Abstract
Application of solid-phase reversible immobilization (SPRI) beads for size selection in molecular biology should be expanded, in light of the property of the beads to accommodate to high MW intervals of DNA fragment size selection, depending on composition of bead-suspension buffer. Here we show how the conventional size selection interval of 150-800 bp be shifted to 1.5-7 Kbp with by adjusting the concentration of NaCl in the stock suspension buffer. The MW capacity of SPRI beads also change when NaCl replaced with other cations and when the concentration of polyethylene glycol (PEG) 8000 is decreased. Testing the limits of SPRI beads revealed cuts as high as 10 Kbp are possible for some salt/PEG combinations of modified SPRI beads-suspension buffers.