Process Optimization for Coating of Acanthus Ilicifolius Extract on Silk Sutures

Abstract

This study investigates the optimization of process parameters for coating silk sutures with Acanthus ilicifolius leaf extract. The increasing awareness of surgical site infections is a critical concern associated with the use of sutures in medical procedure undertaking. Our study aimed to assess the impact of three crucial coating factors, namely extract content, temperature, and duration, on the mechanical and antibacterial characteristics of silk sutures braided together. Through Box–Behnken design, in conjunction with the response surface approach, we conducted a thorough analysis to refine the model. The result showed that extract concentration directly influences both antimicrobial activity and elongation, while temperature and time primarily affect tensile strength and bending stiffness. To achieve the maximum tensile strength, minimum breaking elongation, minimum bending stiffness, and lower friction, all while maintaining the important antimicrobial efficacy of the sutures, this study emphasizes the use of response surface methodology in optimizing coating parameters for A. ilicifolius leaf extract on silk sutures. The response models are developed on the complex relationships between these parameters and the properties of the sutures.

Keywords

Antimicrobial Braiding Coating Leaf extract Silk Suture

Introduction

Surgical site infections have garnered increased attention due to the widespread use of sutures and other surgical instruments. With approximately 27 million surgical procedures performed annually in the United States, it is estimated that 300,000–500,000 surgical site infections may occur each year.¹ Silk stands out for its excellent biocompatibility, characterized by reduced inflammation, minimal immunological reactions, and a reduced propensity for blood clotting—qualities highly sought after in biomaterial systems.² Silks are emerging as valuable biomaterials, boasting superior mechanical performance when compared to a variety of both natural and synthetic polymers. This goes beyond their historical significance in the world of premium textiles.³ Innovative silk sutures, coated with light responsive porous ZnO, have been developed to enhance the healing speed, antimicrobial efficacy, and controlled self-degradation. These sutures have shown significant improvements in wound healing, infection management, and scar formation.⁴

Sutures can contribute to surgical site infections by harboring bacteria, leading to the formation of harmful biofilms as a foreign substance. Antibacterial suture materials excel at inhibiting bacterial growth, preventing biofilm formation, and reducing infection rates.⁵ Currently, triclosan-coated polyglycolic acid sutures are the most widely used antibacterial sutures. However, recent research reveals significant concerns with triclosan-based sutures, as triclosan can accumulate in human milk, cord blood, adipose tissue, and urine, potentially impacting the immune, endocrine, and reproductive systems. Braided structures, formed by intertwining three or more filaments or yarns along the axis, result in a denser and more robust configuration. In braided structures, filaments follow helical paths while creating interconnections, exhibiting nonlinear behaviors when subjected to axial tensile loads.⁶ These structures have a remarkable knot-holding capacity, thanks to the enhanced frictional forces due to the mobility of the threads, preventing knot untying in the case of failure.⁷

Acanthus ilicifolius, also known as sea holly or holly-leaved acanthus, has garnered significant attention from the scientific and medical communities due to its rich reserve of secondary metabolites and its long-standing use in traditional medicine.⁸ This plant naturally thrives in coastal and brackish water environments across diverse regions globally.⁹ Antimicrobial tests have shown its inhibitory effects on specific Gram-positive and Gram-negative bacteria, demonstrating promising antimicrobial properties.¹⁰ The surface treatment of suture materials plays a crucial role in determining their frictional properties. Depending on the type of coating material used, surface treatments can either enhance or diminish frictional characteristics. Understanding these frictional properties is vital for assessing the medical applications of novel coating materials. Coating sutures with A. ilicifolius as a natural antimicrobial agent has the potential to reduce infection risks, inflammation, and the likelihood of antimicrobial resistance while promoting sustainability in surgical procedures. This extract was chosen due to its unique properties, including its demonstrated antimicrobial efficacy against a broad spectrum of pathogens, its potential for reduced toxicity compared to synthetic alternatives, and its sustainable sourcing. In addition, prior research suggests that A. ilicifolius possesses wound healing properties, making it a promising candidate for enhancing the biological performance of surgical sutures.

