s, colloidal gold particles were used as an immune-staining and
contrast agent for electron microscopy (Faulk and Taylor 1971). Nowadays, gold
nanoparticles have been extensively employed as the labels for different biological
receptors, e.g., enzyme, DNA, antigen/antibody, and other biomolecules (Ghosh
et al. 2008; Ambrosi et al. 2007). More significantly, gold nanoparticles can be also
used as catalysts in a number of chemical reactions. Yang and Tang (Tang et al.
2011) designed two types of ultrasensitive electrochemical immunoassay using
nanometer gold labels as catalysts. The catalytic properties mainly derived from
the catalytic reduction of 4-nitrophenol by gold nano-labels (Zhang et al. 2013).
Based on the characteristic of surface plasmon resonance absorption of gold
nanoparticles, Zhu et al. (2011) constructed an optical sensor for detection of
antibiotics by using UV–vis absorbance spectrometry.
Natan’s group was one of the first research teams demonstrating the potential of
nano-gold probes for signal enhancement. They employed secondary nano-gold
probes (anti-IgG coupled to AuNP) to detect human IgG in a sandwich format (Lyon
et al. 1998). Regarding low molecular weight analytes, few papers report signal
enhancement using 10–40 nm secondary nano-gold probes. The enhancement
allowed reducing the concentration of primary antibody (i.e., from 10 to 1 μg
mL
À1 ) and improved the detectability (i.e., LOD from 0.1 to 0.007 μg L
À1 for
benzaldehyde) (Yuan et al. 2007, 2008; Mitchell and Lowe 2009). Jiang et al.
3 Application of Nanobiosensors for Food Safety Monitoring
105