In Vivo Sensors for Medicine - IEEE Xplore

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University, Oxford, OH, in 1979, the M.S. degree in physics and the Ph.D. ... Dr. Black is a Fellow of the American Institute for Medical and Biological Engineering.
IEEE SENSORS JOURNAL, VOL. 8, NO. 1, JANUARY 2008

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Editorial Introduction for the Special Issue of the Sensors Journal: In Vivo Sensors for Medicine MPLANTABLE medical devices have a distinguished track record in medicine, perhaps most notably in the area of cardiac pacing. More recently, a greater diversity of implantable sensors and associated devices, both diagnostic and therapeutic, have been developed for use with patients or have been evaluated in the laboratory. Clinical usage of devices that are implanted permanently is not always an easy “sell” to physicians, however. It is safe to say that unless the sensor/device seeks to address a life-threatening disease state and only if there is no other equivalent in vitro or noninvasive means for achieving the same endpoints, then significant pushback will arise. Additionally, the regulatory challenges that accrue to permanently implanted devices can lead to significant costs and lengthy clinical trials, especially if the technology has no predicate in commercial use. Despite these hurdles there is a very active community of designers and developers of in vivo sensors and the promise of significant clinical advances is real. This Special Issue provides a sampling of work that is ongoing in the field. The importance of a proper regulatory strategy when designing and implementing an implantable sensor for the clinic cannot be overemphasized. The paper by Smith et al. was included in this issue to provide readers with an overview of the novel requirements set forth by the U.S. Food and Drug Administration (FDA) that cover this device type. An ongoing harmonization of standards is leading to greater commonality between the FDA and regulatory bodies outside the U.S. and, therefore, the lessons are quite generic. Although good design practices are important for all engineered devices, students who enter the medical device field are often taken aback by the strict nature of the requirements. For those who seek to make a career in the device field, even if that career is in an academic setting, it is important to be cognizant of the rules for compliance so as to avoid frustration or, worse, failure during the evolution of an implanted device concept. The use of novel materials in implants illuminates one instance where rigorous preplanning is prudent. Put simply, the FDA approves devices, not materials, and thus a novel configuration needs to be properly tested even if it makes use of materials that have been used in predicate devices. If the candidate material has never been used in a permanent implant, then the level of burden in testing it for

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Digital Object Identifier 10.1109/JSEN.2007.914557

toxicity, carcinogenicity, genetic effects, etc., becomes quite involved. This is not to say that designers should eschew new materials altogether, but the reasons for using them, versus a better-known alternative, need to be carefully weighed. The 16 papers in this Special Issue describe some specific techniques for powering and enabling implanted sensors, overview some device types meant to guide therapeutic interventions (feedback on therapy), outline devices to look at pH and oxygen values, and introduce sensors for measuring analytes (especially glucose). The common theme is to provide information about imbalances in normal physiology or as a guide to therapy. There are no papers addressing therapy applications of in vivo devices, such as cardiac pacing, drug release, or pain reduction, though these are also active areas of exploration. However, the review article by Wilson et al. provides a fascinating history of the evolution of the cochlear implant, which most naturally falls into the “therapeutic” category. Though successful by many measures, the cochlear implant story also provides a revealing look at the public reaction that “corrective” implants, especially those with neural interfaces, may engender. At what age should a cochlear implant be placed? Does the use of such a device somehow detract from the positive strides made by the deaf community in gaining acceptance in the “hearing world?” These are meta-issues that go beyond the concerns of design, development, and deployment. Engineers are used to having sensors placed in relevant locations in complex machines so as to have feedback from those “black boxes,” and thus better ensure proper operation. It seems natural to extend this strategy to medicine and to view the human body as a complex system with sophisticated controls that sometimes break down. That there are relatively few implantable sensor products on the market is a testament to the difficulty of this “natural extension.” In addition to the considerable technical challenges that must be met to successfully deploy such devices, there must be a change, in many cases, in how medicine is practiced. As noted before, significant physician pushback will result if new devices “interfere” with traditional patient care. Therefore, the genesis of implantable sensor systems must include a close collaboration with physicians so that patient protocols can effectively incorporate new data and new capabilities. This is an incremental process and medicine is appropriately conservative in this regard. The only criterion of relevance is

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IEEE SENSORS JOURNAL, VOL. 8, NO. 1, JANUARY 2008

patient health and well-being and on that point all parties can agree. The Guest Editors would like to thank all of the authors who have contributed to this Special Issue, the diligent reviewers who spent time ensuring accuracy in the manuscripts, and the IEEE staff whose patience and persistence allowed this Special Issue to come to press.

