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Review

Electrochemical Signal Substance for Multiplexed Immunosensing Interface Construction: A Mini Review

by
Jiejie Feng
,
Changshun Chu
and
Zhanfang Ma
*
Department of Chemistry, Capital Normal University, Beijing 100048, China
*
Author to whom correspondence should be addressed.
Molecules 2022, 27(1), 267; https://doi.org/10.3390/molecules27010267
Submission received: 6 December 2021 / Revised: 23 December 2021 / Accepted: 30 December 2021 / Published: 2 January 2022
(This article belongs to the Section Electrochemistry)
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Abstract

:
Appropriate labeling method of signal substance is necessary for the construction of multiplexed electrochemical immunosensing interface to enhance the specificity for the diagnosis of cancer. So far, various electrochemical substances, including organic molecules, metal ions, metal nanoparticles, Prussian blue, and other methods for an electrochemical signal generation have been successfully applied in multiplexed biosensor designing. However, few works have been reported on the summary of electrochemical signal substance applied in constructing multiplexed immunosensing interface. Herein, according to the classification of labeled electrochemical signal substance, this review has summarized the recent state-of-art development for the designing of electrochemical immunosensing interface for simultaneous detection of multiple tumor markers. After that, the conclusion and prospects for future applications of electrochemical signal substances in multiplexed immunosensors are also discussed. The current review can provide a comprehensive summary of signal substance selection for workers researched in electrochemical sensors, and further, make contributions for the designing of multiplexed electrochemical immunosensing interface with well signal.

1. Introduction

Cancer is one of the main causes of human death, and its accurate diagnosis always requires a comprehensive monitor for correlative biomarkers [1,2,3]. However, in the present detection of cancer biomarkers, most immunoassays have focused on the improvement of analysis performance, including the limit of detection, detection range, sensitivity or other parameters, and exploitation of novel immunoassay methodologies to contrapose the analysis of single tumor marker [4,5,6,7]. In fact, most cancers have more than one tumor marker associated with their occurrence, and many markers are correlated to more than one kind of cancer or disease condition [8,9,10]. No single tumor marker can specifically meet the exact diagnosis standard, so that many false negative or positive perceptions have been inevitably caused in the traditional single-target immunoassay [11,12,13]. Hence, for the sake of the accurate diagnosis of cancer, an increasing number of analytical techniques like fluorescence [14,15,16], electrochemiluminescence [17,18,19], enzyme-linked immune-sorbent [20,21,22], electrochemistry [23,24,25], and mass spectrometry [26,27] and some others have been designed to satisfy the need for the simultaneous detection of multifarious tumor markers, which are interrelated to provide more numerical references for one cancer. Among the subsistent detection method for cancer biomarkers detection, the electrochemical method has been successfully developed as a sophisticated tool on account of its highly sensitive, superior selective, fast response, and simple operation, efficaciously achieving the accurate diagnosis of cancer [28,29,30,31].
Sensitivity, as the crucial parameter for the evaluation of an electrochemical immunosnesor, is always defined as the signal variation caused by the incubation of antigen per unit concentration [32,33,34,35]. High sensitivity is beneficial for the accurate detection of multiple tumor markers [36,37,38]. Labeling of electrochemical signal substance, a necessary step in the construction of electrochemical immunosening interface [39,40], is closely associated with the final readout of electrochemical signal to influence the sensitivity of immunosensor [41,42]. However, to simultaneously determine the content of multiple tumor markers with high sensitivity, it may demand the labeling of multiple sorts of signal substance or construct one signal-labeled pervasive immunoassay array so that the requirements for the electrochemical signal substance always need convenient loading, easy availability, and excellent electro-redox characterizations [43,44]. Hence, the selection of signal substance is vital to construct an electrochemical immunosensing interface for the analysis of multiple tumor markers.
In this review, we have condensed on the recent advances for the application of an electrochemical signal substance to construct multiplexed electrochemical immunosensing interface, including the usage of dyestuff molecules (methylene blue (MB), thionine (THI)), metal ions (copper(II) ions, lead(II) ions, titanium(IV) ions, cadmium(II) ions, and zinc(II) ions), metal nanoparticles (silver nanoparticle and copper nanoparticle), and other synthesized electroactive materials like Prussian blue. Besides, the current challenges and future prospects are also summarized and discussed. This timely review is aimed to provide a table of reported signal substances used in multiplexed electrochemical immunosensor and help researchers design excellent immunosensing interfaces with good signaling in the future.

2. Electrochemical Signal Substances for Multiplexed Immunoassay

2.1. Organic Molecules

Organic molecules, as the most common redox species, often serve as the electrochemical signal substance to construct the immunosensing interface [45,46]. Among the organic molecules, dyestuff like MB [47,48] and THI [49,50], and other organic redox compounds like ferrocene, are the most representative on account of their easy accessibility, simple loading method, and excellent redox spikes [51,52]. Kong et al. once used MB and THI as the electroactive labels to construct a multiplexed electrochemical immunosensing interface for the simultaneous detection of carcinoembryonic antigen (CEA) and α-fetoprotein (AFP) [53]. They have employed the carboxyl graphene nanosheets (GS) as the substrate materials to load MB and THI molecules, respectively, finally preparing the carboxyl graphene nanosheets-methylene blue (CGS-MB) and carboxyl graphene nanosheets-Prussian Blue (CGS-PB) nanocomposites. For the subsequent process of immune incubation, the carboxyl groups on the GS surface were used as the anchors to fix the coating antibody (Ab1), finally constructing such two sorts of immunosensing interfaces. Meanwhile, these two peaks (related to the reduction of PB and MB) were posited at +0.24 V and −0.33 V after a Differential Pulse Voltammetry (DPV) test, indicating the content of AFP and CEA, respectively. With this method, this immunosensor exhibited an excellent detection performance (a wide detection range of 0.8–80 ng mL−1 for CEA and 0.5–50 ng mL−1 for AFP).
Besides the labeling of methylene blue molecules, Alizadeh et al. reported a sandwich-type electrochemical immunoassay based on two categories of multi-functionalized gold nanoparticles (Au NPs) for simultaneous determination of CEA and AFP (Figure 1(1)) [54]. They fabricated this sensor in virtue of co-immobilization of coating anti-CEA and labeling anti-AFP antibodies on the surface of Fe3O4 NPs and prepared two tags, including thionine-Au NPs and ferrocene-Au NPs employed as the distinguishable labels to indicate the content of CEA and AFP, respectively (Figure 1(3)). Then, in order to testify the feasibility of this experimental mechanism, a series of different concentrations for biomarkers were incubated, and hence corresponding current responses were gradually increased, as shown in Figure 1(2).
Another interesting example reported the four kinds of redox bioprobes as the tool for simultaneously detecting CEA, carbohydrate antigen (CA) 19-9, 12-5, and 24-2 [55]. With the marking of four electroactive species including anthraquinone 2-carboxylic acid, THI, tris(2,2(-bipyridine-4,4(-dicarboxylic acid) cobalt(III) and ferrocenecarboxylic acid, labeling antibodies (Ab2) for CEA, CA 19-9, CA 12-5, and CA 24-2 can be efficaciously labeled to prepare four redox substance@Ab2 bioconjugates, and subsequently these bioconjugates were composited with carbon nanotubes (CNTs), which were linked with poly(diallyldimethylammonium chloride) (PDDA), 3,4,9,10-perylenetetracarboxylic acid (PTCA) and AuNPs, to form the final functional immunoprobes. Besides the above design, the glass carbon electrode (GCE) modified by Au NPs was adopted as an ordinary substrate to link with the Ab1. Once the sandwich bioconjugates were formed and readout in an electrolyte solution, DPV scan exhibited four well-resolved peaks to indicate the content of responsive antigen (Peaks posited at −0.52V, −0.21V, 0.0V, and 0.26V were corresponding to the CEA, CA 19-9, CA 12-5, and CA 24-2). Importantly, various ingredients in bioprobes can greatly accelerate the electron transfer, and the effect on DPV responses was verified, revealing that the current response was gradually increased as the assembly of Au NPs, PDDA/CNTs, and PTCA in turn. In addition, the cross-reactivity for the immunoassay was also verified to be well by testing the effects of coexistent analytes on the signal for each immunoreaction, the changes of the current response for CEA, CA 19-9, CA 12-5, and CA 72-4 were less than 1.3%, 2.1%, 2.6%, and 1.4%, respectively. Non-specific interference (Bovine Serum Albumin (BSA), AFP, and prostate-specific antigen (PSA)) test was also finally tested to be excellent by adding various noncognate proteins to mixed target analytes. With the assistance of this designing strategy, the proposed multiple immunosensor displayed a series of wide detection ranges: 0.016 to 15 ng mL-1 for CEA, 0.008 to 10 ng mL−1 for CA 19-9, 0.012 to 12 ng mL−1 for CA 12-5, and 0.01 to 10 ng mL−1 for CA 24-2.
Based on the labeling of organic molecules, the multiplexed immunosensor all exhibited considerable electrochemical signals, which can be independently present at the corresponding position. Especially for the organic dyestuff, they can generate a high current value even if it was the trace.

