Design And Preparation Of Functionalized Polydopamine Nanomaterials For Biomimetic Aqueous Lubrication

This paper mainly reviews the research progress of osteoarthritis and bionic waterlubricated materials.Through understanding of natural joint lubrication mechanism,various functionalized bionic lubricants with excellent lubricating properties have been synthesized in recent years.The polymer brushes-functionalized nanomaterial is an innovative strategy to achieve both enhanced lubrication and sustained drug release in the treatment of osteoarthritis.Therefore,this paper combines bionic polymer brushes with biocompatible polydopamine nanomaterials to develop biomimetic lubricating materials for potential biological applications.The main contents are as follows:1.Poly(dopamine)/poly(ethylene glycol)(PDA/PEG)nanoparticles were successfully prepared by non-covalent self-assembly,which can be used as green additives for water lubrication.The preparation process of PDA/PEG nanoparticles is very easy and environmentally friendly without using any toxic reagents and organic solvents.The effect of molecular weight and contents of PEG on particle size were systematically investigated.The nanoparticles synthesized with PDA/PEG(8K)=1:5show the smallest particle size and the best dispersion stability in water.The incorporation of PEG can inhibit the aggregation of PDA nanoparticles,and further reduce the particle size and improve the colloidal stability of PDA/PEG nanoparticles.The non-covalent functionalization of PDA nanoparticles with PEG can significantly improve the lubricating properties of water-based fluids.The PDA/PEG(8K)nanoparticles with a mass ratio of 1:5 had the smallest friction coefficient and lowest wear volume.This may be related to the enhanced colloidal stability of PDA/PEG nanoparticles as well ad hydration ability of PEG polymer.2.Because of high drug loading capacity,mesoporous nanoparticles are often used as nanocarriers for drug delivery.In this part,biocompatible mesoporous PDA(m PDA)nanoparticles was used as nanocarrier and further functionalized with poly(3-sulfopropyl potassium methacrylate)brush(PSPMA)via surface-initiated atom transfer radical polymerization(SI-ATRP).PSPMA brushes have a strong hydration ability and m PDAPSPMA exhibit good swelling behavior in aqueous media.Tribological tests showed that the m PDA-PSPMA dispersion had a low coefficient of friction(μ ～ 0.065),which was significantly better than that of unmodified m PDA nanoparticles.In addition,comparative studies of m PDA modified by different types of polymer brushes showed that m PDA-PSPMA has a lower coefficient of friction than m PDA-PMETAC(μ ～ 0.088)and m PDA-PMPC(μ ～ 0.079).The mesoporous structure can load and release antiinflammatory drug.The combination of hydrated lubrication and drug loading capability makes m PDA-PSPMA a promising material for joint lubrication and arthritis treatment.