Edited by Jeong-Yeol Yoon, Academic Press, 2020, ISBN: 9780128170441 (paperback), xii + 237 pages, $130 (list)
This reviewer has an interest in the use of smartphones for various tasks, such as documentation of device failures (photography), inspection of parts (use of borescopes), thermal imaging (attachments for infrared imaging), personal health monitoring (step counting, heart rate monitoring, stress monitoring), and the like. This text was chosen for review as the title purported to cover the overall field of medical diagnostics that might be replaced by point-of-care smartphone assisted analysis.
The text consists of 11 chapters, contributed by some 25 authors, including the editor. An overview of the chapters follows.
Chapter 1 (Introduction) gives a quick definition of “biosensors” and “medical diagnostics,” lists and labels the sensors typically found on smartphones, gives an overview of the remaining ten chapters, and gives mention to regulatory issues. Chapter 2 overviews, at a first-year physics level, the basics of light, its generation, composition, scattering, fluorescence, absorbance, and sensing. Chapter 3 gives an overview of smartphone electrochemical biosensing by mentioning Ohm’s law, the Nernst equation, amperometry and conductometric sensing of reactions, as well as a brief mention of temperature sensing, A/D conversion, and data porting.
Chapter 4 gives an overview of the current technologies used in glucose monitoring (optical and electrochemical methods) and smartphone-based attempts to replace this methodology. It is a good primer for elucidating current problems with these attempts, such as the need for the use of light boxes to ensure adequate and uniform illumination of the measurand (optical method) and the necessity for meeting current FDA accuracy, repeatability, and traceability requirements. Chapter 5 overviews flow cytometry techniques and current microfluidic sensors under development. Applications mentioned include cell counting for determination of various diseases (malaria, HIV, etc.) as well as sperm analysis for fertility testing. The reader is informed (again) that smartphones have been used to assist in making measurements currently done by more complex and expensive devices, regulatory constraints exist that need to be addressed. “Smartphone use for rapid kits” (chapter 6) overviews the detection of various items such as zika disease, dengue, blood hemolysis, peanut allergen detection, fertility disorders (sperm counting), etc. using smartphones and various available kits. Chapter 7 reiterates and slightly expands on the earlier discussion of smartphone diagnostics using microfluidic devices.
Current technologies for evaluating and monitoring such items as pressure, foot, and venous ulcers are discussed in Chapter 8. At this point, the smartphone is most useful for documenting items such as ulcer size and patient activity, thus providing data for the physician to act upon, future work may enable smartphone patient guidance. Chapter 9 gives an overview of microscopy techniques (brightfield, darkfield, phase and fluorescence imaging, etc.) and a few examples of the use of these techniques using smartphones. This largely reviews what is possible, but not yet implemented, especially in low resource settings. The many uses of smartphones for periodic and/or chronic monitoring of heath are overviewed in Chapter 10. These uses include pulse oximetry, pulse rate, “stress,” activity, etc., with attachments (devices) for monitoring: temperature, glucose, biopotentials, hydration, etc. A listing of devices on market rounds out this chapter. The text conclude with a final chapter on food safety applications, where the use of smartphones for detection of parasites, viruses, bacteria, salmonella, pesticides, and allergens, etc., is reviewed. A four-page table of such uses, including references, is included.
Overall, this text provides a reasonable overview of current and potential uses of current smartphones in medical diagnostics. It should be of value to persons interested in the possibility of developing new or improved versions of current laboratory or clinic-based monitoring or diagnostic systems. Each chapter is reasonably or very well documented in terms of references, a good starting point for work in areas of each of thechapters is therefore provided.
For the text to be used for motivation of entrepreneurs (as is suggested in related advertising), however, such items as the need for such devices must be articulated. What might be the return on investment if one were to provide a point of care 10-minute diagnosis for Ebola, for example? What areas of development are most needed for a given society? How would one prioritize new endeavors?