2.2. Metal Ions

Metal ions possess good electrochemical redox activity, which makes them ideal materials as electrochemical signal substances [56,57]. With the advantages of easy accessibility and generated sharp electrochemical signal peaks, metal ions like silver ions, copper(II) ions, lead(II) ions usually serve as the excellent labels to indicate the content of multiple biomarkers [58,59,60,61]. Our group has come up with a method based on the chip-like GCE composed of three electrodes connected in a parallel for simultaneous detection [43]. Based on a novel redox-active hydrogel containing such metal ions (copper(II) ions, lead(II) ions, and titanium(IV) ions) and sodium alginate (SA) (Figure 2(1)), this analysis of multiple targets (CEA, Neuron specific enolase (NSE), Cytokeratin 19 fragments (CYFRA 21-1)) adopted a series improvement for the GCEs, synchronously obtaining three current peaks located at 0, −0.45 and −0.75 V (vs. Ag/AgCl) (Figure 2(2A)). With this method, they have successfully accomplished the assembly of an immunosensor (Figure 2(2B)) and got a series of proportion relations between tumor markers and responsive current, improving the accurate diagnosis for lung cancer.
Besides, a multiplexed electrochemical immunosensing interface based on metal ions doped chitosan-poly(acrylic acid) nanospheres (CP) was proposed for the simultaneous detection of CEA, CA 19-9, CA 12-5, and CA 24-2 [62]. As depicted in Figure 3, with the crosslinking of glutaraldehyde (GA), four types of metal ions doped CP nanospheres were combined with different Ab2 to synthesize the new immuoprobes, and chitosan-Au NPs were used as a common substrate to fix on the Ab1. Once sandwich conjugate was formed, four independent potential peaks were produced by copper(II), lead(II), cadmium(II), and zinc(II) ions when the whole system was readout with the Square wave voltammograms (SWV) method, indicating the content of CEA, CA 19-9, CA 12-5, and CA 24-2, respectively. Notably, the preparation of the metal ions doped CP composites was first reported by this work and successfully used as the electrochemical signals. With this design, the proposed electrochemical immunosensor exhibited wide linear ranges towards these four biomarkers: 0.1 to 150 ng mL−1 for CEA, 1 to 150 U mL−1 for CA 19-9, CA 12-5, and CA 24-2.
In addition, Putnin prepared a sort of dually functional polyethylenimine (PEI)-coated gold nanoparticles as immunoprobes, using the strong electrostatic adsorption to loading of four different types of metal ions, including lead(II) ions, copper(II) ions, cadmium(II) ions, and silver ions [63]. On account of four independent voltammetric signals generated by these four metal ions, which were posited at −0.80, −0.55, −0.20, and +0.05 V, respectively, this multiplexed electrochemical immunosensor can efficaciously detect AFP, CEA, PSA, and interleukin-8 (IL-8).
Metal ions, as the common electrochemical signal substance, have been maturely applied into the labeling of immunosensing interface, especially for the silver ions and copper(II) ions, all can generate sharp and strong electrochemical signal peaks. Besides, metal ions like copper(II) ions also own the excellent catalytic activity to some substrates, for example, hydrogen peroxide.

2.3. Metal Nanoparticles

With the advantages of small size, high surface-to-bulk ratio, interesting electric and catalytic properties, metal nanoparticles attract much attention and have been widely used as promising electrochemical signal substances [64,65,66]. Besides, metal nanoparticles as sensing elements can serve as an excellent anchor to fix biomolecules or be directly electrodeposited on immunosensing interfaces to become the electrochemical signal indicator [67,68,69]. Hence, by employing a cascade reaction to form silver nanoparticles, a multiplexed immunosensor array fabricated on a carbon electrode array was prepared with screen-printed technology to simultaneously detect CEA, CA 15-3, and CA 12-5, using the measurement of linear-sweep stripping voltammetric (LSV) [70]. Concretely, pretreated screen-printed carbon electrodes (SPCEs) were covered with the Au NPs/graphene (GR) to serve as the substrate to fix Ab1. Once the 3-indoxyl phosphate (3-IP) and silver ions were present in this sensor system, 3-IP was quickly hydrolyzed and produced an indoxyl intermediate which can subsequently reduce silver ions to get a silver deposition. For the synthesis of immunoprobes, many uniform Au NPs were in situ synthesized on the surface of pretreated GR and used to immobilize Ab2 and alkaline phosphatase (ALP), finally preparing a catalytic probe. Finally, this electrochemical multiple immunosensor exhibited a limit detection of 0.0015 U mL−1 for CA 15-3, 0.00034 U mL−1 for CA 12-5, and 0.0012 ng mL−1 for CEA.
Besides, Lai and coworkers constructed a multiplexed immunosensing interface based on the SPCEs, using deposited silver nanoparticles as the electrochemical labels to indicate the content of CEA and AFP, respectively (Figure 4) [71]. With the assistance of the chemical coupling of GA, the Ab1 of CEA and AFP were fixed on the surface of SPCEs, and sandwich composites were subsequently formed after the process of silver deposition had been accomplished. Thanks to the fact that deposited silver nanoparticles could be directly measured by LSV to generate a sharp and high-signal peak, the proposed multiplexed immunoassay method showed low detection limits down to 3.5 and 3.9 pg mL−1, respectively.
For the multiplexed electrochemical immunosensor based on the labeling of metal nanoparticles, the electrochemical signal can be present in a variety of ways, such as nitrification of metal nanoparticles to generate metal ions and the replacement reaction between the inert metal ions and active metal, simultaneously can well serve as the anchors to fix biomolecules.

