Thinking small: PhyNexus protein separation tips.

Sometimes you can do more with less. Proprietary pipette tips developed by PhyNexus in San Jose, California, promise high performance in tiny volumes with minimum fuss. The key lies in encapsulating very small quantities — just 5–10 microlitres — of protein separation resin between hydrophilic screens in the very end of the pipette tip. “The whole sample is obliged to make highly intimate contact with that resin,” says Chris Hanna, vice-president of business development. “That results in high trapping efficiency for the sample. We can get a 10–20-fold increase in the target protein sample from just a few hundred microlitres of sample, and get purities that are often over 95% with a single separation step.”

As well as the technical collaboration with Caliper of Hopkinton, Massachusetts, PhyNexus has designed its PhyTips to be compatible with liquid-handling robots from Tecan of Männedorf, Switzerland, Beckman Coulter of Fullerton, California, and PerkinElmer of Boston, Massachusetts. The firm has also agreed licences to use some of the most advanced resins in its tips, including Qiagen's Ni-NTA resin for purifying histidine-tagged proteins. The combination of tips, resins and platforms makes for exquisite control of the separation process, Hanna says. “You can control the number of cycles that go back and forth through the bed, the rate they do so, the composition of the washes. We can really make that microvolume of material dance and perform at its best,” he says. “To be able to do that and maintain fully functional proteins at these very small scales gives you ÄKTA-type purification off a very small amount of starting sample. People can avoid scaling up.”

The tips are initially being deployed for rapid purification and enrichment of antibodies from small cultures of Escherichia coli for use in high-throughput cell-based assays, giving significant savings in time and money. “People are wanting to get real biological information much earlier in their screening process, and to do that they have to have the stuff properly prepped,” notes Hanna. Interest is also coming from protein engineering and biopharmaceutical companies looking to miniaturize their protein-expression systems.

Tim Chapman