Wave-Shaped Microstructure Cancer Detection Sensor in Terahertz Band: Design and Analysis
, Atiqul Alam Chowdhury 1,†, Mohammad Rakibul Islam 1,†, Md Sanowar Hosen 1,2,†, Mhamud Hasan Mim 1,†and Mirza Muntasir Nishat 1,†
Round 1
Reviewer 1 Report
Thanks to the Editor for the opportunity to review the manuscript “Wave Shaped Microstructure Cancer Detection Sensor in Terahertz Band: Design and Analysis” submitted to Applied Sciences. My reviewing comments are below.
In this work, the authors have designed a ZEONEX-based terahertz waveguide PCF which could be a potential waveguide for terahertz biosensing applications. The field is an active research area and the reported results are novel. Here I recommend the manuscript can be accepted if the authors properly address the following questions or suggestions:
Q1: The introduction is too lengthy in description of the disease and its detection techniques. Please trim it down appropriately to highlight the key points.
Q2: Is it necessary to keep four significant digits after the decimal point for the relative sensitivity in the simulation results? Can the experimental instrument detect this accuracy during the actual test?
Q3: Lines 102-104 of the manuscript describe the refractive index as a basis for the sensor to differentiate between different biomaterials. Some biosensor examples are mentioned in the lines 108-110, but the authors should place more emphasis on fiber biosensors in this section. Meanwhile, the authors should discuss why they choose to work with Terahertz band PCF in detail.
Q4: In equation (7), whose absorption loss is αmat referring to? Is it necessary to take into account the loss factor of the material to be measured in the effective material loss?
Q5: Line 256 of the manuscript states that "In current manufacturing methods, 6.5 µm strut width is bearable". This statement needs to be supported by references.
Q6: Is it necessary to list the mode diagrams for all analyses in Figure 3? I do not think that the differences between the eight pairs of mode fields are significant. It is suggested that two sets of mode fields be selected as examples, along with a brief analysis of the mode diagrams.
Q7: I would like to know if the performance of the fiber is better if the support arm width is narrower than 10µm? If so, why did choose 10µm as the optimal parameter in the manuscript?
Q8: What is the role of discussing birefringence, dispersion, spot size, and beam divergence in discriminating the target in terahertz biosensors?
Q9: In Figure 4-14, in exception to the lines given in the legend, there are six other dashed lines that are not explained in the article. In addition, a comparative analysis of the sensor's performance against normal and cancer cells should be added to the text to show the ability of the biosensor to discriminate between cancer and normal cells.
Comments for author File: 
Comments.pdf
Author Response
Dear Reviewer, on behalf of all the co-authors I would like to warmly thank you for your constructive comments. "Please see the attachment, where we describe how we addressed your recommendations.
Author Response File: Author Response.pdf
Reviewer 2 Report
In this research, Khan et al. have carried out a series of simulations for the identification of cancer cells based on differences in refractive index in a fiber biosensor. The article is organized well, and it is structured in good shape. Though, the following points are strongly suggested to be addressed before possible publication:
1. The introduction is too long and laborious to follow. It is suggested to improve the structure of the introduction by summarizing some of the information and presenting 3 cohesive paragraphs with the first two emphasizing the importance of the work/literature and the last one describing the gist of the work.
2. Some information in the introduction such as Line 77: “After breast cancer, cervical cancer is the second most common type of cancer in women worldwide….”, Line 90 “cancer stages” and other ones, are partially irrelevant to the topic of the paper. Since the research focuses on an optic biosensor and performing simulations, it is strongly suggested to cover information from recent literature on these topics.
3. It is strongly recommended that a new Figure 1 be created for this research. Figure 1 usually should show the general workflow of the work, in this case, four subfigures can be suggested as the design of the sensor, mechanism of detection, method of simulation, and result/which cancer cells are identified. Figure 15 may be considered to be part of this new figure.
4. It is recommended to merge other figures together in a meaningful way, for example, Figures 5, 6, and 7 can be merged into a new figure with four subfigures to show the relation of parameters with frequency.
5. It is suggested that the authors expand the conclusion section by providing more insights for future perspectives such as the potential implementation of the proposed sensor for detection in systems that include more than one cell. Some helpful references can be: doi.org/10.3390/fluids7070238 and doi.org/10.3390/mi13071099
6. It is suggested to proofread the article for small typos and/or inconsistent styling. For example, in several places punctuation marks are missing (lines 27, 31, and so on) (line 300 please be aware that…).
Author Response
Dear Reviewer, on behalf of all the co-authors I would like to warmly thank you for your constructive comments. "Please see the attachment" where we describe how we addressed your recommendations.
Author Response File: Author Response.pdf
Reviewer 3 Report
Authors have used the hollow-core optical waveguide based on Photonic Crystal Fiber (PCF) for the identification of diverse types of cancer cells. I have following concerns regarding the manuscript.
Major
1. A sequential steps diagram should be included for explaining biosensor design and performance evaluation.
2. When talking about the refractive index of cancer cells and normal cells, their concentrations are ignored. Provide references to support these data.
3. Why are normal cell values and names not expressed in figures and captions?
4. Figure captions should be explained properly that one could easily understand the content without reading the main text.
5. Why authors have compared only the blood cancer (table 3) while, previously described sensors were also used for other types of cancers.
6. Authors should also discuss the study's limitations.
Minor
7. There are minor draft writing errors like mentioning the full names and abbreviations repeatedly, for instance, PML, FEM and etc. Once the abbreviation has been defined, there is no need to write the full name again.
8. Write the diameters of each sensor parameter in the figure 2 for ease of understanding.
9. Authors should divide the results and discussion into separate parts using subheadings.
10. Figure 15 explanation is missing from the text.
Author Response
Dear Reviewer, on behalf of all the co-authors I would like to warmly thank you for your constructive comments. "Please see the attachment" where we describe how we addressed your recommendations.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors addressed the comments.
Reviewer 3 Report
The author has made all the targeted modifications, and right now I suggest it can be accepted for publication.
