Moving Ions Around Corners To Revolutionize Disease Detection and Biotherapeutic Development

Whilst genomics may hold the key to the cause and effective treatment of some diseases, for many others, scientists must delve deeper to find the answers they are looking for. The study of proteins, lipids, metabolites and other related molecules therefore become invaluable in early disease detection and biotherapeutic development. This, however, requires tools that are fast, accurate and have the resolving capabilities to differentiate even small differences.

An innovative separation technology borne out of a US Federal Laboratory, known as structures for lossless ion manipulation (SLIM^TM), is achieving just that. We spoke with Melissa Sherman, CEO, MOBILion Systems Inc., to learn about how SLIM^TM works, what makes it so different to current separation solutions and how it is improving early disease detection and therapeutic development.

Karen Steward (KS): For those unfamiliar with it, can you tell us a bit about what SLIM^TM is and how it works?

Melissa Sherman (MS): Structures for lossless ion manipulation (SLIM^TM) was originally developed in the laboratory of Dr Richard D. Smith at Pacific Northwest National Laboratory (PNNL) and MOBILion Systems has exclusive license to commercialize the technology. The SLIM^TM separations technology provides unprecedented capability to separate and identify clinically relevant molecules that are practically indistinguishable by current instruments.

SLIM^TM separations is in a sense “digitizing separations”, where separations are achieved on conventional printed circuit boards in the gas phase (rather than via column chemistry interactions in the liquid phase as compared to liquid chromatography), saving hours of analysis time. The real scientific breakthrough is that it is possible to achieve unprecedented resolution by moving ions around corners of a serpentine path of electrodes on circuit boards through very long path lengths. The serpentine design packs a 40-foot ion path into a device about the size of a laptop, breaking the boundaries of linear path and achieving characterizations that were previously impossible.

Ion mobility separations are based on fundamental principles that are different from liquid chromatography, achieving separation of ionized molecules based on their size, charge, and shape. As a result, analytes that have the same molecular mass and chemical formula can be separated by their size, shape, and structure. The long path lengths in SLIM^TM are enabled by electric fields that create a conduit in which ions are propelled for separation and prevent them from striking surfaces while moving, preventing loss.

Lossless ion manipulation is a revolutionary technology that facilitates robust analyte-agnostic analysis of clinically significant molecules quickly and easily with greater reproducibility and greater instrument uptime. The technique is much more readily applicable than existing separations techniques.

KS: Where did the idea come from to create a separation system that is so different to previous options?

MS: A lot of classical analytical techniques, like liquid chromatography separations, are too slow, too complicated and/or or not powerful enough to adequately characterize molecular and structural molecules in the biologic drug development, early disease detection and clinical diagnostics markets.

As Dr Richard Smith outlined in our recent press conference, his lab at PNNL was typically using liquid chromatography (LC) for separations in conjunction with mass spectrometry (MS) for detailed characterization in biomedical research; and these techniques presented some significant challenges.

A lot of experience has shown the large gains in understandings that come from being able to make better measurements, e.g. ones providing greater coverage, particularly in proteomics. There is also a huge need to do everything with greater speed, with higher throughput measurements (and at lower overall costs).

Researchers benefit from being able to work with smaller samples, allowing proteomics measurements to be obtained in cases where it was previously impractical, such as having insufficient tumor tissue. This increasingly extends all the way down to proteomics from a single cell; and not just a few of them, many of them.

Our customers must often make trade-offs with their instruments – the incumbent instruments might provide adequate throughput, resolution, or ease of use, but never usually all at the same time. For example, to get the enhanced resolution that enables them to identify the molecules they are looking for, they must often compromise on throughput.

All these needs can be better addressed by the resolution, speed, and efficient ion utilization of SLIM^TM. The technology means that MOBILion Systems’ instrument can enhance performance compared to existing LC-MS workflows while eliminating the trade-offs that our customers typically experience.

Our best in class separations technology combines maximum resolution, faster analysis time and simpler workflows accessible to less sophisticated operators to accelerate the development of new therapies and diagnostics. The combination of these three things is what makes our technology platform unique in the market.

KS: How does SLIM^TM differ from other forms of separation? Does it make it particularly suited to certain applications more than others?

MS: Liquid chromatography separates based on chemical interactions with the column, buffers and solvents, it involves pumps, solvents, buffers, tubing and plumbing. The time it takes for an analyte to travel through the LC system depends on the interactions of the analyte with the column. With SLIM^TM, separations are done in the gas phase on printed circuit boards and analytes are separated on their size and shape. Because SLIM^TM operates in gas phase kinetics versus liquid phase kinetics, analysis times are comparably fast. SLIM^TM is a more analyte agnostic approach, with separations conducted on ionized molecules in the gas phase via an inherent physical property of the analyte. This means the separations are more reproducible and separations of isomeric molecules (same mass and same chemical formula) can be achieved. Method development is much easier with SLIM^TM and push button, software driven methods means the techniques are amenable to a less sophisticated operator. Because SLIM^TM is more ubiquitous across analyte classes, there is no component change out, faster method development and overall greater instrument uptime.

