Modelling Prospects of Bio-Electrochemical Immunosensing Platforms

Round 1

Reviewer 1 Report (Previous Reviewer 4)

The authors have made some improvements in this revised version of the review.

I would suggest acceptation for publication.

There are still typos and full sentences to be revised.

Author Response

Ref: electrochem-2907748

Title of the manuscript: “Modelling Prospects of Bio-Electrochemical Immunosensing Platforms.”

1. Reply to the Reviewer #1’s comments:

Recommendation: Minor Revision

Regarding “The authors have made some improvements in this revised version of the review. I would suggest acceptation for publication.”

Author’s Reply: Thanks for the positive feedback. Thank you.

Reviewer 2 Report (New Reviewer)

In this manuscript, the author reviewed the platform approaches and applications of electrochemical immunosensors. The author discussed different types of electrochemical measurements, design and fabrication of electrochemical immunosensing platforms, comparison with traditional immunosensing techniques and the current market of electrochemical immunosensors. I think this work fits well with the scope of electrochem journal and provides useful information for the new researchers in this field. However, the following comments need to be addressed before final publication.

1. I encourage the author to polish the contents of Table 1. I feel the information in the table is too general and misses some necessary details. For example, the conventional immunoassays include many different techniques and each of them looks at the sample with different angles. The comments the authors has in the table apply to some techniques but not to other ones, which makes the comparison with electrochemical techniques not straightforward. Also, the author commented the conventional immunoassays have “high limit of detection”, I think the author actually meant “low limit of detection” since they can detect pico or femto molar levels?

2. In Page 8, line 2-4, the author is encouraged to add more references when talking about various materials used as electrode base for loading nanomaterials. In line 6-7, the author mentioned “They are classified as zero (0D), one (1D), two (2D) and three dimensions (3D) based on how large they are <100 nm.” I am confused with this statement as this should be based on the structure instead of size?

3. In Page 10, Section 2, the author mentioned “complications associated with immune inactive components, their immobilization, non-specific adsorption and background noise are few

practical complications which are dealt with precautions”. Can the author elaborate on the approaches of precautions or the solution of removing those complication? The author also mentioned the upgrade of electro-immunoassay will likely be driven by development of microfluidic analysis. Can author provide the details of the integration of electro-immunoassay into microfluidic devices?

4. In Page 11, the author discussed the effort of high-throughput analysis with integrating multiple processors in a single device. How to improve the consistency of multi-electrode and make sure each electrode can output the same level of signal when exposed to the same sample?

Moderate editing of English language required. I would suggest having a native English speaker to review this manuscript to improve the grammar and logical flow.

Author Response

Ref: electrochem-2907748

Title of the manuscript: “Modelling Prospects of Bio-Electrochemical Immunosensing Platforms.”

1. Reply to the Reviewer #2’s comments:

Recommendation: Minor Revision

Regarding “In this manuscript, the author reviewed the platform approaches and applications of electrochemical immunosensors. The author discussed different types of electrochemical measurements, design and fabrication of electrochemical immunosensing platforms, comparison with traditional immunosensing techniques and the current market of electrochemical immunosensors. I think this work fits well with the scope of electrochem journal and provides useful information for the new researchers in this field. However, the following comments need to be addressed before final publication.”

Author’s Reply: Thanks for the positive feedback. Thank you.

• Regarding “I encourage the author to polish the contents of Table 1. I feel the information in the table is too general and misses some necessary details. For example, the conventional immunoassays include many different techniques and each of them looks at the sample with different angles. The comments the authors has in the table apply to some techniques but not to other ones, which makes the comparison with electrochemical techniques not straightforward. Also, the author commented the conventional immunoassays have “high limit of detection”, I think the author actually meant “low limit of detection” since they can detect pico or femto molar levels?”.

Author’s Reply: Thanks for the correction. The Table 1 is generalized for conventional Immunoassays but specific for Electrochemical Immunoassays. We have updated a few details in the revised version of the manuscript.

• Regarding “In Page 8, line 2-4, the author is encouraged to add more references when talking about various materials used as electrode base for loading nanomaterials. In line 6-7, the author mentioned “They are classified as zero (0D), one (1D), two (2D) and three dimensions (3D) based on how large they are <100 nm.” I am confused with this statement as this should be based on the structure instead of size?”

Author’s Reply: Thanks for the comment. We have suitably added the references in the revised version of the manuscript in Page 8, lines 2-4.

The statement “They are classified as zero (0D), one (1D) ……” is to provide readers with a broad outlook that the nanomaterials are of varied dimensions. But even though the size goes in the range of 1nm to 999 nm, the usual upper limit for their size is 100 nm. So, the readers could relate the size with different materials and dimensions. A few additional line are incorporated “For example, fullerene (0 Dimension having size of 1.1 nm), an allotrope of carbon consists of single and double bonds wherein its molecules can be tubular, ellipsoidal, hollow spheres or other shapes”.

