What are the best practices for using SPRIselect or VAHTS DNA Clean Beads?

Answer:
Magnetic bead-based size selection is a highly sensitive step. Small deviations in operation may significantly affect fragment size distribution and downstream sequencing quality. Strict adherence to protocol and careful handling are essential.

Key considerations:

• Bead ratio is critical:
  The ratio directly determines fragment size selection. Even slight deviations can shift the fragment size distribution toward smaller or larger sizes. Therefore, the ratio specified in the protocol must be strictly followed. 
• Check reagent validity: Ensure beads are within expiration date.  
• Thorough mixing is required: 
  Vortex beads thoroughly before use to ensure homogeneity. After adding beads to the sample, mix thoroughly to ensure proper binding.
• Avoid over-aspiration of beads:
  During pipetting, avoid transferring excess beads that may adhere to the outer wall or tip of the pipette. This can alter the effective bead ratio and affect size selection accuracy. 
• Use freshly prepared 80% ethanol (same day) for washing. Ethanol evaporation may change concentration, affecting washing efficiency. 
• Bead retention during washing and elution:
  Carefully monitor pipetting steps to ensure beads are not accidentally aspirated and lost during supernatant removal or washing. 

Do not over-dry beads:
Over-dried beads may reduce DNA recovery efficiency. Properly dried beads should appear matte (dull) but not cracked.