Magnetic separation technologies, though conventionally being used for ore
and chemical industries, have gained importance for biotechnological applications quite recently [5, 6]. Similarly, aqueous two-phase extraction and reverse
micellar extraction have recently gained prominence for the downstream
processing of macromolecules. In the present review these methods are analyzed especially in terms of the reasons for not realizing their full market
potential. We present mainly our own research on the development of unified
multistage extraction processes that are versatile enough to handle cells as well
as macromolecules as given below.
We describe multistage methods, namely ADSEP (Advanced Separator),
MAGSEP (Magnetic Separator), and ELECSEP (Electrophoretic Separator), for
quantitatively separating cells, particles, and other macromolecules by using
magnetically and electrophoretically assisted extraction processes. These
methods are expected to cost much less in comparison with the competing
technologies at similar scale and precision. These multistage methods build on
the counter-current distribution technology of classical chemical engineering
separations, stemming from the seminal work of Craig and Craig [7] and later
applied to aqueous two-phase extraction (ATPE). Earlier exploitation of this
sliding chamber concept has been attempted with only partial success due to
some shortcomings related to convenience and practicability. In the present
review we indicate how these shortcomings can be alleviated by combining
concepts, so that more efficient and convenient automated magnetic and
electrophoretic bioextraction processes can be developed. We also presented a
few suggestions for future work while analyzing the scale-up and economic
aspects of these extraction processes. Commercial uses of the magnetic and
electrophoretic processes, having both ground and space based research
elements, also are presented in this review.
To the best of our knowledge, multistage magnetic and electophoretic separations have not been reported in the earlier literature. While other processes
involve some element of trial and error (e.g., identifying an appropriate
solution), the theory behind magnetic and electric field assisted separations
provide the ability to predict how unknown cells, particles, and macromolecules will react to magnetic and electric fields. Hence mathematical modeling is
stressed in the proposed review, discussing our own models while reviewing the
models reported in the literature.
2
Cell and Particle Separations
2.1
Magnetic Extraction
Magnetic extraction has been used in various biological processes such as biochemistry, biotechnology, and environmental technologies. Magnetic extraction, based on magnetic sorbents, carriers, and modifiers, has been used
for isolation, modification, detection, immobilization, and removal of a variety
of biologically active compounds, xenobiotics, cellular organelles, and cells.
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K.S.M.S. Raghavarao et al.
and chemical industries, have gained importance for biotechnological applications quite recently [5, 6]. Similarly, aqueous two-phase extraction and reverse
micellar extraction have recently gained prominence for the downstream
processing of macromolecules. In the present review these methods are analyzed especially in terms of the reasons for not realizing their full market
potential. We present mainly our own research on the development of unified
multistage extraction processes that are versatile enough to handle cells as well
as macromolecules as given below.
We describe multistage methods, namely ADSEP (Advanced Separator),
MAGSEP (Magnetic Separator), and ELECSEP (Electrophoretic Separator), for
quantitatively separating cells, particles, and other macromolecules by using
magnetically and electrophoretically assisted extraction processes. These
methods are expected to cost much less in comparison with the competing
technologies at similar scale and precision. These multistage methods build on
the counter-current distribution technology of classical chemical engineering
separations, stemming from the seminal work of Craig and Craig [7] and later
applied to aqueous two-phase extraction (ATPE). Earlier exploitation of this
sliding chamber concept has been attempted with only partial success due to
some shortcomings related to convenience and practicability. In the present
review we indicate how these shortcomings can be alleviated by combining
concepts, so that more efficient and convenient automated magnetic and
electrophoretic bioextraction processes can be developed. We also presented a
few suggestions for future work while analyzing the scale-up and economic
aspects of these extraction processes. Commercial uses of the magnetic and
electrophoretic processes, having both ground and space based research
elements, also are presented in this review.
To the best of our knowledge, multistage magnetic and electophoretic separations have not been reported in the earlier literature. While other processes
involve some element of trial and error (e.g., identifying an appropriate
solution), the theory behind magnetic and electric field assisted separations
provide the ability to predict how unknown cells, particles, and macromolecules will react to magnetic and electric fields. Hence mathematical modeling is
stressed in the proposed review, discussing our own models while reviewing the
models reported in the literature.
2
Cell and Particle Separations
2.1
Magnetic Extraction
Magnetic extraction has been used in various biological processes such as biochemistry, biotechnology, and environmental technologies. Magnetic extraction, based on magnetic sorbents, carriers, and modifiers, has been used
for isolation, modification, detection, immobilization, and removal of a variety
of biologically active compounds, xenobiotics, cellular organelles, and cells.
144
K.S.M.S. Raghavarao et al.