An ideal suture must meet several criteria, encompassing mechanical properties, infection resistance, and inflammatory response. However, despite ongoing efforts, achieving an ideal choice remains elusive within the current market landscape. In addressing these challenges, our research focuses on optimizing the coating process of A. ilicifolius extract onto silk sutures.¹¹

The speed and efficacy of wound healing following a surgical procedure are intricately linked to the cleanliness of the surgical site. Mitigating microbial accumulation is pivotal for prompt patient recovery, thereby averting the substantial economic burdens associated with antibiotic usage.¹²

Even with the wide range of commercial sutures that are available in clinics, improving the biological performance of the sutures that are currently in use is still quite challenging. Wound infection is more prevalent following surgery, primarily as a result of bacterial infection at the wound site.

Materials and Methods

The leaves of A. ilicifolius were collected from Pichavaram village near Chidambaram in Tamil Nadu, India. They were washed and dried in a dark and ventilated environment. A dark and ventilated environment means that the leaves were kept under room conditions. Then, the dried leaves were powdered.

The 3-cm-long braided silk sutures were treated with acetone, allowed to dry for 5 h at room temperature, and then coated using the dip coating technique, which required them to be submerged in solution. Following their removal from the solution, the coated sutures were allowed to air dry for a full day at room temperature.

Braided silk sutures were coated by soaking them in solutions containing water, A. ilicifolius extract, and surfactants such as Triton X-100, at concentrations of 5%, 10%, and 15%, employing a dip coating technique. The levels of the process parameters were chosen in accordance with the relevant literature.¹³ Following their removal from the solutions, the coated sutures were allowed to air dry for a full day at room temperature.

Antimicrobial Activity

An agar diffusion test (SN 195920–1992) was used to assess the antimicrobial activity of the A. ilicifolius leaf extract coated sutures against gram-positive Staphylococcus aureus ATCC 25923 and Gram-negative Escherichia coli ATCC 25922. A range of concentrations of treated and untreated silk sutures was tested for antibacterial activity. A non-inhibitory agar substrate was used to take up the bacterial strains to obtain a zone of inhibition. Subsequently, the untreated and A. ilicifolius extract-treated sutures were gently inserted into the bacterial layer. The bacterial inhibition zones of all three sutures were measured and captured on a camera following a 24-h incubation period at 37°C. A lack of bacterial development immediately surrounding the suture sample is indicative of antimicrobial activity.

Morphological Analysis

Surface topography analysis of sutures was conducted before and after coating through the examination of images captured by a Quanta 200 Scanning Electron Microscope (SEM).

Development of Antimicrobial Coated Braided Suture

The impact of three distinct coating parameters—namely, extract concentration (at 5%, 10%, and 15%), temperature (at 50°C, 60°C, and 70°C), and duration (at 30, 60, and 90 min)¹³ on the tensile strength, elongation, bending stiffness, and friction of braided silk sutures with a 1/2 structure was systematically investigated.¹⁴ The selection of these specific coating parameters was informed by the relevant literature.¹⁵ To unravel the intricate relationship between these parameters and the desired outcomes, we employed the response surface methodology (RSM) using the Box–Behnken design (BBD) due to its ability to provide a robust coefficient approximation for modeling these relationships.¹⁶

The particulars of the coating parameters employed in this study are detailed in Table 1. Using the designated boundary values and the Box–Behnken methodology, we executed a series of experiments, and the results, encompassing tensile strength, elongation, bending stiffness, friction, and inhibition zone (in millimeters), are outlined in Table 2.

Table 1.

Experimental range of independent variables.

Variable	Levels
Variable	−1	0	1
Extract concentration, % (X₁)	5	10	15
Temperature, °C (X₂)	50	60	70
Time, min (X₃)	30	60	90

Table 2.

Experimental design for the independent variables and their response values.

Sample no.	Factors
Sample no.	A: concentration, % (X₁)	B: temperature, °C (X₂)	C: time, min (X₃)
1	5	50	60
2	15	50	60
3	5	70	60
4	15	70	60
5	5	60	30
6	15	60	30
7	5	60	90
8	15	60	90
9	10	50	30
10	10	70	30
11	10	50	90
12	10	70	90
13	10	60	60
14	10	60	60
15	10	60	60

The validity of the derived equations was established through an analysis of variance (ANOVA), where the p-value served as a measure of the model’s reliability. A small p-value, typically below 0.05, was considered statistically significant.¹⁷ The R² value, denoting the fraction of the variance in response that the model explains, was used to assess model validity. Models with an R² exceeding 60% were deemed valid. The nature of the fitted quadratic model was characterized using the coefficient of determination R² and the predicted R² (Pred-R²). The response surface approach was employed to delineate the individual and interactive effects of the test variables on the mechanical and handling properties.¹⁸

