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Downs AM, Plaxco KW. Real-Time, In Vivo Molecular Monitoring Using Electrochemical Aptamer Based Sensors: Opportunities and Challenges. ACS Sens 2022; 7:2823-2832. [PMID: 36205360 PMCID: PMC9840907 DOI: 10.1021/acssensors.2c01428] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The continuous, real-time measurement of specific molecules in situ in the body would greatly improve our ability to understand, diagnose, and treat disease. The vast majority of continuous molecular sensing technologies, however, either (1) rely on the chemical or enzymatic reactivity of their targets, sharply limiting their scope, or (2) have never been shown (and likely will never be shown) to operate in the complex environments found in vivo. Against this background, here we review electrochemical aptamer-based (EAB) sensors, an electrochemical approach to real-time molecular monitoring that has now seen 15 years of academic development. The strengths of the EAB platform are significant: to date it is the only molecular measurement technology that (1) functions independently of the chemical reactivity of its targets, and is thus general, and (2) supports in vivo measurements. Specifically, using EAB sensors we, and others, have already reported the real-time, seconds-resolved measurements of multiple, unrelated drugs and metabolites in situ in the veins and tissues of live animals. Against these strengths, we detail the platform's remaining weaknesses, which include still limited measurement duration (hours, rather than the more desirable days) and the difficulty in obtaining sufficiently high performance aptamers against new targets, before then detailing promising approaches overcoming these hurdles. Finally, we close by exploring the opportunities we believe this potentially revolutionary technology (as well as a few, possibly competing, technologies) will create for both researchers and clinicians.
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Affiliation(s)
- Alex M. Downs
- Sandia National Laboratories, Albuquerque, NM 87106, USA
| | - Kevin W. Plaxco
- Center for Bioengineering, University of California Santa Barbara, Santa Barbara, CA 93106, USA,Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA,Corresponding author:
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An integrated wearable microneedle array for the continuous monitoring of multiple biomarkers in interstitial fluid. Nat Biomed Eng 2022; 6:1214-1224. [PMID: 35534575 DOI: 10.1038/s41551-022-00887-1] [Citation(s) in RCA: 152] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/25/2022] [Indexed: 12/16/2022]
Abstract
Implementations of wearable microneedle-based arrays of sensors for the monitoring of multiple biomarkers in interstitial fluid have lacked system integration and evidence of robust analytical performance. Here we report the development and testing of a fully integrated wearable array of microneedles for the wireless and continuous real-time sensing of two metabolites (lactate and glucose, or alcohol and glucose) in the interstitial fluid of volunteers performing common daily activities. The device works with a custom smartphone app for data capture and visualization, comprises reusable electronics and a disposable microneedle array, and is optimized for system integration, cost-effective fabrication via advanced micromachining, easier assembly, biocompatibility, pain-free skin penetration and enhanced sensitivity. Single-analyte and dual-analyte measurements correlated well with the corresponding gold-standard measurements in blood or breath. Further validation of the technology in large populations with concurrent validation of sensor readouts through centralized laboratory tests should determine the robustness and utility of real-time simultaneous monitoring of several biomarkers in interstitial fluid.
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Madden J, Vaughan E, Thompson M, O' Riordan A, Galvin P, Iacopino D, Rodrigues Teixeira S. Electrochemical sensor for enzymatic lactate detection based on laser-scribed graphitic carbon modified with platinum, chitosan and lactate oxidase. Talanta 2022; 246:123492. [PMID: 35487014 DOI: 10.1016/j.talanta.2022.123492] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 03/01/2022] [Accepted: 04/15/2022] [Indexed: 12/20/2022]
Abstract
We developed a flexible laser scribed graphitic carbon based lactate biosensor fabricated using a low cost 450 nm laser. We demonstrated a facile fabrication method involving electrodeposition of platinum followed by two casting steps for modification with chitosan and lactate oxidase. The biosensor demonstrated chronoamperometric lactate detection within a linear range from 0.2 mM to 3 mM, (R2 > 0.99), with a limit of detection of 0.11 mM and a sensitivity of 35.8 μA/mM/cm2. The biosensor was successful in performing up to 10 consecutive measurements (one after the other) indicating good working stability (RSD <5%). Concerning storage stability, there was no decrease in signal response after 30 days of storage at 4 °C. Additionally, we demonstrate enzymatic lactate detection whilst the flexible polyimide substrates were fixed at a curvature (K) of 0.14 mm-1. No noticeable change in signal response was observed in comparison to calibrations obtained at a curvature of 0 mm-1, signifying potential opportunities for sensor attachment or integration with oral-care products such as mouth swabs. Both laser scribed graphitic carbon and Ag/AgCl modified-laser scribed graphitic carbon were successful as reference electrodes for chronoamperometric lactate measurements. Furthermore, using a three-electrode configuration on polyimide, lactate detection in both artificial saliva and sterile human serum samples was achieved for two spiked concentrations (0.5 mM and 1 mM).
