Perhaps, one could ask the question why are such manuscripts still being accepted?

Thank you Mila for your excellent answer; you are completely right!! During my time as Editor-in-Chief of the Elsevier Journal "Sensors & Actuators" we had a rejection quote of > 50% and tried to prevent many of those too optimistic papers. Nevertheless, POC and LOC devices are still much more fashionable for non-analytical chemists, with only minor experience of failing in inter-laboratory comparison studies.  

Several years ago journals with a certain reputation in the area of Analytical chemistry demanded more than a simple calibration plot in a matrix-free aqueous solution. Either a high quality standard reference material with a similar matrix had to be analyzed or the result of taking part in a robin round study had to be presented to proof that the method delivers the true result (EURACHEM’s “fit for the purpose” concept). The weakest point of most papers is connected to calibration issues in the user’s lab. The crucial topic of the stability of the calibrants (often fragile biomolecules) after the device has been sold is seldom addressed. In addition,  slightly different matrices (POC devices being confronted with the biological bandwidth) demanding a standard addition procedure are seldom considered. 

Provoking statement: After half a century working in the area of analytical chemistry I came to the conclusion: the more papers on a certain topic, the more problems seem to be exist. My long lasting experience with inter-laboratory comparison studies showed, e.g., those participants using an isotope dilution method achieved most often the best results. Consequently fewer papers concerning further improvements of this method are needed.

Dr. Cammann, do you believe there should be more papers with a more in depth study of a particular POC or LOC design instead of a plethora of papers with many, many designs with surface-only results?

While I agree that papers providing only a matrix-free calibration plot are virtually useless as far as real-world sensing is concerned and should not be published, I believe that many researchers are not interested in commercializing their devices, but are more interested in advancing the state of the art by developing novel approaches to solving problems.  In these cases, the technology is then available for those in the sensor industry to develop into marketable devices.  Not everyone is an entrepreneur who is interested in commercialization, but this should not preclude them from doing good analytical research.

Dear colleagues,

thanks for your response. I will try to answer the questions raised with only short comments: In-length depth studies can be boring for an expert in this particular area. The experts want innovative, practical, reliable and preferably proven solutions for the crucial points, for POC devices per example:  

a) Starting with an introduction why just this or those parameters (analytes) at the point of care should be measured. Does the medical community support this need? How to plan the mandatory External Quality Assessment (EQA) program demanded fort commercial success from the very beginning?

b) How to gain plasma without a centrifuge and not violating diverse patents for alternative on-chip methods?

c) How to present a novel innovative calibration strategy? Can it be proven, that a single factory calibration strategy will be confirmed by the EQA step? In case of calibrations before or after the sample measurements: will the calibrants be stable and traceable to an accepted Standard or reference?

d) Is the presented detection limit based on results obtained with real samples? Very often the practical detection limit is given by 3 x standard deviation of blank measurements, which can be many orders higher than theoretical estimates of the transducer sensitivity.

e) Finally, before publishing the paper real blood samples with certified analyte concentrations (or standard reference materials) should be measured to demonstrate that the developed prototype delivers a reliable und true result being confirmed also by any EQA system. In order to reach this demand, validation studies should start as early as possible in the course of the R&D work.   

The last point is the most important: It demonstrates the “fit-for-purpose” concept and could pave the way to a successful market introduction by interested industrial partners. Very valuable with respect to a broader market acceptance is the “DKE – Deutsche Normungs-Roadmap for Mobile Diagnostiksysteme”; Herausgeber: VDE VERBAND DER ELEKTROTECHNIK - ELEKTRONIK INFORMATIONSTECHNIK e. V. und der DGBMT Deutsche Gesellschaft für Biomedizinische Technik im VDE vom Oktober 2014. This 54 page brochure in German could be very helpful in the planning of novel POC testing systems. Knowing in advance the demands of regulative authorities could direct the R&D work to be successful also commercially.

A final remark on LOC devices: Having evaluated hundreds of international proposals and also performed mid-term reviews of the latter, the main reason for failing to achieve all objectives was mostly a too late validation study without time for corrections or improvements. Only if each sub-unit of a LOC system (sampling, pre-treatment, separations, detection, etc.) reaches the expected specifications, the total assembly will probably survive a thorough validation with real world samples! If the academic researchers could fully convince an entrepreneur that any later mandatory EQA could be easily passed by the novel system described in a research paper, more systems would be on the market.

An interesting discussion you have started here! Thank you also for the Roadmap-Document, that is interesting as well (will also be avialable in english soon).

However, I think to answer your initial question some more factors have to be considered. In addition to your points, I have the feeling that real-world applicability is not as valued as it should be. As long as fanciness is top priority for publication the chip-in-a-lab systems, designed to produce nice images won't die.