• Regarding “On Page 10, Section 2, the author mentioned “complications associated with immune inactive components, their immobilization, non-specific adsorption and background noise are few practical complications which are dealt with precautions”. Can the author elaborate on the approaches of precautions or the solution of removing those complication? The author also mentioned the upgrade of electro-immunoassay will likely be driven by development of microfluidic analysis. Can author provide the details of the integration of electro-immunoassay into microfluidic devices?”

Author’s Reply: Thanks for the comment. The complications referred here are due to electro-inactive and few electro-active systems. We can deal with them with precautions accordingly. For example, there are sweat-based microchips for electrochemical sensing. For example, sweat consists of a range of biomarkers and a mixture of metabolites, electrolytes, urea, etc. The other interfering elements can be removed from coming in contact with the sensor by putting a layer of filter systems. A sweat-based microfluidic electrochemical integrated device has been developed by Cao et al. wherein, he has elaborately discussed the sweat collector, followed by vertical channel, transverse channel, electrochemical sensor and finally sweat evaporator also. This example fits as a perfect example for both questions of the reviewer.

A recent article from “Flexible Electronics (2020) 4:2 ; https://doi.org/10.1038/s41528-020-0065-1” is the perfect example for removal of various interfering systems before analysis. They have given perfect layering patterns for non-invasive electrochemical sensors of various kinds.

We have updated the same in the revised version of the manuscript.

• Regarding “In Page 11, the author discussed the effort of high-throughput analysis with integrating multiple processors in a single device. How to improve the consistency of multi-electrode and make sure each electrode can output the same level of signal when exposed to the same sample?”

Author’s Reply: Thanks for the comment. The high throughput systems help us to have better analysis at the same time for one or multiple analytes. For example, an article published by Hui et al. involved high-performance electrochemical heavy metal sensors for non-invasive detection in human fluids. The high throughput systems allow very sensitive detection of analytes in ppb level i.e. 0.1 ppb and 0.5 ppb for copper and zinc heavy metals. In continuation, integrating multiple processors like Scanning Electrochemical probe microscopy (SPECM) enables better spatial resolution of imaging. These next-generation systems put enormous emphasis on big data and its analysis, storage, curation, and parallelization. Thus, these intelligent instruments and experiments have active control of nanoscale systems and the integration of nano-electrochemistry and nanoscale micro(Spectro)scopy too.

We have updated the same in the revised version of the manuscript with the required references.

• Regarding “Moderate editing of English language required. I would suggest having a native English speaker to review this manuscript to improve the grammar and logical flow.”

Author’s Reply: Thanks for the correction asked. We have used licensed software and English colleagues to ensure proper English flow and grammatical corrections.

Reviewer 3 Report (New Reviewer)

The review of Dr. Mansi Gandhi aims at prospect of electrochemical Immunosensing. The review is not well organized and crucial aspects are missing or not well presented. I cannot recommend acceptance of this review for the following reasons:

The review is too focused on the work of the author (9/55 references) when there are plenty of works by many authors on the topic and in the field.

The presented aspects have very limited explanation, which makes the review impractical.

Many important aspects are missing. For example, designing an electrochemical immunosensor or biosensor in general takes into account that electrochemical biosensor is at the solid/liquid interface (Langmuir 2019, 35, 22, 7067–7091, Langmuir 2022, 38, 2, 849–855).

The claims in table 1 need to be supported by references, for example give a reference that confirms that ellipsometric and acoustic immunosensors are considered conventional. Claiming things in a review without a proper support for the claim cannot be accepted.

There are many reviews that cover the topic with well reasoning for the importance of the works and the limitations and design consideration for example https://doi.org/10.1016/j.bios.2017.11.029, Biosensors 2019, 9(3), 86, Anal. Chem. 2017, 89, 1, 138–156, https://doi.org/10.1039/D3CS00921A.

The manuscript is hard to read because the paragraphs sentences are not correctly organized.

Author Response

Ref: electrochem-2907748

Title of the manuscript: “Modelling Prospects of Bio-Electrochemical Immunosensing Platforms.”

1. Reply to the Reviewer #3’s comments:

Regarding “The review of Dr. Mansi Gandhi aims at prospect of electrochemical Immunosensing. The review is not well organized and crucial aspects are missing or not well presented. I cannot recommend acceptance of this review for the following reasons.”

Author’s Reply: Thanks for the critical feedback. We have incorporated several changes as suggested by you to make it acceptable.

