Non-Acoustic Sensors 18.4 Biological Sensor Systems 429
Part B | 18.4
cal sensor system for AUVs. Direct reduction methods
and adsorptive styles, such as anodic stripping voltammetry illustrate the analytical performance and size of
these sensors [18.19]. Potentiometric sensors are also
applicable to AUV deployment, however the individual
capability of a system is coupled to the performance of
the ion selective coating that separates the sample from
the medium. Further development of new ion-selective
coatings is critical for the expansion of the chemical vision of these electrochemical metal species sensors for
AUVs.
Automated wet chemical analysis has a proven history in aquatic observations, in particular for metals
relevant to micronutrient activity. Continuous flow injection instrumentation has been used for profiling and
surface ion detection mapping of specific metals (Fe,
Co, Mn, Cu, Zn). As was mentioned prior, wet chemical systems have the ability to be tuned to different
chemical species and in many ways can be viewed as
hardware processors that are programmed to different
chemicals based on the reaction chemistry used. This
applies to electrochemistry applications and beyond. Insertion on AUV platforms will become more prevalent
over time as form factors shrink and the cost of components is reduced.
Many chemical instrument systems benefit from
the incorporation of microelectronics, which results
in significant miniaturization. The realm of AUVs
should substantially benefit from developments occurring in these miniaturized engineered instrument systems. An example of this is the water-stable organic
transistor, which has already been developed and applied to chemical sensors [18.20]. The development
of low-cost, organic thin-film transistor (OTFTs) devices capable of converting an analyte binding event
to an easily read electrical signal is already leading
to new chemical specific devices with reduced size
and cost. OTFT sensors have been demonstrated in
aqueous solutions with concentrations as low as ppb
for trinitrobenzene, methylphosphonic acid, and other
chemicals. This work indicates reliable OTFT operation in aqueous media, hence opening new possibilities
of chemical sensing with OTFTs chemical sensors and
on mobile platforms. OTFTs are ideal for inexpensive,
chemical sensors because of their compatibility with
flexible, large-area substrates, simple processing, and
highly tunable active layer materials.
Nanomaterials also show promise in aquatic chemical analysis mainly due to their highly tunable size
and shape-dependent chemical and physical properties [18.21]. Although a broad definition, nanomaterials
are structured components materials that have at least
one dimension less than 100 nm. Furthermore, they exhibit unique surface chemistry, thermal stability, high
surface area, and large pore volume per unit mass that
can be exploited for ocean chemical sensor fabrication.
Nanoscale materials can be implemented as scaffolds
for chemosensing. Nanomaterials have proven to be
useful for the fabrication of sensors and have compositions including metals, metal oxides, chalcogenides,
and polymers. Their structures range from nanoparticles, nanorods, and nanowires to nanoporous structures
and core-shells. A few nanomaterials have been functionally altered to work with various kinds of ligands
and active groups that produce sensitive and selective
sensors for specific analytes. The ever expanding group
of nanocomponents has the potential to allow chemical
sensor designers to create highly selective chemoreception systems able to function within the complex
background of ocean waters. Migration of this technological toolbox into ocean chemical sensor systems
will emerge over time as they are implemented in industrial and medical applications and adapted to ocean
research.
18.4 Biological Sensor Systems
Similar to the chemical research space, biosensor research and monitoring is fragmented in such a way
that at best we can provide a broad overview of important AUV amenable sensors. The spectrum of sensors
available, however, can address biogeochemical cycles,
primary and secondary production, species distribution,
animal movements, habitats, and pollutants. It is impossible to discuss all relevant systems or to provide
appropriate detail for all of those discussed in this
chapter. Therefore, this is an introduction to the sensor technologies currently in process or soon to be, and
what variables are quantified.
The advancement of instruments has frequently preceded many major discoveries in the field of science
and technology. The microscope is a classic example
of the influence of scientific instrumentation on sensing
within the biological sciences. Efforts in engineering
ocean instrumentation and developing the associated
sensors must take into consideration the inherent environmental limitations encountered in underwater applications. Environmental issues include the corrosive nature of seawater, bio-fouling, limited energy resources,
pressure tolerant enclosures, data transfer reliability and
the dynamic nature of the ocean itself.
