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Vargas E, Aiello EM, Ben Hassine A, Ruiz-Valdepeñas Montiel V, Pinsker JE, Church MM, Laffel LM, Doyle FJ, Patti ME, Dassau E, Wang J. Concept of the "Universal Slope": Toward Substantially Shorter Decentralized Insulin Immunoassays. Anal Chem 2022; 94:9217-9225. [PMID: 35715001 DOI: 10.1021/acs.analchem.2c02178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Decentralized sensing of analytes in remote locations is today a reality. However, the number of measurable analytes remains limited, mainly due to the requirement for time-consuming successive standard additions calibration used to address matrix effects and resulting in greatly delayed results, along with more complex and costly operation. This is particularly challenging in commonly used immunoassays of key biomarkers that typically require from 60 to 90 min for quantitation based on two standard additions, hence hindering their implementation for rapid and routine diagnostic applications, such as decentralized point-of-care (POC) insulin testing. In this work we have developed and demonstrated the theoretical framework for establishing a universal slope for direct calibration-free POC insulin immunoassays in serum samples using an electrochemical biosensor (developed originally for extended calibration by standard additions). The universal slope is presented as an averaged slope constant, relying on 68 standard additions-based insulin determinations in human sera. This new quantitative analysis approach offers reliable sample measurement without successive standard additions, leading to a dramatically simplified and faster assay (30 min vs 90 min when using 2 standard additions) and greatly reduced costs, without compromising the analytical performance while significantly reducing the analyses costs. The substantial improvements associated with the new universal slope concept have been demonstrated successfully for calibration-free measurements of serum insulin in 30 samples from individuals with type 1 diabetes using meticulous statistical analysis, supporting the prospects of applying this immunoassay protocol to routine decentralized POC insulin testing.
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Affiliation(s)
- Eva Vargas
- Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
| | - Eleonora M Aiello
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Allston, Massachusetts 02134, United States.,Sansum Diabetes Research Institute, Santa Barbara, California 93105, United States
| | - Amira Ben Hassine
- Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
| | | | - Jordan E Pinsker
- Sansum Diabetes Research Institute, Santa Barbara, California 93105, United States
| | - Mei Mei Church
- Sansum Diabetes Research Institute, Santa Barbara, California 93105, United States
| | - Lori M Laffel
- Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts 02215, United States
| | - Francis J Doyle
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Allston, Massachusetts 02134, United States.,Sansum Diabetes Research Institute, Santa Barbara, California 93105, United States
| | - Mary-Elizabeth Patti
- Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts 02215, United States
| | - Eyal Dassau
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Allston, Massachusetts 02134, United States.,Sansum Diabetes Research Institute, Santa Barbara, California 93105, United States
| | - Joseph Wang
- Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
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Clark KM, Henry CS. Thermoplastic Electrode (TPE)‐based Enzymatic Glucose Sensor Using Polycaprolactone‐graphite Composites. ELECTROANAL 2021. [DOI: 10.1002/elan.202100446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Kaylee M. Clark
- Department of Chemistry Colorado State University 1872 Campus Delivery Fort Collins 80523 Colorado USA
| | - Charles S. Henry
- Department of Chemistry Colorado State University 1872 Campus Delivery Fort Collins 80523 Colorado USA
- School of Biomedical Engineering Colorado State University Fort Collins 80523 Colorado USA
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Idili A, Parolo C, Ortega G, Plaxco KW. Calibration-Free Measurement of Phenylalanine Levels in the Blood Using an Electrochemical Aptamer-Based Sensor Suitable for Point-of-Care Applications. ACS Sens 2019; 4:3227-3233. [PMID: 31789505 PMCID: PMC8097980 DOI: 10.1021/acssensors.9b01703] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
By analogy to the revolution the "home glucose monitor" created in the treatment of diabetes, the availability of a modular, "platform" technology able to measure nearly any metabolite, biomarker, or drug "at-home" in unprocessed, finger-prick volumes of whole blood could revolutionize the monitoring and treatment of disease. Thus motivated, we have adapted here the electrochemical aptamer-based sensing platform to the problem of rapidly and conveniently measuring the level of phenylalanine in the blood, an ability that would aid the monitoring and management of phenylketonuria (PKU). To achieve this, we exploited a previously reported DNA aptamer that recognizes phenylalanine in complex with a rhodium-based "receptor" that improves affinity. We re-engineered this to undergo a large-scale, binding-induced conformational change before modifying it with a methylene blue redox reporter and attaching it to a gold electrode that supports the appropriate electrochemical interrogation. The resultant sensor achieves a useful dynamic range of 90 nM to 7 μM. When challenged with finger-prick-scale sample volumes of the whole blood (diluted 1000-fold to match the sensor's dynamic range), the device achieves the accurate (±20%), calibration-free measurement of blood phenylalanine levels in minutes.
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Affiliation(s)
- Andrea Idili
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
- Center for Bioengineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Claudio Parolo
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
- Center for Bioengineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Gabriel Ortega
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
- Center for Bioengineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Kevin W. Plaxco
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
- Center for Bioengineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
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Li H, Dauphin-Ducharme P, Ortega G, Plaxco KW. Calibration-Free Electrochemical Biosensors Supporting Accurate Molecular Measurements Directly in Undiluted Whole Blood. J Am Chem Soc 2017; 139:11207-11213. [PMID: 28712286 DOI: 10.1021/jacs.7b05412] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The need to calibrate to correct for sensor-to-sensor fabrication variation and sensor drift has proven a significant hurdle in the widespread use of biosensors. To maintain clinically relevant (±20% for this application) accuracy, for example, commercial continuous glucose monitors require recalibration several times a day, decreasing convenience and increasing the chance of user errors. Here, however, we demonstrate a "dual-frequency" approach for achieving the calibration-free operation of electrochemical biosensors that generate an output by using square-wave voltammetry to monitor binding-induced changes in electron transfer kinetics. Specifically, we use the square-wave frequency dependence of their response to produce a ratiometric signal, the ratio of peak currents collected at responsive and non- (or low) responsive square-wave frequencies, which is largely insensitive to drift and sensor-to-sensor fabrication variations. Using electrochemical aptamer-based (E-AB) biosensors as our test bed, we demonstrate the accurate and precise operation of sensors against multiple drugs, achieving accuracy in the measurement of their targets of within better than 20% across dynamic ranges of up to 2 orders of magnitude without the need to calibrate each individual sensor.
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Affiliation(s)
- Hui Li
- Faculty of Materials Science and Chemistry, China University of Geosciences , Wuhan 430074, China.,Department of Chemistry and Biochemistry, University of California Santa Barbara , Santa Barbara, California 93106, United States.,Center for Bioengineering, University of California Santa Barbara , Santa Barbara, California 93106, United States
| | - Philippe Dauphin-Ducharme
- Department of Chemistry and Biochemistry, University of California Santa Barbara , Santa Barbara, California 93106, United States.,Center for Bioengineering, University of California Santa Barbara , Santa Barbara, California 93106, United States
| | - Gabriel Ortega
- Department of Chemistry and Biochemistry, University of California Santa Barbara , Santa Barbara, California 93106, United States.,Center for Bioengineering, University of California Santa Barbara , Santa Barbara, California 93106, United States.,CIC bioGUNE , Bizkaia Technology Park, Building 801 A, 48170 Derio, Spain
| | - Kevin W Plaxco
- Department of Chemistry and Biochemistry, University of California Santa Barbara , Santa Barbara, California 93106, United States.,Center for Bioengineering, University of California Santa Barbara , Santa Barbara, California 93106, United States
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