2.4. Prussian Blue

Prussian blue (PB) nanoparticles, an iron-based nanomaterial, also serve as an inherent electrochemical activity [72,73]. Since Neff firstly reported the electrochemical behavior of PB and the successful deposition of a thin layer of PB on a platinum foil in 1978 [74], the wide application of PB has been promoted in various construction of electrochemical immunosensing interface, especially for its development in multiplexed electrochemical immunoassay [75,76]. Moreover, for the modification ways of PB on an electrode surface, there are two main sorts of common methods, including post-modification [77,78] and in-situ preparation [79,80], and both of them can generate the legible signal peaks. For example, Lai and coworkers reported on an ultrasensitive multiplexed electrochemical immunosensing interface to simultaneously detect CEA and AFP [81]. By developing a dual signal amplification tracer based on glucose oxidase (GOD)-functionalized carbon nanotubes, the PB-mediated electron transfer process can be effectively accelerated to improve the detection performance of the whole immunoassay array (Figure 5(2)). To prepare this signal substrate, they synthesized uniform and nanosized PB nanoparticles in a PDDA and chitosan (1% HAc solution) and directly dropped them on the surface of SPCEs (Figure 5(1)). With a DPV measurement, PB in this signal substrate was well readout and generated an excellent signal peak at about +0.05V. Interestingly, this immunoassay array can complete the analysis of multiple biomarkers by selecting only one electrochemical signal substance as a label, avoiding the fussy labeling of different electrochemical signal substances.
The PB-constructed signal substrate can also be used in preparing a label-free microfluidic paper-based electrochemical aptasensor. Wang et al. successfully fabricated a paper device with microfluidic channels while a three-electrode system was made by the screen-printing method [82]. As illustrated in Figure 6, two sorts of working electrodes were modified by different substrate materials (amino-functional graphene-thionine and PB-poly(3,4-ethylenedioxythiophene) (PEDOT)), detecting CEA and NSE in a clinical sample, respectively. Just for the addition of PEDOT, it not only facilitated electron transfer capability during the readout of electrochemical signal but also increased the amount of immobilized aptamers, thus increasing the sensitivity of the electrochemical immunosensing interface for detecting NSE.
Prussian blue, whether it is post-synthesis or in-situ preparation, can all generate an electrochemical signal. The rise of its derivatives has promoted the sensitive detection of multiple tumor markers based on the multiplexed immunosensing interface.

2.5. Other Substance for Electrochemical Signal Generation

As a substitute for biozyme, some artificial nanozymes have been widely applied to the designing of multiplexed electrochemical immunosensing interfaces due to their considerable environmental tolerance, easy storage, and ideal catalytic activity [83,84,85]. Except for the aforementioned ways in which electrochemical signals are generated by the redox of electroactive species, nanozymes with peroxidase-like activity can also catalyze the H2O2 to generate current variation with an i-t measurement [86,87]. Employing the platinum nanoparticle-functionalized mesoporous silica (Pt@SBA-15) to form an immunosensor array has been successfully used for the simultaneous determination of different analytes. Ma and coworkers used Pt@SBA-15 as a label to improve the limited stability of the process in which biozyme is attached to the Ab2 with a time-consuming, costly labeling process that often leads to the denaturization of the biomolecules [88]. Benefiting from this label, this multiplexed electrochemical immunosensing interface showed low detection limits for diethylstilbestrol (0.28 pg mL−1) and estradiol (1.2 pg mL−1).
Besides the aforementioned Pt nanozymes with peroxidase-like activity, Sun and coworkers proposed a multiplexed enzyme-free electrochemical immunosensor based on the ZnO nanorods modified reduced graphene oxide-paper electrode, using the catalytic amplification strategy induced by BSA-stabilized silver nanoparticles (Figure 7) [89]. Because of the existence of silver nanoparticles, H2O2 can be well reduced to induce a current response. With this strategy, the proposed multiplexed immunosensor exhibited a wide linear range of 0.002–120 mIU mL−1 for human chorionic gonadotropin (HCG), 0.001–110 ng mL−1 for PSA, and 0.001–100 ng mL−1 for CEA.
In consideration of some nanozymes prepared with noble metals like Pt and Pd; it is necessary for future studies to develop artificial nanozymes based on the advantages of low-cost, high catalysis activity. Catalytic-amplification system is an excellent mediator to sensitively detect multiple tumor markers and deserves to be promoted in more analysis fields, like inorganic molecules detection.

3. Conclusions and Future Prospects

Overall, we have summarized recent advances in the labeling of electrochemical signal molecules for the analysis of multiple tumor markers. We fully introduced the characterizations of every signal material, including organic molecules, metal ions, metal nanoparticles, Prussian blue, and other substances for signal generation, and discussed their concrete application (such as the participation of immunoprobe synthesis, substrate construction) in designing electrochemical immunosensing interface (Table 1). However, for the labeling of electrochemical signal substances for multiplexed immunosensors, there are some challenges that still need to be solved. (1) Existing fixation methods of signal substance always have the deficiencies, such as the unstable physisorption to cause leakage, fussy covalent bonding to lead time-consuming. Hence, developing good stability and a time-saving labeling method is necessary for improving the readout of the electrochemical signal method. (2) Considering the pollution problem of organic molecules or heavy metal ions (such as methylene blue, thionine, and lead ions, etc.), it is recommended to design a signal attenuation interface (it can effectively degrade the harmful signal substance to reduce electrochemical signal) or reproducible interface (it can reuse these signal labels).

Author Contributions

Conceptualization and constructive comments, J.F. and C.C.; data collection, J.F. and C.C.; writing—original draft preparation, J.F.; writing—review and editing, J.F. and Z.M.; supervision, Z.M.; project administration, Z.M.; funding acquisition, Z.M. All authors have read and agreed to the published version of the manuscript.

Funding

This research was financed by grants from the Joint Project of Beijing Municipal Education Commission and Beijing Natural Science Foundation (KZ202110028042), National Natural Science Foundation of China (22172104), and Capacity Building for Sci-Tech Innovation-Fundamental Scientific Research Funds (20530290087, 20530290055).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

No new data were created or analyzed in this study. Data sharing is not applicable to this article.

Conflicts of Interest

The author declares there are no conflicts of interest.

Abbreviations

Ab1Coating antibody
Ab2 Labeling antibodies
AFP α α-fetoprotein
ALP Alkaline phosphatase
BSA Bovine Serum Albumin
CA Carbohydrate antigen
CEA Carcinoembryonic antigen
CGS-MB Carboxyl graphene nanosheets-methylene blue
CGS-PB Carboxyl graphene nanosheets-Prussian Blue
CNTs Carbon nanotubes
CP Chitosan-poly(acrylic acid) nanospheres
CYFRA 21-1Cytokeratin 19 fragments
DPV Differential Pulse Voltammetry
GA Glutaraldehyde
GCE Glass carbon electrode
GOD Glucose oxidase
GR Graphene
GS Graphene nanosheets
HCG Human chorionic gonadotropin
IL-8 Interleukin-8
LSV Linear-sweep stripping voltammetric
MB Methylene blue
NPs Nanoparticles
NSE Neuron specific enolase
PDDA Poly(diallyldimethylammonium chloride)
PEDOT Poly(3,4-ethylenedioxythiophene)
PSA prostate specific antigen
PTCA 3,4,9,10-perylenetetracarboxylic acid
Pt@SBA-15 Platinum nanoparticle-functionalized mesoporous silica
TB Toluidine blue
THI Thionine
SA Sodium alginate
SPCEs Screen-printed carbon electrodes
SWV Square wave voltammograms

