Portable instrumentation & point of care technologies

We are excited to introduce this themed issue on portable instrumentation and point-of-care (POC) technologies, a field addressing the pressing issue of rapid quantification of analytes for environmental, industrial, food or biological/biomedical applications. The field of portable instrumentation is very diverse and covers several disciplines, such as physics to understand and design transducer elements of greater sensitivity, engineering for miniaturization of components and integrating them into optimal devices, biology and biochemistry to develop biological entities to recognize and transduce the signal from analytes, and analytical sciences for designing new assays and instrumentation based on the aforementioned principles. This is typically done in collaboration with scientists from diverse horizons for validating their use in actual applications. In this themed issue, we have collected a series of articles focusing on the development of new assays, sample preparation, instrumentation and sensing schemes for applications in the environment, food and the pharmaceutical industry.

The field of portable instrumentation and POC devices has already had an impact in medical sciences and environmental sciences with the commercialization of several devices. Millions of diabetic patients can now better manage their health status through using the widely available glucometer, demonstrating the potential of these technologies. Despite this important success, the number of technologies and their successful applications have room for growth and, thus, the potential of portable instrumentation and POC devices will only be fully harvested with further scientific innovations. The scientific community must find solutions to develop new sensors and instruments that are low cost, small, simple to use, robust, stable in time and highly sensitive for providing solutions to the series of applications that are in need of portable instruments and POC devices. This represents an incredible research opportunity for our community.

While portable instrument and POC devices were relatively dominated by electrochemical techniques early-on, there is now an increasing interest in optical techniques to facilitate the detection of optically active analytes, analytes that are rendered optically active from chemical reactions or analytes detected from optical transducers. The availability of small optical components and the relative ease of assembling them in devices are providing opportunities for the development of small instruments. The field of cell phone-based spectrophotometers is highly active and may offer customers a suite of assays that can be read on their cell phones (e.g. see the Minireview of McCracken and Yoon, DOI: 10.1039/c6ay01575a). This is not limited to cell phone-based assays, however, and several articles published in this themed issue further contribute to the development of optical techniques for portable instrumentation or POC devices.

Anyone who has visited a laboratory equipped with mass spectrometers would recognize that classical mass spectrometric systems are far from being portable. However, exciting research has been going on in the past decade to miniaturize mass spectrometers and facilitate ambient-condition ionization and direct sample introduction. This field of portable mass spectrometric measurements is heralded to provide highly selective and sensitive instrumentation for a series of applications. Examples of this vibrant research field are provided in articles collected in this themed issue.

Portable instruments and POC devices should analyze samples with little or no preparation so that lengthy steps and increased complexity of the assay for untrained users is avoided. However, it is in most cases necessary to perform sample preparation to remove interfering compounds from the sample, to pre-concentrate the analyte to detectable levels for the technology or to avoid the effects of the matrix on the analysis. Articles in this themed issue discuss options for improving sample preparation. Lastly, the analysis of real samples must be performed early-on in the development of portable instruments and POC devices, to identify the challenges related to the application. Once again, the articles in this themed issue will address these challenges.

Therefore, readers will learn in this themed issue about several key issues and potential applications in the field of portable instrumentation and POC devices. The detection of chlorinated hydrocarbons, a pressing environmental issue, is reported by Taylor et al. who use a portable mass spectrometric technique (DOI: 10.1039/c6ay00375c) and by Mizaikoff et al. who use a mid-infrared sensor (DOI: 10.1039/c6ay01450j). The latter article reports on the integration of several novel mid-infrared components into a device that facilitates the in-field deployment of the technology. The same group also reports in the article of Mizaikoff et al. (DOI: 10.1039/c6ay01447j) on a novel muciPRECON approach to increase concentration of methane by a factor up to 6.7. The importance of sample preparation and the optimization of extraction conditions for malachite green, crystal violet and their metabolites was also demonstrated in the article by Liu, Luan et al. (DOI: 10.1039/c6ay01466f), a topic of environmental importance due to the use of these molecules in the treatment of fungal diseases and parasitic infections. In another example of environmental monitoring, Bowden et al. used a commercially available device and applied it for screening the level of total cholesterol and triglycerides in Mozambique tilapia for classifying pansteatitis-affected and healthy fish (DOI: 10.1039/c6ay00446f).

Other articles will also surely interest readers avid for the application of these technologies for the detection of analytes in the food and pharmaceutical industries. In a first example, Guo et al. report the detection of the pesticide triazophos using a fluorescence polarization immunoassay (DOI: 10.1039/c6ay00908e). A colorimetric detection of hydrogen peroxide associated with foodborne bacteria is also reported by Chen et al. In this article (DOI: 10.1039/c6ay01453d), they report the sensitivity of the formation of silver nanoparticles to hydrogen peroxide and exploit it to detect the activity of catalase-positive bacteria. Lastly, the article of Fernández et al. (DOI: 10.1039/c6ay01418f) deals with the issue of falsified pharmaceuticals and their detection using a compact mass spectrometer. The detection of counterfeit drugs is a major issue worldwide and techniques able to rapidly identify them are greatly needed.

We hope you will enjoy reading these articles as much as we did.

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Footnote

† Analyst Associate Editor for Reviews.

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