Applications that are particularly suited to the SLIM^TM technology include glycans, lipids and peptides/post translational modifications. These all have characterization challenges because there are very small differences between different molecules in these classes that are either impossible or very difficult to separate with incumbent techniques. Because SLIM^TM separates based on size and shape, it can separate analytes that were previously indistinguishable and provides additional structural information that is important to the function of the analyte being interrogated.

We separate and identify the most challenging clinically significant molecules that incumbent LC-MS instruments fail to detect. Higher resolution means our instrument can provide molecular characterization, but also additional deeper level structural information. This is all possible with software-driven methods, greater instrument uptime, reduced operator skill and cost, and 5 x to 60 x faster analysis.

Our analysis times tend to be around 2 minutes compared with LC separations which can range from 15 minutes, to 2-3 hours. We are analyte-agnostic, so it is one size fits all analysis and you are not changing out a lot of components.

MOBILion’s first instrument is focused on the biopharma discovery and development markets. With this, we are providing pharmaceutical and academic researchers with faster, better characterization of protein-based biologic therapeutics by providing a 2-minute SLIM^TM versus a 90-minute LC-MS run for glycan analysis and peptide mapping. In clinical research, SLIM^TM has the potential to accelerate biomarker discovery and validation with much faster analysis time, population scale studies required for validation become feasible.

Looking further ahead, our technology could be used in clinical markets, and in particular cardiovascular diagnostics, to increase the accuracy of existing cardiac mortality assays by detecting critical lipids that LC-MS cannot see – to help predict cardiac events in patients before they happen. In early disease detection, we can improve the specificity of existing liquid biopsy assays with faster, higher resolution analysis for DNA methylation or peptide panel analysis. We provide 5-minute versus 5-hour multi-modal analysis of existing and emerging biomarkers in one test to enable population scale studies for faster discovery.

KS: Can you highlight any specific cases where the use of SLIM^TM has been instrumental in making scientific advances?

MS: Since 2014, more than 35 papers have been published describing the scientific theory behind SLIM^TM, as well as the evidence in support of its adoption as the new gold standard in separations. There are several areas where SLIM^TM is already making scientific advances.

James R. Arndt, an Applications Scientist at MOBILion Systems, has been working on monoclonal antibody (mAb) characterization with SLIM^TM, which highlights how SLIM^TM technology could potentially revolutionize the biopharma pipeline by improving structural characterization of the drugs and improving throughput relative to traditional LC-MS. This paper will be released later in 2020.

Another area of significant impact is in solving the isomeric problems associated with the complexities of glycomics and lipidomics. The isomeric separations of glycans is a huge step forward for understanding relationships between structure and function. SLIM^TM mobility resolution for glycan separations is also compelling for providing better characterization of COVID-19 and it can show host susceptibility, which will be instrumental in the race to develop a vaccine.

Combining the capabilities of SLIM^TM technology with the speed and throughput that MOBILion’s instrument can provide means that researchers can now run large cohorts of patient samples to generate a more complete picture of disease and fully characterize the biotherapeutics used to treat them.

KS: Scientists have been working tirelessly to improve our understanding of SARS-CoV-2 in recent months. Can you tell us how SLIM^TM has been applied to this mission?

MS: MOBILion Systems has an active collaboration with Drs Lance Wells and Michael Tiemeyer, researchers at the Complex Carbohydrate Research Center (CCRC), University of Georgia, to conduct COVID-19 glycan analysis using our SLIM^TM separations technology.

The project is working to detail the glycosylation microheterogeneity in the spike glycoprotein that decorates the surface of the SARS-CoV-2 (COVID-19) viral capsid. Understanding the heterogeneity in glycosylation on the surface protein will add to the understanding of how the virus binds to its target and will be essential in development of an effective treatment. There are multiple glycan analysis approaches related to COVID-19 research and SLIM^TM technology offers the potential to achieve very high-resolution information on compounds of interest and dramatically increase throughput, leading to more meaningful results in a shorter amount of time. Given the urgent requirement for researchers to understand the virus better to tackle the global pandemic, these time savings really are incredibly valuable.

KS: Do you foresee that SLIM^TM could replace chromatography or are there niches for both?

MS: The separations instrumentation market is a very large market with numerous applications. We do not expect SLIM^TM to replace LC holistically, and there will be applications where each technology is best suited. SLIM^TM technology can address a lot of the pain points that are associated with liquid chromatography, but we do not expect it to completely replace it. We are pleased to be adding an alternative method of analysis for researchers who are looking for an instrument that can deliver higher resolution faster analysis time, and greater ease of use.

Melissa Sherman was speaking to Dr Karen Steward, Science Writer for Technology Networks.