References

  1. Pashayan, N.; Pharoah, P. The challenge of early detection in cancer. Science 2020, 368, 589–590. [Google Scholar] [CrossRef]
  2. Kalinich, M.; Haber, D.A. Cancer detection: Seeking signals in blood. Science 2018, 359, 866–867. [Google Scholar] [CrossRef]
  3. Brentnall, T.A. Progress in the Earlier Detection of Pancreatic Cancer. J. Clin. Oncol. 2016, 34, 1973–1974. [Google Scholar] [CrossRef]
  4. Chikkaveeraiah, B.V.; Bhirde, A.A.; Morgan, N.Y.; Eden, H.S.; Chen, X.Y. Electrochemical immunosensors for detection of cancer protein biomarkers. ACS Nano 2012, 6, 6546–6561. [Google Scholar] [CrossRef] [Green Version]
  5. Farka, Z.; Jurik, T.; Kovar, D.; Trnkova, L.; Skladal, P. Nanoparticle-based immunochemical biosensors and assays: Recent advances and challenges. Chem. Rev. 2017, 117, 9973–10042. [Google Scholar] [CrossRef] [PubMed]
  6. Yu, X.; Munge, B.; Patel, V.; Jensen, G.; Bhirde, A.; Gong, J.D.; Kim, S.N.; Gillespie, J.; Gutkind, J.S.; Papadimitrakopoulos, F.; et al. Carbon nanotube amplification strategies for highly sensitive immunodetection of cancer biomarkers. J. Am. Chem. Soc. 2006, 128, 11199–11205. [Google Scholar] [CrossRef] [Green Version]
  7. Zhao, C.; Li, X.; An, S.; Zheng, D.; Pei, S.; Zheng, X.; Liu, Y.; Yao, Q.; Yang, M.; Dai, L. Highly sensitive and selective electrochemical immunosensors by substrate-enhanced electroless deposition of metal nanoparticles onto three-dimensional graphene@Ni foams. Sci. Bull. 2019, 64, 1272–1279. [Google Scholar] [CrossRef] [Green Version]
  8. Cheng, L.; Song, S.-Y.; Pretlow, T.G.; Abdul-Karim, F.W.; Kung, H.-J.; Dawson, D.V.; Park, W.-S.; Moon, Y.-W.; Tsai, M.-L.; Linehan, W.-M.; et al. Evidence of independent origin of multiple tumors from patients with prostate cancer. J. Natl. Cancer Inst. 1998, 90, 233–247. [Google Scholar] [CrossRef] [Green Version]
  9. Shen, C.; Che, G. A different method in diagnosis of Multiple Primary Lung Cancer. J. Thorac. Oncol. 2016, 11, 53–54. [Google Scholar] [CrossRef] [Green Version]
  10. Zhang, C.; Yin, K.; Liu, S.Y.; Yan, L.X.; Su, J.; Wu, Y.L.; Zhang, X.C.; Zhong, W.Z.; Yang, X.N. Multiomics analysis reveals a distinct response mechanism in multiple primary lung adenocarcinoma after neoadjuvant immunotherapy. J. Immunother. Cancer 2021, 9, 1–6. [Google Scholar] [CrossRef] [PubMed]
  11. Zhao, L.; Han, H.; Ma, Z. Improved screen-printed carbon electrode for multiplexed label-free amperometric immuniosensor: Addressing its conductivity and reproducibility challenges. Biosens. Bioelectron. 2018, 101, 304–310. [Google Scholar] [CrossRef]
  12. Guo, W.; Ding, H.; Gu, C.; Liu, Y.; Jiang, X.; Su, B.; Shao, Y. Potential-resolved multicolor electrochemiluminescence for multiplex immunoassay in a single sample. J. Am. Chem. Soc. 2018, 140, 15904–15915. [Google Scholar] [CrossRef]
  13. Yang, S.M.; Lin, Q.; Zhang, H.; Yin, R.; Zhang, W.; Zhang, M.; Cui, Y. Dielectrophoresis assisted high-throughput detection system for multiplexed immunoassays. Biosens. Bioelectron. 2021, 180, 113148. [Google Scholar] [CrossRef]
  14. Wu, Z.; Zeng, T.; Guo, W.J.; Bai, Y.Y.; Pang, D.W.; Zhang, Z.L. Digital single virus immunoassay for ultrasensitive multiplex avian influenza virus detection based on fluorescent magnetic multifunctional nanospheres. ACS Appl. Mater. Interfaces 2019, 11, 5762–5770. [Google Scholar] [CrossRef]
  15. Zhang, B.; Yang, J.; Zou, Y.; Gong, M.; Chen, H.; Hong, G.; Antaris, A.L.; Li, X.; Liu, C.-L.; Chen, C.; et al. Plasmonic micro-beads for fluorescence enhanced, multiplexed protein detection with flow cytometry. Chem. Sci. 2014, 5, 4070–4075. [Google Scholar] [CrossRef]
  16. Xu, S.; Feng, X.; Gao, T.; Liu, G.; Mao, Y.; Lin, J.; Yu, X.; Luo, X. Aptamer induced multicoloured Au NCs-MoS2 “switch on” fluorescence resonance energy transfer biosensor for dual color simultaneous detection of multiple tumor markers by single wavelength excitation. Anal. Chim. Acta 2017, 983, 173–180. [Google Scholar] [CrossRef] [PubMed]
  17. Zhang, Y.; Liu, W.; Ge, S.; Yan, M.; Wang, S.; Yu, J.; Li, N.; Song, X. Multiplexed sandwich immunoassays using flow-injection electrochemiluminescence with designed substrate spatial-resolved technique for detection of tumor markers. Biosens. Bioelectron. 2013, 41, 684–690. [Google Scholar] [CrossRef]
  18. Lv, W.; Ye, H.; Yuan, Z.; Liu, X.; Chen, X.; Yang, W. Recent advances in electrochemiluminescence-based simultaneous detection of multiple targets. Trends Anal. Chem. 2020, 123, 115767. [Google Scholar] [CrossRef]
  19. Zhao, J.W.; Du, J.W.; Luo, J.H.; Chen, S.H.; Yuan, R. A novel potential-resolved electrochemiluminescence immunosensor for the simultaneous determination of brain natriuretic peptide and cardiac troponin I. Sens. Actuators B Chem. 2020, 311, 127934. [Google Scholar] [CrossRef]
  20. Dzgoev, A.; Mecklenburg, M.; Xie, B.; Miyabayashib, A.; Larsson, P.-O.; Danielsson, B. Optimization of a charge coupled device imaging enzyme linked immuno sorbent assay and supports for the simultaneous determination of multiple 2,4-D samples. Anal. Chim. Acta 1997, 347, 87–93. [Google Scholar] [CrossRef]
  21. Gao, L.; Yang, Q.; Wu, P.; Li, F. Recent advances in nanomaterial-enhanced enzyme-linked immunosorbent assays. Analyst 2020, 145, 4069–4078. [Google Scholar] [CrossRef]
  22. Li, C.; Yang, Y.; Wu, D.; Li, T.; Yin, Y.; Li, G. Improvement of enzyme-linked immunosorbent assay for the multicolor detection of biomarkers. Chem. Sci. 2016, 7, 3011–3016. [Google Scholar] [CrossRef] [Green Version]
  23. Wang, N.; Wang, J.; Zhao, X.; Chen, H.; Xu, H.; Bai, L.; Wang, W.; Yang, H.; Wei, D.; Yuan, B. Highly sensitive electrochemical immunosensor for the simultaneous detection of multiple tumor markers for signal amplification. Talanta 2021, 226, 122133. [Google Scholar] [CrossRef] [PubMed]
  24. Liu, X.; Li, Y.; He, L.; Feng, Y.; Tan, H.; Chen, X.; Yang, W. Simultaneous detection of multiple neuroendocrine tumor markers in patient serum with an ultrasensitive and antifouling electrochemical immunosensor. Biosens. Bioelectron. 2021, 194, 113603. [Google Scholar] [CrossRef]
