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A polycationic antimicrobial and biocompatible hydrogel with microbe membrane suctioning ability


Despite advanced sterilization and aseptic techniques, infections associated with medical implants have not been eradicated. Most present coatings cannot simultaneously fulfil the requirements of antibacterial and antifungal activity as well as biocompatibility and reusability. Here, we report an antimicrobial hydrogel based on dimethyldecylammonium chitosan (with high quaternization)-graft-poly(ethylene glycol) methacrylate (DMDC-Q-g-EM) and poly(ethylene glycol) diacrylate, which has excellent antimicrobial efficacy against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Fusarium solani. The proposed mechanism of the antimicrobial activity of the polycationic hydrogel is by attraction of sections of anionic microbial membrane into the internal nanopores of the hydrogel, like an ‘anion sponge’, leading to microbial membrane disruption and then microbe death. We have also demonstrated a thin uniform adherent coating of the hydrogel by simple ultraviolet immobilization. An animal study shows that DMDC-Q-g-EM hydrogel coating is biocompatible with rabbit conjunctiva and has no toxicity to the epithelial cells or the underlying stroma.

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Figure 1: qC-g-EM polymers and the antimicrobial killing mechanism of their hydrogels.
Figure 2: Antimicrobial activities of qC-g-EM hydrogels against various bacteria and fungi.
Figure 3: Coating of DMDC-Q-g-EM hydrogel on fluoropolymer substrate.
Figure 4: In vitro and in vivo biocompatibility studies.


  1. Hetrick, E. M. & Schoenfisch, M. H. Reducing implant-related infections: Active release strategies. Chem. Soc. Rev. 35, 780–789 (2006).

    CAS  Article  Google Scholar 

  2. Ferreira, L. & Zumbuehl, A. Non-leaching surfaces capable of killing microorganisms on contact. J. Mater. Chem. 19, 7796–7806 (2009).

    CAS  Article  Google Scholar 

  3. Klibanov, A. M. Permanently microbicidal materials coatings. J. Mater. Chem. 17, 2479–2482 (2007).

    CAS  Article  Google Scholar 

  4. Kristinsson, K. G. et al. Antimicrobial activity of polymers coated with iodine-complexed polyvinylpyrrolidone. J. Biomater. Appl. 5, 173–184 (1991).

    CAS  Article  Google Scholar 

  5. Smith, A. W. Biofilms and antibiotic therapy: Is there a role for combating bacterial resistance by the use of novel drug delivery systems. Adv. Drug Delivery Rev. 57, 1539–1550 (2005).

    CAS  Article  Google Scholar 

  6. Milovic, N. M., Wang, J., Lewis, K. & Klibanov, A. M. Immobilized N-alkylated polyethylenimine avidly kills bacteria by rupturing cell membranes with no resistance developed. Biotechnol. Bioeng. 90, 715–722 (2005).

    CAS  Article  Google Scholar 

  7. Lin, J., Qiu, S. Y., Lewis, K. & Klibanov, A. M. Bactericidal properties of flat surfaces and nanoparticles derivatized with alkylated polyethylenimines. Biotechnol. Prog. 18, 1082–1086 (2002).

    CAS  Article  Google Scholar 

  8. Tiller, J. C., Liao, C. J., Lewis, K. & Klibanov, A. M. Designing surfaces that kill bacteria on contact. Proc. Natl Acad. Sci. USA 98, 5981–5985 (2001).

    CAS  Article  Google Scholar 

  9. Ilker, M. F., Nusslein, K., Tew, G. N. & Coughlin, E. B. Tuning the hemolytic and antibacterial activities of amphiphilic polynorbornene derivatives. J. Am. Chem. Soc. 126, 15870–15875 (2004).

    CAS  Article  Google Scholar 

  10. Kuroda, K. & DeGrado, W. F. Amphiphilic polymethacrylate derivatives as antimicrobial agents. J. Am. Chem. Soc. 127, 4128–4129 (2005).

    CAS  Article  Google Scholar 

  11. Tew, G. N., Clements, D., Tang, H., Arnt, L. & Scott, R. W. Antimicrobial activity of an abiotic host defense peptide mimic. Biochim. Biophys. Acta 1758, 1387–1392 (2006).

    CAS  Article  Google Scholar 

  12. Gabriel, G. J., Som, A., Madkour, A. E., Eren, T. & Tew, G. N. Infectious disease: Connecting innate immunity to biocidal polymers. Mater. Sci. Eng. R 57, 28–64 (2007).

    Article  Google Scholar 

  13. Kenawy, E. R., Worley, S. D. & Broughton, R. The chemistry and applications of antimicrobial polymers: A state-of-the-art review. Biomacromolecules 8, 1359–1384 (2007).

    CAS  Article  Google Scholar 

  14. Bagheri, M., Beyermann, M. & Dathe, M. Immobilization reduces the activity of surface-bound cationic antimicrobial peptides with no influence upon the activity spectrum. Antimicrob. Agents Chemother. 53, 1132–1141 (2009).

    CAS  Article  Google Scholar 

  15. Imazato, S., Russell, R. R. B. & McCabe, J. F. Antibacterial activity of MDPB polymer incorporated in dental resin. J. Dent. 23, 177–181 (1995).

    CAS  Article  Google Scholar 

  16. Sambhy, V., Peterson, B. R. & Sen, A. Antibacterial and hemolytic activities of pyridinium polymers as a function of the spatial relationship between the positive charge and the pendant alkyl tail. Angew. Chem. Int. Ed. 47, 1250–1254 (2008).