In accordance with the BBD, 15 meticulously planned tests were executed to explore the impact of the three specified factors, and the results are thoughtfully presented in Table 2. The functional relationship between the experimental variables and the response values can be expressed through Equation (1):

\begin{matrix} Y = β_{0} + β_{1} X_{1} + β_{2} X_{2} + β_{3} X_{3} + β_{12} X_{1} X_{2} + β_{13} X_{1} X_{3} \\ + β_{23} X_{2} X_{3} + β_{11} X_{1}^{2} + β_{22} X_{2}^{2} + β_{33} X_{3}^{2} \end{matrix}

(1)

where Y symbolizes the responses, while β₀ serves as the constant coefficient. In addition, the coefficients β₁, β₂, β₁₂, β₁₃, and so on, are associated with the linear, quadratic, and interaction effects, respectively. Furthermore, X₁, X₂, and X₃ represent the concentrations of the extract, temperature, and time, respectively.

The p-values obtained for this model are less than 0.0001 for parameters related to tensile strength, elongation, bending stiffness, and friction. These extremely low p-values provide strong evidence that the quadratic models obtained are statistically significant. Consequently, these models can be reliably employed to predict the mechanical and handling characteristics of braided silk sutures (Table 3).

Table 3.

Mechanical and antimicrobial properties of developed sutures.

Sample no.	Tensile strengthN	Breaking elongation%	Bending stiffnesscN/mm²	FrictioncN	Staphylococcus aureus (SA) (inhibition zone) mm	Escherichia coli (EC) (inhibition zone) mm
1	44	24	2.8	12.4	15	16
2	45	26	2.3	12.3	25	18
3	39	24	2.2	16.0	17	22
4	39	26	2.2	12.9	25	25
5	44	23	2.1	12.9	17	18
6	44	26	1.8	12.7	23	23
7	48	24	2.8	12.8	15	21
8	48	27	2.4	11.2	28	24
9	43	24	1.6	13.0	20	18
10	39	24	1.8	15.2	24	26
11	49	25	2.5	11.9	23	24
12	41	24	2.2	14.2	26	26
13	45	22	1.6	11.8	25	26
14	45	22	1.6	12.0	25	25
15	42	22	1.6	11.9	24	27

Result and Discussion

Effect of the Coating Parameters on Tensile Strength

The coefficients of the response surface model for tensile strength, as presented in Equation (2), yield a predicted R² value of 0.9331. This prediction demonstrates a strong alignment with the adjusted R² value of 0.9453, indicating that the disparity between the two values is minimal, with a difference of less than 0.2.

Figure 1(a) presents a contour plot depicting the impact of extract concentration and temperature on tensile strength while keeping the coating process duration constant. The highest tensile strength, measuring 45 N, is achieved at an extract concentration of 15% and a temperature of 50°C. Notably, the results indicate that the interaction between concentration and temperature does not significantly affect tensile strength, as shown in Figure 1(a). This suggests that the coating treatment exclusively influences the surface of the suture material and has no discernible impact on the underlying suture material. A similar observation was made in the work by Debbabi and Abdessalem¹⁹ when coating polyamide braided sutures with chitosan.

Figure 1.

Effect of (a) extract concentration and temperature, (b) temperature and time, (c) extract concentration and time, and (d) perturbation on tensile strength of the silk sutures.

In Figure 1(b), we can observe a contour plot representing the influence of temperature and time on tenacity, with the extract concentration held constant. It is worth noting that increasing the temperature and time leads to a reduction in tensile strength across all levels. Furthermore, the contour depicted in Figure 1(c) reveals a direct correlation between time and tensile strength of the suture. Figure 1(d) presents a perturbation plot for tensile strength, clearly demonstrating that temperature and time exert a significant influence on tensile strength:

\begin{matrix} Tensile strength = 44.34 - 2.99 X_{2} + 2.13 X_{3} \\ - 1.15 X_{2} X_{3} - 2.66 {X_{2}}^{2} \\ + 1.47 {X_{3}}^{2} \end{matrix}

(2)

Effect of the Coating Parameters on Elongation

The coefficients for the response surface model of elongation, as defined by Equation (3), demonstrate the impact of coating parameters on elongation, as depicted in the contour plots shown in Figure 2.

Figure 2.

Effect of (a) extract concentration and temperature, (b) temperature and time, (c) extract concentration and time, and (d) perturbation on breaking elongation of the silk sutures.