• Regarding “The review is too focused on the work of the author (9/55 references) when there are plenty of works by many authors on the topic and in the field.”

Author’s reply and action taken: Thanks for your feedback. The paper is regarding Modelling Prospects of Bio-Electrochemical Immunosensing platforms. All the references are cited as per the requirement of the text.

As suggested, we have added several new references to make it more appropriate. In addition, we have also incorporated more data points and texts from various new references. We have incorporated the new suggested changes in the revised version of the manuscript.

• Regarding “The presented aspects have very limited explanation, which makes the review impractical.”

Author’s reply and action taken: Thanks for your critical comment. The review accounts for various aspects of immunosensor modelling and electrochemical approach.

In the introduction section, a brief background of electrochemical techniques, and various research articles are discussed along with immunohistochemistry and histochemical tools.

While in Section 2 emphasis is laid on the basics of an immunosensor (with a comparison to traditional approaches).

Section 3 defines the most important part i.e. the designing of the platform with emphasis laid on the various nanomaterials, and functional bonding models for the electrode set-up. This section has various aspects incorporated for mechanism, ways to enhance sensitivity and selectivity along with options for high throughput.

Section 4 is dedicated to a realistic market study for real prototype systems. Readers find this part most engaging for practical life usage of electrochemical immunosensor prototypes.

Section 5 is the summary of the paper with the conclusion, discussion and future outlook.

The work has been designed to keep the reader interested in a review article.

• Regarding “Many important aspects are missing. For example, designing an electrochemical immunosensor or biosensor in general takes into account that electrochemical biosensor is at the solid/liquid interface (Langmuir2019, 35, 22, 7067–7091, Langmuir 2022, 38, 2, 849–855).

Author’s reply and action taken: Thanks for your critical comment. The basics of the interface study have been explained at various places in the article. Please check the introduction part, followed by section 3.2 functional model of bonding along with proper citation of papers with examples.

We have incorporated the new suggested articles in the revised version of the manuscript.

• Regarding “The claims in table 1 need to be supported by references, for example give a reference that confirms that ellipsometric and acoustic immunosensors are considered conventional. Claiming things in a review without a proper support for the claim cannot be accepted.”

Author’s Reply: Thanks for the critical mistake. We have updated the same in the revised version of the manuscript. A few references in the correlation are Applied Surface Science, 2020, 145091 and Sens. Actuators B Chem., 2013,189, 123–129. 

• Regarding “There are many reviews that cover the topic with well reasoning for the importance of the works and the limitations and design consideration for example https://doi.org/10.1016/j.bios.2017.11.029, Biosensors2019, 9(3), 86,  Chem. 2017, 89, 1, 138–156, https://doi.org/10.1039/D3CS00921A.”

Author’s Reply: Thanks for the critical comment. There are recent references and text in the support (Recent Advances in Biomolecular Detection Based on Aptamers and Nanoparticles. Biosensors (Basel) 2023;13. https://doi.org/10.3390/bios13040474.). Apart from reviews various specific articles have been cited in correlation to text.

We have incorporated the new suggested articles in the revised version of manuscript as suggested by the reviewer.

• Regarding “The manuscript is hard to read because the paragraphs sentences are not correctly organized.”

Author’s Reply: Thanks for the correction asked. We have used licensed software and English colleagues to ensure proper English flow and grammatical corrections.

Round 2

Reviewer 3 Report (New Reviewer)

The review by Gandhi improved. however, more references are required for table 1 and for sections 2 and 3 to justify claims in a review.

Author Response

Ref: electrochem-2907748

Title of the manuscript: “Modelling Prospects of Bio-Electrochemical Immunosensing Platforms.”

1. Reply to the Reviewer #3’s comments:

Regarding “The review by Gandhi improved. however, more references are required for table 1 and for sections 2 and 3 to justify claims in a review.”

Author’s Reply: Thanks for the feedback. We have incorporated 20 new references in the above mentioned sections as suggested by the reviewer to make the manuscript acceptable.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Modelling Prospects of Bio-Electrochemical Immunosensing Platforms.

The author reviews various bio-electrochemical immunosensing methods and describing various possibilities as well as their usage in real applicative technologies in the market. Although many methods are described, a more comprehensive explanation of the methods, how they work, and what are their advantages and disadvantages should be provided. Also, many of the figures are not clear and should be revised especially by adding a proper explanation in the figure's captions. All in all, I recommend accepting the manuscript after a major revision.

*Abstarct –  The author states . "The combination of bioconjugation techniques (optical spectroscopy, raman scattering, column chromatography, HPLC, X-ray diffraction)",  these are all analytical methods, what is the relevance to bioconjugation. The author should elaborate or rephrase.

Also, why are these methods relevant to the topic of the manuscript?