    CAS  Article  Google Scholar 

  17. Stratton, T. R., Rickus, J. L. & Youngblood, J. In vitro biocompatibility studies of antibacterial quaternary polymers. Biomacromolecules 10, 2550–2555 (2009).

    CAS  Article  Google Scholar 

  18. Zumbuehl, A. et al. Antifungal hydrogels. Proc. Natl Acad. Sci. USA 104, 12994–12998 (2007).

    CAS  Article  Google Scholar 

  19. Fuchs, A. D. & Tiller, J. C. Contact-active antimicrobial coatings derived from aqueous suspensions. Angew. Chem. Int. Ed. 45, 6759–6762 (2006).

    CAS  Article  Google Scholar 

  20. Nurdin, N., Helary, G. & Sauvet, G. Biocidal polymers active by contact. 2. Biological evaluation of polyurethane coating with pendant quaternary ammonium-salts. J. Appl. Polym. Sci. 50, 663–670 (1993).

    CAS  Article  Google Scholar 

  21. Madkour, A. E., Dabkowski, J. A., Nusslein, K. & Tew, G. N. Fast disinfecting antimicrobial surfaces. Langmuir 25, 1060–1067 (2009).

    CAS  Article  Google Scholar 

  22. Jia, Z. S., Shen, D. F. & Xu, W. L. Synthesis and antibacterial activities of quaternary ammonium salt of chitosan. Carbohydr. Res. 333, 1–6 (2001).

    CAS  Article  Google Scholar 

  23. Mao, S. R. et al. Synthesis, characterization and cytotoxicity of poly(ethyleneglycol)-graft-trimethyl chitosan block copolymers. Biomaterials 26, 6343–6356 (2005).

    CAS  Article  Google Scholar 

  24. Zhu, S. Y., Qian, F., Zhang, Y., Tang, C. & Yin, C. H. Synthesis and characterization of PEG modified N-trimethylaminoethylmethacrylate chitosan nanoparticles. Eur. Polym. J. 43, 2244–2253 (2007).

    CAS  Article  Google Scholar 

  25. Theis, T. & Stahl, U. Antifungal proteins: Targets, mechanisms and prospective applications. Cell. Mol. Life Sci. 61, 437–455 (2004).

    CAS  Article  Google Scholar 

  26. Peppas, N. A., Hilt, J. Z., Khademhosseini, A. & Langer, R. Hydrogels in biology and medicine: From molecular principles to bionanotechnology. Adv. Mater. 18, 1345–1360 (2006).

    CAS  Article  Google Scholar 

  27. Li, Q., Wang, D. A. & Elisseeff, J. H. Heterogeneous-phase reaction of glycidyl methacrylate and chondroitin sulfate: Mechanism of ring-opening-transesterification competition. Macromolecules 36, 2556–2562 (2003).

    CAS  Article  Google Scholar 

  28. Sadovskaya, I., Brisson, J. R., Lam, J. S., Richards, J. C. & Altman, E. A. Structural elucidation of the lipopolysaccharide core regions of the wild-type strain PAO1 and O-chain-deficient mutant strains AK1401 and AK1012 from Pseudomonas aeruginosa serotype O5. Eur. J. Biochem. 255, 673–684 (1998).

    CAS  Article  Google Scholar 

  29. Cheng, G., Xue, H., Zhang, Z., Chen, S. & Jiang, S. A switchable biocompatible polymer surface with self-sterilizing and nonfouling capabilities. Angew. Chem. Int. Ed. 47, 8831–8834 (2008).

    CAS  Article  Google Scholar 

  30. Ostuni, E., Chapman, R. G., Holmlin, R. E., Takayama, S. & Whitesides, G. M. A survey of structure–property relationships of surfaces that resist the adsorption of protein. Langmuir 17, 5605–5620 (2001).

    CAS  Article  Google Scholar 

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This work was funded and supported by Menicon Holdings (Japan), a Singapore Ministry of Education Tier 2 grant (M45120007), Nanyang Technological University (Singapore) and a Singapore SingHealth Foundation grant (SHF/09/GMC(1)/012(R) (R705)). R.W.B. and H-Y.Z. were supported by NMRC/TCR/002-SERI/2008 R618. Y.C. was supported by SingHealth Foundation SHF/09/GMC(1)/012(R) (R705). W.L. and Y.M. were supported by a Singapore Ministry of Education Tier 2 grant (T206B3210RS). We acknowledge the Singapore General Hospital (Pathology Department) for carrying out some of the early antimicrobial tests. We thank Y. Shucong, W. Xiujuan and F. Ning for their help in using field emission scanning electron microscopy, scanning electron microscopy and atomic force microscopy. The provision of computation time from the NTU HPC centre is gratefully acknowledged.

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Authors and Affiliations



P.L. carried out the testing and coating experiments. Y.F.P., P.L. and S.H.Y. did the syntheses and characterization of all the polymers. Y.C. carried out the in vitro biocompatibility studies. X.Q. carried out some early antimicrobial testing. W.L. and Y.M. did the computer simulation and related writing. H-Y.Z. and R.W.B. did the animal study and related writing. C.Z., E-T.K., M.L., M.W.C., S.S.J.L., C.M.L. and M.B.C-P. advised on the design and interpretation of the experiments. M.B.C-P. directed the overall project. P.L., Y.F.P. and M.B.C-P. did the main writing of the manuscript.

Corresponding author

Correspondence to Mary B. Chan-Park.

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Competing interests

M.B.C-P. was the PI of this project funded by Menicon, which was directly interested in this product.

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Li, P., Poon, Y., Li, W. et al. A polycationic antimicrobial and biocompatible hydrogel with microbe membrane suctioning ability. Nature Mater 10, 149–156 (2011).

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