Optimization of Mechanical and Setting Properties in Acrylic Bone Cements Added with Graphene Oxide

Round 1

Reviewer 1 Report

1. The current study aims to optimise mechanical and setting characteristics of a mixture made from acrylic bone cement and graphene using design of experiments. The material used in orthopaedics and use of acrylic generally have some disadvantages in terms of performance and impact on the patient health. The authors analyse several parameters namely sonication time, graphene oxide percentage and other metrics. The authors reported that temperature was reduced during polymerization when using the GO and most combinations analysed gave desirable properties for the acrylic ABS.
2. The abstract needs improvement, please consider reviewing the abstract and highlight the novelty, major findings and conclusions.
3. Please consider revising the title, perhaps the words randomized factorial design can be removed, I don’t think this extra words add any value to the title.
4. At the end of the introduction just before line 81 please answer the following question: What is the research gap did you find from the previous researchers in your field? Mention it properly. It will improve the strength of the article.
5. Please avoid using we or our in the manuscript please check this issue everywhere
6. Please combine smaller paragraphs in the introduction into larger ones, please check this issue elsewhere as well. For example lines 78-80 this is a small paragraph which can be merged with previous one.
7. Materials and method section lacks any images or figures of the test equipment, experimental setup or produced samples before and after testing..etc this is an experimental study and detailed information of all experimental tests and methods used must be shown using proper graphs and images.
8. Please consider removing figure 2 we know every well how the stress strain diagram of an ABS material looks like, perhaps this graph is more suitable for a lab report or a thesis..but not in a scientific paper
9. Again please merge smaller paragraphs into larger ones there are many of them in the results and discussion section
10. Please add a table summarising the input parameters used in the design of experiments and the generated array, how many input parameters, how many analysed output parameters, what are their levels and how many runs in total you tested?
11. The materials and method section can be better presented using tables and graphs instead of text only.
12. The quality of figures 3, 4, 5, 6, 7, 8  are very poor please upload one with better resolution
13.  In figure 3 the authors used two levels for the solid ratio, five for the liquid ratio and two for sonication? Is that correct, any way why you choose those levels, is it according to literature or recommendation from industry or just decided by the authors for the sake of this study?
14. Can the authors please show us the percentage contributions of the ANOVA and which input parameters are significant and which ones are not on each of the analysed output parameters
15. Very repetitive pattern of writing Based on Tukey's test… please try to change it sometimes to make the reading of the manuscript more interesting.
16. The results are described to good level but still limited to comparing the experimental observation found from the experimental design. The authors are encouraged to include more detailed discussion and critically discuss the observations from this investigation with existing literature.
17. Please add some bars graphs showing the results from different tests this can better help us evaluate your findings.
18. Also there are many repetitive tables 1-7, please consider moving them to an appendix as they don’t give any valuable information other than showing the different combinations of input parameters. Instead it is better to plot some bar graphs and representative figures in addition to the mean plots.
19. Also please consider combining many of the mean plots into one figure (recommended)

Author Response

Referee 1

Recommendation: Major revisions

Comments:

1. 
   The current study aims to optimise mechanical and setting characteristics of a mixture made from acrylic bone cement and graphene using design of experiments. The material used in orthopaedics and use of acrylic generally have some disadvantages in terms of performance and impact on the patient health. The authors analyse several parameters namely sonication time, graphene oxide percentage and other metrics. The authors reported that temperature was reduced during polymerization when using the GO and most combinations analysed gave desirable properties for the acrylic ABS.

 

We appreciate the reviewer's comment, and we want to specify that although all the conditions studied to reach the maximum temperature established in the standard, it is clear that a more significant reduction in this parameter generates a reduction in the thermal necrosis of the periprosthetic tissue, which will have a considerable impact on the applicability of the cement and the patient's health. Each of the factors studied in this research showed a substantial effect on the T_max, and therefore the paper reports in lines 205 - 207 that "Figure 4 exhibits the interaction plot for T_max. Increasing the sonication time and the BPO/Solid ratio promoted T_max's higher values_, while higher GO percentages decrease the T_max reached during polymerization". Knowledge of the effect of each of these factors will allow the development of improved ABC formulations with the lowest possible T_max.

 

 

2. The abstract needs improvement, please consider reviewing the abstract and highlight the novelty, major findings and conclusions.

 

We appreciate the reviewer's comment, and we improved the abstract according to the recommendation.

 

3. Please consider revising the title, perhaps the words randomized factorial design can be removed, I don't think this extra words add any value to the title.

