"Better, faster, stronger” is the mantra that has defined the last 15 years of the omics era.
The rise of next-generation sequencing in microbial genomics is a perfect example. Progressive gains in resolution and accuracy with high-speed sequencers have allowed microbiologists to solve outbreaks in days rather than months. Such was the case when the E. coli O104:H4 strain struck Europe in May 2011. It took less than two weeks to sequence its bacterial genome and develop rapid diagnostics, and by early June, microbe hunters had tracked the source to a beansprout farm in Germany.
Proteomics, whose mainstream popularity has arguably lagged behind genomics, is poised to vault into the scientific zeitgeist. The last two years has featured a slate of discoveries with the field’s signature tool—mass spectrometry (MS)—to unite the speed and power of high-throughput proteomics with simplicity of use.
“There was no other way, as far as we knew, to dynamically measure this drug from biopsies,” said U.S. Army medical resident surgeon Preston Sparks, D.O., who capitalized on the clarity of PerkinElmer’s AxION Direct Sample Analyzer (DSA) to measure the delivery of gemcitabine.
Picking an adequate dose of chemotherapy without excess drug filtering into peripheral organs is a common challenge for oncologists. Proven useful against the advanced stages of multiple types of cancer, gemcitabine is hampered, like many chemo agents, by deleterious side-effects in nontarget organs, such as the kidneys and liver.
Dr. Sparks and his research partner at PerkinElmer, Jesse Hines, relied on the AxION DSA to create a simplified method for analyzing tissue samples from various organs in a pig model of gemcitabine delivery.
Typically prior to running time-of-flight (TOF) MS, lengthy gas and liquid chromatography steps are required to purify compounds before ionization and injection into the mass analyzer. The AxION DSA accomplishes this compound separation in a single step, by vaporizing the sample before shooting it into the mass analyzer. This unique adaptation cuts the time for a single MS run from 25 minutes to 25 seconds.
“We had spent months troubleshooting HPLC methods, but continued to see ion suppression effects with wetform preparations on our quadrupole instrument,” said Hines, who stated that their readouts instantly became stronger with dried, pulverized tissue samples examined by DSA.
Hines continued, “You would expect with tissue extracts that the spectra would be far too complex for DSA analysis because everything in the sample would be ionized at once. However, what actually happened was the lightest, smallest compounds floated off first and DSA-based ionization left interfering compounds behind.”
This extra resolution led to a quick and targeted measurement of gemcitabine levels in pig tissue samples of kidney, lung, liver, blood, and lymph nodes. At one stage, they analyzed 120 samples in triplicate in less than three hours.