Topics in Current Chemistry (2020) 378:13
1 3
[108] or cesium chloride gradient centrifugation [109], follow almost the same
principles.
In comparison to the above-mentioned convential methods, solid-phase isolation
protocols allow a quick and efficient purification due to the prevention of incomplete
phase separation in the liquid–liquid extraction and the use of toxic organic solvents.
Solid-phase purification is most commonly performed using a spin column operated
under centrifugal force. Silica matrices, glass particles, diatomaceous earth, and
anion-exchange adsorbents are materials that have been employed as support in such
systems [110]. The initial step in a solid-phase extraction process is to condition the
column for sample adsorption. Column conditioning can be accomplished by using
a buffer at a particular pH to convert the surface or functional groups on the solid
column material into a particular chemical form. For the elution step, Tris–EDTA
buffer or water is introduced to release the desired nucleic acid from the column so
that it can be collected in a purified state [111].
As mentioned above, commonly used quick DNA isolation methods often contain chemicals that can lead to the degradation of DNA or be toxic to both humans
and the environment [112, 113]. Moreover, they include time-consuming and laborintensive complex steps, such as centrifugation, precipitation, and filtration, all
of which are able to compromise DNA integrity. A number of publications have
reported in detail on DNA isolation techniques, emphasizing the special advantages
of DNA magnetic separation [113, 114], which are a fast and simple handling of
samples and the opportunity to deal with large volumes without the need for centrifugation steps. In addition, biomagnetic separation offers many benefits, including
a high-quality product, simple treatment methodology, reduced need for chemicals,
high-throughput system, and the potential for being used in automated processes
[115].
The use of magnetic carriers such as IONPs functionalized with affinity ligands
is preferred due to the high surface area and binding capacity of the IONPs and the
ease manipulation [17]. Although many magnetic carriers are commercially available, the cost of using commercialized separation kits hinders the routine application of this facile technology for biochemical or clinical screening. In addition, new
alternatives are developed almost every year in the continuing effort to improve
separation efficiency. Such materials are MNPs modified with synthetic and natural polymers, porous glass, or material simply based on inorganic coatings, such as
silica and organosilane precursors [17, 95, 116]. For example, Biao et al. reported
the rapid purification of plasmid DNA from crude cell lysates using IONPs modified
with silica [114]. These authors compared their method with a commercial kit as
well as with a traditional phenol–chloroform technique, with their results demonstrating the advantages of their system. Tanaka et al. studied the adsorption and desorption behavior of DNA on aminosilane-modified MNPs for PCR analysis [117]. A
comparison of some of the reported adsorbents in DNA isolation systems is given in
Table 2.
The successful application of silica-coated IONPs in DNA separation is associated with selective binding. Following the same principles as those for silica spin
columns, such magnetic nanoplatforms require the use of a binding buffer to charge
the surface of the nanoparticles. This surface charging creates a high affinity of the
30
Reprinted from the journal
1 3
[108] or cesium chloride gradient centrifugation [109], follow almost the same
principles.
In comparison to the above-mentioned convential methods, solid-phase isolation
protocols allow a quick and efficient purification due to the prevention of incomplete
phase separation in the liquid–liquid extraction and the use of toxic organic solvents.
Solid-phase purification is most commonly performed using a spin column operated
under centrifugal force. Silica matrices, glass particles, diatomaceous earth, and
anion-exchange adsorbents are materials that have been employed as support in such
systems [110]. The initial step in a solid-phase extraction process is to condition the
column for sample adsorption. Column conditioning can be accomplished by using
a buffer at a particular pH to convert the surface or functional groups on the solid
column material into a particular chemical form. For the elution step, Tris–EDTA
buffer or water is introduced to release the desired nucleic acid from the column so
that it can be collected in a purified state [111].
As mentioned above, commonly used quick DNA isolation methods often contain chemicals that can lead to the degradation of DNA or be toxic to both humans
and the environment [112, 113]. Moreover, they include time-consuming and laborintensive complex steps, such as centrifugation, precipitation, and filtration, all
of which are able to compromise DNA integrity. A number of publications have
reported in detail on DNA isolation techniques, emphasizing the special advantages
of DNA magnetic separation [113, 114], which are a fast and simple handling of
samples and the opportunity to deal with large volumes without the need for centrifugation steps. In addition, biomagnetic separation offers many benefits, including
a high-quality product, simple treatment methodology, reduced need for chemicals,
high-throughput system, and the potential for being used in automated processes
[115].
The use of magnetic carriers such as IONPs functionalized with affinity ligands
is preferred due to the high surface area and binding capacity of the IONPs and the
ease manipulation [17]. Although many magnetic carriers are commercially available, the cost of using commercialized separation kits hinders the routine application of this facile technology for biochemical or clinical screening. In addition, new
alternatives are developed almost every year in the continuing effort to improve
separation efficiency. Such materials are MNPs modified with synthetic and natural polymers, porous glass, or material simply based on inorganic coatings, such as
silica and organosilane precursors [17, 95, 116]. For example, Biao et al. reported
the rapid purification of plasmid DNA from crude cell lysates using IONPs modified
with silica [114]. These authors compared their method with a commercial kit as
well as with a traditional phenol–chloroform technique, with their results demonstrating the advantages of their system. Tanaka et al. studied the adsorption and desorption behavior of DNA on aminosilane-modified MNPs for PCR analysis [117]. A
comparison of some of the reported adsorbents in DNA isolation systems is given in
Table 2.
The successful application of silica-coated IONPs in DNA separation is associated with selective binding. Following the same principles as those for silica spin
columns, such magnetic nanoplatforms require the use of a binding buffer to charge
the surface of the nanoparticles. This surface charging creates a high affinity of the
30
Reprinted from the journal