• Synthesis and characterization of bilayer biocompatible MOF-Chitosan nanoparticles conjugated with novel antiobiotic recombinant chimeric protein
  • Mahnaz Malekian,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: Today overuse of antibiotics in the treatment of human and animal’s diseases has caused multi drug resistance of bacteria against antibiotics. In addition, by using a handful of antibiotics, the resistance genes transmitted horizontally or vertically among a population. The enzymes purified from bacteriophages can play a role as an antibiotic. The aim of the present study was, to evaluate the function of chimeric endolysin antibiotic protein conjugated on the surface of MOF-Chitosan nanoparticles on gram-positive and gram-negative pathogenic bacteria.
  • Methods: Expression of chimeric endolysin protein in pET22, which was transformed in the BL21 host, was evaluated in TB and 2XYT media to optimize protein expression by 1 mM IPTG at 37 °C. Purification of chimeric endolysin protein was performed by NI-NTA affinity chromatography. Expression rate was assessed by SDS-PAGE. synthesis of MOF nanoparticles from, zinc acetate, bdc and dabco in dimethylformamide solvent were used. Then MOF nanoparticles were coated with, low molecular weight and the chimeric endolysin protein was conjugated to chitosan amine groups covalently (MOF-CS-CHAP(C)) and non-covalently (MOF-CS-CHAP(NC)). Finally, the physicochemical properties and morphology of nanoparticles were investigated by DLS, FTIR and TEM assays. Finally, to evaluate the antibacterial effect of nano particles against Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aurous and Escherichia coli by MIC / MBC assay, the biofilm formation and synergistic with vancomycin were evaluated.
  • Results: Protein expression with TB medium in 18 hours by adding 5% glycerol and 2% glucose was achieved. MOF nanoparticles were coated by chiosan and characterized by DLS. TEM results, confirmed the spherical shape of the MOF with a porous center. In the MIC/MBC experiment against Pseudomonas aeruginosa by MOF-CS-CHAP(C) at concentrations of 4 and 8 ng/ml and in 24 to 48 hours, inhibition was observed. In the biofilm test, the concentration of 1,2,4,8ng/ml MOF-CS-CHAP(NC) nanoparticles on Pseudomonas aeruginosa had the greatest effect on the biofilm. And in Staphylococcus aureus in MOF-CS-CHAP(C) and MOF-CS-CHAP(C) at all concentrations inhibition of biofilm formation was elicited. In Escherichia coli, in MOF-CS-CHAP(NC) and MOF-CS-CHAP(C) treatment at 8 ng/ml, it had the same effect on biofilm formation as Staphylococcus aureus. In evaluating the synergistic effect of vancomycin antibiotic with treatment groups, it had a significant effect on Staphylococcus aureus in both MOF-CS-CHAP(NC) and MOF-CS-CHAP(C) in 24 hours. A significant effect was observed in the synergistic effect of vancomycin antibiotic with CHAP protein in Pseudomonas aeruginosa at 24 and 48 hours.
  • Conclusion: The MOF-Chitosan nanoparticles conjugated with chimeric endolysin covalently and non-covalently can be an effective novel antibiotic against common infections.
  • Keywords: Chimeric protein, Antibiotic resistance, MOF-Chitosan, Gram positive and Gram negative bacteria