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Sensors Journal, IEEE

Issue 1 • Date Jan. 2008

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Displaying Results 1 - 24 of 24
  • [Front cover]

    Publication Year: 2008 , Page(s): C1
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  • IEEE Sensors Journal publication information

    Publication Year: 2008 , Page(s): C2
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  • Table of contents

    Publication Year: 2008 , Page(s): 1 - 2
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  • Editorial Introduction for the Special Issue of the Sensors Journal: In Vivo Sensors for Medicine

    Publication Year: 2008 , Page(s): 3 - 5
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  • A Novel Method to Read Remotely Resonant Passive Sensors in Biotelemetric Systems

    Publication Year: 2008 , Page(s): 6 - 11
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (337 KB) |  | HTML iconHTML  

    Resonant passive sensors composed by resistive, inductive, and capacitive (RLC) simple sensors are widely used in biotelemetric systems. In this paper, a novel method to read remotely these RLC sensors is presented. The developed method is based on the simultaneous application of three excitation signals of same amplitudes, set at different frequencies, to determine remotely the RLC sensor resonance frequency and quality factor . Theoretical analysis and experimental results are also presented. View full abstract»

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  • Intraocular Pressure Monitoring Sensors

    Publication Year: 2008 , Page(s): 12 - 19
    Cited by:  Papers (26)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (614 KB) |  | HTML iconHTML  

    Continuous measurement of intraocular pressure is important in the detection and treatment of glaucoma. While a point check of intraocular pressure in a doctor's office using indirect measurements such as the tonometer is helpful, it is inadequate to track circadian variation. Circadian variation is an independent risk factor in addition to elevated pressure levels. This paper is aimed at providing an up-to-date review of various intraocular pressure sensing techniques and in vivo sensor design approaches. The basic operating principles of various implantable sensors are reviewed and categorized into groups to delineate their differences. A discussion is presented identifying the drawbacks of existing designs and key design questions are proposed for future progress. View full abstract»

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  • Review Paper: Materials and Techniques for In Vivo pH Monitoring

    Publication Year: 2008 , Page(s): 20 - 28
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (685 KB) |  | HTML iconHTML  

    Advances in semiconductor sensor technology, medical diagnostics, and health care needs a rapid boost in research into novel miniaturized pH sensors, which can be used in vivo for continuous patient monitoring. Requirements for the in vivo sensor are materials biocompatibility, high measurement precision, a response time of an order of less than seconds, and the possibility of continuous 24-h monitoring. Monitoring of the pH values is important in the study of tissue metabolism, in neurophysiology, cancer diagnostics, and so forth. Muscle pH can be used to triage and help treat trauma victims as well as to indicate poor peripheral blood flow in diabetic patients. Clearly, to avoid infection and spread of diseases, all in vivo monitoring devices should be single-use/disposable, which puts strict requirement on their price. This paper reviews the wide range of methods and materials used for in vivo measurement of pH levels, such as using the optical fibers, pH-sensitive polymers, ion-sensitive field effect transistors, near infrared spectroscopy, nuclear magnetic resonance, and fluorescent pH indicators. View full abstract»

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  • A Magnetically Controlled Wireless Optical Oxygen Sensor for Intraocular Measurements

    Publication Year: 2008 , Page(s): 29 - 37
    Cited by:  Papers (20)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (733 KB) |  | HTML iconHTML  

    The influence of oxygen on various ophthalmological complications is not completely understood and intraocular oxygen measurements are essential for better diagnosis and treatment. A magnetically controlled wireless sensor device is proposed for minimally invasive intraocular oxygen concentration measurements. This device will make it possible to make measurements at locations that are currently too invasive for human intervention by integrating a luminescence optical sensor and a magnetic steering system. The sensor works based on quenching of luminescence in the presence of oxygen. A novel iridium phosphorescent complex is designed and synthesized for this system. A frequency-domain lifetime measurement approach is employed because of the intrinsic nature of the lifetime of luminescence. Experimental results of the oxygen sensor together with magnetic and hydrodynamic characterization of the sensor platform are presented to demonstrate the concept. In order to use this sensor for in vivo intraocular applications, the size of the sensor must be reduced, which will require an improved signal-to-noise ratio. View full abstract»

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  • An Implantable MOSFET Dosimeter for the Measurement of Radiation Dose in Tissue During Cancer Therapy

    Publication Year: 2008 , Page(s): 38 - 51
    Cited by:  Papers (11)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2390 KB) |  | HTML iconHTML  

    This paper describes the functionality, radiation characteristics, and clinical implementation of an implantable MOSFET radiation detector (dosimeter). The dosimeter is powered by radio frequency telemetry eliminating the need for a power source inside the dosimeter. The data can be accessed telemetrically for each treatment day during the course of therapy. The detector has been validated in vitro to confirm its accuracy. Variance between predicted and measured dose in patients is discussed. Factors such as patient setup, treatment plan error, and physiologic motion can affect the accuracy of dose delivery in moving from in vitro to in vivo dose measurements. The initial data suggests that the dosimeters can play a useful role in tracking dose discrepancies, both random and systematic, in patients treated with external beam radiation therapy. The implantable dosimeter can be used, together with the current radiation delivery and planning techniques, to optimize radiation treatment on an individual basis. View full abstract»

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  • FDA Regulation of Implantable Sensors: Demonstrating Safety and Effectiveness for Marketing in the U.S.

