Journal of Oral Research and Review

: 2022  |  Volume : 14  |  Issue : 2  |  Page : 104--108

Copper nanoparticle-coated suture: A novel antimicrobial agent

Shraddha Rajendra Shimpi, Swapna Arunkumar Mahale, Dipali Dhanraj Chaudhari, Ankita A Katkurwar, Jui Vilas Bhandare 
 Department of Periodontics, KBH Dental College and Hospital, Nashik, Maharashtra, India

Correspondence Address:
Shraddha Rajendra Shimpi
MGV's KBH Dental College and Hospital, Mumbai Agra Road, Panchavati, Nashik 422 003, Maharashtra


Introduction: As a new emerging nanotechnology approach, copper nanoparticles (CuNPs) coated on traditional silk suture were used. Its antimicrobial and anti-inflammatory properties, led to its increasing medical applications. Commercially available as wound dressings, surgical instruments and bone prostheses. Objectives: To compare physical parameters of nano-copper and silk suture. Methodology: Copper nanoparticles and deionized water were adopted for the preparation of the copper solution. The copper solution was obtained by dissolving 0.5 wt/v % of copper nanoparticles in a mixture of 5 v/v % of deionized water. The silk suture were dipped in the copper solution for 24 hr and then exposed to UV lamp in order to induce the synthesis of copper clusters on the surface of the suture. Inverted electron microscopy was performed in order to analyse the braided structure of the multifilament silk sutures and to verify the presence of copper on the surface. A quantitative spectrophotometry analysis was performed to quantify the percentage of copper deposited. Tensile strength was measured by Universal Testing Machine. Results: Nano-copper suture showed enhanced physical parameters as compared to silk suture. Conclusion: Copper nanoparticles due to their beneficial effects as antibacterial and wound healing accelerator in the periodontal surgeries could reduce inflammation and promote healing process.

How to cite this article:
Shimpi SR, Mahale SA, Chaudhari DD, Katkurwar AA, Bhandare JV. Copper nanoparticle-coated suture: A novel antimicrobial agent.J Oral Res Rev 2022;14:104-108

How to cite this URL:
Shimpi SR, Mahale SA, Chaudhari DD, Katkurwar AA, Bhandare JV. Copper nanoparticle-coated suture: A novel antimicrobial agent. J Oral Res Rev [serial online] 2022 [cited 2022 Aug 16 ];14:104-108
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Surgical sutures are sterile threads that are used to seal wounds and give support as they heal.[1] They can be divided into three categories based on their degradation, composition, and structure.[2] Sutures, in particular, can be classed as absorbable or nonabsorbable, and some can be made in a multifilament or monofilament structure.[3] Nonabsorbable sutures elicit little tissue reactions, but absorbable sutures might cause varying degrees of tissue response due to their breakdown by hydrolysis and enzymatic digestion.[4],[5] Silk suture and its fragments cause an inflammatory reaction,[6] although silk is more thrombotic at first than other absorbable sutures, this impact resolves within a few weeks. Only traces of thrombogenicity are associated with silk sutures 2 months after implantation. The silk is then totally endothelialized, showing that regenerated endothelial tissue is present.[7] The presence of suture in a surgical wound is known to have a negative impact on the local tissue condition as well as enhance infection susceptibility.[8] Silk suture is used in oral, periodontal, and endodontic surgery due to its ease of handling.[9] It is commonly employed in mucosal and intertriginous areas because of its softness and pliability.[10] Ocular, neurological, and cardiovascular surgery are among the other applications.[11] Because of its moist and vascularized environment, the oral cavity provides a favorable site for the development of bacterial infections.[9] Multifilamentous and braided silk sutures cause a larger inflammatory response in the oral mucosa than monofilament sutures[12] due to bacteria adherence in their interstices.[13] Even if the suture is left in for longer, the risk of bacterial infection is lower than with conventional sutures.[14] Sutures can also be exposed to bacterial insults due to the nature of the wound or subsequent inoculation events. Surgical wounds are commonly exacerbated by infections of various severity, resulting in a variety of clinical issues as well as higher hospitalization and health-care expenses.[15],[16] As a result, defining preventive tactics is critical, taking into account probable sources of contamination as well as the onset of serious complications. Many factors can create such complications, including the type of surgery performed, the patient's general health, and the duration of the operation.[17] Furthermore, the widespread use of antibiotics or antimicrobial medicines to prevent postsurgery infections[18],[19] adds to antibiotic resistance.[20] Surgical wounds infected with antibiotic-resistant bacteria can increase the patient's morbidity and cost them more money.[21] The use of antimicrobial sutures could be a novel technique to prevent the early contamination of surgical wounds by microorganisms from the environment.