 

We appreciate the reviewer's comment. The indicated words "using a completely randomized factorial design" in the title were deleted.

 

4. At the end of the introduction just before line 81 please answer the following question: What is the research gap did you find from the previous researchers in your field? Mention it properly. It will improve the strength of the article.

 

We appreciate the reviewer's comment, and we added the following paragraphs at the end of the introduction:

"This article shows for the first time the interactions present between the factors sonication time and GO percentage in the liquid phase, together with the percentage of benzoyl peroxide (BPO) in the solid phase, on the mechanical and setting properties established for cements in the ISO 5833-02 standard. Optimizing the factors using a completely randomized experimental design with a factorial structure resulted in selecting nine formulations that presented an increase in compression, flexion, and the setting time and decreased the maximum temperature during the polymerization. Some of these combinations have not yet been studied, which broadens the possibilities for new formulations with desirable characteristics to improve the clinical performance of ABCs, that could be used in orthopedics."

 

5. Please avoid using we or our in the manuscript please check this issue everywhere

 

We appreciate the reviewer's comment. Some sentences were corrected according to the indication.

 

6. Please combine smaller paragraphs in the introduction into larger ones, please check this issue elsewhere as well. For example lines 78-80 this is a small paragraph which can be merged with previous one.

 

We appreciate the reviewer's comment. The combination of some paragraphs was introduced in the manuscript according to the suggestion.

 

7. Materials and method section lacks any images or figures of the test equipment, experimental setup or produced samples before and after testing..etc this is an experimental study and detailed information of all experimental tests and methods used must be shown using proper graphs and images.

 

We appreciate the reviewer's comment. Figures 2 and 3 were added with photographs of the molds and equipment used.

 

8. Please consider removing figure 2 we know every well how the stress strain diagram of an ABS material looks like, perhaps this graph is more suitable for a lab report or a thesis but not in a scientific paper

 

We appreciate the reviewer's comment, and we removed figure 2.

 

9. Again please merge smaller paragraphs into larger ones there are many of them in the results and discussion section

 

We appreciate the reviewer's comment, and we merged smaller paragraphs in the results and discussion section.

 

10. Please add a table summarising the input parameters used in the design of experiments and the generated array, how many input parameters, how many analysed output parameters, what are their levels and how many runs in total you tested?

 

We appreciate the reviewer's comment. Table 1 was added with the completely randomized experimental design with factorial structure applied in this study.

 

11. The materials and method section can be better presented using tables and graphs instead of text only.

 

We appreciate the reviewer's comment, and we added to table 1 and figures 1 and 2 to the materials and methods section.

 

12. The quality of figures 3, 4, 5, 6, 7, 8  are very poor please upload one with better resolution

 

We appreciate the reviewer's comment. The quality in the figures indicated was improved.

 

13. In figure 3 the authors used two levels for the solid ratio, five for the liquid ratio and two for sonication? Is that correct, any way why you choose those levels, is it according to literature or recommendation from industry or just decided by the authors for the sake of this study?

 

We appreciate the reviewer's comment. The sentence "Each level selected for the factors was based on a review of the values used in formulations of cements containing GO." In section 2.2, Experimental design was added.

 

 

14. Can the authors please show us the percentage contributions of the ANOVA and which input parameters are significant, and which ones are not on each of the analysed output parameters

 

We appreciate the reviewer's comment. In the random effect models, a variance components table is obtained showing the proportion (%) of the variation attributable to each of the main effects and, optionally, the interactions of the random variable with the other factors. However, since a fixed-effects model was used, the components' percentage contribution comes from analyzing the sum of squares of each element concerning the total (Adj SS in tables S2, S3, and S4 of the supplementary materials).

 

15. Very repetitive pattern of writing Based on Tukey's test… please try to change it sometimes to make the reading of the manuscript more interesting.

 

We appreciate the reviewer's comment. The correction was included.

 

16. The results are described to good level but still limited to comparing the experimental observation found from the experimental design. The authors are encouraged to include more detailed discussion and critically discuss the observations from this investigation with existing literature.

 

We appreciate the reviewer's comment, and we included some new references for an extended discussion of the results.

 

17. Please add some bars graphs showing the results from different tests this can better help us evaluate your findings.

 

R// We appreciate the reviewer's comment, and we want to specify that data include error bars (standard deviation) when the data is presented descriptively; for example, bar charts must be accompanied by standard deviations. The graphs presented in this paper are called interaction graphs, and they are used when the effect of one factor depends on the level of the other factor, and it is used to visualize the possible interactions during the ANOVA analysis, as it happened in this case. With bar graphs (means and standard deviations), the conclusions obtained are intuitive because they do not have an associated level of meaning.