  25. Qi, H.; Ling, C.; Ma, Q.; Gao, Q.; Zhang, C. Sensitive electrochemical immunosensor array for the simultaneous detection of multiple tumor markers. Analyst 2012, 137, 393–399. [Google Scholar] [CrossRef]
  26. Monteleone, M.; Naccarato, A.; Sindona, G.; Tagarelli, A. A reliable and simple method for the assay of neuroendocrine tumor markers in human urine by solid-phase microextraction-gas chromatography-triple quadrupole mass spectrometry. Anal. Chim. Acta 2013, 759, 66–73. [Google Scholar] [CrossRef]
  27. Giesen, C.; Mairinger, T.; Khoury, L.; Waentig, L.; Jakubowski, N.; Panne, U. Multiplexed immunohistochemical detection of tumor markers in breast cancer tissue using laser ablation inductively coupled plasma mass spectrometry. Anal. Chem. 2011, 83, 8177–8183. [Google Scholar] [CrossRef]
  28. Cao, X.; Han, Y.; Gao, C.; Huang, X.; Xu, Y.; Wang, N. PtAg nanowires: Facile synthesis and their applications as excellent oxygen reduction electrocatalysts for label-free electrochemical immunoassay. J. Mater. Chem. A 2013, 1, 14904–14909. [Google Scholar] [CrossRef]
  29. Cui, R.; Liu, C.; Shen, J.; Gao, D.; Zhu, J.-J.; Chen, H.-Y. Gold nanoparticle-colloidal carbon nanosphere hybrid material: Preparation, characterization, and application for an amplified electrochemical immunoassay. Adv. Funct. Mater. 2008, 18, 2197–2204. [Google Scholar] [CrossRef]
  30. Lu, D.; Lu, F.; Pang, G. A novel tetrahydrocannabinol electrochemical nano immunosensor based on horseradish peroxidase and double-layer gold nanoparticles. Molecules 2016, 21, 1377. [Google Scholar] [CrossRef] [Green Version]
  31. Zheng, L.; Jia, L.; Li, B.; Situ, B.; Liu, Q.; Wang, Q.; Gan, N. A sandwich HIV p24 amperometric immunosensor based on a direct gold electroplating-modified electrode. Molecules 2012, 17, 5988–6000. [Google Scholar] [CrossRef]
  32. Chen, X.; Jia, X.L.; Han, J.M.; Ma, J.; Ma, Z.F. Electrochemical immunosensor for simultaneous detection of multiplex cancer biomarkers based on graphene nanocomposites. Biosens. Bioelectron. 2013, 50, 356–361. [Google Scholar] [CrossRef]
  33. Shan, J.; Wang, L.Y.; Ma, Z.F. Novel metal-organic nanocomposites: Poly(methylene blue)-Au and its application for an ultrasensitive electrochemical immunosensing platform. Sens. Actuators B Chem. 2016, 237, 666–671. [Google Scholar] [CrossRef]
  34. Gao, Q.; Han, J.M.; Ma, Z.F. Polyamidoamine dendrimers-capped carbon dots/Au nanocrystal nanocomposites and its application for electrochemical immunosensor. Biosens. Bioelectron. 2013, 49, 323–328. [Google Scholar] [CrossRef]
  35. Li, W.X.; Ma, Z.F. Conductive catalytic redox hydrogel composed of aniline and vinyl-ferrocene for ultrasensitive detection of prostate specific antigen. Sens. Actuators B Chem. 2017, 248, 545–550. [Google Scholar] [CrossRef]
  36. Liu, Z.M.; Ma, Z.F. Fabrication of an ultrasensitive electrochemical immunosensor for CEA based on conducting long-chain polythiols. Biosens. Bioelectron. 2013, 46, 1–7. [Google Scholar] [CrossRef]
  37. Feng, J.J.; Chu, C.S.; Ma, Z.F. Fenton and Fenton-like catalysts for electrochemical immunoassay: A mini review. Electrochem. Commun. 2021, 125, 106970. [Google Scholar] [CrossRef]
  38. Zheng, Y.; Ma, Z.F. Dual-reaction triggered sensitivity amplification for ultrasensitive peptidecleavage based electrochemical detection of matrix metalloproteinase-7. Biosens. Bioelectron. 2018, 108, 46–52. [Google Scholar] [CrossRef] [PubMed]
  39. Shi, W.T.; Ma, Z.F. Amperometric glucose biosensor based on a triangular silver nanoprisms/chitosan composite film as immobilization matrix. Biosens. Bioelectron. 2010, 26, 1098–1103. [Google Scholar] [CrossRef]
  40. Wang, C.G.; Chen, Y.; Wang, T.T.; Ma, Z.F.; Su, Z.M. Biorecognition-driven self-assembly of gold nanorods: A rapid and sensitive approach toward antibody sensing. Chem. Mater. 2007, 19, 5809–5811. [Google Scholar] [CrossRef]
  41. Yang, Z.H.; Zhuo, Y.; Yuan, R.; Chai, Y.Q. An amplified electrochemical immunosensor based on in situ-produced 1-naphthol as electroactive substance and graphene oxide and Pt nanoparticles functionalized CeO2 nanocomposites as signal enhancer. Biosens. Bioelectron. 2015, 69, 321–327. [Google Scholar] [CrossRef]
  42. Zhang, N.N.; Xu, Y.; Ma, Z.F. Signal amplification based on tannic acid-assisted cyclic conversion of Fe(III)/Fe(II) for ultrasensitive electrochemical immunoassay of CA 12-5. Sens. Actuators B Chem. 2020, 317, 128244. [Google Scholar] [CrossRef]
  43. Wang, H.Q.; Ma, Z.F. Simultaneous detection of multiple tumor markers by label-free electrochemical immunoassay using chip-like glass carbon electrodes. Sens. Actuators B Chem. 2018, 256, 402–407. [Google Scholar] [CrossRef]
  44. Shan, J.; Ma, Z.F. Simultaneous detection of five biomarkers of lung cancer by electrochemical immunoassay. Microchim. Acta 2016, 183, 2889–2897. [Google Scholar] [CrossRef]
  45. Liang, X.Y.; Zhao, J.C.; Ma, Z.F. Improved binding induced self-assembled DNA to achieve ultrasensitive electrochemical proximity assay. Sens. Actuators B Chem. 2020, 304, 127278. [Google Scholar] [CrossRef]
  46. Qu, L.; Yang, L.; Li, Y.; Ren, X.; Wang, H.; Fan, D.; Wang, X.; Wei, Q.; Ju, H. Dual-signaling electrochemical ratiometric method for competitive immunoassay of CYFRA 21-1 Based on Urchin-like Fe3O4@PDA-Ag and Ni3Si2O5(OH)4-Au Absorbed Methylene Blue Nanotubes. ACS Appl. Mater. Interfaces 2021, 13, 5795–5802. [Google Scholar] [CrossRef] [PubMed]
  47. Gan, C.; Wang, B.; Huang, J.; Qileng, A.; He, Z.; Lei, H.; Liu, W.; Liu, Y. Multiple amplified enzyme-free electrochemical immunosensor based on G-quadruplex/hemin functionalized mesoporous silica with redox-active intercalators for microcystin-LR detection. Biosens. Bioelectron. 2017, 98, 126–133. [Google Scholar] [CrossRef] [PubMed]
