• Design and preparation of chitosan nanoparticles conjugated with LysK bacteriophage chimeric endolysine as a novel bacterial antibiotic
  • Paria Abbasi,1 Sepideh Khaleghi,2,* Hossein Fahimi,3
    1. Department of Biotechnology, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
    2. Department of Biotechnology, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
    3. Department of Genetics, Faculty of Advanced Science and Technology, Tehran Medical Science, Islamic Azad University, Tehran, Iran.


  • Introduction: In recent years, resistance to antimicrobial drugs has become a growing global concern. To solve this problem, efficient solutions such as the use of nanomaterial such as chitosan nanoparticles with unique physicochemical properties and the use of chimeric endolysin protein derived from bacteriophage have been used. In this project, the aim is to synthesize chitosan nanoparticles to which the said peptide antibiotic is attached with covalent and non-covalent junctions
  • Methods: In this project, plasmid pET32 will be used to increase the expression, solubility, and proper folding of chimeric endolaysin protein. The expression of recombinant protein was improved by different culture conditions and purified with Ni-NTA column. Chitosan nanoparticles attached covalently and noncovalently with chimeric endolysine protein will be synthesized using Ionic gelation method. The physical properties and morphology of nanoparticles will be investigated with a TEM, DLS and FT-IR. Finally, the antibacterial effect of nanoparticles were evaluated against Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aurous and Escherichia coli by MIC / MBC, biofilm and synergistic effect with vancomycin.
  • Results: Protein expression was improved in TB medium. Covalent of nanoparticles with endolysin chimeric protein by FTIR method showed that covalent bindings were performed correctly in a certain range and TEM electron microscopy showed that the nanoparticles were monodispersed and spherical. antibacterial experiments showed that the MIC / MBC assay had a positive effect of nanoparticles on all three bacteria at a concentration of 8ng/ ml in 24 to 48 hours, but in the biofilm assay, it only affected Escherichia coli and did not cause biofilm formation. The synergy assay also affected three bacteria in CS-ChAmc (NC) treatment mode in 48 hours, but the most effect was observed on Pseudomonas aeruginosa in CS-ChAmc (NC) treatment mode
  • Conclusion: The chitosan nanoparticles conjugated with chimeric endolysin covalently and non-covalently can be an effective novel antibiotic against common infections.
  • Keywords: chitosan nanoparticles, Protein antibiotics, LysK, Bacteriophage