 

The graph that the evaluator requests is, for example, for the compressive strength that could go into a descriptive analysis of the behavior of the treatments, but not in the modeling, because they do not show the interaction effect (only means and deviations) and how it is said previously, it does not have a significance level associated with it.

 

 

Other researchers have reported the use of Random Factorial Design, and they have used the same graphics used in this paper (Balasundaram & Sharma, 2015; Kritikos et al., 2020; Shukr et al., 2021)

 

18. Also there are many repetitive tables 1-7, please consider moving them to an appendix as they don't give any valuable information other than showing the different combinations of input parameters. Instead it is better to plot some bar graphs and representative figures in addition to the mean plots.

 

We appreciate the reviewer's comment. It should be noted that Tukey's tables of mean comparisons provide the necessary information in the analysis since the ANOVA does not specify between which treatments there are significant differences; however, with tests such as these, we can make comparisons between our treatments taking into account the control of the error rate per group at a specified level.

In this study, the analysis of which treatments had a statistically equal effect on the response variables was based on Tukey's mean comparison tables.

 

 

19. Also please consider combining many of the mean plots into one figure (recommended)

 

We appreciate the reviewer's comment; however, we considered that in a plot such as the one recommended by the reviewer, it would be difficult to show the behavior of each factor studied and the possible interactions between them.

 

 

References

Balasundaram, K., & Sharma, M. (2015). Investigations into a thiol-impregnated CaCO3-based adsorbent for mercury removal: a full factorial design approach. RSC Advances, 5(90), 73868–73874. https://doi.org/10.1039/c5ra10902g

Kritikos, M., Concepción Maure, L., Leyva Céspedes, A. A., Delgado Sobrino, D. R., & Hrušecký, R. (2020). A Random Factorial Design of Experiments Study on the Influence of Key Factors and Their Interactions on the Measurement Uncertainty: A Case Study Using the ZEISS CenterMax. In Applied Sciences  (Vol. 10, Issue 1). https://doi.org/10.3390/app10010037

Shukr, M. H., Ismail, S., El-Hossary, G. G., & El-Shazly, A. H. (2021). Design and evaluation of mucoadhesive in situ liposomal gel for sustained ocular delivery of travoprost using two steps factorial design. Journal of Drug Delivery Science and Technology, 61, 102333. https://doi.org/https://doi.org/10.1016/j.jddst.2021.102333

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

In the paper "Optimization of mechanical and setting properties in acrylic bone cements added with graphene oxide using a completely randomized factorial design" authors analysed the influence of variation in 3 factors (sonication time, GO admixture in the liquid phase and BPO addition in the solid phase) and its combinations on selected functional, thermal and mechanical properties of PMMA bone cements.

There is not really much to complain about while reading the submitted paper. The paper is well written and the results are supported by data. The abstract is concise yet comprehensive. Results may someday be important in clinical practice.

I’d suggest adding “PMMA” to keywords as it is the acronym often used for acrylic bone cements and using it may allow reaching wider circle of potential readers.

Maybe, in order to show wider picture of the presented research it would be good to add a small paragraph in introduction section discussing other research results on improving selected properties of bone cements using different chemical additives (biodegradable additives - cellulose, chitosan, magnesium, polydioxanone, or tricalcium-phosphate), antibiotics, hardening solutions (hardystonite with brushite, calcium phosphate), antimicrobial particles of silver sodium hydrogen zirconium phosphate, etc.) or research examining the admixture of other materials (contamination) present in the surgical field (saline solution, blood).

Also, I don’t know motivation of authors behind submitting this specific paper to Applied Sciences Journal, but I think it fits Materials or Polymers even better. The two Journals have number of special issues dedicated to orthopaedic biomaterials, bone regeneration medicine, etc. I’m not saying that the submitted paper is not appropriate for publications in Applied Sciences. It is. To my opinion, it would just fit in those two journals better.

Regarding the references list, I’d suggest getting familiar also with:

• as additional source of information about GO influence on thermal properties of bone cement:
• Graphene Oxide and Graphene Reinforced PMMA Bone Cements: Evaluation of Thermal Properties and Biocompatibility. Materials 2019, 12, 3146 (and related),
• as an information on influence of different addons on mechanical properties of bone cements:
• Effect of Physiological Saline Solution Contamination on Selected Mechanical Properties of Seasoned Acrylic Bone Cements of Medium and High Viscosity. Materials 2021, 14, 110. (and related)
• Influence of several biodegradable components added to pure and nanosilver-doped PMMA bone cements on its biological and mechanical properties. Mater. Sci. Eng. C 2020, 117, 111286 (and related),

Also references 39 and 40 are not really necessary in my opinion (esp. 40) as they refer to experiment planing techniques and statistic analysis methods that are currently well known and widely used.