    Publication Year: 2008 , Page(s): 52 - 56
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (194 KB) |  | HTML iconHTML  

    Implantable sensors are gaining considerable attention in the research and medical communities due to their potential to enhance the detection and monitoring of medical conditions such as cancer, diabetes, and heart disease. The use of implantable sensors for these exciting applications bring them under the regulatory oversight of the United States Food and Drug Administration (FDA). As medical devices intended for long-term implantation that inherently involve some risk, the FDA will carefully evaluate these products prior to allowing them to enter the U.S. market. This paper provides a brief overview of the FDA medical device regulatory framework under which implantable sensors for medical purposes are regulated. It also addresses particular concerns the FDA may raise with respect to these products including, potential sensor breakage and migration in vivo, biocompatibility, electromagnetic compatibility, electromagnetic interference, wireless telemetry, risk/benefit, and clinical utility. View full abstract»

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  • Improved Wireless, Transcutaneous Power Transmission for In Vivo Applications

    Publication Year: 2008 , Page(s): 57 - 62
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (759 KB) |  | HTML iconHTML  

    Electric power, sufficient for many in vivo applications, can be transmitted wirelessly from a small external solenoid (filled with a soft magnetic core), to a novel, magnetoelectric (ME) receiver a few centimeter (cm) inside the body. The ME receiver is a sandwich of electroactive (e.g., piezoelectric) material bonded between two magnetostrictive layers. The electroactive layer may be poled in its plane so that it can function in the stronger g33 mode (induced voltage parallel to the direction of principal magnetostrictive stress). Preliminary experimental results indicate that a 7 cm long ferrite-filled solenoid (NI ap 122 Amp-turns) producing an RMS magnetic field of order 1600 A/m (20 Oe) at the ME receiver (of volume 0.1 cm3) 3 cm from the field source, generates in the ME receiver a power of 200 mW (2 W/cm3). The receiver, in turn, generates a power of 160 mW. View full abstract»

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  • Ex Vivo Continuous Glucose Monitoring With Microdialysis Technique: The Example of GlucoDay

    Publication Year: 2008 , Page(s): 63 - 70
    Cited by:  Papers (5)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (770 KB) |  | HTML iconHTML  

    The use of a glucose biosensor in conjunction with a microdialysis probe used to sample the interstitial fluid of the patient has been demonstrated to be extremely useful and advantageous for obtaining a continuous glucose monitoring instrument capable of detecting glycemic level in real time for a long period. The first example of this kind of instrument which was cleared for commercialization is the GlucoDay made by Menarini. The approach used by the GlucoDay presents several advantages if compared with other instruments and its features and future prospective are thoroughly discussed. View full abstract»

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  • Clinical Evaluation of a Novel Interstitial Fluid Sensor System for Remote Continuous Alcohol Monitoring

    Publication Year: 2008 , Page(s): 71 - 80
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1059 KB) |  | HTML iconHTML  

    This study describes the functioning of a novel sensor that measures the alcohol concentration in the interstitial fluid (ISF) of a human subject. ISF is extracted using vacuum pressure from micropores on the stratum corneum layer of the skin. The pores are created by focusing a near infrared laser on a layer of black die attached to the skin. This poration procedure is essentially painless. Clinical studies show that the sensor readings are correlated with alcohol levels in blood and collected using a breathalyzer. Alcohol could be detected in the subject's ISF within 15 min of the first oral intake of alcohol. Tests in a laboratory setup show that the sensor exhibits a linear response to alcohol concentrations in the range 0%-0.2%. The sensor is minimally invasive and alcohol monitoring using the sensor was shown to continue even when the subject is asleep. The sensor is viable for approximately three days after skin poration. The sensor is interfaced to a wireless health monitoring system that transfers sensor data over existing wide-area networks such as the Internet and a cellular phone network to enable real-time remote monitoring of subjects. View full abstract»

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  • In Vivo Monitoring of a Fluorescently Labeled Antibody in Mice With Breast Cancer Xenografts

    Publication Year: 2008 , Page(s): 81 - 88
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (771 KB) |  | HTML iconHTML  

