An antibacterial suture with improved mechanical properties and produced from organic fibers

Abstract

The invention relates to a surgical suture made from hemp fibers, which exhibits wound-healing properties, high strength, durability, absorbency, antibacterial activity, and increased environmental benefits, as well as its method of production. These sutures are colored with organic walnut shell dye to make the thread more visible during surgery and sterilized for surgical use. The primary goal of these innovative sutures, subject to the invention, is to support the wound-healing process while reducing the risk of infection.

Description

[0001] AN ANTIBACTERIAL SUTURE WITH IMPROVED MECHANICAL PROPERTIES AND PRODUCED FROM ORGANIC FIBERS

[0002] Technical Area to which the Invention Relates

[0003] The invention relates to a surgical suture made from hemp fibers, exhibiting woundhealing properties, high strength, durability, absorbency, antibacterial activity, and increased environmental benefits, as well as its method of production. These sutures are dyed with organic walnut shell dye to improve visibility during surgery and are sterilized for surgical use. The purpose of sutures subject to the invention is to support the wound-healing process while reducing the risk of infection.

[0004] Known State of the Art

[0005] A surgical suture, or suture, is a natural or synthetic, sterile material used to approximate body tissues cut during surgical operations or injuries, to attach prostheses to tissues, and to connect blood vessels or ducts, thereby preventing bleeding or other leaks until healing occurs.

[0006] Surgical sutures are essential medical materials used in surgical interventions to hold wounds together and support the healing process. They are generally divided into two main categories: natural and synthetic. Natural threads include silk and catgut, while synthetic threads are made from a wider range of materials such as polyglactin, polypropylene, nylon, and stainless steel. Threads can also be classified according to their absorbability; some threads are absorbed by the body, while others are nonabsorbable and need to be removed once the wound has healed. Surgeons select the most suitable thread based on the type of surgical intervention and the patient's needs. These threads support the healing process by holding wounds together, reducing the risk of infection.

[0007] Among the sutures in the current technique, the most commonly preferred materials include nylon (e.g., Ethilon, Dermaion), polyester, silk, and stainless steel. While nylon is robust, its primary disadvantage is the difficulty in achieving secure knots. Monofilaments have more memory (a tendency to return to their packed shape) than braided sutures, making them prone to unraveling if not tied correctly. Achieving a secure final node typically requires at least four to five carefully constructed "shots" or knots [1]. Polyester sutures are more expensive than most alternatives and do not offer significant advantages over cheaper sutures, limiting their widespread use. Additionally, braided polyester sutures are unsuitable for use in contaminated and infected wounds, as bacteria can become trapped between the fibers, isolated from the phagocytic cells, and potentially lead to sinus tract formation [2], Silk sutures also have several disadvantages: they are non-absorbable and require removal, their multifilament structure can lead to bacterial and fluid accumulation, they provide less tension during early wound retraction, and they may trigger stronger inflammatory reactions, thereby increasing the risk of incision dehiscence [3]. Stainless steel sutures are not suitable for highly mobile areas as they can cut tissues and have poor handling properties [2],

[0008] An improvement in the field of sutures has become necessary due to the limitations and inadequacies of current solutions, the risk of unraveling caused by difficulties in knotting, high costs, risks of contamination and infection, the need for professional removal, and potential tissue damage.

[0009] Brief Description and Objectives of the Invention

[0010] The invention relates to a surgical suture with enhanced wound-healing properties, high strength, durability, absorbency, antibacterial activity, and environmental benefits, as well as its method of production. The suture subject to the invention is produced as follows; hemp fibers are dyed with a brown pigment with the chemical formula 5-hydroxy-1,4-naphthoquinone obtained from walnut shells, coated with polylactic acid (PLA), and then knitted into multifilaments using a five-thread machine, Finally, the fibers are coated with a mixture containing chlorhexidine diacetate, bay leaf oil, St. John's wort oil, and melted beeswax.

