Calibration-Free Electrochemical Biosensors Supporting Accurate Molecular Measurements Directly in Undiluted Whole Blood

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.

High frequency, calibration-free molecular measurements in situ in the living body

“…vasculature. 24 As expected, while the currents produced by their reporters vary dramatically from sensor to sensor, their ratio is, again, quite reproducible ( Fig. 2A, 1C and D).…”

Single Molecule Profiling of Molecular Recognition at a Model Electrochemical Biosensor

“…The heterogeneous local density of probe molecules was thought to have difficult-to-predict influences on the accessibility of target molecules to the probe molecules (crowding interactions). 9,[16][17] Numerous studies provided indirect evidence that the impacts of the poorly controlled, often heterogeneous spatial organization of probe molecules 18 may be profound: they may not only limit detection sensitivity 4,16 but also be the root cause of the large device-to-device signal variabilities 6,[19][20][21][22] of many of these surface-based sensors devices. Immobilization procedures that enhance probe dispersion 18 were found to improve reproducibility in target binding.…”

Recent Developments of Electrochemical and Optical Biosensors for Antibody Detection

“…Many current biosensor platforms rely on externally labeled biomolecules in order to process a transducing signal [39][40][41][42][43]. A non-label platform was developed to simplify the detection process for pathogens like hantaviruses ( Figure 3c) [44].…”