Part B | 18.4
cal sensor system for AUVs. Direct reduction methods
and adsorptive styles, such as anodic stripping voltammetry illustrate the analytical performance and size of
these sensors [18.19]. Potentiometric sensors are also
applicable to AUV deployment, however the individual
capability of a system is coupled to the performance of
the ion selective coating that separates the sample from
the medium. Further development of new ion-selective
coatings is critical for the expansion of the chemical vision of these electrochemical metal species sensors for
AUVs.
Automated wet chemical analysis has a proven history in aquatic observations, in particular for metals
relevant to micronutrient activity. Continuous flow injection instrumentation has been used for profiling and
surface ion detection mapping of specific metals (Fe,
Co, Mn, Cu, Zn). As was mentioned prior, wet chemical systems have the ability to be tuned to different
chemical species and in many ways can be viewed as
hardware processors that are programmed to different
chemicals based on the reaction chemistry used. This
applies to electrochemistry applications and beyond. Insertion on AUV platforms will become more prevalent
over time as form factors shrink and the cost of components is reduced.
Many chemical instrument systems benefit from
the incorporation of microelectronics, which results
in significant miniaturization. The realm of AUVs
should substantially benefit from developments occurring in these miniaturized engineered instrument systems. An example of this is the water-stable organic
transistor, which has already been developed and applied to chemical sensors [18.20]. The development
of low-cost, organic thin-film transistor (OTFTs) devices capable of converting an analyte binding event
to an easily read electrical signal is already leading
to new chemical specific devices with reduced size
and cost. OTFT sensors have been demonstrated in
aqueous solutions with concentrations as low as ppb
for trinitrobenzene, methylphosphonic acid, and other
chemicals. This work indicates reliable OTFT operation in aqueous media, hence opening new possibilities
of chemical sensing with OTFTs chemical sensors and
on mobile platforms. OTFTs are ideal for inexpensive,
chemical sensors because of their compatibility with
flexible, large-area substrates, simple processing, and
highly tunable active layer materials.
Nanomaterials also show promise in aquatic chemical analysis mainly due to their highly tunable size
and shape-dependent chemical and physical properties [18.21]. Although a broad definition, nanomaterials
are structured components materials that have at least
one dimension less than 100 nm. Furthermore, they exhibit unique surface chemistry, thermal stability, high
surface area, and large pore volume per unit mass that
can be exploited for ocean chemical sensor fabrication.
Nanoscale materials can be implemented as scaffolds
for chemosensing. Nanomaterials have proven to be
useful for the fabrication of sensors and have compositions including metals, metal oxides, chalcogenides,
and polymers. Their structures range from nanoparticles, nanorods, and nanowires to nanoporous structures
and core-shells. A few nanomaterials have been functionally altered to work with various kinds of ligands
and active groups that produce sensitive and selective
sensors for specific analytes. The ever expanding group
of nanocomponents has the potential to allow chemical
sensor designers to create highly selective chemoreception systems able to function within the complex
background of ocean waters. Migration of this technological toolbox into ocean chemical sensor systems
will emerge over time as they are implemented in industrial and medical applications and adapted to ocean
research.
18.4 Biological Sensor Systems
Similar to the chemical research space, biosensor research and monitoring is fragmented in such a way
that at best we can provide a broad overview of important AUV amenable sensors. The spectrum of sensors
available, however, can address biogeochemical cycles,
primary and secondary production, species distribution,
animal movements, habitats, and pollutants. It is impossible to discuss all relevant systems or to provide
appropriate detail for all of those discussed in this
chapter. Therefore, this is an introduction to the sensor technologies currently in process or soon to be, and
what variables are quantified.
The advancement of instruments has frequently preceded many major discoveries in the field of science
and technology. The microscope is a classic example
of the influence of scientific instrumentation on sensing
within the biological sciences. Efforts in engineering
ocean instrumentation and developing the associated
sensors must take into consideration the inherent environmental limitations encountered in underwater applications. Environmental issues include the corrosive nature of seawater, bio-fouling, limited energy resources,
pressure tolerant enclosures, data transfer reliability and
the dynamic nature of the ocean itself.