The lab finally comes to the chip!

The “lab” is finally coming to the chip! A promise of lab-on-a-chip technology was to marry the small size of chips (with the attendant virtues of low requirements for samples and reagents, rapid operation, high convenience, and low cost) with applications in analysis, synthesis, and separations. That is, it would become a new class of “laboratory”: one able to carry out a wide range of functions carried out in laboratories, but on a much smaller scale and with new characteristics and capabilities. Although this promise has remained bright over the last decade, the emphasis in LoC technology (at least academic LoC technology) has, in fact, been on methods of microfabrication of devices, the physics of microscale flows, and exploratory studies of phenomena that were largely at a level of development too preliminary to be considered as real applications. LoC devices were more “test-beds-on-a-chip” than working devices designed to solve real problems.

The series of Insights in this issue demonstrate how the emphasis in LoC science and technology is now shifting from these foundational areas to serious explorations of uses, and to demonstrations of applications (and capabilities leading to applications) with real potential to provide the incentive for further and more extensive industrial engineering development, and ultimately to incorporation into products. Takayama (DOI: 10.1039/C4LC00125G) addresses a critical capability that has limited many applications of microdevices from the beginning of the field: that is, sampling, and the introduction of the samples onto the chip. Chiu (single-cell genomics, DOI: 10.1039/C4LC00175C) and Walt (protein analysis in microwells, DOI: 10.1039/C4LC00277F) demonstrate the value of microfluidic systems in ultrasensitive bioanalysis, and Ismagilov (DOI: 10.1039/C4LC00248B) outlines the remarkable potential of microfluidic systems to provide the unique forms of information generated by so-called “digital biology”. Jensen (practical-scale organic synthesis in flow microfluidic systems, DOI: 10.1039/C4LC00330F) and de Mello (synthesis of nanocrystals, DOI: 10.1039/C4LC00429A) show that LoC systems can, in fact, compete with larger-scale, conventional methods of synthesis in appropriate applications, with the accompanying benefit of improved control over reaction conditions. Meng (DOI: 10.1039/C4LC00127C) outlines approaches for implantable medical devices, and Escarpa (DOI: 10.1039/C4LC00172A) outlines one of a number of underexplored areas – here, analysis of food – that have the potential to benefit greatly from analysis using fluidic microsystems. Even research in the new scientific area of nanofluidics (fluidics in channels with the smallest dimensions less than ~100 nm) by Segerink (DOI: 10.1039/C4LC00298A) and by Tabeling (DOI: 10.1039/C4LC00325J) points to clear applications in the science of pores and confined spaces especially relevant to a range of important small structures (especially pores important in biology, and separation membranes), while Sinton (DOI: 10.1039/C4LC00267A) discusses a range of applications related to micro- and nanoflows in understanding important problems in energy (e.g., fluid flow in porous media).

Parker (organ on a chip, or OoC, DOI: 10.1039/C4LC00276H) and Berthier (gradient generation and cell migration, DOI: 10.1039/C4LC00448E) provide an update on another area of great potential: cell biology on a chip. Microsystems have the right dimensions to accommodate cells (either for POC diagnostics, for testing of human – even patient-specific – cells for compatibility with a proposed treatment, or as part of programs testing for efficacy and toxicity in pharmaceutical drug development). These types of applications in human cell biology were identified early in the development of microdevices as potentially excellent fits between biomedical analysis and LoC technology, and although their development has been slower and more difficult than anticipated (as is almost everything in cell biology), they seem finally to be happening.

And of course there is the question of what to do with the information LoC devices produce, and that needed to operate them. Ozcan (DOI: 10.1039/C4LC00010B) and Erickson (DOI: 10.1039/C4LC00142G) both emphasize the universally held and very probably correct potential of phones as future and ubiquitous components for readout and operation of fluidic microdevices. A range of other microelectronic systems developed for other purposes will also partner well with LoC devices: Ozcan also discusses one obviously important candidate (flat-bed scanners, DOI: 10.1039/C4LC00530A).

All of the emphasis on legitimate, and important, applications constitutes steps toward commercialization, with the accompanying benefits of optimization of the technology, reduction in cost, and production at scale. However, discussions with contributors from industry – with experience of commercialization – point out, importantly, that despite the great progress that has been made, the field is still not yet there, and that more work on engineering, and on important, field-wide issues such as interoperability of devices from different areas of application and with different functions, is a further essential step in maturation of the subject.

It's an exciting time for LoC technology. The science is working its way into technology, and preparing (soon, based on these Insights) to become products!

It is a great pleasure to introduce these Insights to you and I hope you enjoy reading them to inspire and further your own research and applications.

 

George Whitesides

Editorial Board Chair

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