In Figure 2(a), we observe that a higher concentration of extract leads to an increase in breaking elongation. This phenomenon might be due to the complex interactions between the extract concentration and other factors. At lower concentrations, the extract might have a strengthening effect on the silk suture, leading to increased breaking elongation. The highest breaking elongation value, 27%, is achieved at an extract concentration of 15%, a temperature of 60°C, and a time of 90 min. The relationship between these three factors and elongation, as the response, is elucidated in Equation (4). Figure 2(b) portrays the influence of temperature and time on breaking elongation. Notably, as the temperature rises, the length of filament elements relative to the braid axis also increases. Figure 2(c) showcases the impact of extract concentration and time on breaking elongation, providing valuable insights into this relationship. Finally, Figure 2(d) presents the perturbation plot for breaking elongation, further enhancing our understanding of this critical parameter:

\begin{matrix} Elongation = 22.00 + 1.25 X_{1} - 0.125 X_{2} \\ + 0.375 X_{3} + 1.88 X_{1}^{2} + 1.13 X_{2}^{2} \\ + 1.12 X_{3}^{2} \end{matrix}

(3)

Effect of the Coating Parameters on Bending Stiffness

The coefficients derived from Equation (4) elucidate the bending stiffness within the response surface model. The interplay among extract concentration (X1), temperature (X2), and time (X3) reveals elliptical contours, signifying the presence of ideal factor interactions. Figure 3(a) illustrates a contour plot showcasing the relationship between bending stiffness and extract concentration along with temperature. It discerns a notable trend: as extract concentration escalates from 5% to 11%, bending stiffness decreases, but beyond 11%, it exhibits an upward trajectory. Figure 3(b) presents another contour plot, this time exploring the influence of temperature and time on bending stiffness.

Figure 3.

Effect of (a) extract concentration and temperature, (b) temperature and time, (c) extract concentration and time, and (d) perturbation bending stiffness of the silk sutures.

The 1/1 structure exhibits reduced bending stiffness when the temperature remains constant. The greatest bending stiffness value, measuring 2.8 cN/mm², is achieved at a 5% extract concentration and a temperature of 50°C. In Figure 3(c), you can observe a contour plot illustrating the impact of extract concentration and time on bending stiffness. Figure 3(d) provides a perturbation plot depicting the variations in bending stiffness:

\begin{matrix} Bending stiffness = 1.71 - 0.1625 X_{1} - 0.1000 X_{2} \\ + 0.3125 X_{3} + 0.5069 X_{1}^{2} \\ + 0.2569 X_{2}^{2} \end{matrix}

(4)

Effect of the Coating Parameters on Friction

The response surface model’s coefficients for friction, as described in Equation (5), are presented. In Figure 4(a), a contour plot visually depicts the impact of extract concentration and temperature on friction while keeping the suture’s structure constant:

\begin{matrix} Friction = 12.12 - 0.5769 X_{1} + 1.09 X_{2} \\ - 0.4163 X_{3} - 0.7412 X_{1} X_{2} \\ - 0.4600 X_{1} X_{3} + 1.38 X_{2}^{2} \end{matrix}

(5)

Figure 4.

Effect of (a) extract concentration and temperature, (b) temperature and time, (c) extract concentration and time, and (d) perturbation friction of the silk sutures.

In this situation, both temperature and time exhibit an indirect influence on friction. Figure 4(b) illustrates a contour plot depicting how friction is influenced by temperature and time. In Figure 4(c), you can observe a contour plot showcasing the impact of extract concentration and time on friction. It is noteworthy that an increase in the duration of the coating process, spanning from 30 to 90 min, results in a reduction in frictional values.

The highest friction value, measuring 16 cN, is achieved when employing a 5% extract concentration and maintaining a temperature of 70°C. To provide further insight into the behavior of friction, Figure 4(d) presents a perturbation plot for this parameter.

Effect of Coating Parameters on Antimicrobial Activity Against S. aureus

The antimicrobial activity coefficients derived from the response surface model, as delineated in Equation (6), exhibit elliptical contours when illustrating the interplay between extract concentration (X1), temperature (X2), and time (X3). This distinctive pattern emerges when there are ideal interactions between these factors.

