Miniaturization and Microfluidics
Microfluidic lab-on-a-chip represents another area of fairly rapid expansion in technology. Raj Singh, Ph.D., director of biology R&D at Caliper Life Sciences, gave some examples of high-sensitivity LabChip® applications for quality control and characterization of monoclonal antibodies and other proteins in his talk in Beijing.
“Miniaturization using the microfluidics platform has many advantages, including speed and robustness,” said Dr. Singh. “However, it is possible to go too small; if you go too small, you cannot scale up. We are finding that microfluidics, as opposed to nanofluidics, gives the robustness, repeatability, and speed, as well as scalability that scientists require.”
Microfluidic chips form the key components of Caliper’s LabChip systems, which also include a LabChip instrument and experiment-specific reagents and software. Dr. Singh said that the chips contain a network of miniaturized, microfabricated channels through which fluids and chemicals are moved to perform experiments.
The instrument and software control the movement of fluids via pressure or voltage, and an integrated optical system detects the results of the particular experiment. “Because we have great flexibility in channel design and can exert split-second computer control over fluid flow, we have the ability to create chips for a multitude of applications,” said Dr. Singh.
Selling a platform is not enough, he noted. “Generic small molecules are easy to make and characterize; biosimilars, which is where protein characterization lives, are much harder to make, and biosimilar has evolved to biobetter. What we have done is take all the components of the assay—for example, glycan profiling—and put it on a plate and integrate it with our LabChip GXII reader. Just add compounds, follow the protocol, and you have your results. It comes out the same every time. Repeatable and robust—we think this is important in cell culture.”
Waters’ Dr. Phillips provided an overview of UPLC technology in Beijing and how it can be used to characterize proteins. “Advances in HPLC for biomolecules were few and far between until 2004, which is when Waters introduced its UPLC technology that allows scientists to achieve significant increases in resolution, speed, and sensitivity.”
“But as the biotherapeutics technology advances, the separations problems become more complex. For example, the challenges that we face include thoroughly characterizing biotherapeutics—among them proteins, peptides, and monoclonal antibodies—with about 40 percent of the current biomolecules drug pipeline devoted to monoclonal antibodies. Small molecule—less than 800 dalton molecular weight—analysis is more straightforward than that for large molecules, which require multiple analytical techniques including LC/MS and two-dimensional LC.”
Dr. Phillips explained that working with large molecules presents its own set of problems. “They are made using a biological process rather than organic reactions. Hence, it is critical that any change in the process be well controlled and understood so you create the same biotherapeutic with the same efficacy and safety every time.”
Waters introduced a new Acquity UPLC methodology for size-exclusion chromatography in March specifically to address the challenges of separating the monoclonal antibody monomers from their aggregates (e.g., dimers and trimers of the parent molecule). “Regulatory agencies such as the FDA require that you monitor and measure the percent of the aggregate present in the drug product,” explained Dr. Phillips. “Improving the level of confidence that you are making the same biotherapeutic every time comes from the use of separations techniques such as Waters UPLC technology.”
Finding the solutions to this problem requires new thinking in terms of the biochemistry of the molecule and chromatography, noted Dr. Phillips. “Thinking in terms of protein technology has brought us back to column chemistry.”