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Indian Researchers Exploring MALDI for Clinical, Routine Applications

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NEW YORK (360Dx) – While liquid chromatography mass spec (LC-MS) has traditionally dominated the applied and clinical mass spec space, MALDI-MS has carved out a niche in areas like microbiology and has drawn interest as a potential platform for other routine and clinical applications due to its relative simplicity and high throughput.

Such advantages are relevant to labs globally, but they could be particularly notable for a densely populated and resource-constrained market like India, suggested Venkateswarlu Panchagnula, a senior scientist and assistant professor at that country's National Chemical Laboratory and the founder of mass spec method development firm Barefeet Analytics.

When it comes to routine and clinical assays, the most challenging portion of LC-MS workflows is, arguably, the LC. These separations can take on the order of minutes or even hours for complex samples and low abundance analytes, and require careful maintenance to ensure reproducible results.

MALDI workflows typically skip the LC step, greatly speeding up assay throughput while also simplifying the process. However, researchers have questioned whether MALDI can provide enough sensitivity and accuracy for quantification of clinical biomarkers, for instance.

Microbiology aside, efforts to use MALDI for such purposes have been relatively limited, though some studies have suggested the technique's potential. Last month, researchers at the University of Victoria published a study on an assay using MALDI to measure levels of the proteins AKT1 and AKT2 in breast and colorectal cancer tissue. And last year, Mayo Clinic researchers presented a MALDI-based assay for monitoring levels of monoclonal proteins (M-proteins) in patients with plasma cell disorders like multiple myeloma.

In his lab at India's NCL, Panchagnula recently developed a MALDI-based assay for measuring urine levels of dimethyl arginine (DMA), a biomarker for heart attack risk that has also been linked to diabetes and kidney disease.

DMA exists in two forms, asymmetric DMA (ADMA) and symmetric DMA (SDMA), with each form providing different information regarding a patient's cardiovascular and renal health. Distinguishing between the two forms is challenging for immunoassays, Panchagnula said, noting that this has led clinicians to explore LC-MS assays.

Hoping to improve assay throughput, he and his colleagues worked to develop a MALDI-based assay for ADMA/SDMA. In a study of around 400 subjects including both healthy controls and patients with complications from diabetes, the researchers were able to use the MALDI test to distinguish between these two patient populations with performance equivalent to that of LC-MS assays for ADMA/SDMA, Panchagnula said. He added that he and his colleagues are currently preparing a manuscript detailing the study that they plan to submit for publication in the next month or so.

"When this assay actually enters the clinical setting, doing the test for a large number of people will be much easier, because MALDI is much easier that LC-MS in a pathology setting," he said. "And that is where we are trying to drive this."

His group at the NCL is exploring MALDI for food testing and drug development applications, as well. This year they published a paper in the Journal of AOAC International using an atmospheric pressure MALDI source coupled to a Thermo Fisher Scientific Q Exactive to measure pesticide levels in grapes. They are also using MALDI to measure levels of drugs in urine samples for pharmacokinetic studies.

Panchagnula said he first gained experience with the technology working for PerkinElmer in the US roughly a decade ago exploring use of the technology coupled to 2D electrophoresis. When he returned to India, he moved into MALDI "straightaway," with the aim of improving assay efficiencies by decoupling chromatography from mass spec analysis.

The demand for higher-throughput methods (and consequently lower costs) is widespread throughout the clinical mass spec space, but the matter is particularly acute for a country like India, Panchagnula suggested.

"Here, with a billion-plus people, we run into the challenge of numbers," he said. "If there is any chance to lower the cost [of assays] it is a major concern."

"Additionally … I'm hearing from some of the major corporations I meet with that current analytic methods take too much time," he said. "If [results from an] analysis don't show up in a day or so, it's just not useful to them."

He noted that he founded Barefeet Analytics with this issue in mind. The company specializes in mass spec method development, establishing and optimizing workflows that it then helps outside service and clinical labs implement.

"Most of the hardware that comes to India, especially the mass spectrometry hardware, was not designed in India," he said. "The methods [developed for these instruments] have been optimized for labs in the US and other countries."

And while "most of these methods are quite applicable to India," there is still demand for improved throughput and cost efficiencies, he said. "So, the way I am positioning the company is that we use the same hardware and instrumentation as [the rest of the] world, but we are developing methods that are either specific to India or specific to resource-limited [areas] or methods that are scalable and cost efficient" more generally.

The company currently has two full-time employees and plans to expand to around four or five this year, Panchagnula said. It was initially funded by an Indian government grant designed to support startups similar to the National Institutes of Health's Small Business Innovation Research grants, and two months ago it received an additional grant through this program.

The firm also generates revenue through mass spec consulting services with a number of companies including several multinational outfits, Panchagnula said, adding that Barefeet Analytics has posted a profit in each of the last two years.