  48. Feng, J.J.; Yao, T.; Chu, C.S.; Ma, Z.F.; Han, H.L. Proton-responsive annunciator based on i-motif DNA structure modified metal organic frameworks for ameliorative construction of electrochemical immunosensing interface. J. Colloid Interface Sci. 2021, 608, 2050–2057. [Google Scholar] [CrossRef] [PubMed]
  49. Biniaz, Z.; Mostafavi, A.; Shamspur, T.; Torkzadeh-Mahani, M.; Mohamadi, M. Electrochemical sandwich immunoassay for the prostate specific antigen using a polyclonal antibody conjugated to thionine and horseradish peroxidase. Microchim. Acta 2017, 184, 2731–2738. [Google Scholar] [CrossRef]
  50. Zhou, Q.; Li, G.; Zhang, Y.; Zhu, M.; Wan, Y.; Shen, Y. Highly selective and sensitive electrochemical immunoassay of Cry1C using nanobody and pi-pi stacked graphene oxide/thionine assembly. Anal. Chem. 2016, 88, 9830–9836. [Google Scholar] [CrossRef]
  51. Zhang, X.; Shen, Y.; Zhang, Y.; Shen, G.; Xiang, H.; Long, X. A label-free electrochemical immunosensor based on a new polymer containing aldehyde and ferrocene groups. Talanta 2017, 164, 483–489. [Google Scholar] [CrossRef] [PubMed]
  52. Viswanathan, S.; Rani, C.; Anand, A.V.; Ho, J.A. Disposable electrochemical immunosensor for carcinoembryonic antigen using ferrocene liposomes and MWCNT screen-printed electrode. Biosens. Bioelectron. 2009, 24, 1984–1989. [Google Scholar] [CrossRef] [PubMed]
  53. Kong, F.Y.; Xu, B.Y.; Du, Y.; Xu, J.J.; Chen, H.Y. A branched electrode based electrochemical platform: Towards new label-free and reagentless simultaneous detection of two biomarkers. Chem. Commun. 2013, 49, 1052–1054. [Google Scholar] [CrossRef] [PubMed]
  54. Alizadeh, N.; Salimi, A.; Hallaj, R. Magnetoimmunosensor for simultaneous electrochemical detection of carcinoembryonic antigen and α-fetoprotein using multifunctionalized Au nanotags. J. Electroanal. Chem. 2018, 811, 8–15. [Google Scholar] [CrossRef]
  55. Zhu, Q.; Chai, Y.; Yuan, R.; Zhuo, Y. Simultaneous detection of four biomarkers with one sensing surface based on redox probe tagging strategy. Anal. Chim. Acta 2013, 800, 22–28. [Google Scholar] [CrossRef]
  56. Wang, Z.F.; Liu, N.; Ma, Z.F. Platinum porous nanoparticles hybrid with metal ions as probes for simultaneous detection of multiplex cancer biomarkers. Biosens. Bioelectron. 2014, 53, 324–329. [Google Scholar] [CrossRef]
  57. Xu, T.; Jia, X.L.; Chen, X.; Ma, Z.F. Simultaneous electrochemical detection of multiple tumor markers using metal ions tagged immunocolloidal gold. Biosens. Bioelectron. 2014, 56, 174–179. [Google Scholar] [CrossRef]
  58. Li, L.; Wei, Y.; Zhang, S.; Chen, X.; Shao, T.; Feng, D. Electrochemical immunosensor based on metal ions functionalized CNSs@Au NPs nanocomposites as signal amplifier for simultaneous detection of triple tumor markers. J. Electroanal. Chem. 2021, 880, 114882. [Google Scholar] [CrossRef]
  59. Tang, Z.X.; Ma, Z.F. Ratiometric ultrasensitive electrochemical immunosensor based on redox substrate and immunoprobe. Sci. Rep. 2016, 6, 35440. [Google Scholar] [CrossRef] [Green Version]
  60. Ma, Z.F.; Liu, N. Design of immunoprobes for electrochemical multiplexed tumor marker detection. Expert Rev. Mol. Diagn. 2015, 15, 1075–1083. [Google Scholar] [CrossRef] [PubMed]
  61. Zhao, L.H.; Yin, S.; Ma, Z.F. Ca2+-triggered pH-response sodium alginate hydrogel precipitation for amplified sandwich-type impedimetric immunosensor of tumor marker. ACS Sens. 2019, 4, 450–455. [Google Scholar] [CrossRef] [PubMed]
  62. Rong, Q.F.; Feng, F.; Ma, Z.F. Metal ions doped chitosan-poly(acrylic acid) nanospheres: Synthesis and their application in simultaneously electrochemical detection of four markers of pancreatic cancer. Biosens. Bioelectron. 2016, 75, 148–154. [Google Scholar] [CrossRef]
  63. Putnin, T.; Ngamaroonchote, A.; Wiriyakun, N.; Ounnunkad, K.; Laocharoensuk, R. Dually functional polyethylenimine-coated gold nanoparticles: A versatile material for electrode modification and highly sensitive simultaneous determination of four tumor markers. Microchim. Acta 2019, 186, 305. [Google Scholar] [CrossRef]
  64. Siangproh, W.; Dungchai, W.; Rattanarat, P.; Chailapakul, O. Nanoparticle-based electrochemical detection in conventional and miniaturized systems and their bioanalytical applications: A review. Anal. Chim. Acta 2011, 690, 10–25. [Google Scholar] [CrossRef] [PubMed]
  65. Popov, A.; Brasiunas, B.; Kausaite-Minkstimiene, A.; Ramanaviciene, A. Metal nanoparticle and quantum dot tags for signal amplification in electrochemical immunosensors for biomarker detection. Chemosensors 2021, 9, 85. [Google Scholar] [CrossRef]
  66. Fang, Y.; Xu, Y.; He, P. DNA biosensors based on metal nanoparticles. J. Biomed. Nanotechnol. 2005, 1, 276–285. [Google Scholar] [CrossRef]
  67. Liu, L.; Chang, Y.; Xia, N.; Peng, P.; Zhang, L.; Jiang, M.; Zhang, J.; Liu, L. Simple, sensitive and label-free electrochemical detection of microRNAs based on the in situ formation of silver nanoparticles aggregates for signal amplification. Biosens. Bioelectron. 2017, 94, 235–242. [Google Scholar] [CrossRef]
  68. Xia, N.; Cheng, C.; Liu, L.; Peng, P.; Liu, C.; Chen, J. Electrochemical glycoprotein aptasensors based on the in-situ aggregation of silver nanoparticles induced by 4-mercaptophenyl boronic acid. Microchim. Acta 2017, 184, 4393–4400. [Google Scholar] [CrossRef]
  69. Liu, X.; Tseng, C.-L.; Lin, L.-Y.; Lee, C.-A.; Li, J.; Feng, L.; Song, L.; Li, X.; He, J.-H.; Sakthivel, R.; et al. Template-free synthesis of mesoporous Ce3NbO7/CeO2 hollow nanospheres for label-free electrochemical immunosensing of leptin. Sens. Actuators B Chem. 2021, 341, 130005. [Google Scholar] [CrossRef]
  70. Ge, S.; Yu, F.; Ge, L.; Yan, M.; Yu, J.; Chen, D. Disposable electrochemical immunosensor for simultaneous assay of a panel of breast cancer tumor markers. Analyst 2012, 137, 4727–4733. [Google Scholar] [CrossRef]
  71. Lai, G.; Wang, L.; Wu, J.; Ju, H.; Yan, F. Electrochemical stripping analysis of nanogold label-induced silver deposition for ultrasensitive multiplexed detection of tumor markers. Anal. Chim. Acta 2012, 721, 1–6. [Google Scholar] [CrossRef] [PubMed]