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Affiliation(s)
- Julia Madden
- Tyndall National Institute, University College Cork, Lee Maltings, Cork, Ireland
| | - Eoghan Vaughan
- Tyndall National Institute, University College Cork, Lee Maltings, Cork, Ireland
| | | | - Alan O' Riordan
- Tyndall National Institute, University College Cork, Lee Maltings, Cork, Ireland
| | - Paul Galvin
- Tyndall National Institute, University College Cork, Lee Maltings, Cork, Ireland
| | - Daniela Iacopino
- Tyndall National Institute, University College Cork, Lee Maltings, Cork, Ireland.
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Monitoring of Lactate in Interstitial Fluid, Saliva and Sweat by Electrochemical Biosensor: The Uncertainties of Biological Interpretation. CHEMOSENSORS 2021. [DOI: 10.3390/chemosensors9080195] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Lactate electrochemical biosensors were fabricated using Pediococcus sp lactate oxidase (E.C. 1.1.3.2), an external polyurethane membrane laminate diffusion barrier and an internal ionomeric polymer barrier (sulphonated polyether ether sulphone polyether sulphone, SPEES PES). In a needle embodiment, a Pt wire working electrode was retained within stainless steel tubing serving as pseudoreference. The construct gave linearity to at least 25 mM lactate with 0.17 nA/mM lactate sensitivity. A low permeability inner membrane was also unexpectedly able to increase linearity. Responses were oxygen dependent at pO2 < 70 mmHg, irrespective of the inclusion of an external diffusion barrier membrane. Subcutaneous tissue was monitored in Sprague Dawley rats, and saliva and sweat during exercise in human subjects. The tissue sensors registered no response to intravenous Na lactate, indicating a blood-tissue lactate barrier. Salivary lactate allowed tracking of blood lactate during exercise, but lactate levels were substantially lower than those in blood (0–3.5 mM vs. 1.6–12.1 mM), with variable degrees of lactate partitioning from blood, evident both between subjects and at different exercise time points. Sweat lactate during exercise measured up to 23 mM but showed highly inconsistent change as exercise progressed. We conclude that neither tissue interstitial fluid nor sweat are usable as surrogates for blood lactate, and that major reappraisal of lactate sensor use is indicated for any extravascular monitoring strategy for lactate.
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Zhang Q, Meyerhoff ME. Nitric Oxide Release for Enhanced Biocompatibility and Analytical Performance of Implantable Electrochemical Sensors. ELECTROANAL 2021. [DOI: 10.1002/elan.202100174] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Qi Zhang
- Department of Chemistry University of Michigan Ann Arbor MI 48109 USA
| | - Mark E. Meyerhoff
- Department of Chemistry University of Michigan Ann Arbor MI 48109 USA
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Ho KKY, Peng YW, Ye M, Tchouta L, Schneider B, Hayes M, Toomasian J, Cornell M, Rojas-Pena A, Charpie J, Chen H. Evaluation of an Anti-Thrombotic Continuous Lactate and Blood Pressure Monitoring Catheter in an In Vivo Piglet Model undergoing Open-Heart Surgery with Cardiopulmonary Bypass. CHEMOSENSORS (BASEL, SWITZERLAND) 2020; 8:56. [PMID: 35310780 PMCID: PMC8932942 DOI: 10.3390/chemosensors8030056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Blood lactate and blood pressure measurements are important predictors of life-threatening complications after infant open-heart surgeries requiring cardiopulmonary bypass (CPB). We have developed an intravascular nitric oxide (NO)-releasing 5-Fr catheter that contains a lactate sensor for continuous in-blood lactate monitoring and a dedicated lumen for third-party pressure sensor attachment. This device has antimicrobial and antithrombotic properties and can be implanted intravascularly. The importance of this design is its ability to inhibit thrombosis, due to the slow release of NO through the surface of the catheter and around the electrochemical lactate sensors, to allow continuous data acquisition for more than 48 h. An in vivo study was performed using six piglets undergoing open-heart surgery with CPB and cardioplegic arrest, in order to mimic intra-operative conditions for infants undergoing cardiac surgery with CPB. In each study of 3 h, two 5-Fr NO-releasing lactate and blood-pressure monitoring catheters were implanted in the femoral vessels (arteries and veins) and the CPB circuitry to monitor changing lactate levels and blood pressures during and immediately after aortic cross-clamp removal and separation from CBP. Electrical signals continuously acquired through the sensors were processed and displayed on the device's display and via Bluetooth to a computer in real-time with the use of a two-point in vivo calibration against blood gas results. The study results show that lactate levels measured from those sensors implanted in the CPB circuit during CPB were comparable to those acquired by arterial blood gas measurements, whereas lactate levels measured from sensors implanted in the femoral artery were closely correlated with those acquired intermittently by blood gas prior to CPB initiation, but not during CPB. Blood pressure sensors attached to one lumen of the device displayed accurate blood pressure readings compared to those measured using an FDA approved pressure sensor already on the market. We recommend that the sensor be implanted in the CPB's circuit to continuously monitor lactate during CPB, and implanted in the femoral arteries or jugular veins to monitor lactate before and after CPB. Blood pressures dramatically drop during CPB due to lower blood flow into the lower body, and we suspect that the femoral arteries are likely collapsing or constricting on the implanted catheter and disrupting the sensor-to-blood contact. This study shows that the device is able to accurately and continuously monitor lactate levels during CPB and potentially prevent post-surgery complications in infants.
