A Lens into The Future

With the expanding research on the intricacies of technologies in electrophoresis, the older techniques have transitioned from fundamental understanding to routine application, while new approaches that would be more powerful, selective, and more applicable to untreated samples are still being developed. Conventional analytical methods, such as capillary electrophoresis (CE–SDS), capillary zone electrophoresis (CZE), or ion exchange chromatography (IEC) are very precise and reproducible but, unfortunately, have only a low sample throughput. Therefore, there is clearly a need for new high-throughput analytical technologies to handle the increasing number of samples.

The electrophoresis market is on the cusp of a revolutionary change with the emergence of microfluidics and lab-on-a-chip technology providing a platform that can integrate various laboratory and analytical protocols ranging from mixing, separation, and detection etc. into a single microchip. Microfluidics has been undergoing fast development since its introduction in the electrophoresis market due to its promising applications in biotechnology, medicine, and chemistry. The next-generations of lab-on-chip focus on enhancing sensitivity and resolution to meet detection limits because of dilute sample concentrations, ultra-small sample volumes, and short detection lengths in microfluidic devices.

The advancements in techniques like mass spectroscopy have broadened the applications of traditional capillary electrophoresis in diagnosis and research. Currently, the research is focused on finding new CE–MS based approaches for metabolomics that show improved analytical performances as compared to conventional CE–MS methods over the past few years. This approach can be considered a highly attractive and unique analytical tool for the metabolic profiling in ultra-small biological samples. To survive in the markets flooded with competitive partners, the focus of the industry remains to come up with the best technologies that offer high-throughput and improved sensitivity. With the existing innovative techniques and the forthcoming upgradations in these systems, the market is expected to flourish by leaps and bounds.

Advances in Instrumentation
Automated parallel capillary electrophoresis. With the continuous updates in instrumentation, vendors offer exquisite platforms with exceptional sensitivities and detection range. Through an advanced instrument design, large molecular weight DNA fragments can be separated and nucleic acids detected in the femtogram range. With higher sensitivity for nucleic acid smears and nucleic acid fragments, these platforms find a wide applicability in the analysis of single-cell total RNA or genomic DNA, low-quantity NGS library preparations (PCR-free), and single DNA or multiple DNA fragments from low-concentration samples.

Microchip capillary electrophoresis (MCE). MCE has come up as a better alternative for monitoring and characterizing classical and novel formats of antibody-based bio-therapeutics as it offers a high-throughput approach to speed up sample throughput with a resolution superior to conventional capillary electrophoresis. The vendors have come up with products which enable automated analysis of 96–384 samples in one run. MCE–SDS assays offer several advantages compared to the conventional CE–SDS in terms of faster time and a better resolution.

Miniaturized electrophoresis electrochemical protein sensor (MEEPS). The MEEPS provides a platform capable of detecting specific and multiplexed signals from small volumes of sample (10 L) as well as reducing the effect of background interferences. The multiplexed capability and the reduced-effect of background interference are achieved using the electrophoresis unit of the MEEPS. The small foot-print system and sensitive signal detection are enabled via electrochemical sensors unit.

CE MEEPS–MS and metabolomics. At present, advanced analytical techniques such as mass spectrometry hyphenated to capillary electrophoresis are used for the global profiling of metabolites in biological samples. Hyphenation of capillary electrophoresis to mass spectrometry is generally performed via a sheath–liquid interface. However, the electrophoretic effluent is significantly diluted in this configuration thereby limiting the utility of this method for highly sensitive metabolomics studies. The technological advancements have significantly improved the performance of capillary electrophoresis–mass spectrometer using a sheathless porous tip sprayer for the analysis of highly polar and charged metabolites. Sheathless CE–MS offers a robust approach for probing the polar metabolome while providing low nanomolar detection limits for a wide range of polar metabolite classes by only using an injection volume of 20 nL (or less) from a few microliters of sample in the vial. Though very good concentration sensitivities can be obtained with this approach, the next important step is to show its utility for large-scale clinical metabolomics studies. Such data are crucial to endorse the sheathless CE–MS method as a potential diagnostic tool. Therefore, this approach can be considered a highly attractive and unique analytical tool for probing the polar metabolome in ultra-small biological samples.

The forthcoming improvements in CE–MS employ an effective injection strategy which allows the selective transfer of target analytes into the CE system. Pre-analytics and injection are especially important for metabolic profiling of low-abundance metabolites in ultra-small biological samples. An efficient and selective transfer of ions into the separation capillary will significantly increase the durability of a single sheathless porous tip emitter, which at this stage can only be used for the analysis of up to 200 samples, and which may increase the overall sensitivity even further if a larger portion of the sample is injected.Further developments in this field will result in a viable CE–MS approach for probing the polar metabolome.

Road Ahead
The advancements in microfluidics and lab-on-a-chip devices and the miniaturization processes are the key drivers for the electrophoresis markets.The versatility of miniaturized systems combined with their low-cost could become a major trend in recombinant drugs and bioprocess analysis. Miniaturized systems are capable of performing conventional analytical and proteomic tasks, allowing for interfaces with other powerful techniques, such as mass spectrometry.

Over the past years, the advancements in CE–MS have touched new horizons in the highly sensitive metabolite profiling. The future technologies focus on improving the detection sensitivity of CE–MS for metabolic profiling with respect to the isolation and preconcentration of metabolites. These innovations allow the development of fast, portable, and easy-to-use systems with a high level of functional integration for applications such as point-of-care diagnostics, forensics, the analysis of biomolecules, environmental or food analysis, and drug development.