18
L. Hao and H. Gu
Fig. 1.12 Schematic illustration of qPCR-SELEX [62]
Open qPCR was used to optimize the number of cycles for PCR amplification,
and magnetic microspheres coated with target were used for positive selection and
magnetic microspheres with nontarget for negative selection.
1.3.6 Other Selection Strategies
1.3.6.1 Cell-SELEX
The SELEX process is universally applicable to different classes of targets. Besides
defined single targets, complex target structures or mixtures without proper knowledge of their composition are suitable for a successful aptamer selection. Using
complete living cells as target molecules, cell-SELEX can be utilized to screen
specific aptamers to identify potential or discover novel biomarkers on the cell
surface. Generally, cell-SELEX includes two steps: first, the target cells are incubated
with oligonucleotides and applied for positive screening; secondly, nontarget cells
are subject to negative screening. The advantages of cell-SELEX are listed as follows:
(i) multiple aptamers targeting different receptor molecules on the target cell surface
can be screened simultaneously; (ii) targeting aptamers can effectively recognize the
receptor molecules on the cell surface under normal cellular growth condition; (iii)
L. Hao and H. Gu
Fig. 1.12 Schematic illustration of qPCR-SELEX [62]
Open qPCR was used to optimize the number of cycles for PCR amplification,
and magnetic microspheres coated with target were used for positive selection and
magnetic microspheres with nontarget for negative selection.
1.3.6 Other Selection Strategies
1.3.6.1 Cell-SELEX
The SELEX process is universally applicable to different classes of targets. Besides
defined single targets, complex target structures or mixtures without proper knowledge of their composition are suitable for a successful aptamer selection. Using
complete living cells as target molecules, cell-SELEX can be utilized to screen
specific aptamers to identify potential or discover novel biomarkers on the cell
surface. Generally, cell-SELEX includes two steps: first, the target cells are incubated
with oligonucleotides and applied for positive screening; secondly, nontarget cells
are subject to negative screening. The advantages of cell-SELEX are listed as follows:
(i) multiple aptamers targeting different receptor molecules on the target cell surface
can be screened simultaneously; (ii) targeting aptamers can effectively recognize the
receptor molecules on the cell surface under normal cellular growth condition; (iii)