    Following the uptake kinetics of a monoclonal antibody cancer therapy in vivo is addressed in this study via the use of a surface probe to assay a fluorescent label attached to the antibody. Female NCr-nu athymic mice were implanted with cells from a human breast cancer MCF7HER2 line that over expresses clinically relevant levels of the HER2/neu protein. Herceptin (trastuzumab) and a negative control antibody for mouse IgG Ab-1 were labeled with Alexa Fluor 647 fluorescent dye and the mice received a single bolus injection (tail vein) of one of the two antibodies. The relative signal in the tumor region was compared with that from normal tissue and a ratio of the signal levels was recorded as a function of time. As expected, Herceptin was found to concentrate in the HER2+ tumors (high tumor-to-normal ratio), whereas the tumor-to-normal ratio for the negative control antibody was flat in time and close to unity. It is suggested that fluorescence assays of this type might be possible in vivo in humans using a telemetric, implantable version of the probe used in this study. View full abstract»

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  • The Benefit of Subcutaneous Glucagon During Closed-Loop Glycemic Control in Rats With Type 1 Diabetes

    Publication Year: 2008 , Page(s): 89 - 96
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1169 KB) |  | HTML iconHTML  

    Because of its prolonged action, subcutaneously administered insulin has a potential for overcorrection hypoglycemia during closed-loop glucose control. For this reason, we hypothesized that subcutaneous glucagon, whose action is faster, could lessen the risk for hypoglycemia during closed-loop control. We therefore compared insulin alone versus insulin plus glucagon in diabetic rats in a controlled closed-loop study. Both hormones were delivered by algorithms based on proportional error, derivative error, and the glucose history. Based on this algorithm, glucagon was delivered when glucose was declining and approaching a hypoglycemic level. The delivery of glucagon was largely reciprocal with the delivery of insulin. With the addition of glucagon, there was less hypoglycemia at the glucose nadir, less hyperglycemia later in the study, and lower absolute error values during these periods. We also found that for 7 days after glucagon reconstitution, commercially available glucagon retained its original ability to quickly raise glucose level. We conclude that when subcutaneous insulin delivery is accompanied by subcutaneous glucagon, glycemic control during closed-loop treatment is improved. Since its action is faster than that of insulin, glucagon may prove useful during closed-loop diabetes control. View full abstract»

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  • Transcutaneous Implantation Methods for Improving the Long-Term Performance of Glucose Sensors in Rats

    Publication Year: 2008 , Page(s): 97 - 103
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (556 KB) |  | HTML iconHTML  

    Translation of sensor design and function in animal models to human use is an ongoing challenge due to tissue anatomical and physiological differences between species, even at presumably analogous implant locations. Nevertheless, preclinical testing of sensors for long-term glucose monitoring in animals is required for evaluating sensor function in order to improve sensor design. Long-term glucose sensor testing in common laboratory animals (e.g., mice and rats) is especially difficult due to their small size, as well as limited site availability for sensor placement without disturbance or removal by the subject. However, improvements in sensor design and implantation methods to improve sensor survival in these animals could accelerate our understanding of the role of tissue reactions to sensor components, as well as allow reliable testing of biomaterials and various drug or growth factor delivery systems to potentially minimize or modulate tissue reactions. In this study, methods to secure a wire-type subcutaneous sensor in rats for a long period of time (ges28 d), utilizing new implantation techniques and devices were evaluated. Anchoring devices were incorporated into the sensor design and appropriate implantation methods were used to: (1) minimize potential membrane damage caused by animal motion; (2) prevent removal of the entire sensor or sensor wires by the animal; and (3) allow exterior access to wires for periodic sensor performance testing. The anchoring devices for securing sensors to the skin internally, which were sequentially investigated and improved (Protocol A to C), included a modified 22 gauge intravenous winged catheter (Protocol A), Silastic tubing (Protocol B) or silk suture loops held in place by Silastic tubing (Protocol C). The results show that after four weeks implantation, 60% (n = 10), 70% (n = 10), and 92% (n = 12) of the implanted devices survived (Protocols A, B, and C, respectively). Functional testing showed that 30% (n = 10), 40% (- n = 10), and 58% (n = 12) of the sensors still worked well four weeks after implantation (Protocols A, B, and C, respectively). No infections were visibly evident at the sites of sensor implantation at any time during the testing period for all protocols. Protocol C shows promise as a viable method for future sensor studies because of the anchoring device's small size and because it was nearly impossible for rats to remove or damage the sensors. View full abstract»

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  • Foreign Body Response Investigated With an Implanted Biosensor by In Situ Electrical Impedance Spectroscopy

    Publication Year: 2008 , Page(s): 104 - 112
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1375 KB) |  | HTML iconHTML  

