In affinity pull down capture, a target molecule is attached to the column. Then the column is treated with sample to determine the components that are extracted by the target molecule. The affinity pull down capture molecule is attached to the resin using only a small molar excess of reagents to bind the molecule. The total mole amount of reagent only has to be in slight excess to stationary phase site mole amount to completely react and load the column. The columns are very small again limiting the need for expensive reagents. Since the volume of liquid needed to load the column is small, a high concentration of the loading molecule can be used. This drives the loading reaction to completion quicker at higher yield with lower amounts of reagent. No other commercial system can compare.
Once the column is loaded, sophisticated experiments can be performed in parallel. For example the stringency of the attraction can be determined by controlling sampling buffer. Low stringency conditions may be chosen so that many materials or classes of materials are collected. Then these in turn may be processed under higher stringency conditions to determine the tightest binding materials.
Unlike batch binding reactions, the PhyTip columns utilize active transport. The immobilized target molecule is guaranteed to be exposed to the complete sample. Unlike tumbling or shaking of loose beads in batch, active transport is fast and complete.