Microfluidic Systems for Marine Biotechnology 20.2 Microfluidic Devices for Marine Biology and Ecosystem Studies 511
Part C | 20.2
macromolecules to the channel wall. A higher SAV of
liquid in the microchannel helps in conducting efficient
capillary electrophoreses.
20.1.3 Diffusion
Diffusion arises when two fluids with a concentration
gradient come into contact with each other (Fig. 20.1b).
In microfluidic systems, diffusion is an inefficient way
of mixing two or more fluids because of the presence of
a laminar regime. Mixing at microscale mainly occurs
by the process of diffusion and due to the absence of
turbulence.
20.1.4 Mixing
In microfluidics, quick mixing of fluids flowing through
the microchannel is one of the key challenges. In
the microchannel, the Reynolds number is very small
due to the smaller channel dimensions. In the laminar
flow regime, mixing of fluids occurs mainly by diffusion and, hence, happens very slowly (Fig. 20.1c).
To solve this problem, various micromixers, such as
chaotic flow micromixers, electrokinetic micromixers,
peristaltic micromixers, etc., have been developed in recent years [20.17–21].
20.1.5 Wetting
Wetting is an interfacial phenomenon due to the balance
of surface energies at gas-liquid-solid interfaces. The
value of contact angle (Â ) determines the type of wetting on the surfaces, viz. hydrophilicity and hydrophobicity. The behavior of fluid wetting on hydrophilic
and hydrophobic surfaces is shown in Fig. 20.1d and
e, respectively. The principle of wetting is exhaustively used in droplet-based microfluidic devices [20.4,
15].
20.2 Microfluidic Devices for Marine Biology and Ecosystem Studies
A major challenge in the field of marine biotechnology
is to develop an efficient procedure for the discovery
of novel biomolecules in the marine environment or
marine bioprospecting. Because of the high level of
biodiversity of marine organisms, an understanding of
marine biology and ecology is an important first step to
the discovery of new active molecules.
20.2.1 Microfluidics for Cell Analysis
(RNA Amplification, Single-Cell
Analysis, and Fish Embryology)
In this part, we will describe how microfluidic systems
can be used to study marine organisms at different levels: molecular (genomics), cellular, and multicellular
(tissues and the whole organism).
Genomics
Genome sequencing is a powerful tool that can be applied to explore the genetic materials of organisms, such
as microorganisms [20.22–24]. Recently, single-cell genomics (SCG) emerged both as a potent complement
to cultivation and metagenomics [20.25] and as an
independent analytical tool [20.26, 27], by providing
genomic information and delivering unequivocal information about the organization of the genes discovered
within genomes [20.28–34]. However, to obtain highquality SCG, expensive and large instrumentation (e.g.,
cell sorters, robotic liquid handlers, DNA sequencers)
and infrastructure (clean rooms, high-performance information technology (IT)) are required, which limit
their use in most individual research groups. Microfluidic technology provides an alternative to conventional
methods, offering numerous advantages including automation, enhanced sensitivity and reaction efficiency
in small volumes [20.35, 36], and the potential for scalable and cost effective small volume assays [20.37]
that can be used for genomics (Fig. 20.2a) [20.9, 38].
It effectively addresses the three classes of contamination with the potential to compromise single-cell
amplification reactions: the laboratory environment,
amplification reagents, and cells/DNA from the sample itself [20.39]. Microfluidic devices produced by
Blainey et al. illustrate the capability to perform SCG
analysis on a chip [20.39]. The device, shown in
Fig. 20.2b, originally developed by Marcy et al. [20.26],
was used to perform multiple displacement amplification (MDA) reactions with nanoliters of reagent. The
microfluidic chip was composed of 32 microchambers
implemented with a laser tweezer system [20.40, 41].
