Biological research instrumentation is getting smaller and smaller as genetic and biomarker analysis moves out of the laboratory and into the clinic or the field. Smaller technologies now available include handheld immunoassay strips, flow assays, PCR systems, and mass spec equipment, but sample-prep hasn’t always kept pace with the latest advances.
Centrifuges, chromatography columns, spectrometers, and other sample-prep tools are not quite so portable yet. Not surprisingly, the Knowledge Foundation’s “Sample Prep” meeting held earlier this month in Baltimore was packed with presentations featuring small and sleek sample-prep technologies.
Microfluidics offers one way around the sample bottleneck, automating and miniaturizing the same sample-prep steps users would carry out at the bench. Other approaches seek to skip the prep step entirely through direct detection.
InnovaPrep, which was formed last year to commercialize sample-prep technology developed at AlburtyLab, is trying to close the gap between sample-prep technologies and runaway miniaturization of biodetection technology. “We feel that what is missing in that trend and in the world is, of course, the sample prep,” said CEO David Alburty. “We think of it as a link between the real-world sample size and the microliter world that those systems operate in. A macro-micro interface.”
In developing its sample-concentration system, the InnovaPrep HSC-40, for the biodefense industry, AlburtyLab sought to address issues associated with collecting samples in the field. Although many detection devices are now small enough to be portable, even handheld, the size and dilution of many samples in nature remains a problem.
Taking 5 µL of water from a lake, for example, is probably not going to provide very good results, unless you can concentrate a larger volume of sample from the lake. The conventional methods are centrifugation and filtration, but Alburty thought there might be a better way.
“Centrifugation is hard to automate, and with most filtration it is easy to automate but difficult to extract the sample again from the filter. Once you trap the sample, our discovery was how to get it in and out of the hollow fiber.” The solution was a carbonated foam that can be designed to be compatible with the rapid assay. The foam sweeps through the fiber, extracting the sample.
The InnovaPrep HSC-40 was designed to concentrate airborne aerosols to a smaller volume that more closely matches the detector’s requirements. However, the method can be extended to any volume of liquid sample, including clinical diagnostic applications. For example, the device can be used to concentrate whole blood by first removing the blood cells in a single pre-treatment step, and then achieving 100-fold concentration using the filter device.