Separations and Detection
Yolanda Fintschenko, Ph.D., director of sales, marketing, and new technologies at LabSmith discusses her work on an automated modular interface for microfluidic separations and fluorescent detection. She conducted this work with the team of Holger Becker, Ph.D., co-founder and CSO at microfluidic ChipShop. The two concur with the problems of variability and range as mentioned by Harvard’s Smejkal.
“Current challenges in automation are very application-dependent. For R&D, one of the greatest challenges is having both automation and flexibility. Particularly in the field of microfluidics, researchers and product developers alike go through a fairly long stage of breadboarding their systems,” Dr. Fintschenko says. “However, while transient, this phase is extremely important, with reproducible and accurate data required to move on to the next step. Automation of fluid and sample manipulation, particularly outside the chip where necessary, can be helpful, but it also needs to be flexible.”
Dr. Becker concurs. “One of the main challenges lies in the varying requirements (volumes, flow rates, etc.) from the application side that demand a high degree of flexibility from any automation solution. Furthermore, a lack of standards in the microfluidics world continues to aggravate this problem.”
In November 2010, the companies announced an agreement under which LabSmith will distribute select microfluidic ChipShop chips that are compatible with LabSmith’s CapTite™ microfluidic interconnection products. The idea is to facilitate researchers’ building and rebuilding of microfluidic circuits.
The microfluidic ChipShop chips are also being sold as part of LabSmith’s LabPackage microfluidics laboratory kit that includes LabSmith’s HVS448 high-voltage sequencer, SVM340 synchronized video microscope for real-time visual monitoring and video capture, and SPS01 programmable syringe pumps for volumetrically controlled flow rates, in addition to the CapTite components.
“Our approach is to simplify and standardize tools by focusing on modular components and a breadboard platform designed for ease of use, as well as control of fluid connections, pressure-driven flow, and ease of high-quality visualization,” Dr. Fintschenko says. “Our partnership with microfluidic-ChipShop highlights this approach by allowing us to provide off-the shelf chips that are easily connected to and controlled by these modules.”
Dr. Fintschenko believes that the field of “microfluidics, in particular, has become quite mature. This means we have to continue to understand how the automated control of small volumes, pressure, and electric fields are being taken advantage of by scientists of diverse backgrounds who may not be interested in microfluidics, per se. These scientists want to apply off-the-shelf tools to automate measurements that are very difficult to make in any other way.”
“The message should be that using microfluidics to solve an application doesn’t require a degree in rocket science,” Dr. Becker adds. “We see a significant development in the commercialization of microfluidics as a true enabling technology for analytical sciences, drug discovery, biology, and diagnostics. Some of the early promises, like speeding up the analytical process or integrating a complete analysis on a chip, are becoming reality, and this is very exciting.”
Sample Prep and Target Analysis
As with R&D applications, the challenges in point-of-care molecular diagnostics lie in preparation of biosamples, target analysis, and “providing users with comprehensible readouts,” explains Jeff Tza-Huei Wang, Ph.D., assistant professor of mechanical and biomedical engineering at Johns Hopkins University’s Whitaker Biomedical Engineering Institute. “All of this involves multiple, separated processes done with a number of instruments that, to date, despite the high degree of automation for individual tasks, still require operator intervention to transfer samples between different equipment at various stages.”
Dr. Wang’s research team has aimed to develop an “entire sample-to-answer process in a fully automated fashion, with the high degree of parallelization desired for the great number of samples that often need to be tested in a single study,” he says.
They have developed a droplet-based micro total analysis system (μTAS) that, according to Dr. Wang, is most beneficial in its simplicity.
“No complicated microfluidic component is required, since the droplet itself functions as the fluid-containment compartment as well as the transportation unit. With magnetic particles, the droplet is actuated with an external magnet. The functionalized magnetic particles then serve as the substrate for biomolecule adsorption, allowing solid-phase-based sample preparation in the droplets.”
This simplification affords integration of multiple processes within a single µTAS platform that, when combined with a miniaturized sample-handling stage and fluorescence-detection module, allows, as Dr. Wang describes, “true sample-in/answer-out capability.”
“Droplet-based microfluidic systems have been emerging at a fast pace in recent years. Numerous studies that focus on various aspects of droplet microfluidics have been reported,” he says. “Nonetheless, only a limited number of groups have looked deep into the potential of droplets as a great platform for automated biosample analysis.”