Perspective Article
Synthesis and antibacterial activities of quaternary ammonium salts with different alkyl chain lengths grafted on polyvinyl alcohol-formaldehyde sponges

https://doi.org/10.1016/j.reactfunctpolym.2020.104797Get rights and content

Highlights

  • Antibacterial PVF-g-QA sponges are synthesized via grafting reaction.

  • PVF-g-QA sponges exhibit excellent antibacterial effect on both S. aureus and E. coli bacteria strains.

  • PVF-g-QA sponges almost have no cytotoxicity for cells.

Abstract

Antibacterial polyvinyl alcohol-formaldehyde (PVF) sponges containing quaternary ammonium salts (QA) with different alkyl chain lengths are obtained through the grafting reaction of QA onto the PVF network under alkaline conditions. The grafting percentages of obtained PVF-g-QA sponges are in the range of 1.1–1.6%. As-prepared PVF-g-QA sponges show average pore sizes ranging from 60 μm to 90 μm with high porosity and interconnected pore structure. PVF-g-QA sponges with different alkyl chain lengths display the absorption capacity (Qs) of 13.3–14.2 g·g−1 in deionized water, 13.9–14.8 g·g−1 in saline solution, and 13.9–14.8 g·g−1 in artificial blood and can attain absorption equilibrium within 1 min. Notably, the PVF-g-QA sponges demonstrate excellent antibacterial effects on both S. aureus and E. coli bacteria strains. With high initial inoculum concentration (1 × 108 CFU/mL), with increasing the alkyl chain length of QA, the antibacterial activities of PVF-g-QA sponges against E. coli increase from 20.47% to 99.98% firstly and then decrease to 92.91%, the antibacterial activities against S. aureus increase from 16.67% to 99.96% and then decrease to 93.21%. None of the samples have cytotoxicity for cells. The as-prepared PVF-g-QA sponges with remarkable absorption capacity and excellent antibacterial performance can be considered as a new kind of antibacterial functional material.

Introduction

Medical dressings are an important class of medical materials used to cover sores, wound dressings can replace damaged skin and act as a temporary barrier to avoid wound infections and provide a beneficial environment for wound healing [1]. Traditional cotton dressings including cotton balls, cotton gauze and cotton bandages which have the characteristics of water absorption and heat preservation are still widely used in various types of wounds [2]. However, these products have no antibacterial effects and are prone to cause wound infection during used. In addition, the traditional cotton dressings are easy to stick to the wound when they are removed, so there are great defects for cotton dressings used as medical dressings [3]. With new requirements of medical dressings, such as antibacterial effect, anti-adhesion and high liquid absorption, some medical dressings with special functions have been developed in recent years [[4], [5], [6]]. At present, according to the type of antibacterial dressing materials, it can be roughly divided into sponge dressings [7], film dressings [8] and hydrogel dressings [9].

The sponge antibacterial dressings have the advantages of excellent exudate absorption capacity, good oxygen transmission rate and outstanding biocompatibility [[10], [11], [12]] which are beneficial for wound healing and can also be used as a drug carrier. Chen et al. [13] reported a chitosan/poly(vinyl alcohol) (PVA) composite sponge and demonstrated the antibacterial and hemostatic activities, the chitosan/PVA sponge with high liquid absorption and antibacterial properties can effectively promote the wound healing. Liang et al. [14] reported a novel silver nanoparticles (AgNPs)/chitosan composite dressing and tested the antimicrobial activity. The AgNPs/chitosan dressing with excellent absorption capacity promoted wound healing and accelerated the reepithelialization and collagen deposition.

Because of its low toxicity, low price, excellent antibacterial spectrum and other outstanding features, the quaternary ammonium salt is currently the most widely used organic antibacterial agent. Shao et al [15] reported a quaternary ammonium salt containing perfluoroalkyl and tested the antimicrobial activity. The results showed that the quaternary ammonium salt had an excellent antibacterial effect on both E. coli and S. aureus, the minimum inhibitory concentration (MIC) was 7.8 μg/mL. Zhang et al. [16] synthesized twelve quaternary ammonium compounds and tested their antimicrobial activities and vitro cytotoxicity. The minimum inhibitory concentration (MIC) of E. coli and S. aureus ranges from 2.8–167.7 μg/mL. Compared with small molecular compounds, polymeric quaternary ammonium salt antibacterial agent has a higher charge density and stronger antibacterial ability. In addition, it has the characteristics of high chemical stability, low residual toxicity, easy processing and so on. Kim et al. [17] introduced quaternary ammonium salts grafted chitosan and studied their antimicrobial activities against S. aureus. The results showed that the antimicrobial activity of chitosan modified by quaternary ammonium salt was significantly higher than that of quaternary ammonium salt small molecules. Tang et al. [18] synthesized an antimicrobial biopolymer dye with chitosan modified by quaternary ammonium salt. The results showed that the antimicrobial effect of this polymer on E. coli and S. aureus was excellent. The antibacterial rates were greater than 99%.

Polyvinyl alcohol–formaldehyde (PVF) sponges with open-cell structure exhibit remarkable absorption capacity, excellent mechanical properties and good biocompatibility [19,20]. Because of the hydroxyl groups in the PVF sponges, it has been widely used as cleaning materials and biomedical materials. Meanwhile, a large amount of hydroxyl groups in PVF sponges provide a chance to modify the surface property to obtain grafting PVF sponges [21,22]. In this study, antibacterial PVF sponges are successfully prepared via grafting quaternary ammonium salts with different alkyl chain lengths (n = 4, 6, 8, 10, 12, 14, 16, 18) onto the PVF network under alkaline condition and the antibacterial activities of the PVF-g-QA sponges are investigated extensively.