  72. Lee, P.K.; Woi, P.M. Current innovations of metal hexacyanoferrates-based nanocomposites toward electrochemical sensing: Materials selection and synthesis methods. Crit. Rev. Anal. Chem. 2020, 50, 393–404. [Google Scholar] [CrossRef] [PubMed]
  73. Song, X.; Song, S.; Wang, D.; Zhang, H. Prussian blue analogs and their derived nanomaterials for electrochemical energy storage and electrocatalysis. Small Methods 2021, 5, 2001000. [Google Scholar] [CrossRef] [PubMed]
  74. Ricci, F.; Palleschi, G. Sensor and biosensor preparation, optimisation and applications of Prussian blue modified electrodes. Biosens. Bioelectron. 2005, 21, 389–407. [Google Scholar] [CrossRef]
  75. Dos Santos, P.L.; Katic, V.; Toledo, K.C.F.; Bonacin, J.A. Photochemical one-pot synthesis of reduced graphene oxide/Prussian blue nanocomposite for simultaneous electrochemical detection of ascorbic acid, dopamine, and uric acid. Sens. Actuators B Chem. 2018, 255, 2437–2447. [Google Scholar] [CrossRef]
  76. Sgobbi, L.F.; Razzino, C.A.; Machado, S.A.S. A disposable electrochemical sensor for simultaneous detection of sulfamethoxazole and trimethoprim antibiotics in urine based on multiwalled nanotubes decorated with Prussian blue nanocubes modified screen-printed electrode. Electrochim. Acta 2016, 191, 1010–1017. [Google Scholar] [CrossRef]
  77. Buleandra, M.; Rabinca, A.A.; Mihailciuc, C.; Balan, A.; Nichita, C.; Stamatin, I.; Ciucu, A.A. Screen-printed Prussian blue modified electrode for simultaneous detection of hydroquinone and catechol. Sens. Actuators B Chem. 2014, 203, 824–832. [Google Scholar] [CrossRef]
  78. Soleh, A.; Kanatharana, P.; Thavarungkul, P.; Limbut, W. Novel electrochemical sensor using a dual-working electrode system for the simultaneous determination of glucose, uric acid and dopamine. Microchem. J. 2020, 153, 104379. [Google Scholar] [CrossRef]
  79. Jia, X.L.; Liu, Z.M.; Liu, N.; Ma, Z.F. A label-free immunosensor based on graphene nanocomposites for simultaneous multiplexed electrochemical determination of tumor markers. Biosens. Bioelectron. 2014, 53, 160–166. [Google Scholar] [CrossRef]
  80. Habibi, M.M.; Mirhosseini, S.A.; Sajjadi, S.; Keihan, A.H. A novel label-free electrochemical immunesensor for ultrasensitive detection of LT toxin using prussian blue@gold nanoparticles composite as a signal amplification. Bioelectrochemistry 2021, 142, 107887. [Google Scholar] [CrossRef]
  81. Lai, G.S.; Yan, F.; Ju, H.X. Dual signal amplification of glucose oxidase-functionalized nanocomposites as a trace label for ultrasensitive simultaneous multiplexed electrochemical detection of tumor markers. Anal. Chem. 2009, 81, 9730–9736. [Google Scholar] [CrossRef]
  82. Wang, Y.; Luo, J.; Liu, J.; Sun, S.; Xiong, Y.; Ma, Y.; Yan, S.; Yang, Y.; Yin, H.; Cai, X. Label-free microfluidic paper-based electrochemical aptasensor for ultrasensitive and simultaneous multiplexed detection of cancer biomarkers. Biosens. Bioelectron. 2019, 136, 84–90. [Google Scholar] [CrossRef] [PubMed]
  83. Feng, W.; Han, X.; Hu, H.; Chang, M.; Ding, L.; Xiang, H.; Chen, Y.; Li, Y. 2D vanadium carbide MXenzyme to alleviate ROS-mediated inflammatory and neurodegenerative diseases. Nat. Commun. 2021, 12, 2203. [Google Scholar] [CrossRef]
  84. Liu, B.; Wang, Y.; Chen, Y.; Guo, L.; Wei, G. Biomimetic two-dimensional nanozymes: Synthesis, hybridization, functional tailoring, and biosensor applications. J. Mater. Chem. B 2020, 8, 10065–10086. [Google Scholar] [CrossRef]
  85. Huang, Y.; Ren, J.; Qu, X. Nanozymes: Classification, Catalytic Mechanisms, Activity Regulation, and Applications. Chem. Rev. 2019, 119, 4357–4412. [Google Scholar] [CrossRef] [PubMed]
  86. Liao, X.; Wang, X.; Ma, C.; Zhang, L.; Zhao, C.; Chen, S.; Li, K.; Zhang, M.; Mei, L.; Qi, Y.; et al. Enzyme-free sandwich-type electrochemical immunosensor for CEA detection based on the cooperation of an Ag/g-C3N4-modified electrode and Au@SiO2/Cu2O with core-shell structure. Bioelectrochemistry 2021, 142, 107931. [Google Scholar] [CrossRef] [PubMed]
  87. Wan, Y.; Deng, W.; Su, Y.; Zhu, X.; Peng, C.; Hu, H.; Peng, H.; Song, S.; Fan, C. Carbon nanotube-based ultrasensitive multiplexing electrochemical immunosensor for cancer biomarkers. Biosens. Bioelectron. 2011, 30, 93–99. [Google Scholar] [CrossRef] [PubMed]
  88. Ma, H.; Mao, K.; Li, H.; Wu, D.; Zhang, Y.; Du, B.; Wei, Q. Ultrasensitive multiplexed immunosensors for the simultaneous determination of endocrine disrupting compounds using Pt@SBA-15 as a non-enzymatic label. J. Mater. Chem. B 2013, 1, 5137–5142. [Google Scholar] [CrossRef]
  89. Sun, G.; Zhang, L.; Zhang, Y.; Yang, H.; Ma, C.; Ge, S.; Yan, M.; Yu, J.; Song, X. Multiplexed enzyme-free electrochemical immunosensor based on ZnO nanorods modified reduced graphene oxide-paper electrode and silver deposition-induced signal amplification strategy. Biosens. Bioelectron. 2015, 71, 30–36. [Google Scholar] [CrossRef]
Molecules 27 00267 g001 550
Figure 1. (1) Sandwich-type electrochemical immunosensor for the simultaneous detection of CEA and AFP. (2) DPV responses of the immunosensor incubated with a series of different concentrations of CEA and AFP. (3) Assembly schematic of electrochemical immunosensor for the detection of CEA and AFP (reprinted with permission from Ref. [54], Copyright 2018, Elsevier).
Figure 1. (1) Sandwich-type electrochemical immunosensor for the simultaneous detection of CEA and AFP. (2) DPV responses of the immunosensor incubated with a series of different concentrations of CEA and AFP. (3) Assembly schematic of electrochemical immunosensor for the detection of CEA and AFP (reprinted with permission from Ref. [54], Copyright 2018, Elsevier).
Molecules 27 00267 g001
Molecules 27 00267 g002 550
Figure 2. (1) Schematic for the fabrication process of the immunosensing interface. (2) Typical SWV signals of SA−Cu (a), SA−Pb (b), SA−Ti (c), and a mixture of these three hydrogels (d) (A). SWV characterizations of the modified procedure of electrodes (B) (reprinted with permission from Ref. [43], Copyright 2018, Elsevier).
