Scanning Electrochemical Microscopy Imaging of DNA Arrays for High Throughput Analysis Applications - Applications of Electrochemistry and Nanotechnology in Biology and Medicine - page 113

Table 1. A Summary for the Types and the Features of DNA Microarrays in Different Formats.

Probe DNA prepara-
tion method

Array size and probe
DNA density

Labeling and
detection method

Functionality and
significant
application

Suppliers

Microarrays Robotic printing or

piezoelectric inkjet
printing of synthe-
sized DNA probes
or PCR products.

2.5-cm by 7.5-cm
glass slide with ap-
proximately 10,000
genes.

Fluorescent labeling
prior to hybridiza-
tion; fluorophore is
added after hybrid-
ization.

Complimentary DNA
(cDNA) library.

Agilent Technologies,
GE Healthcare Life
Science, and others.

Oligonucleotide
arrays

In-situ synthesis by
light-directed, com-
binatorial solid-
phase chemistry.

1-cm by 1-cm fused
silica with ap-
proximately 40,000
genes

Fluorescent labeling
prior to hybridiza-
tion.

The densest array. Affymetrix, Nim-

bleGen (Roche),
Febit, CombiMa-
trix.

Macroarrays Probes are spotted

onto nylon mem-
brane, plastic or
nitrocellulose solid
matrix.

8-cm by 12-cm with
approximately 200
to 5,000 genes.

Radioactive labeling;
use of phosphor-
imager detector.

The most sensitive
detection.

Clontech Laborato-
ries, Research Ge-
netics.

Microelectronics
array

Electrical field or
current delivers
DNA probes to chip
surface.

Dependent on the
number of ultrami-
croelectrode array
that can be formed
on substrate sur-
face.

Fluorescent labeling
prior to hybridiza-
tion.

Active hybridization;
electrical or elec-
trochemical lead-
out of hybridiza-
tion..

ELI Tech Molecular
Diagnostic.