Preparation Of Functional Polymer Nanoparticles And Their Application In Biomedicine

Nanomedicine can be selectively enriched in lesions,thereby reducing the toxic and side effects on normal tissues,increasing the concentration of drug in pathological tissues and improving the utilization rate of drugs.Since the concept of such nano drug administration was proposed,nano drugs have always attracted the interest of medical researchers.Among these,polymer nanoparticles have become an extremely important research hotspot in both macromolecular drugs and drug delivery carriers due to their strong plasticity.In this thesis,a brief review of the research work on the rapid development of functionalized polymer nanoparticles is presented.Based on this,the preparation of functionalized polymer nanoparticles,the characterization of their properties,and the related research work in the biomedical field were carried out:1.A Bactericidal Dendritic Polycation Cloaked with Stealth Material via Lipase-Sensitive Intersegment.Antibacterial peptide mimic polymer is a new class of antibacterial agents that are expected to overcome bacterial resistance.As net cationicity of membrane-disruptive antimicrobials is necessary for their activity but may elicit immune attack when administered intravenously.We obtain a nanoparticle antimicrobial,G2-g-(PCL-b-PEG)by cloaking a dendritic polycation(G2)with poly(caprolactone-b-ethylene glycol)(PCL-b-PEG).The observed activity may be attributed PCL's responsive degradation by bacterial lipase and the consequent exposure of the membrane-disruptive,bactericidal G2 core.Moreover,G2-g-(PCL-b-PEG)exhibits good colloidal stability in the presence of serum and insignificant hemolytic toxicity even at ?2,048 ?g/mL,suggesting good blood compatibility.2.Platelet Membrane Coating Endows A Photodynamic Nanoparticle with Improved Antitumor EfficacyThe extremely short lifetime of reactive oxygen species limits the radius of their action to tens-of-nanometer scale;functionalizing a photodynamic nanosystem with active targeting moieties helps bring the target cells into reach of ROS but requires extra research efforts.We herein show that platelet membrane-coating over a photodynamic nanoparticle coupled with low dose light irradiation.Platelet membrane-coating provides both long circulation and active targeting,leading to preferential internalization by tumor over fibroblast cells in vitro and higher tumor uptake than the red blood cell(RBC)membrane-coated counterpart.Upon irradiation with NIR light from a solar simulator at extremely low output power density(0.05 W/cm2),the platelet membrane-coated photodynamic-nanoparticle outperforms its RBC membrane-coated counterpart and effectively ablates tumor without causing skin damagesites.