Strategies for Enhancing the Sensitivity of Electrochemiluminescence Biosensors

Abstract

Electrochemiluminescence (ECL) has received considerable attention as a powerful analytical technique for the sensitive and accurate detection of biological analytes owing to its high sensitivity and selectivity and wide dynamic range. To satisfy the growing demand for ultrasensitive analysis techniques with high efficiency and accuracy in complex real sample matrices, considerable efforts have been dedicated to developing ECL strategies to improve the sensitivity of bioanalysis. As one of the most effective approaches, diverse signal amplification strategies have been integrated with ECL biosensors to achieve desirable analytical performance. This review summarizes the recent advances in ECL biosensing based on various signal amplification strategies, including DNA-assisted amplification strategies, efficient ECL luminophores, surface-enhanced electrochemiluminescence, and ratiometric strategies. Sensitivity-enhancing strategies and bio-related applications are discussed in detail. Moreover, the future trends and challenges of ECL biosensors are discussed.

Keywords: DNA; amplification strategy; biosensor; electrochemiluminescence; sensitivity.

Scheme 1

Overview of signal amplification strategies integrated with ECL biosensors for single-signal or multiple-signal outputs.

Figure 1

Example of the sensitive biosensor explored for HIV DNA fragment detection: (A) double recognition-triggered single-target recycling and (B) concatenated DNA structure-controlled rolling circle amplification; (C) construction process of the proposed ECL. Reproduced with permission from [30]. Copyright 2021, American Chemical Society.

Figure 2

Example of the ECL biosensor for ALP detection based on BHCR amplification. Reproduced with permission from [60]. Copyright 2021, American Chemical Society.

Figure 3

Example of the ECL biosensor for miRNA-21 detection based on the DNA walker strategy: (A) generation process of the tripedal DNA walker; (B) walking cycles of the DNA walker. Reproduced with permission from [22]. Copyright 2020, American Chemical Society.

Figure 4

(A) Preparation of the signal probe. (B) Possible mechanism of IRMOF−3 accelerator-mediated enhancement of cTnI detection in the CdTe/S₂O₈²⁻ system. Reproduced with permission from [70]. Copyright 2018, American Chemical Society.

Figure 5

Potential-resolved ratiometric strategy for the detection of miRNA-155. Reproduced with permission from [25]. Copyright 2020, American Chemical Society.

Figure 6

(A) Preparation of Au-g-C₃N₄NSs; (B) fabrication of Ru@TiO₂@Au-Ab2 conjugate; and (C) assembly process of DWR-ECL immunosensor. Reproduced with permission from [88]. Copyright 2021, American Chemical Society.

Figure 7

The proposed SEECL mechanism. Reproduced with permission from [94]. Copyright 2015, Scientific Reports.