The contour plots in Figure 5 provide a visual representation of the bacterial reduction (S. aureus (SA)) in response to variations in extract concentration, temperature, time, and their combined effects. Let us delve into each plot individually. In Figure 5(a), the contour plot illustrates how the bacterial reduction (SA) changes with varying extract concentration and temperature. Notably, it reveals that an increase in extract concentration from 5% to 15% leads to a corresponding increase in bacterial reduction (SA). Figure 5(b) showcases the contour plot for bacterial reduction (SA) concerning the interplay of temperature and time. Of particular interest, the plot highlights that the most significant zone of inhibition, measuring 28 mm (SA), is achieved when employing a 15% extract concentration, operating at 90°C, and a duration of 60 min.

Figure 5.

Effect of (a) extract concentration and temperature, (b) temperature and time, (c) extract concentration and time, and (d) perturbation bacterial reduction (SA) of the silk sutures.

In Figure 5(c), we can observe the contour plot depicting the combined influence of extract concentration and time on bacterial reduction (SA). The contours reveal the intricate relationship between these two factors in shaping bacterial reduction. Figure 5(d) introduces the perturbation plot, shedding light on the variations in bacterial reduction (SA). This plot offers insights into how different factors may perturb or influence the bacterial reduction, adding a valuable layer of understanding to the study’s findings:

\begin{matrix} Bacterial reduction (SA) = 23.69 + 4.59 X_{1} \\ + 1.26 X_{2} + 1.00 X_{3} + 1.50 X_{1} X_{3} - 3.22 X_{1}^{2} \end{matrix}

(6)

Effect of Coating Parameters on Antimicrobial Activity Against E. coli

The antimicrobial activity coefficients, as determined by the response surface model outlined in Equation (7), reveal an interesting interaction pattern among three key variables: extract concentration (X1), temperature (X2), and time (X3). This pattern is characterized by elliptical contours, which typically manifest when these factors exhibit perfect interactions.

The effects of extract concentration and temperature on the lower of SA bacteria are shown in Figure 6 as the percentage of reduction (E. coli (EC)) with time is constant. The results visibly explain the trend: the bacterial reduction (EC) increases along with the extract concentration (X1) as it rises from 5% to 15%. The contour figure presented in Figure 6(b) investigates the link among temperature, time, and bacterial reduction (EC). Notably, the maximum zone of inhibition, measuring 27 mm (EC), is achieved with a 10% extract concentration, a temperature of 60°C, and a treatment time of 60 min. This highlights the significance of these factors in maximizing the effectiveness of the treatment.

Figure 6.

Effect of (a) extract concentration and temperature, (b) temperature and time, (c) extract concentration and time, and (d) perturbation bacterial reduction (EC) of the silk sutures.

In Figure 6(c), we observe another contour plot, this time focusing on the interplay between extract concentration and time concerning bacterial reduction (EC). This analysis sheds further light on how varying these parameters impacts the reduction of SA bacteria. Figure 6(d) presents a perturbation plot, offering additional insights into bacterial reduction (EC). Overall, these graphical representations emphasize the importance of extract concentration and temperature in enhancing the efficacy of the treated sutures, thereby reducing the presence of SA bacteria:

\begin{matrix} Bacterial reduction (EC) = 26.40 + 1.69 X_{1} \\ + 2.70 X_{2} + 1.39 X_{3} \\ - 1.27 X_{2} X_{3} - 4.12 X_{1}^{2} \\ - 1.95 X_{2}^{2} - 0.9750 X_{3}^{2} \end{matrix}

(7)

Zone of Inhibition Assay

Figure 7 illustrates a distinct area of inhibition surrounding a silk suture coated with A. ilicifolius extract, exhibiting its remarkable efficacy against both S. aureus and E. coli. This observable zone emerges due to the gradual release of the extract into the agar medium. Undoubtedly, the A. ilicifolius extract displays exceptional antimicrobial properties.

Figure 7.

Antimicrobial activity of sutures coated with A. ilicifolius leaf extract against (a) S. aureus and (b) E. coli.