Section snippets

Materials

Polyvinyl alcohol (PVA 17–99) and Triton X-100 were purchased from Aladdin. Epichlorohydrin and N,N-dimethylalkylamine (n = 4, 6, 8, 10, 12, 14, 16, 18) were obtained from Energy Chemical. Yeast extract (LP0021), Tryptone (LP0042) and Nutrient Agar (CM1160) were purchased from Sigma-Aldrich. E. coli ATCC 25922 and S. aureus ATCC 6538 were obtained from Huankai Microbial Technology Co., Ltd., China. LIVE/DEAD™ BacLight™ Bacterial Viability Kit was purchased from Thermo Fisher Scientific Company,

Characterization of chemical structure of as-prepared PVF-g-QA sponges with different alkyl chain lengths

The FTIR spectra of as-prepared PVF-g-QA sponges (n = 4, 6, 8, 10, 12, 14, 16, 18) are exhibited in Fig. 1. The peaks of 3200–3600 cm−1, 2843–2943 cm−1 and 1012 cm−1 for original PVF are attributed to the Osingle bondH, Csingle bondH and C-O-C stretching vibration in the network. After the grafting reaction, because of the low grafting percentage of PVF-g-QA sponges, the absorption peak intensity of 3200–3600 cm−1 corresponding to the hydroxyl groups (Osingle bondH) has no significant reduction and the strong characteristic

Conclusions

Antibacterial PVF-g-QA sponges with different alkyl chain lengths (n = 4, 6, 8, 10, 12, 14, 16, 18) are successfully synthesized through a facile grafting reaction of quaternary ammonium salts (QA) to the PVF network. The grafting percentages of PVF-g-QA sponges are from 1.1% to 1.6%. As-prepared PVF-g-QA sponges display interconnected pore structure, high porosity and broad distribution from a few microns to 200 μm and reach absorption equilibrium only within 1 min in both saline solution and

Data availability

The raw/processed data required to reproduce these findings cannot be shared at this time due to technical or time limitations.

Declaration of Competing Interest

The authors declare no conflict of interest.

Acknowledgements

This work was supported by the National Key Laboratory of Human Factors Engineering of China (Grant Nos. SYFD061906K).

References (39)

  • Z. Lu et al.

    Enhanced antibacterial and wound healing activities of microporous chitosan-Ag/ZnO composite dressing

    Carbohydr. Polym.

    (2017)
  • C. Yao et al.

    Surface modification and antibacterial activity of electrospun polyurethane fibrous membranes with quaternary ammonium moieties

    J. Membr. Sci.

    (2008)
  • H. Bakhshi et al.

    Synthesis and characterization of antibacterial polyurethane coatings from quaternary ammonium salts functionalized soybean oil based polyols

    Mat. Sci. Eng. C-Mater.

    (2013)
  • E. Oblak et al.

    Antifungal activity of gemini quaternary ammonium salts

    Microbiol. Res.

    (2013)
  • P.F. Zou et al.

    Wound dressing from polyvinyl alcohol/chitosan electrospunfiber membrane loaded with OH-CATH30 nanoparticles

    Carbohydr. Polym.

    (2020)
  • D. Archanaa et al.

    Evaluation of chitosan nano dressing for wound healing: characterization, in vitro and in vivo studies

    Int. J. Biol. Macromol.

    (2013)
  • J.V. Edwards et al.

    Modified cotton gauze dressings that selectively absorb neutrophil elastase activity in solution

    Wound Repair Regen.

    (2001)
  • G.F. Hu et al.

    Antibacterial hemostatic dressings with nanoporous bioglass containing silver

    Int. J. Nanomedicine

    (2012)
  • P.B. Céline et al.

    Development and characterization of composite chitosan/active carbon hydrogels for a medical application

    J. Appl. Polym. Sci.

    (2013)
  • Cited by (13)

    • Polymeric diallyl quaternary ammonium salts for inhibiting banana Fusarium wilt

      2022, Reactive and Functional Polymers
      Citation Excerpt :

      The above three types of PDPQASs have a certain inhibitory effect on Foc4 mycelia, and their inhibitory activity will decrease with increasing molecular weight. The stronger the side group hydrophobicity is, the better the inhibitory effect will be [17,28]. As a typical cationic ammonium salt bacteriostatic agent, both the bacteriostatic effect and the biotoxicity should be evaluated.

    • Preparation of bactericidal surfaces with high quaternary ammonium content through photo-initiated polymerization of N-[2-(acryloyloxy)ethyl]-N,N-dimethyl-N-butylammonium iodide from native and thiolated PDMS surfaces

      2021, Reactive and Functional Polymers
      Citation Excerpt :

      Cationic polymers bearing quaternary ammonium (QA) groups exhibit high biocidal activity against bacteria, fungi, parasites and viruses. Moreover, this activity is dramatically dependent on the chemical structure of the polymer involving the hydrophilic-hydrophobic balance, the molecular weight and the length or nature of the alkyl chains of the QA groups [26–34]. For instance, Lu et al. [33] have prepared by quaternization poly(dimethylaminoethyl methacrylate (poly(DMAEMA)) with benzyl chloride (BC), butyl bromide (BB), dodecyl bromide (DB) or hexadecyl bromide (HB) and have found that polymers quaternarized with BC and BB exhibited the highest bactericidal activity in solution.

    View all citing articles on Scopus
    View full text