461 ISSN 1473-7159 © 2011 Expert Reviews Ltd www.expert-reviews.com
Editorial
10.1586/ERM.11.30
Application of 3D hydrogel microarrays
in molecular diagnostics: advantages
and limitations
Expert Rev. Mol. Diagn. 11(5), 461–464 (2011)
“Microarrays are among state-of-the art techniques addressing
the bottlenecks of efficient and highly parallel identification,
measurement and analysis of significant molecules in
‘omics’-based diagnostics. ”
According to Schrenzel et al. “microarrays
consist of an orderly arrangement of probes
(oligonucleotides, DNA fragments, pro-
teins, sugars or lectins) attached to a solid
surface” [1] .
Over the past 20 years, in the bio-
marker discovery, qualification and vali-
dation domain, there has been a constant
evolution towards the increase of sample
through-put, ‘shrinkage’ of both detectors
and sample volumes, and increase in sam-
ple types with emphasis on biological fluids
for noninvasive detection. In this complex
picture, microarrays have been one of the
main biological tools in the last decade [2] .
Future array systems will be used for
high-throughput functional annotation of
gene products. The concept of using sur-
face immobilization of probes is common
to a broad range of applications based on
molecular recognition; diagnostics repre-
sents a major field in molecular recognition,
but is not limited to this. Originally, chips
and arrays were developed on planar sur-
faces and probe fixation was achieved based
on different interactions, including physi-
cal (such as adsorption) and chemical (e.g.,
covalent or ionic), due to specific surface
activation and binding of reactive groups [3] .
Biological integrity of
molecules triggered the need
for developing hydrogels
The probes are immobilized on a range
of different substrates or coated slides
including poly-l-lysine, nitrocellulose,
hydrogel, polyacrylamide gel, agarose,
aldehyde, epoxy or other polymeric coat-
ings. In recent years, the use of gel matrices
in slide preparation has often been cited,
mostly using gels of a hydrophilic nature.
Hydrogel coatings include polyacrila-
mide, polyuretan, agarose, sephadex and
polyethyleneglycol. Hydrogel-coated slides
allow the use of multiple buffer types with-
out pH modification or without the use of
tertiary amine-free buffers [4] .
The need for the development of
hydrogel-based microarrays comes from the
delicate structure of proteins that comprise
biological functions in intimate relation to
their complex structure. These proteins are
difficult to immobilize on a solid support
without harming their function. Keeping
their structure intact and, consequently,
their biological function is essential, thus
testing them in a liquid environment is
a prerequisite. The development of these
tools was designed to measure complex
arrays of proteins, precisely and simulta-
neously for applications in comprehensive
proteomics, protein networks and path-
ways. Microarrays are highly involved in
the validation steps of genomic discoveries
and clinical biomarkers [5] . As stated, the
need to develop these hydrogel microarrays
came from the disadvantages of 2D acti-
vated epoxy or aldehyde glass slides that
immobilize proteins through covalent or
electrostatic interactions. In 2D microarray
KEYWORDS:3D-hydrogel•biomarker•biomolecule•coating•gelmatrix•immobilization
•microarray•moleculardiagnostics
Cristiana Pistol
Tanase
Author for correspondence
’Victor Babes’ National
Institute of Pathology, 99-101
Splaiul Independentei,
Sector 5, Bucharest, Romania
Tel.: +40 213 194 528
Fax: +40 213 194 528
bioch@vbabes.ro
Radu Albulescu
’Victor Babes’ National
Institute of Pathology, 99-101
Splaiul Independentei,
Sector 5, Bucharest, Romania
and
National Institute for
Chemical-Pharmaceutical
R&D, Bucharest, Romania
Monica Neagu
Department of
Immunology,’Victor Babes’
National Institute of
Pathology, 99-101 Splaiul
Independentei, Sector 5,
Bucharest, Romania
Authors contributed equally to this manuscript
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