[0011] One purpose of the invention is to produce a suture with enhanced wound-healing properties. Thanks to the high drug-carrying capacity of biocompatible and biodegradable PLA, the suture subject to the invention is modified with St. John's wort oil, which promotes wound healing. Additionally, hemp supports healing by preventing bacterial accumulation, scarring, and delayed healing. Chlorhexidine diacetate provides an antibacterial effect, while bay leaf oil provides antioxidant properties. Another purpose of the invention is to provide a suture that is easy to handle during surgery. Hemp fibers with high knot safety are dyed with a brown pigment with the chemical formula 5-hydroxy-1,4-naphthoquinone, a naturally occurring compound found in various parts of walnut trees, such as leaves, roots, and bark, making the thread easily visible during the operation. Additionally, the multifilament structure of the wax-coated suture allows smooth passage and reduces the risk of tissue trauma and reaction formation due to its low friction. Its absorbable nature ensures that no foreign body remains in the body.

[0012] In addition, the invention aims to present a durable suture. For this purpose, hemp fiber, a natural material offering high strength, durability, and absorbency, is used in the suture's structure. Furthermore, hemp has additional benefits such as UV protection and anti-allergic properties. By coating it with durable, highly workable PLA, the suture's overall durability is further enhanced.

[0013] Another purpose of the invention is to produce a more environmentally friendly suture with increased sustainability. For this reason, agricultural and forestry waste produced in large quantities, such as walnut shells — which have a very limited usage area — are used. Additionally, PLA is a sustainable bioplastic material derived from renewable resources, including corn, starch, and sugar beets, thereby reducing the environmental impact of the invention.

[0014] Explanation of Figures

[0015] Figure 1. Structure of the suture subject to invention.

[0016] Figure 2. Final sample.

[0017] Figure 3. SEM image of five thread samples made from hemp fiber.

[0018] Figure 4. Tensile test results of five thread samples made of hemp fiber. (B1-B4: Five thread knitted master samples made of hemp fiber)

[0019] Figure 5. Comparison of tensile test results of a cotton thread (reference) sample and five thread samples made of hemp fiber (B1: Five-thread knitted specimen made of hemp fiber, P: Cotton thread (reference) sample)

[0020] Figure 6. FTIR graph of five thread samples made from hemp fiber (B1: Five-thread knitted specimen made of hemp fiber) Figure 7. Graph showing the rate at which surgical sutures (a) and coated sutures (patented invention) (b) reduce S. aureus and E. coli bacteria logarithmically.

[0021] Reference Numbers

[0022] 1. Hemp suture

[0023] 2. Polylactic acid (PLA) coating

[0024] 3. Beeswax, chlorhexidine diacetate, bay leaf oil, and St. John's wort oil blend coating

[0025] Detailed Description of the Invention

[0026] The invention relates to a surgical suture with enhanced wound healing properties, high strength, durability, absorbency, antibacterial properties, and environmental benefits, as well as its production method. The suture subject to invention contains;

[0027] a. multifilament hemp suture (1) consisting of five hemp fibers dyed with 5- hydroxy-1,4-naphthoquinone obtained from walnut shell and coated with polylactic acid (PLA) (2),

[0028] b. PLA coating (2) coated on the outer surface of hemp suture (1 ),

[0029] c. Beeswax coating (3) containing 20-80% by weight chlorhexidine diacetate, 25- 30% by weight bay leaf oil, 20-50% by weight St. John's wort oil, and 20-50% by weight beeswax

[0030] In one application of the invention, the surgical suture that is the subject of the invention includes the following:

[0031] a. multifilament hemp suture (1) consisting of five hemp fibers dyed with 5- hydroxy-1,4-naphthoquinone obtained from walnut shell and coated with polylactic acid (PLA) (2),

[0032] b. PLA coating (2) coated on the outer surface of hemp suture (1 ),

[0033] c. Beeswax coating (3) containing 8 mL chlorhexidine diacetate, 5 mL bay leaf oil, 5 mL St. John's wort oil, and 25 mL beeswax The invention relates to a surgical suture with enhanced wound healing properties, high strength, durability, absorbency, antibacterial properties, and environmental benefits, as well as its production method. The suture subject to invention contains hemp multifilaments obtained by knitting fibers dyed with 5-hydroxy-1,4-naphthoquinone pigment obtained from walnut shells and coated with polylactic acid (PLA) with five spinning machines, and a beeswax coating (3) containing chlorhexidine diacetate, bay leaf oil, and St. John's wort oil.