Figure 2. (1) Schematic for the fabrication process of the immunosensing interface. (2) Typical SWV signals of SA−Cu (a), SA−Pb (b), SA−Ti (c), and a mixture of these three hydrogels (d) (A). SWV characterizations of the modified procedure of electrodes (B) (reprinted with permission from Ref. [43], Copyright 2018, Elsevier).
Molecules 27 00267 g002
Molecules 27 00267 g003 550
Figure 3. Preparation of various immunoprobes based on metal ions doped chitosan-poly(acrylic acid) nanospheres (A). Schematic representation for the electrochemical multiplexed immunosensor of CEA, CA 19-9, CA 12-5, and CA 24-2 (B) (reprinted with permission from Ref. [62], Copyright 2016, Elsevier).
Figure 3. Preparation of various immunoprobes based on metal ions doped chitosan-poly(acrylic acid) nanospheres (A). Schematic representation for the electrochemical multiplexed immunosensor of CEA, CA 19-9, CA 12-5, and CA 24-2 (B) (reprinted with permission from Ref. [62], Copyright 2016, Elsevier).
Molecules 27 00267 g003
Molecules 27 00267 g004 550
Figure 4. Schematic of the electrochemical immunosensor array and detection strategy by linear-sweep stripping voltammetric analysis of Ag NPs catalytically deposited on the immunosensor surface by gold nanolabels (reprinted with permission from Ref. [71], Copyright 2012, Elsevier).
Figure 4. Schematic of the electrochemical immunosensor array and detection strategy by linear-sweep stripping voltammetric analysis of Ag NPs catalytically deposited on the immunosensor surface by gold nanolabels (reprinted with permission from Ref. [71], Copyright 2012, Elsevier).
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Molecules 27 00267 g005 550
Figure 5. (1) Schematic representation of the preparation of immunosensors (A) and sandwich-type electrochemical immunoassay (B). (2) Schematic representation of a multiplexed electrochemical immunoassay with an immunosensor array and electrochemical response mechanism (reprinted with permission from Ref. [81], Copyright 2009, American Chemical Society).
Figure 5. (1) Schematic representation of the preparation of immunosensors (A) and sandwich-type electrochemical immunoassay (B). (2) Schematic representation of a multiplexed electrochemical immunoassay with an immunosensor array and electrochemical response mechanism (reprinted with permission from Ref. [81], Copyright 2009, American Chemical Society).
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Molecules 27 00267 g006 550
Figure 6. Fabrication and modification process of the multi-parameter electrochemical paper-based aptasensor (reprinted with permission from Ref. [82], Copyright 2019, Elsevier).
Figure 6. Fabrication and modification process of the multi-parameter electrochemical paper-based aptasensor (reprinted with permission from Ref. [82], Copyright 2019, Elsevier).
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Molecules 27 00267 g007 550
Figure 7. The fabrication process of the multiplexed enzyme-free electrochemical immunosensor based on the BSA-stabilized silver nanoparticles (reprinted with permission from Ref. [89], Copyright 2015, Elsevier).
Figure 7. The fabrication process of the multiplexed enzyme-free electrochemical immunosensor based on the BSA-stabilized silver nanoparticles (reprinted with permission from Ref. [89], Copyright 2015, Elsevier).
Molecules 27 00267 g007
Table
Table 1. Summary of the advantages and limitations for various electrochemical signal substances and some reported works.
Table 1. Summary of the advantages and limitations for various electrochemical signal substances and some reported works.
SpeciesAdvantagesLimitationsElectrochemical Signal SubstanceDetection ObjectRef.
Organic moleculesEasy accessibility,
Simple loading, Excellent redox spikes		Unstable physisorption to cause leakage,
Fussy covalent bonding to lead time-consuming,
Environmental contamination		Methylene blue,
Thionine		CEA, AFP[53]
Thionine,
Ferrocene		CEA, AFP[54]
Anthraquinone 2-carboxylic acid,
Thionine,
Tris(2,2(-bipyridine-4,4(-dicarboxylic acid) cobalt(III),
Ferrocene		CEA,
CA 19-9,
CA 12-5,
CA 24-2 		[55]
Metal ionsEasy accessibility,
Sharp electrochemical signal peaks		Consideration of heavy metal ions contaminationCopper(II) ions,
Lead(II) ions,
Titanium(IV) ions		CEA, NSE,
CYFRA 21-1		[43]
Copper(II) ions,
Lead(II) ions,
Cadmium(II) ions,
zinc(II) ions		CEA,
CA 19-9,
CA 12-5,
CA24-2		[62]
Copper(II) ions,
Lead(II) ions,
Cadmium(II) ions, Silver ions		CEA, AFP,
PSA, IL-8		[63]
Metal nanoparticlesSmall size,
High surface-to-bulk ratio,
High catalytic activity		Easily oxidation for a long period of storageSilver nanoparticlesCEA,
CA 12-5,
CA 15-3		[70]
Silver nanoparticlesCEA, AFP[71]
Prussian blueHigh catalytic activity,
Excellent electrochemical signal peaks		Requirement of pre-preparationPB-PDDA-CSCEA, AFP[81]
PB-PEDOTCEA, NSE[82]
Other substancesExcellent catalytic system
Needlessness of signal molecules labeling		Common usage of noble metal-based nanozyme Pt NPs-functionalized mesoporous silicaDiethylstilbestrol
Estradiol		[88]
BSA-stabilized silver nanoparticlesCEA, PSA, HCG[89]
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Feng, J.; Chu, C.; Ma, Z. Electrochemical Signal Substance for Multiplexed Immunosensing Interface Construction: A Mini Review. Molecules 2022, 27, 267. https://doi.org/10.3390/molecules27010267

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Feng J, Chu C, Ma Z. Electrochemical Signal Substance for Multiplexed Immunosensing Interface Construction: A Mini Review. Molecules. 2022; 27(1):267. https://doi.org/10.3390/molecules27010267

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Feng, Jiejie, Changshun Chu, and Zhanfang Ma. 2022. "Electrochemical Signal Substance for Multiplexed Immunosensing Interface Construction: A Mini Review" Molecules 27, no. 1: 267. https://doi.org/10.3390/molecules27010267

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