The only publishing remark concerns mixed en dashes (–), em dashes (—) and hyphens (-) in tables 1-7.

 

Author Response

Referee 2

Recommendation: Minor revisions

Comments:

 

In the paper "Optimization of mechanical and setting properties in acrylic bone cements added with graphene oxide using a completely randomized factorial design" authors analysed the influence of variation in 3 factors (sonication time, GO admixture in the liquid phase and BPO addition in the solid phase) and its combinations on selected functional, thermal and mechanical properties of PMMA bone cements.

There is not really much to complain about while reading the submitted paper. The paper is well written and the results are supported by data. The abstract is concise yet comprehensive. Results may someday be important in clinical practice.

 

1, I'd suggest adding "PMMA" to keywords as it is the acronym often used for acrylic bone cements, and using it may allow reaching a wider circle of potential readers.

 

We appreciate the reviewer's comment. PMMA was added as a keyword

 

Maybe, in order to show wider picture of the presented research it would be good to add a small paragraph in introduction section discussing other research results on improving selected properties of bone cements using different chemical additives (biodegradable additives - cellulose, chitosan, magnesium, polydioxanone, or tricalcium-phosphate), antibiotics, hardening solutions (hardystonite with brushite, calcium phosphate), antimicrobial particles of silver sodium hydrogen zirconium phosphate, etc.) or research examining the admixture of other materials (contamination) present in the surgical field (saline solution, blood).

 

We appreciate the reviewer's comment. Text added is observed in lines 55 – 61:

"Some fillers like hydroxyapatite (HA) [14–17], phosphate bioglasses [18,19], silicate and borate bioglasses [20,21], tricalcium phosphates [22,23], Sepia Officinalis cuttlebone [24] and biodegradable polymers such as cellulose, chitosan, polydioxanone [25], polylactic acid (PLA), β-polyhydroxy butyrate (PHB), and thermoplastic starch (TPS) have been added to the solid phase of the cement for improving different properties; however, due to the inorganic nature of some of them and the biodegradable behavior of others, losses in their mechanical properties have been generated [26]."

 

 

Also, I don't know motivation of authors behind submitting this specific paper to Applied Sciences Journal, but I think it fits Materials or Polymers even better. The two Journals have number of special issues dedicated to orthopaedic biomaterials, bone regeneration medicine, etc. I'm not saying that the submitted paper is not appropriate for publications in Applied Sciences. It is. To my opinion, it would just fit in those two journals better.

 

We appreciate the reviewer's comment. Applied Sciences Journal was selected since the article's subject is related to the topics of Materials, nanotechnology, Applied nanoscience, and biomedical engineering published in this journal.

 

Regarding the references list, I'd suggest getting familiar also with:

• as additional source of information about GO influence on thermal properties of bone cement:
• Graphene Oxide and Graphene Reinforced PMMA Bone Cements: Evaluation of Thermal Properties and Biocompatibility. Materials 2019, 12, 3146 (and related),
• as an information on influence of different addons on mechanical properties of bone cements:
• Effect of Physiological Saline Solution Contamination on Selected Mechanical Properties of Seasoned Acrylic Bone Cements of Medium and High Viscosity. Materials 2021, 14, 110. (and related)
• Influence of several biodegradable components added to pure and nanosilver-doped PMMA bone cements on its biological and mechanical properties. Mater. Sci. Eng. C 2020, 117, 111286 (and related),

 

We appreciate the reviewer's comment. Some of the recommended references were added, and others. Some references such as "Mater. Sci. Eng. C 2020, 117, 111286" are not appropriate to discuss the present results due to the difference in the percentages of filler used (greater than 2%); however, the information provided in this paper was used as a reference to show the use of this type of filler.

 

Also references 39 and 40 are not really necessary in my opinion (esp. 40) as they refer to experiment planing techniques and statistic analysis methods that are currently well known and widely used.

 

We appreciate the reviewer's comment, and we removed references 39 and 40.

 

The only publishing remark concerns mixed en dashes (–), em dashes (—) and hyphens (-) in tables 1-7.

 

We appreciate the reviewer's comment, and we corrected this mistake.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

All questions were answered. the paper can be accepted,

congratulations to authors