    One of the principal challenges for the long-term implantation of biosensors is that the normal physiological response of the body creates a fibrotic capsule of scar tissue surrounding the implanted sensor (the foreign body response). This dense, collagenous capsule isolates the device from the local environment, causing a time-dependent degradation of the signal. We utilize this degradation or change to an electrical signal as an indicator of the physiological responses to the implantation of the biomaterial device. We thus track the foreign body response electronically, an important analytical method for our program that aims to reduce the foreign body response. We applied electrical impedance spectroscopy (EIS) to track changes of the electrical signal behavior over time between micro-electrode arrays. We have performed experiments both in vitro and ex ova. In vitro, we used a reservoir of phosphate buffered saline into which selected proteins were introduced that adsorb onto the electrode surface. Three proteins were studied and each was found to affect the EIS results differently. We have investigated the foreign body response ex ova using the chick chorio-allantoic membrane (CAM) model. Following implantation of the electrode array the chick CAM exhibited a response similar to the mammalian foreign body response. We report that the electrical signal degrades with tissue growth during the healing and remodeling following the traumatic implantation of the electrode needle through the ectoderm side of the CAM tissue. View full abstract»

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  • Needle Enzyme Electrode for Lactate Measurement In Vivo

    Publication Year: 2008 , Page(s): 113 - 120
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (637 KB) |  | HTML iconHTML  

    Electrochemical lactate needle enzyme electrodes were fabricated based on lactate oxidase with a conventional hydrogen peroxide detection regimen with a linear range up to 7 mM, response time ~ 3 min, and sensitivity ~ 1 nA/mM. A negatively charged inner (sulphonated polyether ether sulphone-polyether sulphone) membrane was applied for ensuring selectivity by limiting oxidazible anion diffusion to the Pt working electrode; polyurethane outer membrane layers were dip coated over the enzyme layer to limit substrate diffusion to the enzyme layer to achieve: (1) stir independence and (2) a low oxygen requirement. Lactate was monitored subcutaneously in rats during controlled haemorrhage and hypovolaemic shock. Tissue lactate showed agreement with blood lactate before haemorrhage and for limited haemorrhage (up to 2 ml blood withdrawal from 16 ml total blood volume) but with blood loss above 3 ml the tissue lactate rise was less pronounced than in blood. Loss of intercompartmental equilibrium due to diffusion limitation is suggested as a factor in causing this difference. An experimental in vitro model was developed which employed the needle lactate electrode within a cylindrical collagen gel to monitor inward diffusion of lactate as a basis for determining lactate diffusion coefficient. The high precision measurement gave a diffusion coefficient consistent with report values 3.54 times 10-6 cm2/s. The simplified experimental approach could allow lactate transport studies across tissue analogues. View full abstract»

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  • Integrated In Vivo Neural Imaging and Interface CMOS Devices: Design, Packaging, and Implementation

    Publication Year: 2008 , Page(s): 121 - 130
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2091 KB) |  | HTML iconHTML  

    We have developed two CMOS devices to demonstrate the use of CMOS technology for neural imaging and interfacing with the aim of studying the functions of the brain at the molecular level. In this work, we discuss the design, packaging, and implementation of a compact, single device imaging system for imaging inside the mouse brain. We show that the device is capable of imaging and measuring fluorophore concentrations down to 1 mum . The packaged device was tested for in vivo fluorescence imaging by imaging the activity of serine protease in the mouse hippocampus. The result shows imaging of neural activity with spatial resolution close to the pixel size of 7.5 mum and less than 300 ms temporal resolution. A second device was developed to image neuronal network activity and to provide a means for electrical interfacing with neurons. Characterization tests show that the device has comparable performance to current tools used in electrophysiological experiments of the brain. This work paves the way for simultaneous imaging and electrophysiological experiments using a single compact and minimally invasive device in the future. View full abstract»

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  • Interfacing Sensors With the Nervous System: Lessons From the Development and Success of the Cochlear Implant

    Publication Year: 2008 , Page(s): 131 - 147
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1286 KB) |  | HTML iconHTML  

    The cochlear implant is the most successful neural prosthesis to date and may serve as a paradigm for the development or further development of other systems to interface sensors with the nervous system, e.g., visual or vestibular prostheses. This paper traces the history of cochlear implants and describes how the current levels of performance have been achieved. Lessons and insights from this experience are presented in concluding sections. View full abstract»

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  • IEEE Sensors 2008

    Publication Year: 2008 , Page(s): 148
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    Freely Available from IEEE
  • IEEE Foundation [advertisement]

    Publication Year: 2008 , Page(s): 149
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    Freely Available from IEEE
  • IEEE order form for reprints

    Publication Year: 2008 , Page(s): 150
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  • IEEE Sensors Council Information

    Publication Year: 2008 , Page(s): C3
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    Freely Available from IEEE

Aims & Scope

The IEEE Sensors Journal is a peer-reviewed, monthly online/print  journal devoted to sensors and sensing phenomena

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Krikor Ozanyan
University of Manchester
Manchester, M13 9PL, U.K.