*The Author generally states different immune-electro-analytical methods stating that they are better than other existing methods. The author does not describe the disadvantages of this methods. The author should add a table summarizing the advantages and disadvantages of the described methods vs. other immunohistochemical methods that are based on fluorescence. The limit of detection of the different methods should appear in the table.

*Page.1 – "Electroanalytical Techniques", should be techniques.

*Page.1 – the author describe advances in the field of electrochemistry e.g. designs, tailored interfaces etc. Compatible references should be added.

*The concept green electrodes is not trivial. The author should elaborate or cite a paper that explains this concept.

*Page. 2 – " electrode-electrolyte interface  . Electrochemical reactions occur at the electrode surface, stating the electrolyte here is not relevant.

*In all figures, the captions are too short and not sufficient to describe the figure clearly.

*Page .3 – the author states that electrodes modified with nanoparticles are biocompatible. An explanation and a reference proving this statement should be added.

*Fig.3 (page. 4 ) – the figure consist of many unexplained elements and the mechanism is not clear.

*Page. 5 – "gold IMA", what is IMA?

* "5. Conclusion, Discussion and Future Outlook", Is this the correct format, perhaps just conclusions?

Minor corrections should be done.

Reviewer 2 Report

The manuscript titled "Modelling Prospects of Bio-Electrochemical Immunosensing Platforms " has several significant issues with that hinder its suitability for publication in its current form.

Specific Points:

1. One of the concerns is the age of many references in the manuscript, with many of them being older than 2010. Electrochemistry is a rapidly evolving field, and it is crucial to include recent and relevant references to provide an accurate overview of the current state of the art.

2. The manuscript falls short in delivering new perspectives or insights into the world of electrochemical sensing. While the title suggests a focus on modeling prospects, the content primarily consists of a descriptive list of various electrochemical sensors and the techniques employed for detection. This lack of originality is a critical weakness and does not contribute significantly to the existing knowledge base.

3. Despite the title emphasizing modeling prospects, the topic of modeling is not addressed throughout the paper. The only mention of modeling occurs in the conclusion section, where it is merely referenced from someone else's work. This is highly misleading and contradicts the manuscript's title and focus.

4. The organization of the manuscript lacks clear structure, making it challenging to follow. The content appears to be presented in a random manner, with electrochemical techniques and nanomaterials being introduced randomly without any logical progression.

The manuscript has numerous grammatical and spelling errors. Given the manuscript has no proper structure, it also makes it very unreadable.

Reviewer 3 Report

This review submitted by Mansi Gandhi can be useful to the potential readers. However there are several major improvements required to this article prior to publication.

(1). Author do not provide sufficient mechanistic explanation (i.e., by using schematic flow charts, cartoon or diagrams) to explain the mechanism of the action of these sensing models.

(2). Authors is only using very limited number of the scope in this review article which is strongly believe to be not sufficient.

(3). Categorize different sensing methods based on the detection method, limit of detection or the nature of the sensor, and must perform a comparison.

(4). Clearly outline the current limitations and potential possible improvements to increase the sensitivity.

(5). Conclusion/future direction section must be improved.

There are multiple grammatical. textual and spelling errors in the manuscript which must be corrected accordingly.

Reviewer 4 Report

This paper by M. Gandhi aims at reviewing some aspects of bioelectrochemical immunosensing.

I have major concerns that prevent me to accept this paper for publication:

1- The manuscript must be completely reorganized so that the readers can get the discussion if any in each section.

2- Section 2 is not useful. It contains just few general presentations of what an immunosensor is that can be included in the introduction.

3- on the contrary, section 3 must be strengthened and divided in sub-sections with one question/challenge addressed in each of them.

4- Section 3.1: synergetic effects between metals and carbon nanomaterials should be discussed in more details.

5- Figure 3 is a simple reproduction of one figure in the related paper. It should be relevant to get here the consecutive electrochemical sensing signal.

6- section 3.2:

- Why does the author use the term “model” in the title (same for the title of the manuscript). What is this paper modelling?

- The first part of this section must be completely rewritten with recent references. The papers included there (ref 12 to 20) are more than 20 years old.

- The following part contains papers that are not focusing on immunosensors (ref 23 for example). It must be divided in sub-sections focusing one point which is specifically addressed instead of a mixture of many concepts.

- After ref 28, it is not clear where avidin is coming from.

- What is EQCM for?

- Figure 5 seems a little bit out of the topic of the review since biological products are not even mentioned.

- It is interesting to report the main challenges as stability and T°. But it would be more interesting to have a discussion on the potential solutions to overcome them.

There are many typos that must be edited and English must be improved.

There are many typos that must be edited and English must be improved.