Miniaturization is a key current trend in analytical chemistry, and, over recent years, there have been several developments to downsize three key elements – sample preparation, separation, and detection. Examples include both solid- and liquid-phase microextraction, chip-based gas chromatography, and capillary electrophoresis, and miniaturized ion source methods based on electron spray ionization. There are many products already on the market that harness these technologies.
Now, microfluidics, the smallest endpoint of miniaturization, is emerging as a powerful technology. Although around for many years, only now is the full potential of this science beginning to be realized.
In addition to developments in analytical sciences, microfluidics has been intertwined with progress in the consumer electronics industry, harnessing many of the same techniques and materials. Indeed, the first truly microfluidic device was the inkjet printer. However, now materials and micro components are used to tailor the technology to specific analytic functions, overcoming obstacles to portability and cost-efficacy, and facilitating experiments not previously possible.
This year’s Pittcon, which took place in Chicago, Illinois, brought together leaders in the field of microfluidics, offering a unique opportunity to hear about this technology and its promising future. Microfluidics is set to have a transformative impact on analytical chemistry and biomedical science, and even in the consumer market. Below are just some of the advances the field has already made.
An entire lab-on-a-chip
One of the driving forces behind the development of microfluidics has been the desire to create lab-on-a-chip (LOC) devices. These are microfluidic devices that can perform single or multiple laboratory functions on a single chip. Examples include electrophoresis, DNA microarrays, biosensors, and flow cytometers. These devices are particularly suited to automation, making them incredibly useful in the fields of molecular biology, diagnostics, and drug development.
Another slant on this technology is organ-on-a-chip (OOC) devices. These seek to recapitulate the behavior of cells, organs, and whole organ systems, in a manner that provides more reliable results that existing methods of cell culture and animal testing. They may also assist a shift away from animal testing, driven by ethical and efficacy concerns. Microfluidics, due to its small-scale and ease of manipulation is uniquely suited to this aim. Cells can be cultured within an OOC device and their environment closely controlled, in terms of the nutrients, mechanics and even the microbes they are exposed to. Such technology could ultimately give way to personalized medicine, with a person’s own cells used to create a model organ, as well as discoveries about fundamental human biology.
Microfluidics meets the body
As well as laboratory-based research, the future of microfluidic devices is likely to involve their direct integration with the human body. This poses several challenges, not least the basic incompatibility between solid electrical components, and the flexible, dynamic nature of tissue.
Recently, researchers have developed microfluidic devices embedded in skin-like adhesives, similar to a transfer tattoo that can be worn on the skin. One such device, created by John Rogers’ lab at Northwestern University, is a battery-free continuous monitor that absorbs sweat from the skin and provides instant information on the rate of sweating and electrolyte concentrations. It could have a wide range of applications and the team have already explored its use in patients recovering from a stroke and professional athletes.
The technology is also likely to simplify the measurement of the many medical observations that can be derived externally, such as heart rate, blood pressure, skin temperature, and respiration rate. This could be particularly important in neonatal care settings, eliminating the many sensors and wires currently required for continuous monitoring of premature newborns.
Microfluidics at Pittcon
Microfluidics was a major topic at this year’s Pittcon, held in Chicago, Illinois. The event featured talks from some of the most distinguished researchers in the field. These included John Rogers, whose work is mentioned above, who presented the Wallace H Coulter Lecture at this year’s conference. The conference also included the Coblentz Society William-Wright Award, which this year recognized the achievements of Chris Brown from 908 devices, for his work developing high-performance miniature analytical systems.
This year’s Ralph N Adams Award went to Nancy Allbritton from the University of North Carolina, whose lab has made significant developments in OOC devices, in particular recreation of the large intestine. The conference heard her describe the technologies they have developed for creating cell-based arrays, OOCs and tissue scaffolds.
Also speaking at the conference was Andrew deMello from ETH Zurich, one of the recipients of the Advances in Measurement Science Lectureships Awards, who discussed the use of droplet-based microfluidic systems, and the advances his laboratory have made in developing an imaging-based flow cytometer.
In addition to this impressive program of talks, the Pittcon expo was attended by all the leading players in the field of analytical chemistry. This included companies such as ThermoFisher Scientific, Shimadzu, Malvern Panalytical, and Kaiser Optical, who have already harnessed miniaturized technologies to bring compact or portable devices to the market.