Portable Surface Plasmon Resonance Detector for COVID-19 Infection

Round 1

Reviewer 1 Report

Major correction

1.       Results: Very limited results have been presented. Try to modify your results.

2.       Discussion: Your discussion part needs a lot of improvement. The authors used only three references which is not good at all. Please re-write it again.

3.       Conclusion: Your conclusion part is not comprehensive. No need to use reference in the conclusion part. You should write just relied on your results. Please re-writ it again.

4.       The author should improve the structure of some of the sentence. Read carefully again and re-write some of confusing statements as I have presented below.

Other specific corrections

1.       Abstract – need modification. Line 24 “RBD”. What is RBD. It is not advisable to use abbreviation in abstract.

2.       Figure 2 and Figure 4.  Please keep the font type and size of X and Y axis of Figure 2 and Figure 4 similar to the text.

3.       Figure 1. In your abstract you have mentioned detection limit as (within 15-minute timeframe) however in Figure 1 you have indicated as <10min. Confusing???? Check also line 215.

4.       Line 200. The structure of the sentence not good. Please re-write the sentence.

5.       Figure 1. Try to modify the quality of the graphical representation and include other relevant information. Make it descriptive.

6.       Discussion. Line 231. It seems recommendation ”The specificity of detection should be thus improved” . Similarly check Line 240/241……..“In order to provide better sensitivity this parameter should be optimized.”

7.       Discussion. Line 224 – 228. Try to discuss by comparing with other formerly reported data.

8.       Discussion Line 224 – 228. Try to integrate your discussion with previously reported data - use reference.

9.       Line 242 – 246 . It seems limitation of your study. Please try to discuss your result with previous data.

10.   You have used only three references in your discussion which is not good at all. Hence, your discussion must be revised again.

11.   Line 271 – 273. Not necessary

12.   Line 273 – 279. Move to discussion part. No need to use reference in the conclusion part.

Author Response

Dear Reviewer

Thank you for all the remarks. I have corrected the manuscript and I am submitting the revised version.

Below my answers to the corrections you have suggested:

ad 1. The amount of data collected could not be enlarged due to the end of the project. I have no longer access to sample base and laboratories where the experiments could be conducted. This is an issue that cannot be corrected. In this point I clarified the data presentation by enhancing the charts. Also I wrote more about the way data was being collected.

ad 2. The discussion part has been re-written. I expanded the number of recent publications on the subject by more than 10. I added two tables with comparison of other detection systems with the presented one. 

ad 3. The conclusions part has been changed.

ad 4. The language in the whole text has been improved with the use of a specialised on-line service. This includes list of improvements suggested by you, as well as many more. 

All the figures have been improved, with figure 1 being completely changed.

I hope the changes I made are making the manuscript better and good enough to publish it. If you have any other remarks please do not hesitate to express them.

Yours Sincerely

Maciej Trzaskowski - corresponding author

Reviewer 2 Report

The authors proposed a portable and rapid COVID-19 antibody detection method based on a surface plasmon resonance chip with high sensitivity. This device can examine human plasma sample within 15-minute timeframe and will be further enhanced by automatization of the detection procedure. But there are still some problems, which I will address in turn.

In line 121, “Another advantage compared to 121 other fast antibody-testing methods is a possible (but not demonstrated herein)”, real advantages over other methods need to be described, not speculated.

In Figure 2, four data points are too few and the fit is not reliable.

In Figure 3, a more detailed explanation is needed, including the distribution of the 7 samples, the difference between the test channel and the control channel and their actual meaning.

In line 224, “Binding of antibodies in the initial SPR experiment resulted in linear quantitative answer in the range of 40-5000 ng/mL”, linear results are not supported by enough data.

Can the chip be used repeatedly? How reproducible are the results from multiple uses?

Minor：

In Abstract line 13, “Nucleic acid detection (PCR) is currently……” This shorthand is misleading.

In line 52-53, “spike glycoprotein (S) and nucleoprotein (N), and B cell epitopes with spike glycoprotein (S) and nucleoprotein (N)……” Abbreviated descriptions are repeated. A similar problem with abbreviations also occurs in line 115.

Author Response

Dear Reviewer

Thank you for all the remarks. I have corrected the manuscript and I am submitting the revised version.

Below my answers to the corrections you have suggested:

1. The unfortunate sentence has been removed. The manuscript includes now much larger comparison with other detection systems.
2. In the picture there are actually five data points, but since the first two points are close to each other (in comparison to other points) they seem to look as one. I clarified this by presenting these results also in the table.
3. I changed the figure 1 which is now more descriptive and shows what happens on each of the channels. I improved the description of experiments.
4. I agree, I changed the sentence. The purpose of the system is not to produce quantitative response.
5. The chip is intended to use repeatedly, the drift of control channel between samples has been included in the supplementary material.

Minor corrections have been applied

I hope the changes I made are making the manuscript better and good enough to publish it. If you have any other remarks please do not hesitate to express them.

Yours Sincerely

Maciej Trzaskowski - corresponding author

Round 2

Reviewer 1 Report

The authors incorporated relevant information (Table) in the discussion part, but they should have to write the newly added information sentence by sentence connected to their findings with good English structure. Table is not allowed in the discussion section.

Author Response

Dear Editor

Thank you for the remarks.

I improved the manuscript by writing information from the tables in the main text. I have also corrected some spelling and grammar mistakes.

Regarding the presence of tables in Discussion section. I could not find the rule forbidding the use of tables here. To me it is the most appropriate place where the table could be placed - right next to the section where its contents are described. 

Of course I may be wrong. Eventually the tables can be moved e.g. to the introduction or totally removed. Can we please leave this decision to the Editor?

Best regards

Maciej Trzaskowski

Reviewer 2 Report

The authors addressed my concerns.  I would like to recommend its publication.

Author Response

Thank you for all the comments and the acceptance of my manuscript. It has been further improved in terms of language and overall structure.

Best regards

Maciej Trzaskowski