The majority of microarray users prefer to use fluorescent dyes as labels in their experiments, as these dyes typically offer high sensitivity and enable the detection of two or more different dyes simultaneously. Unfortunately, microarray scanners are not able to operate at their maximum efficiency, as the detectors do not acquire all the total emitted fluorescence.

NEXTERION® HiSens Slides are available with most of the NEXTERION® functional coatings.

The NEXTERION® HiSens product is an innovative microarray slide based on an ultraflat, high quality borosilicate glass slide coated with reflective dielectric layers (US patent No. 7939339 and European patent No. EP1591773). The reflective layers on NEXTERION®HiSens significantly enhance sensitivity and signal response. The characteristics of the reflective layers have been optimized for the fluorescent wavelengths most commonly used in microarray experiments, and will simultaneously improve the performance in both the Cy3™ and Cy5™ channels. The slide is produced according to industry standard slide dimensions and is available with SCHOTT’s standard high quality functional coatings for DNA and protein microarraying. This means that the NEXTERION® HiSens Slide is fully compatible with all microarray printing technologies and most slide processing protocols, allowing customers a smooth transition from industry-standard transparent microarray slides.

The NEXTERION® HiSens coating is able to enhance signal amplification by exploiting several optical effects:

• Fluorescence enhancement and reflection of excitation light
  On a standard glass microarray slide, the fluorescently labelled spots absorb only some of the excitation light. By placing a dielectric coating beneath the spots, this “lost” light is reflected back onto the spots. In addition, the multiple layers of the HiSens coating have been specifically designed so that the incoming and reflected excitation light waves overlap and interfere with each other. The interference is constructive at the slide surface, enhancing the excitation by a theoretical factor of up to 6.3 times.

• Reflection of the emission light.

• The fluorescence emission in the Cy3™ and Cy5™ channels from the labelled spots is redirected towards the detector rather than being lost by passing through the glass or by scattering. This effectively doubles the detected fluorescence signal.

Taken together, these effects can theoretically enhance the fluorescence signal by up to 12.6 times when compared to standard transparent microarray slides.

Increased sensitivity

Significant increases in fluorescent signal intensities and signal-to-background ratios have been demonstrated with the NEXTERION® HiSens E and A+ products, the first two slide surfaces launched by SCHOTT in the HiSens range in 2006 (all slide surfaces are now available). The functional coatings are identical to the standard NEXTERION® slides and were processed with standard slide processing protocols. The results clearly exhibit the same impressive spot size and morphology that users typically associate with NEXTERION® Slide E and Slide A+, but the signal intensity is significantly enhanced thanks to the HiSens coating.

Identical oligonucleotide probes were printed on NEXTERION® HiSens A+ and the standard NEXTERION® Slide A+. The slides were hybridized and scanned on an Axon 4000B scanner with identical settings. Images of the NEXTERION® HiSens reflective coating are compared to standard Slide A+. The NEXTERION® HiSens A+ data was normalized against the standard NEXTERION® Slide A+. An 8 to 10 fold increase in signal-to-background ratios was obtained with the NEXTERION®HiSens reflective coating compared to the standard NEXTERION® Slide A+.