ROBERT D. BLACK, Guest Editor Sicel Technologies, Inc. Morrisville, NC 27560 USA WILLIAM M. REICHERT, Guest Editor Duke University Durham, NC 27708 USA ANTHONY P. F. TURNER, Guest Editor Cranfield University Bedforshire MK43 0AL, U.K.

Robert D. Black received the B.S. degrees in physics, mathematics, and English from Miami University, Oxford, OH, in 1979, the M.S. degree in physics and the Ph.D. degree in electrical engineering from the University of Illinois, Urbana, in 1980 and 1984, respectively. He has been a Scientist at the General Electric R&D Center, an Assistant Professor at Duke University, and an Executive/Co-Founder of three medical device companies. Currently, he is the President of Civatech Oncology, a medical device company in the cancer space. He has authored or coauthored 33 peer-reviewed publications. Dr. Black is a Fellow of the American Institute for Medical and Biological Engineering (AIMBE).

William M. Reichert was born in San Francisco, CA. He received the B.A. degree in biology and chemistry from Gustavus Adolphus College, Saint Peter, MN, in 1975, and the Ph.D. degree macromolecular science and engineering from the University of Michigan, Ann Arbor, in 1982. He was a NIH National Research Service Award Postdoctoral Fellow, a Whitaker Fellow, and a NIH New Investigator Fellow at the Department of Bioengineering, University of Utah, where he “learned the ropes” from Prof. Joe Andrade and Prof. Art Janata. He joined the Department of Biomedical Engineering at Duke University in 1989 and is currently Professor of Biomedical Engineering and Chemistry, and Director of the Center for Biomolecular and Tissue Engineering. He is Program Director of an NIH predoctoral training grant that supports graduate fellowships in biotechnology. He has trained a number of doctoral and postdoctoral students now working in academics and industry. He has published over 100 scientific manuscripts, and holds patents in multianalyte waveguide sensors and protein detection arrays. His current research interests are wound healing related implant failure, biosensors, vascular graft endothelialization, and cytokine profiling. Dr. Reichert is a Fellow of the American Institute of Medical and Biological Engineering. He is on editorial boards for the Journal of Biomedical Materials Research and Langmuir. He has received the Catalyst for Institutional Change from Quality Education for Minorities Network, the Pioneer Award from the Samuel DuBios Cook Society, and the Dean’s Award for Excellence in Mentoring at Duke University.

IEEE SENSORS JOURNAL, VOL. 8, NO. 1, JANUARY 2008

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Anthony P. F. Turner’s name is synonymous with the field of biosensors. Formerly Principal of Cranfield University at Silsoe, he returned to full-time research in February 2006 and is now a Distinguished Professor of Biotechnology in Cranfield Health, a new school, Cranfield University. He has held a Personal Chair in Biosensor Technology at Cranfield University since 1989 and has a number of honorary and visiting positions elsewhere. He is a Governor of the University of Bedfordshire. He has edited the principal journal in the field, Biosensors and Bioelectronics, since its foundation in 1985 and edited the first textbook on Biosensors in 1987. He played a key role in coordinating research activities in medical and environmental sensors in the European Union and led concerted actions and thematic networks since 1988. He founded the World Congress on Biosensors in 1990 and has chaired it since then. In addition to his academic activities, he has held a range of commercial positions continuously since 1982, commencing with Project Director for MediSense’s in vitro diagnostics program. In this role, he led the team that invented, designed, and developed the world’s most successful type of biosensor, the mediated amperometric enzyme electrode for glucose. He continues this commitment to innovation today as a Director and Chairman of the Scientific Advisory Board for Pelikan Technologies, Palo Alto, CA. In addition to advising companies and governments worldwide in the general area of analytical biotechnology, he has served as an expert witness in patent litigations on three continents. He was elected a Fellow of the Royal Society of Chemistry in 1996 and invited to Fellowship at the Institute of Biology in 1999 and to Fellowship at the Institute of Physics in 2006. He has over 580 publications and patents in the field of biosensors and biomimetic sensors. Dr. Turner was awarded a higher doctorate for his exceptional contribution to Biosensors by the University of Kent in 2001 and admitted to the USA National Academy of Engineering in 2006 for his work on medical and environmental diagnostics and on synthetic receptors. He has won a number of prestigious scientific awards worth over £100 000 in personal prize money and presented well over 350 keynote and plenary lectures at a range of international meetings and honor ceremonies around the world. www.silsoe.cranfield.ac.uk/staff/apturner.htm.