Construction Of Asymmetric Structures And Propulsion Performance Of Mesoporous Nanomotors

Synthetic nanomotors are capable of autonomous movement in liquids using chemical energy around them or in response to external physical stimuli,which have great potential for applications such as cargo delivery.Mesoporous nanomaterials show unique features including high surface area,large pore size,tunable pore structures,diverse nanostructures,high stability and easy functionalization modification.Combination with nanomotors can significantly improve cargo loading and delivery efficiency.In this dissertation,we design and prepare mesoporous silica/carbon nanomotors with different structures and investigated their effect on propulsion property,including controllable Janus structured center-radial dendritic,yolk@spike-shell structured,jellyfish-like and core@satellite structured mesoporous nanomotors.The main contents are as follows.1.Dendritic mesoporous silica nanomotors with precisely controllable Janus structure:We prove that spherical nanomotors with 50%coverage of catalyst on their surface possess the best propulsion property by investigating the relationship between catalyst coverage and self-propulsion.The dendritic mesoporous structure significantly improves the motility in hydrogen peroxide solution and protein loading of nanomotors,providing a potential delivery vehicle for efficient cargo transport.2.Near-infrared light-responsive yolk@spike-shell structured mesoporous silica/carbon nanomotors:Optimization of the diameter of the carbon yolk within the cavity and the roughness of the spiky silica/carbon shell enables efficient fuel-free light-propulsion and high loading capacity of lipase,propelling the nanomotors to aggregate at the oil-water interface for rapid degradation of triglycerides.3.Single-atom copper-doped jellyfish-like mesoporous carbon nanomotors:Compared with hollow mesoporous carbon spherical nanoparticles,the jellyfish-like mesoporous carbon nanomotors can achieve more efficient self-thermophoretic propulsion under NIR light irradiation,significantly improving cell uptake efficiency and penetration depth of three-dimensional multicellular tumor spheroids/in vivo tumor.Further combination with the high catalytic activity of single-atom copper and the excellent photothermal property of carbon materials elevates the efficacy of chemodynamic and photothermal synergistic therapy.4.pH-responsive core@satellite structured mesoporous silica nanomotor:Gold nanoparticles uniformly distributed in satellites on the surface of mesoporous silica cores can undergo structural reconfiguration in response to weakly acidic environments.,which triggers multiple transitions in the propulsion mechanism,including self-diffusiophoresis,self-electrophoresis,and self-thermophoresis.The combination of multiple propulsion modes is expected to improve the viability of nanomotors in complex liquids.