Real-Time Tunable Dynamic Range for Calibration-Free Biomolecular Measurements with a Temperature-Modulated Electrochemical Aptamer-Based Sensor in an Unprocessed Actual Sample

Abstract

The sensing technologies for monitoring molecular analytes in biological fluids with high frequency and in real time could enable a broad range of applications in personalized healthcare and clinical diagnosis. However, due to the limited dynamic range (less than 81-fold), real-time analysis of biomolecular concentration varying over multiple orders of magnitude is a severe challenge faced by this class of analytical platforms. For the first time, we describe here that temperature-modulated electrochemical aptamer-based sensors with a dynamically adjustable calibration-free detection window could enable continuous, real-time, and accurate response for the several-hundredfold target concentration changes in unprocessed actual samples. Specifically, we could regulate the electrode surface temperature of sensors to obtain the corresponding dynamic range because of the temperature-dependent affinity variations. This temperature modulation method relies on an alternate hot and cold electrode reported by our group, whose surface could actively be heated and cooled without the need for altering ambient temperature, thus likewise applying for the flowing system. We then performed dual-frequency calibration-free measurements at different interface temperatures, thus achieving an extended detection window from 25 to 2500 μM for procaine in undiluted urine, 1–500 μM for adenosine triphosphate, and 5–2000 μM for adenosine in undiluted serum. The resulting sensor architecture could drastically expand the real-time response range accessible to these continuous, reagent-less biosensors.

Electrochemical Aptamer-Based Sensors with Tunable Detection Range

“…Thus, it is reasonable to regulate the detection range and LOD by controlling the test/immobilization conditions. For example, the incubating or detecting temperature has a linear relationship with the dissociation constant ( K d ) of the aptamer . Thus, it can indirectly affect the detection range of the E-AB sensors.…”

“…Besides, a temperature-dependent signal efficiency has been reported for E-AB sensors, which could also be advantageous to the detection of low target concentration . Based on these mechanisms, Sun et al have realized the modulation of the dynamic range for the detection of urine, adenosine triphosphate, procaine, and adenosine by altering the interface temperature of the electrode (Figure a) . Using the detection of procaine as an example, the dynamic range is 1–50 μM and 100–2500 μM at the temperature of 10 and 35 °C, respectively.…”

“…For example, the incubating or detecting temperature has a linear relationship with the dissociation constant (K d ) of the aptamer. 130 Thus, it can indirectly affect the detection range of the E-AB sensors. Specifically, reducing the incubating or detecting temperature can optimize the stability and thermodynamic equilibrium state of the aptamer−target complex, which could benefit the affinity between the aptamer and the target.…”

“…55 Based on these mechanisms, Sun et al have realized the modulation of the dynamic range for the detection of urine, adenosine triphosphate, procaine, and adenosine by altering the interface temperature of the electrode (Figure 5a). 130 Using the detection of procaine as an example, the dynamic range is 1−50 μM and 100−2500 μM at the temperature of 10 and 35 °C, respectively. Furthermore, employing a variable temperature together with a dualfrequency strategy, the dynamic range of the procaine sensor can be broadened to 200-fold.…”

Electrochemical Aptamer Biosensor Based on ATP-Induced 2D DNA Structure Switching for Rapid and Ultrasensitive Detection of ATP

“…Adenosine triphosphate (ATP) as the energy currency is an essential small biological molecule in living organisms, − which plays an important role in regulating cell metabolism, participating in all kinds of enzyme reactions and guiding the life activities of tissues and cells. , An abnormal level of ATP has been demonstrated to be relevant to many diseases, such as Parkinson’s disease, Alzheimer’s disease, and angiocardiopathy. − Hence, it is of great significance for human health to establish rapid, sensitive, and specific analytical methods for ATP detection. Nowadays, the aptamer-based methods have attracted wide and increasing attention due to the advantages of aptamer, like their small size, high stability, easy synthesis, high designability, and low cost. − The biosensors coupled with aptamer strategies have been employed to specifically detect ATP based on the distinctive binding affinity between ATP and the aptamer. − However, the traditional aptamer biosensors always suffered from slow detection speed and low sensitivity tissues due to the deficient binding affinity of ATP and weak capture efficiency of ATP, as well as low loading capacity of molecular beacons. Therefore, it is urgently required to develop a new type of DNA structure that could not only significantly improve the capture efficiency and binding affinity of the target ATP, but also enhance the loading capacity of the signal molecule for the great promotion of detection speed and sensitivity.…”