Large-scale oligonucleotide synthesizers. I. Basic principles and system design

Area of Science:

• Chemical Engineering
• Biotechnology
• Organic Synthesis

Background:

• Scaling up oligonucleotide synthesis presents challenges in maintaining uniform reagent exposure across large synthesis beds.
• Fluid path length is a primary limitation in achieving consistent reaction conditions during scale-up.

Purpose of the Study:

• To address the limitations of scale-up in oligonucleotide synthesis.
• To develop a method for achieving uniform reagent exposure in larger synthesis beds.

Main Methods:

• Utilized annular beds within uniquely designed zonal centrifuge rotors.
• Controlled reagent flow using a combination of centrifugal force and density differences.
• Employed transparent rotary valves for reagent selection and flow control.
• Integrated a photodiode spectrophotometer for real-time spectral analysis and a balance for continuous effluent weighing.

Main Results:

• Reagent fronts were maintained perpendicular to flow, ensuring uniform conditions across all bed elements.
• Bed volume was successfully increased by enhancing rotor length and diameter.
• Automated control system allowed programming by time, absorbance, or reagent mass.
• On-line integration of trityls and spectral identification of reagents were achieved.

Conclusions:

• The developed zonal centrifuge rotor system effectively overcomes fluid path length limitations in oligonucleotide synthesis scale-up.
• This technology enables the production of larger quantities of oligonucleotides with consistent quality.
• Real-time monitoring and automated control enhance synthesis efficiency and reproducibility.