SEM Analysis

The surfaces of both treated and untreated sutures were meticulously examined through the powerful tool of scanning electron microscopy (SEM). In Figure 8, we present a series of SEM images capturing the treated sutures at varying magnifications, including 100×, 200×, 1000×, and 3000×. These vividly captured images unmistakably reveal a significant and remarkable adhesion between the extracted particles and the surface of the sutures. This adhesion is consistently observed along the entire length of the sutures, emphasizing the effectiveness of the treatment. Furthermore, the SEM analysis uncovers a fascinating revelation: the sutures display an intriguingly uneven distribution and morphology. The deposition of A. ilicifolius particles exhibits a diverse range of particle sizes. This variability in particle size adds an extra layer of complexity to the suture’s overall structure, further underscoring the intricacies of this fascinating observation. A. ilicifolius extract undergoes physical adsorption onto the surface of silk fibers through non-covalent interactions, such as hydrogen bonding, van der Waals forces, and electrostatic interactions. This initial adsorption can provide a foundation for further interactions and bonding. Certain compounds present in the extract, such as polyphenols and tannins, have the potential to form covalent bonds with functional groups on the silk fibers, such as hydroxyl (–OH) and amino (–NH2) groups. This chemical bonding enhances the adhesion of the extract to the silk substrate and contributes to its stability.

Figure 8.

SEM images of the treated sutures.

Optimization of Mechanical and Handling Characteristics

The Design Expert software was employed to optimize the independent variables, ensuring they align with the desired antimicrobial and mechanical characteristics. This optimization process aims to achieve the predefined response that satisfies all the variable properties, as outlined in Table 4.

Table 4.

Constraints used for optimization.

Response	Goal	Lower limit	Upper limit
Tensile strength (N)	Maximum	38.7	49.36
Breaking elongation (%)	Minimum	22	27
Bending stiffness (cN/mm²)	Minimum	1.6	2.8
Friction (cN)	Minimum	11	16
Inhibition zone—SA (mm)	Maximum	15	27
Inhibition zone—EC (mm)	Maximum	16	26

The findings indicate that the mechanical and handling characteristics of the suture are influenced by multiple factors rather than a single one. In Table 5, you can find the projected values for extract concentration, temperature, and time as provided by the model. Table 6 presents the error percentage between the predicted values and the experimental values, which were determined through repeated runs based on the optimization process parameters.

Table 5.

Forecasted values given by the model.

Independent variables	Values
Extract concentration (%)	11
Temperature (°C)	58
Time (min)	69
Dependent variables	Predicted values
Tensile strength (N)	45.6
Breaking elongation (%)	22.6
Bending stiffness (cN/mm²)	1.7
Friction (cN)	11.5
Inhibition zone (SA) mm	25
Inhibition zone (SA) mm	26

Table 6.

Experiment results conducted at optimum parameters.

S. no		1	2	3
Extract concentration		11	11	11
Temperature		58	58	58
Time		69	69	69
Tensile strength (N)	PV	45.65	45.85	45.42
Tensile strength (N)	EV	45	45.2	45.9
Error %		1.42	1.42	−1.06
Breaking elongation (%)	PV	22.66	22.5	22.45
Breaking elongation (%)	EV	22.5	22.9	23.2
Error %		0.71	−1.78	−3.34
Bending stiffness (cN/mm²)	PV	1.74	1.68	1.72
Bending stiffness (cN/mm²)	EV	1.68	1.75	1.76
Error %		3.45	−4.17	−2.33
Friction (cN)	PV	11.5	11.3	11.6
Friction (cN)	EV	11.2	11.6	11.8
Error %		2.61	−2.65	−1.72
Inhibition zone (SA) mm	PV	25.6	25.5	25.3
Inhibition zone (SA) mm	EV	25	25	25
Error %		2.0	1.9	1.1
Inhibition zone (EC) mm	PV	26.4	26.3	26.4
Inhibition zone (EC) mm	EV	26	26	26
Error %		1.5	1.1	1.5

PV: predicted values; EV: experimental values.

Conclusion

This study uncovers the application of advanced design software to fine-tune the coating parameters for braided silk sutures. To investigate this, a statistical analysis was carried out using the ANOVA technique, with a confidence level of 95%. The study delved into the impact of various coating parameters, including extract concentration, temperature, and time.

The primary aim of this research was to optimize the coating parameters for braided silk sutures. The ideal combination of independent variables that yielded the highest tensile strength (42.065 N), the lowest breaking elongation (23.049%), the minimum bending stiffness (1.6 cN/mm²), and a friction value of 15 cN was achieved with a silk extract concentration level of 4.431 twists per inch, a braid angle of 30.19°, and a 1/1 braided structure. This extract offers promising antibacterial characteristics, which could effectively combat microbial colonization at surgical sites. We aim to enhance their biological activity, mitigate biofilm formation, and minimize contamination.

The quadratic models developed through RSM proved to be highly accurate and can be effectively used for predicting the mechanical and handling properties of braided silk sutures.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Sakthivel Santhanam

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