Superparamagnetic Nanostructures for Split-Type and Competitive-Mode Photoelectrochemical Aptasensing

Abstract

Photoelectrochemical sensing has developed rapidly in the past decade because of its inherent advantages of economic devices and low background noise. However, traditional assembly of photoelectric beacons, probes, and targets on the ITO electrode solid−liquid interface inevitably leads to time-consuming, limited selectivity, poor stability, and nonreproducibility. To overcome these drawbacks, in this work, a unique splittype PEC aptasensor for carcinoembryonic antigen (CEA) was developed in virtue of the sandwich-like structure comprised of magnetic-optical Fe 3 O 4 @SiO 2 @CdS-DNA 1 , CEA aptamer, and signal element SiO 2 −Au-DNA 2 . The sandwich-like structure is easily formed in the liquid phase and can be triggered by competition from low-abundance CEA, resulting in dissociation. By further photocurrent measurement in pure phosphate buffer saline (PBS), coexisting species can be effectively removed from the modified electrode, improving selectivity, stability, and repeatability. These advantages benefit from the preparation of uniform and monodispersed Fe 3 O 4 @SiO 2 @CdS and SiO 2 −Au particles, DNAs assembly, and an elegant design. Additionally, the as-designed signal-on PEC aptasensor is highly sensitive, short time-consuming, and economical, enabling the detection of CEA in serum specimens. It not only provides an alternative to CEA immunosensors, but also paves the way for high-performance PEC aptasensors.

Programmable DNA Circuits for Flexible and Robust Exciton–Plasmon Interaction-Based Photoelectrochemical Biosensing

“…This phenomenon further confirms the superparamagnetic Fe 3 O 4 @SiO 2 . Additionally, the structures of Fe 3 O 4 and Fe 3 O 4 @SiO 2 have been confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) in the previous work …”

“…Additionally, the structures of Fe 3 O 4 and Fe 3 O 4 @SiO 2 have been confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) in the previous work. 54 Assessment of the Entropy-Driven Amplifier. The operation of the as-designed entropy-driven amplifier was assessed by native polyacrylamide gel electrophoresis (PAGE, Figure 2).…”

Electrochemistry/Photoelectrochemistry-Based Immunosensing and Aptasensing of Carcinoembryonic Antigen

“…To date, several detection methods, including electrochemistry (EC)-, photoelectrochemistry (PEC)-, electrochemiluminescence-, surface-enhanced Raman scattering-, fluorescence-, and chemiluminescence-based immunoassays have been utilized to trace CEA detection in the early diagnosis of various cancers [8][9][10][11][12][13]. Among them, electrochemical and photoelectrochemical biosensors, practical and potential analytical techniques, can convert specific analyte information into readable electrical signals, which achieve high sensitivity, low cost, and a small background in comparison with common optical methods [14][15][16][17]. In particular, the proper bio-chemical probes (e.g., antibodies and aptamers) are composed of powerful affinity interactions and satisfactory binding sites and have been regard as indispensable recognition elements in sensing devices [18,19].…”

Magnetic-Assisted Methylene Blue-Intercalated Amplified dsDNA for Polarity-Switching-Mode Photoelectrochemical Aptasensing

“…Such a fabrication approach is doomed to make PEC sensors with disadvantages of complex manufacturing process, long time consumption, limited selectivity, as well as poor reproducibility and stability, which may make the accuracy of test results difficult to meet the requirements of practical application. To address these shortcomings, we constructed a novel split-type and signal-on PEC aptasensor with excellent performance by introduction of superparamagnetic Fe 3 O 4 @SiO 2 particles . As is well known, aptamer is a short chain of DNA or RNA that has high affinity to various targets.…”

“…To address these shortcomings, we constructed a novel split-type and signal-on PEC aptasensor with excellent performance by introduction of superparamagnetic Fe 3 O 4 @ SiO 2 particles. 22 As is well known, aptamer is a short chain of DNA or RNA that has high affinity to various targets. Obviously, it is very convenient to assemble the aptamer to DNA molecular machines for signal amplification.…”