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Affiliation(s)
| | - Yun-Wen Peng
- Division of Pediatric Cardiology, Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Minyi Ye
- Biocrede Inc., Plymouth, MI 48170, USA
| | - Lise Tchouta
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Bailey Schneider
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - McKenzie Hayes
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - John Toomasian
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Marie Cornell
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alvaro Rojas-Pena
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
- Section of Transplantation, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - John Charpie
- Division of Pediatric Cardiology, Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Hao Chen
- Biocrede Inc., Plymouth, MI 48170, USA
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Farhoudi N, Leu HY, Laurentius LB, Magda JJ, Solzbacher F, Reiche CF. Smart Hydrogel Micromechanical Resonators with Ultrasound Readout for Biomedical Sensing. ACS Sens 2020; 5:1882-1889. [PMID: 32545953 DOI: 10.1021/acssensors.9b02180] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
One of the main challenges for implantable biomedical sensing schemes is obtaining a reliable signal while maintaining biocompatibility. In this work, we demonstrate that a combination of medical ultrasound imaging and smart hydrogel micromechanical resonators can be employed for continuous monitoring of analyte concentrations. The sensing principle is based on the shift of the mechanical resonance frequencies of smart hydrogel structures induced by their volume-phase transition in response to changing analyte levels. This shift can then be measured as a contrast change in the ultrasound images due to resonance absorption of ultrasound waves. This concept eliminates the need for implanting complex electronics or employing transcutaneous connections for sensing biomedical analytes in vivo. Here, we present proof-of-principle experiments that monitor in vitro changes in ionic strength and glucose concentrations to demonstrate the capabilities and potential of this versatile sensing platform technology.
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Affiliation(s)
- Navid Farhoudi
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112, United States
| | - Hsuan-Yu Leu
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah 84112, United States
| | - Lars B. Laurentius
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112, United States
| | - Jules J. Magda
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah 84112, United States
| | - Florian Solzbacher
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112, United States
- Department of Materials Science & Engineering, University of Utah, Salt Lake City, Utah 84112, United States
- Department of Bioengineering, University of Utah, Salt Lake City, Utah 84112, United States
| | - Christopher F. Reiche
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112, United States
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Monitoring with In Vivo Electrochemical Sensors: Navigating the Complexities of Blood and Tissue Reactivity. SENSORS 2020; 20:s20113149. [PMID: 32498360 PMCID: PMC7308849 DOI: 10.3390/s20113149] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 05/29/2020] [Accepted: 05/31/2020] [Indexed: 12/18/2022]
Abstract
The disruptive action of an acute or critical illness is frequently manifest through rapid biochemical changes that may require continuous monitoring. Within these changes, resides trend information of predictive value, including responsiveness to therapy. In contrast to physical variables, biochemical parameters monitored on a continuous basis are a largely untapped resource because of the lack of clinically usable monitoring systems. This is despite the huge testing repertoire opening up in recent years in relation to discrete biochemical measurements. Electrochemical sensors offer one of the few routes to obtaining continuous readout and, moreover, as implantable devices information referable to specific tissue locations. This review focuses on new biological insights that have been secured through in vivo electrochemical sensors. In addition, the challenges of operating in a reactive, biological, sample matrix are highlighted. Specific attention is given to the choreographed host rejection response, as evidenced in blood and tissue, and how this limits both sensor life time and reliability of operation. Examples will be based around ion, O2, glucose, and lactate sensors, because of the fundamental importance of this group to acute health care.
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Hyland SL, Faltys M, Hüser M, Lyu X, Gumbsch T, Esteban C, Bock C, Horn M, Moor M, Rieck B, Zimmermann M, Bodenham D, Borgwardt K, Rätsch G, Merz TM. Early prediction of circulatory failure in the intensive care unit using machine learning. Nat Med 2020; 26:364-373. [DOI: 10.1038/s41591-020-0789-4] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 02/04/2020] [Indexed: 01/12/2023]
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