Traditional medicine's earliest antibacterial ingredient is copper and its compounds. Copper is essential for the cell metabolism in both animal and plant cells. It is a trace element present in most species, and it is found in more than 30 different types of proteins. More than 9000 years ago, copper and gold were the first metals used by male. Copper consumption is currently over 18 million tonnes per year worldwide. The nanometer scale paves the path for new materials to be developed for the application in cutting-edge medical technologies. The American Environmental Protection Agency has designated copper as the first and only metal with antibacterial characteristics. Within 2 h of contact, this substance eliminates 99.9% of most infections. Furthermore, this metal has qualities that are superior to those of more expensive metals with antibacterial activity, such as silver and gold, in some cases. Bacteria, yeasts, and viruses can be killed by touching copper surfaces, which is referred to as “contact killing” (contact-mediated killing).[22] Copper is thought to have a higher affinity for amines and carboxylic groups in cell walls, resulting in more severe cell bacterial structural destruction. Copper particles with nanometric size have the potential to enter cells or be oxidized to Cu+, which produces reactive oxygen species that cause DNA damage.[23]

Why copper nanoparticles?

  • Anti-inflammatory effect - Proliferation and migration of keratinocytes

    • Cytokine modulation.

  • Wound-healing property - Differentiation of fibroblast into myofibroblast
  • Broad-spectrum antibacterial activity
  • Least bacterial resistance - Decreases bacterial loading and infection
  • Easily impregnated in dressings.[24]

The development of copper-coated surgical sutures, on the other hand, is a innovative field. The goal of this research is to produce low-cost copper coatings for traditional surgical sutures for the treatment of “Surgical Site Infections” caused by bacterial colonization. Nonabsorbable silk sutures were chosen for this study due to their widespread use in surgery and the braided nature of these materials, which allows for the buildup of surface debris and microorganisms.[4] Using a new approach based on the photoreduction of a copper precursor, copper nanoparticles were coated on typical nonabsorbable silk surgical sutures.

Scanning electron microscopy was used to examine the morphology of the copper coating and the distribution of copper clusters on the substrates. Energy-dispersive X-ray spectroscopy was used to determine the amount of copper deposited on the suture. Tensile tests were performed on copper treated and untreated samples to see if the copper treatment affected the mechanical properties of the substrate.

 Materials and Methods

The sutures selected were nonabsorbable multifilament silk sutures with a diameter of 0.3 mm. For the preparation of the copper solution, copper nanoparticles and deionized water were used. The copper solution was prepared by dissolving 0.5 wt/v% copper nanoparticles in a 5 v/v% deionized water solution.

Copper treatment on the silk surgical sutures

To initiate the formation of copper clusters on the surface of the suture, the samples were immersed in copper solution for 24 h [Figure 1] and then subjected to ultraviolet light (k = 365 nm, t = 20 min, distance 20 cm) [Figure 2]. The samples were rinsed in deionized water after treatment to eliminate any unreacted salt.[25],[26]{Figure 1}{Figure 2}

Morphological analysis

The braided structure of the multifilament silk sutures was examined using inverted electron microscopy, and the presence of copper on the surface was confirmed [Figure 3]. The cross section of the materials was also examined for this purpose. To determine the percentage of copper deposited, a quantitative spectrophotometry analysis was done.[25],[26]{Figure 3}

Tensile test

The universal testing machine was used to determine the tensile strength [Figure 4]. The name's “universal” element refers to its ability to perform a wide range of typical tensile and compression tests on materials, components, and structures. Between the grips and an extensometer, the specimen was placed in the machine. When the machine is turned on, it starts applying an increasing load to the specimen. The load and extension or compression of the specimen was recorded by the control system and its related software during the testing. Each sample was stretched to failure and the highest load in Newton (N) was recorded.[25],[26]{Figure 4}


Morphological analysis

An inverted electron microscope was used to examine the distribution of copper particles on silk suture fibers and the cross section of the suture. After washing the suture with water, copper particles were observed among the filaments of the copper-coated suture.