A mixture of ammonia-oxidizing archaea (AOA) microorganisms was introduced into the device. Single
cells, smaller than 1 ¸ tm, were selected upon microscopic inspection and then guided with a laser trap
Part C | 20.2
macromolecules to the channel wall. A higher SAV of
liquid in the microchannel helps in conducting efficient
capillary electrophoreses.
20.1.3 Diffusion
Diffusion arises when two fluids with a concentration
gradient come into contact with each other (Fig. 20.1b).
In microfluidic systems, diffusion is an inefficient way
of mixing two or more fluids because of the presence of
a laminar regime. Mixing at microscale mainly occurs
by the process of diffusion and due to the absence of
turbulence.
20.1.4 Mixing
In microfluidics, quick mixing of fluids flowing through
the microchannel is one of the key challenges. In
the microchannel, the Reynolds number is very small
due to the smaller channel dimensions. In the laminar
flow regime, mixing of fluids occurs mainly by diffusion and, hence, happens very slowly (Fig. 20.1c).
To solve this problem, various micromixers, such as
chaotic flow micromixers, electrokinetic micromixers,
peristaltic micromixers, etc., have been developed in recent years [20.17–21].
20.1.5 Wetting
Wetting is an interfacial phenomenon due to the balance
of surface energies at gas-liquid-solid interfaces. The
value of contact angle (Â ) determines the type of wetting on the surfaces, viz. hydrophilicity and hydrophobicity. The behavior of fluid wetting on hydrophilic
and hydrophobic surfaces is shown in Fig. 20.1d and
e, respectively. The principle of wetting is exhaustively used in droplet-based microfluidic devices [20.4,
15].
20.2 Microfluidic Devices for Marine Biology and Ecosystem Studies
A major challenge in the field of marine biotechnology
is to develop an efficient procedure for the discovery
of novel biomolecules in the marine environment or
marine bioprospecting. Because of the high level of
biodiversity of marine organisms, an understanding of
marine biology and ecology is an important first step to
the discovery of new active molecules.
20.2.1 Microfluidics for Cell Analysis
(RNA Amplification, Single-Cell
Analysis, and Fish Embryology)
In this part, we will describe how microfluidic systems
can be used to study marine organisms at different levels: molecular (genomics), cellular, and multicellular
(tissues and the whole organism).
Genomics
Genome sequencing is a powerful tool that can be applied to explore the genetic materials of organisms, such
as microorganisms [20.22–24]. Recently, single-cell genomics (SCG) emerged both as a potent complement
to cultivation and metagenomics [20.25] and as an
independent analytical tool [20.26, 27], by providing
genomic information and delivering unequivocal information about the organization of the genes discovered
within genomes [20.28–34]. However, to obtain highquality SCG, expensive and large instrumentation (e.g.,
cell sorters, robotic liquid handlers, DNA sequencers)
and infrastructure (clean rooms, high-performance information technology (IT)) are required, which limit
their use in most individual research groups. Microfluidic technology provides an alternative to conventional
methods, offering numerous advantages including automation, enhanced sensitivity and reaction efficiency
in small volumes [20.35, 36], and the potential for scalable and cost effective small volume assays [20.37]
that can be used for genomics (Fig. 20.2a) [20.9, 38].
It effectively addresses the three classes of contamination with the potential to compromise single-cell
amplification reactions: the laboratory environment,
amplification reagents, and cells/DNA from the sample itself [20.39]. Microfluidic devices produced by
Blainey et al. illustrate the capability to perform SCG
analysis on a chip [20.39]. The device, shown in
Fig. 20.2b, originally developed by Marcy et al. [20.26],
was used to perform multiple displacement amplification (MDA) reactions with nanoliters of reagent. The
microfluidic chip was composed of 32 microchambers
implemented with a laser tweezer system [20.40, 41].
A mixture of ammonia-oxidizing archaea (AOA) microorganisms was introduced into the device. Single
cells, smaller than 1 ¸ tm, were selected upon microscopic inspection and then guided with a laser trap