Kinetic effects on signal normalization in oligonucleotide microchips with labeled immobilized probes

Area of Science:

• Biotechnology
• Molecular Diagnostics
• Genomics

Background:

• Oligonucleotide microchips are vital tools in molecular diagnostics.
• Variations in immobilized probe concentration and distribution significantly impact microchip performance.
• Effective quality control and signal normalization are essential for reliable results.

Purpose of the Study:

• To investigate the use of Cy3-labeled immobilized probes for quality control and signal normalization in hydrogel-based oligonucleotide microchips.
• To determine the optimal conditions for signal normalization based on hybridization kinetics.
• To assess the applicability of the developed technique for identifying drug resistance mutations in Mycobacterium tuberculosis.

Main Methods:

• Utilized hydrogel-based oligonucleotide microchips with Cy3-labeled immobilized probes.
• Performed hybridization with Cy5-labeled target DNA.
• Analyzed probe distribution and signal intensity for quality control.
• Investigated signal normalization under different thermodynamic and kinetic conditions, including hybridization far from saturation.
• Assessed the technique on 50 microchips for Mycobacterium tuberculosis mutation detection.

Main Results:

• Cy3-labeled probes provide reliable monitoring of probe distribution and enable signal normalization.
• Signal normalization strategies must differ between thermodynamic equilibrium and transient kinetic regimes, particularly when hybridization is not saturated.
• The kinetic effect on signal normalization is applicable to both hydrogel-based and surface oligonucleotide microchips.
• The technique demonstrated effectiveness in identifying mutations associated with rifampicin and isoniazid resistance in Mycobacterium tuberculosis.

Conclusions:

• Cy3-labeling of immobilized probes is a valuable method for quality control and signal normalization in oligonucleotide microchips.
• Accurate signal normalization requires consideration of hybridization kinetics, especially in non-saturated conditions.
• This approach enhances the reliability of oligonucleotide microchips for diagnostic applications, such as identifying drug resistance in Mycobacterium tuberculosis.