The percentage of copper deposited on nano-copper suture and normal silk suture was measured using quantitative spectrophotometry. With respect to the substrate's components, it resulted in a 60.350% on the suture's surface.

Tensile test

The goal of this study was to compare the tensile strength of untreated and copper-treated sutures to see if the nano-copper coating had an effect on the materials' strength. For silk suture, failure load was 14.4 N, whereas for nano-copper suture, failure load was 16.10 N [Figure 5]. Copper-coated suture had a better tensile strength than standard silk suture.{Figure 5}


Surgical sutures, which are used to close wounds, are a common source of microbial infection. Despite their sterility before use, sutures can become a breeding ground for bacteria once implanted, causing delayed healing, infection susceptibility, and poor tissue regeneration with pathological scarring, and patient's quality of life and health-care costs are also affected. The risk of infection is said to be dependent on the degree of bacterial adhesion and the type of suture used. In terms of tissue reactivity, monofilament sutures produced smaller inflammatory reactions than multifilament materials.

Antibiotic-resistant bacteria are also becoming a growing concern in the treatment of surgical infections, as wound bacterial colonization is frequently linked to rigorous wound management and a restricted treatment options for antibiotics. Bacterial adherence to surgical sutures could operate as an infection focus, causing wound healing to be delayed.[27]

Novel copper-coated silk sutures with antibacterial characteristics were created in this study to help avoid surgical infections. In the medical and therapeutic industries, nano-copper has been regarded as the nanomaterial with the highest degree of commercialization. Another benefit of this approach is the long-term antibacterial characteristics that can be achieved even with very low copper concentrations. The procedure used in this investigation was a copper solution containing 0.5 wt/v % copper nanoparticles dissolved in a mixture of 5 v/v % water, which proved to be successful in giving good antibacterial capabilities. The technology's efficiency in creating a homogenous dispersion of copper particles on the silk filaments was plainly seen under an inverted electron microscope. Spectrophotometry analysis showed the presence of copper and allowed for its quantification, whereas the spectrum of the untreated sample showed no peak. The mechanical properties of the treated silk suture were assessed because a reduction in the suture's strength can lead to premature suture rupture, causing difficulties in the healing tissues. Copper nanoparticles were found to inhibit the growth of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans in a study by Mahale et al.[28]

Alirezaie Alavije et al. found in his study on catgut enriched with CuSO4 nanoparticles, the coating of nanoparticles helped in improving the mechanical strength, antibacterial activity, cytotoxicity of the suture, and also tissue reaction showed that necrosis and inflammatory cells were reduced.[29]

All antibacterial studies show that the use of copper-coated sutures can provide clinical benefits in terms of preventing surgical infection and bacterial colonization without causing cytotoxicity in fibroblasts.[24],[29],]30] Furthermore, low copper percentages were used in the procedure, indicating that the implementation of these sutures into hospital practice might be recommended with no substantial economic impact.

In periodontal flap surgery, its clinical application can reduce inflammation, promote healing, and reduce scarring.

The copper treatment's good adherence and durability suggested that sterilization treatments routinely used in the biomedical area should not have an unfavorable effect on the copper coating's qualities. Future research should concentrate on clinical application and the effect of sterilizing processes on the copper-coated sutures that have been produced.


Because of the accompanying treatment expenses for antibiotics, wound care, prolonged hospitalization, and lost patient's work productivity, and surgical wound management is quite expensive. This study developed and presented a novel and effective technique for preventing infections linked with surgical sutures. The copper deposition process used is distinguished by the copper coating's exceptional adherence to the substrate and its adaptability. Furthermore, the copper coating did not affect the materials' mechanical qualities. The antibacterial-coated sutures produced could be a promising alternative in surgical practice, both in terms of minimizing morbidity and additional treatment expenditures for surgical patients.

Ethical clearance

As the study done was 'in-vitro' no patients were involved. There are no ethical clearance details.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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