[0034] Hemp is a natural fiber that offers high strength, durability, and absorbency, with an annual fiber yield that is quite substantial. It also contains UV protection and antiallergic properties.

[0035] Surgical sutures are dyed with organic walnut shell dye to make the thread easily seen during an operation. Additionally, after the dyeing process, sutures are sterilized using air and chemicals to oxidize the dyestuff in the silk filaments. The main by-products obtained from the walnut fruit are green shell and hard shell. The chemical composition of walnut shell fibers includes ash, lignin, hemicellulose, and cellulose. Juglone can also be used as a natural source of dyeing. Juglone is a brown pigment found naturally in various parts of walnut trees, such as leaves, roots, and bark. Today, the use of green bark as an agricultural by-product is very scarce. However, utilizing walnut shells as a source of phytochemicals or natural compounds with antioxidant and antimicrobial properties can enhance the value of walnut cultivation and create new applications for agricultural waste.

[0036] Beeswax, on the other hand, serves as a natural lubricant, is inert to body fluids, and is resistant to sterilization conditions, making it suitable for coating surgical sutures. It consists of a mixture of acids, alcohols, and esters, both saturated and unsaturated, with a high molecular weight. These are alkaline esters (72%), free fatty acids (14%), hydrocarbons (11%), free alcohols (1%), and other trace substances (2%). The density of beeswax is close to one (0.966). Its melting point is 62-64 °C.

[0037] PLA is a material that has biocompatible and biodegradable properties and can be naturally broken down and absorbed by the body. Therefore, it is ideal for implants, surgical sutures, and other medical devices, which reduces the risk of allergic reactions or tissue rejection. The strong and durable properties of PLA allow it to be used in loadbearing applications such as orthopedic implants, dental supplies, and surgical instruments. PLA's malleability and drug-carrying capacity properties allow it to be used in different medical devices and products.

[0038] The cannabis sutures subject to the invention have a multifilament structure, providing easy passage through the tissue and reducing the risk of tissue trauma and reaction formation due to their low friction strength. Thanks to their absorbable and durable structure properties, they leave no foreign object in the body, and ensure knot safety. The beeswax, St. John's wort oil, chlorhexidine diacetate, and bay leaf oil in the aforementioned beeswax mixture provide surface smoothing, wound-healing properties, and antibacterial and antioxidant effects, respectively. The study results showed that surgical sutures had no antimicrobial activity against E. coli and S. aureus bacteria, but the coated suture sample reduced the growth of E. coli bacteria by 104times and the growth of S. aureus bacteria by 102times (Table 1).

[0039] Table 1: Antimicrobial activity results of surgical thread, coated suture (patented invention), and control sample.

[0040] Bacteria Control Surgical _ rope Logic Coated Thread SampleL°g10

[0041] Sample Reduced concentration _ after Reduced concentration after incubation (CFU. mL-1) incubation (CFU.

[0042] mL-1)

[0043] E. coli 5x1065x1060 8x1026,69 S. aureus 5x1065x1060 8x1044,79

[0044]

[0045] The manufacturing method of the surgical suture subject to the invention consists of the following process steps;

[0046] a. cleaning the bark of the hemp plant with a mechanical decorticator, scraping off the outer layers and pectins,

[0047] b. washing the extracted fiber with tap water and air drying,

[0048] c. immersion of the obtained raw fiber in a 20% by weight sodium hydroxide (NaOH) solution and heating at 95°C for 120 minutes,

[0049] d. afterwards, washing with deionized water to remove NaOH residues and drying at 27°C,

[0050] e. removing the resulting threads by pulling them out with tweezers to a thickness of 0.5 mm, f. mixing 20-30 grams of walnut shell powder into 100 mL of distilled water at 80°C for 15 minutes,

[0051] g. adding fibers to this mixture and stirring at 80°C at 300 rpm for 60 minutes, h. cleaning the fibers extracted at the end of the mixing process with distilled water and air-drying,

[0052] i. for the PLA impregnation process, cutting PLA filaments with 1.75 mm diameter into 30 cm lengths and sterilizing them with ethylene oxide gas,

