Microarrays are powerful
tools in biomedical research and have
become indispensable for high-throughput multiplex analysis, especially
for DNA and protein analysis. The basis for all microarray processing
and fabrication is surface modification of a chip substrate and many
different strategies to couple probe molecules to such substrates
have been developed. We present here a critical assessment of typical
biochip generation processes from a surface science point of view.
While great progress has been made from a molecular biology point
of view on the development of qualitative assays and impressive results
have been obtained on the detection of rather low concentrations of
DNA or proteins, quantitative chip-based assays are still comparably
rare. We argue that lack of stable and reliable deposition chemistries
has led in many cases to suboptimal quantitative reproducibility,
impeded further progress in microarray development and prevented a
more significant penetration of microarray technology into the diagnostic
market. We suggest that surface-attached hydrogel networks might be
a promising strategy to achieve highly sensitive and quantitatively
reproducible microarrays.