Preparation Of Antimicrobial Agents Loaded Nanoparticles For Biological Application

In order to alleviate the increasingly severe situation of antibiotic resistance,we introduced the nano-drug delivery system into the therapy of bacterial infection.We modified some existing antibacterial drugs and new synthetic antimicrobial agents by suitable polymer to improve the drug effect,such as enhancing drug delivery,reducing the bio-toxicity of drugs,and extending the release time of drugs.First,we chose an existed antibacterial drug named vancomycin as the model drug.Then we encapsulated vancomycin by poly(caprolactone-polyethylene glycol(PCL-PEG)to form nanoparticles,which have better effects than that of vancomycin.We synthesized the vancomycin-loaded PCL-PEG nanoparticles successfully through W/O/W complex emulsion solvent evaporation method and a series of physical and chemical characterization tests were conducted,such as hydrogen nuclear magnetic spectrum,dynamic light scattering,scanning electron microscope,ultraviolet spectrum and infrared spectrum.The cytotoxicity test,in vitro release experiments and bacteriostasis experiments against staphylococcus aureus were also carried out to verify their outstanding performance as antibacterial drugs.Through these tests,we found these nanoparticles have many advantages,including small size,good organ penetrability,low cytotoxicity,sustained release properties and strong antibacterial effects.Therefore,we believe that this kind of vancomycin sustained release nanoparticles has a wide application prospect and is expected to be further applied clinically.Next,we found that a large amount of small molecular antimicrobial agents were synthesized to fight against the bacterial but the clinical application in wound-inflection treatment was restricted because of their hydrophobicity and poor skin permeation.So we synthesized a novel quinoline compound to be used as an antimicrobial agent.Due to its hydrophobic property,this quinoline compound could be successfully encapsulated into poly(epsilon-caprolactone)-poly(ethylene glycol)(PCL-PEG)nanoparticles(NPs)and showed a sustained drug release manner in vitro.Compared to the free drug of this quinoline compound,these drug loaded PCL-PEG NPs had better water solubility,stronger antibacterial effect and lower cytotoxicity in vitro.The results of in vivo wound healing experiments demonstrated that these drug loaded NPs could not only greatly suppress the bacterial infection around the wound,but also significantly accelerate the curing rate of wound.Thus these quinoline compound loaded PCL-PEG NPs could act as a promising drug delivery system for wound healing applications.