Superparamagnetic beads and buffer systems, such as AMPure XP Beads from Beckman Coulter, are critical reagents used at multiple points in NGS workflows and many PCR applications. These beads are used to clean-up various NGS and PCR reactions to remove unwanted salts, buffers, adaptors, primers and adaptor or primer dimers. They are also used to size select DNA fragments either before starting NGS library prep or at the end of library prep to produce optimally sized libraries and high quality sequencing results.

sbeadex SAB (sequencing application beads) represent the new generation of size selection and clean-up beads. sbeadex SAB play key roles in in the various steps of NGS and PCR workflows. sbeadex SAB exhibits excellent clean-up properties and provides accurate size selection performance from 200 to 700 bp. sbeadex SAB have improved surface properties minimising the risk of over-drying the beads as well as minimising any interactions with enzymes.

sbeadex SAB are superparamagnetic, double coated beads representing a technical and scientific alternative to common clean-up and size selection systems. Using high salt and different PEG concentrations, the particles allow the capture of nucleic acids of defined sizes on the bead surface. sbeadex SAB can be used in single tubes or in 96-well plates using both manual and automated methods on instruments like the KingFisher™ magnetic particle processor and allows individual, project-specific protocol optimisations.

Same clean-up/left side size selection protocol as other common magnetic clean-up and size selection sequencing beads

Figure 1. Typical sample clean-up protocol.

Highly tunable left side size selection

Figure 2. Agilent high sensitivity DNA electropherogram of left side size selections using various sbeadex SAB to DNA sample volume ratios. The input for each size selection experiment was 1 µg of sheared human genomic DNA (IN, black line) in 100 µL 10 mM Tris, pH 8.0.

Highly controlled right side size selection

Figure 3. Agilent high sensitivity DNA electropherogram of right side size selections. The input for each size selection experiment was 1 µg of sheared human genomic DNA (IN, black line) in 100 µL 10 mM Tris, pH 8.0. The first stage of the right side size selection protocol used the low sbeadex SAB ratios shown on the left side of the legend above. After 1st stage binding, the beads with the larger fragments bound to them were discarded, and additional sbeadex SAB were added to each supernatant to a final ratio of 1.5x. The right side size selected DNA fragments were eluted from the beads and analysed.

Typical dual sided size selection protocol

Figure 4. sbeadex SAB dual sided size selection protocol.

Predictable dual sided size selections

Figure 5. Agilent high sensitivity DNA electropherogram of dual sided size selections. The input for each size selection experiment was 1 µg of sheared human genomic DNA (IN, black line) in 100 µL 10 mM Tris, pH 8.0. For the first stage of the dual sided size selection protocol, the sbeadex SAB/sample ratios show on the left side of the legend above were used and for the second stage, the final sbeadex SAB/sample ratios were used. Final dual sided size selected samples were then analysed.