Metal Loaded Polydopamine Nanoparticles And Its Redox Activity

Dopamine(DA)is a kind of vital neurotransmitter,which self-polymerized to polydopamine(PDA)in alkaline solutions under the oxidation of O2.Polydopamine nanoparticles with specific diameter can be prepared via the fast polymerization of dopamine hydrochloride in NaOH solution or Tris buffer.The functional groups such as amidogen,hydroxide radical and catechol of dopamine and polydopamine enable the nanoparticles suitable platform for further surface modification with excellent biocompatibility,adhesion and effective binding sites for various metal ions.Macrophages(MCs)derive from the blood monocyte and play important role in the process of immune response via its function of antigen presentation.The change of micro-environment especially the influence of metal ions lead to the polarization of the macrophages in the pathway of classically activated macrophages(M1)or alternatively activated macrophages(M2).Polarized macrophages have close connection with the process of immune defense,tumor immunology,inflammatory response,damage repair and maintaining the homeostasis.Researches show that the macrophages attract cancer cells and then triggering the oxidative damage mechanism via the reactive oxygen species(ROS)generated during its polarization process.In this work,we prepared polydopamine nanoparticles with average diameter of 90nm via the copolymerization of dopamine and metal ions include Fe(III),Fe(II),Cu(II),Zn(II),Al(III),Ca(II),Mn(II),Mg(II)in Tris buffer with O2 serving as oxidant.Then we co-incubate the nanoparticles with RAW264.7 macrophages and represent its redox activity by detecting the release of reactive oxygen species(ROS).Thus we represent a facile efficient approach to synthesis the metal loaded polydopamine nanoparticle with significant redox activity.The nano-system synthesized in our research is of great significance to the further study of redox activity for metal loaded nanoparticles and induce of macrophage polarization as well as the the influence of immune response to pathology of neoplasia.