[0053] j. melting PLA filaments at 170 °C,

[0054] k. immersing hemp fibers in molten PLA and waiting for 30-60 seconds, l. removing hemp fibers at the end of the impregnation period, shaking off the excess molten PLA, and drying in a sterile environment,

[0055] m. then, knitting the dyed and PLA-coated fibers by a five-thread machine, n. dipping the knitted threads into a mixture containing 20-80% by weight chlorhexidine diacetate, 25-30% by weight bay leaf oil, 20-50% by weight St. John's wort oil, and 20-50% by weight beeswax, which is melted at approximately 35°C,

[0056] o. drawing fibers after the threads are allowed to solidify in the mixture for 30-60 seconds. References

[0057] 1- Trott, A. T. (2012). Instruments, suture materials, and closure choices. Wounds and Lacerations, 82-94. hUps: / / dos.orq 10.10 6 b978"0"323--07418-6.00008--3 2- Dart, A. J., & Dart, C. M. (2011). Suture material: Conventional and stimuli- responsive. Comprehensive Biomaterials, 573-587.

[0058]

[0059] 3- Suzuki, J. B., & Resnik, R. R. (2018). Wound Dehiscence: Incision Line Opening, Editor(s): Randolph R. Resnik, Carl E. Misch, Misch's Avoiding Complications in Oral Implantology, 402-439. https: / / doj. Org / 0, 1016 / 8978-0- 323-37580-1.00011-1

Claims

CLAIMS1. The surgical suture having enhanced wound-healing properties, improved strength, durability, absorbency, antibacterial properties, and environmental advantages consists of:a. a multifilament hemp suture (1 ), consisting of five hemp fibers dyed with 5-hydroxy-1,4-naphthoquinone obtained from walnut shells and coated with polylactic acid (PLA) (2),b. a PLA coating (2) coated on the outer surface of hemp suture (1 ), c. a beeswax coating (3) containing 20-80% by weight chlorhexidine diacetate, 25-30% by weight bay leaf oil, 20-50% by weight St. John's wort oil, and 20-50% by weight beeswax2. According to Claim 1, the surgical suture that is the subject of the invention in one application of the invention consists of:a. multifilament hemp suture (1 ) consisting of five hemp fibers dyed with 5- hydroxy-1,4-naphthoquinone obtained from walnut shell and coated with polylactic acid (PLA) (2),b. PLA coating (2) coated on the outer surface of hemp suture (1 ), c. beeswax coating (3) containing 8 mL chlorhexidine diacetate, 5 mL bay leaf oil, 5 mL St. John's wort oil and 25 mL beeswax3. A surgical suture manufacturing method according to Claim 1, characterized by the following features:a. cleaning the bark of the hemp plant with a mechanical decorticator, scraping off the outer layers and pectins,b. washing the extracted fiber with tap water and air drying,c. immersion of the obtained raw fiber in a 20% by weight sodium hydroxide (NaOH) solution and heating at 95°C for 120 minutes, d. afterwards, washing with deionized water to remove NaOH residues and drying at 27°C,e. removing the resulting threads by pulling them out with tweezers to a thickness of 0.5 mm,f. mixing 20-30 grams of walnut shell powder into 100 mL of distilled water at 80°C for 15 minutes,g. adding fibers to this mixture and stirring at 80°C at 300 rpm for 60 minutes,h. cleaning the fibers extracted at the end of the mixing process with distilled water and air-drying,i. for the PLA impregnation process, cutting PLA filaments with 1.75 mm diameter into 30 cm lengths and sterilizing them with ethylene oxide gas, j. melting PLA filaments at 170 °C,k. immersing hemp fibers in molten PLA and waiting for 30-60 seconds, l. removing hemp fibers at the end of the impregnation period, shaking off the excess molten PLA, and drying in a sterile environment, m. then, knitting the dyed and PLA-coated fibers by a five-thread machine, n. dipping the knitted threads into a mixture containing 20-80% by weight chlorhexidine diacetate, 25-30% by weight bay leaf oil, 20-50% by weight St. John's wort oil, and 20-50% by weight beeswax, which is melted at approximately 35°C,o. drawing fibers after the threads are allowed to solidify in the mixture for 30-60 seconds.

Images