PONE-D-21-28832The Role of Positively Charge Poly-L-Lysine in the Formation of High Yield Gold Nanoplates on the Surface for Plasmonic Sensing ApplicationPLOS ONE

Dear Dr. Morsin,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Nov 09 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Yuan-Fong Chou Chau

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements. 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. We suggest you thoroughly copyedit your manuscript for language usage, spelling, and grammar. If you do not know anyone who can help you do this, you may wish to consider employing a professional scientific editing service.  Whilst you may use any professional scientific editing service of your choice, PLOS has partnered with both American Journal Experts (AJE) and Editage to provide discounted services to PLOS authors. Both organizations have experience helping authors meet PLOS guidelines and can provide language editing, translation, manuscript formatting, and figure formatting to ensure your manuscript meets our submission guidelines. To take advantage of our partnership with AJE, visit the AJE website (http://learn.aje.com/plos/) for a 15% discount off AJE services. To take advantage of our partnership with Editage, visit the Editage website (www.editage.com) and enter referral code PLOSEDIT for a 15% discount off Editage services.  If the PLOS editorial team finds any language issues in text that either AJE or Editage has edited, the service provider will re-edit the text for free. Upon resubmission, please provide the following: The name of the colleague or the details of the professional service that edited your manuscript A copy of your manuscript showing your changes by either highlighting them or using track changes (uploaded as a *supporting information* file) A clean copy of the edited manuscript (uploaded as the new *manuscript* file)”  3. We note that the grant information you provided in the ‘Funding Information’ and ‘Financial Disclosure’ sections do not match.  When you resubmit, please ensure that you provide the correct grant numbers for the awards you received for your study in the ‘Funding Information’ section. 4. Thank you for stating the following in the Acknowledgments Section of your manuscript:  "The research is funded by FRGS grant (FRGS/1/2019/STG07/UTHM/02/1) from the Ministry of Education (MoE) Malaysia and Hibah Penelitian GBU45 (No. B/515/IT9. C/PT.01.03/2021) from Institut Teknologi Sumatera. The authors also would like to thank to the Universiti Tun Hussein Onn Malaysia for partially sponsored this work. The experiment was conducted at Microelectronics & Nanotechnology - Shamsuddin Research Centre (MiNT-SRC), UTHM." We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form. Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows:  "The research is funded by FRGS grant (FRGS/1/2019/STG07/UTHM/02/1) (MM, FM) from the Ministry of Education (MoE) Malaysia (https://mygrants.gov.my) and Hibah Penelitian GBU45 (No. B/515/IT9. C/PT.01.03/2021) from Institut Teknologi Sumatera. The authors also would like to thank to the Universiti Tun Hussein Onn Malaysia for partially sponsored this work. The experiment was conducted at Microelectronics & Nanotechnology - Shamsuddin Research Centre (MiNT-SRC), UTHM" Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: No

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: In this manuscript, the authors proposed an anisotropic structure, gold (Au) nanoplates was synthesized using a two steps wet chemical seed mediated growth method (SMGM) directly on the substrate surface. They claimed that the high yield of Au nanoplates exhibit dual plasmonic peaks response that are associated with transverse and longitudinal localized surface plasmon resonance (TSPR and LSPR). Furthermore, the proposed structure is novel, and the results are valuable and exciting to the readers. However, the necessary references and physical mechanism are absent in the manuscript to explain the related results. In summary, I recommend that the manuscript undergo a major revision to address my comments below before resubmission to this journal.

1. Line 31-33, it is written that “The high yield of Au nanoplates … are associated with transverse and longitudinal localized surface plasmon resonance (tspr and lspr). The “(tspr and lspr)” should be used capital letters (TSPR and LSPR).

2. Line 55-57, it is written that “The physical method requires high equipment costs and a lengthy preparation process such as lithography [7]”. The suitable reference (Nanomaterials (2019),9(12),1691 and Results in Physics (2020) 17, 103116) are suggested to quote regarding this sentence.

3. Line 76-77, it is written that “Currently, our group have been working with AuNPs specifically in sensing application.” The related articles from your group should be quoted with respect to this sentence.

4. Line 79-80, it is written that “The sensing properties is strongly depending on the size and shape in producing their plasmon band.” The suitable references (J. Electromagn. Waves Appl. (2010) 24(8-9) 1005-1014 and Results in Physics (2019) 13, 102290) are suggested to be cited after this sentence.

5. Line 114, it is written that “The chemicals used for the synthesis are same as published in [Procedia]”. What is [Procedia]? Is it a reference? Please check this sentence.

6. Line 124-126, it is written that” The samples were prepared for 6 different sets of PLL 0.01 % (w/v) concentration; 0 %, 1 %, 5, %, 10 % and labelled as PL0, PL1, PL5 and PL10.” Only four different sets are presented in this sentence. Please check it. Besides, it suggests replacing “6” as “six”.

7. Line 175-176, it is written that” Table 1 listed all the intensity and angles for all samples.” Please clarify in more detail that how to measure the intensity.

8. Line 217-218, it is written that” The two peaks assigned as transverse SPR (tspr) for the first peaks and the second peak is longitudinal SPR (lspr). The tspr is free charges vibration in vertical direction of the AuNPs on the surface and lspr is vibration of free charges in the horizontal direction, i.e., parallel with substrate surface.” I think the explanation of the mechanism is not enough. To help the readers to understand the nature of LSPR and TSPR, authors can refer to “J. Appl. Phys. (2016), 120(9), 093110” and “Plasmonics (2008), 3(4), 157-164” or quote them for simplicity.

9. Line 221-230, the authors deduce the surface positive-negative charge pairs corresponding to Fig. 6. The simulation results is suggested to explain this point. If the authors cannot perform the simulations, they can quote the related articles for simplicity (e.g., J. Nanopart. Res. (2018) 20(7), 190 and Nanoscale Research Letters (2016), 11(1),41)

10. The references used in the text should be improved. To be beneficial for the readers to know the other approaches of plasmonic sensors, the suggested articles need to be included in the suitable place of introduction section, i.e., Nanomaterials (2020), 10(3), 493, Results in Physics (2019) 15, 102567, J. Nanopart. Res. (2020) 22(9), 297, Nanomaterials, 2020, 10(7), 1399, J. Phys. D: Appl. Phys. (2021) 54(11) 115301, Nanomaterials, 2020, 10(3), 493 and Results in Physics (2019) 15, 102567. Besides, please recheck the typos throughout the text.

Reviewer #2: This paper describes the design and it also provides some details of a boric acid sensor based on non-spherical gold nanoparticles (plates) attached to a solid surface. The sensitivity of such sensor to boric acid is low and has little practical importance. In contrast to what the authors are stating, the chemistry of nanoparticle stabilization on the surface coated with poly-lysine is more complex than simple electrostatic interaction. This had to be reviewed (this literature is available) and included in the discussion. The reproducibility of measurements are inadequately described in this manuscript. The paper is poorly written, with multiple grammatical errors.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

The Role of Positively Charge Poly-L-Lysine in the Formation of High Yield Gold Nanoplates on the Surface for Plasmonic Sensing Application

PONE-D-21-28832R1

Dear Dr. Morsin,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Yuan-Fong Chou Chau

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors have revised their manuscript according to my comments. This submission can now be accepted for publication.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No