Biomimetic Self-propelled Janus Silica Nanomo Tors

Artificial micro/nano motors can perform self-propelled motions upon the response of external environments, such as rotating, rolling, and moving straight ly. Many propelled motors moving in a same region that could exhib it regular collective behaviors. Micro/nano motors are commonly made of micro/nano particles, which can be modified and functionalized by biochemistry method, achieve some potentia lly apllications. C urrently, the research of micro/nano motors mainly focus on the level of micro or sub- micro meters. However, nanomotors with diameter of sub-100- nm have less attention, because of the limitation preparative technique and characterization method. This doctoral dissertation mainly talks about the sub-100- nm nanomotors, which processes the investigation of preparation, obserzavion, propelled mechanis m, and potentially bio- inspired applications.The bubble propelled Janus Pt mesoporous silica nanomotor with the diameter about 75 nm, which was fabricated by the metal chemical vapor deposit ion. The motion of nanomotors can be excited in the H2O2 solut ion due to the generation of oxygen bubbles from the catalyt ic decomposition of H2O2. The super high resolut ion fluorescence microscopy technology was employed to record the motion of nanomotors, the speeds distribution of nanomotors have a positive increase with the concentration of H2O2 and temperature. Nanomotors have a largest speed at 20.2 μm/s. The diffusion coefficient was introduced to distinguish the Brownian motion and self-propuls ion; the results indicate that nanomotor can overcome Brownian motion to perform the self-propulsion. Moreover, the self-propelled nanomotors enhance the capture rates of cells; also the lipid modified nanomotor can be applied for drug encapsulation, delivery, and release.Janus Pt nanomotors have a strongly dependence on the additional chemical fuels like other micro/nano motors, while these propelled chemical fuels always have serious biological toxic ity. In order to resolve the independence of chemical fuels for micro/nano motors, a near- infrared- light(N IR light) powered Janus Au mesoporous silica nanomotor was prepared, which can take self- thermophoresis motion without chemical fuels. The “on/off” motion can be achieved by the NIR light open and close. The speed of nanomotors can be regulated by adjusting the NIR light power, the largest speed of nanomotor is about 41 μm/s. Light powerd activity and mean square displacement were introduced to ind icate that N IR light powered nanomotor can effectively overcome Brownian motion. In the simultaneous, the light powered nanomotors have saturation of receiving N IR light, there is no benefit to increase the speed beyond 60.36 W/cm2.In order to enhance the biocompatibility of Janus nanomotors, cell membranes from an immune cell(macrophage cells) were isolated and purified by low permeability pyrolys is and gradient ultracentrifugation. C ell me mbrane was reconstructed and camouflaged on the surface of mesoporous silica nanoparticle by the mechanical extrusion. The macrophage cell me mbranes camouflaged nanoparticles can effectively reduce the possibility of immune clearance, thus a long circulating time was achieved in biological entity. N anoparticles can highly concentrate in the tumor stie by the specific unit(protein, polysaccharide, and lipid) dispersed on the macrophage cell membrane, effectively improve the efficiency of targeting drug delivery.Based on the preparation of NIR light powered nanomotor and cell me mbrane isolution, a macrophage cell membrane camouflaged N IR light powered Janus mesoporous silica nanomotor was prepared. The macrophage cell membrane not only provides a bio-camouflaged impact for nanomotors, but also conduct a bioantifouling and antiadhesion, thus cell membrane camouflaged nanomotor can move in different biological media solut ions. Moreover, cell membrane camouflaging function enhanced the recognition capability of nanomotors for tumor cells, also the Au half- shell of nanomotor can be applied for in- vitro photothermal therapy upon the irridiation of NIR light.In summary, based on the preparation of Janus silica nanomotor, driving mechanism research, and bio- inspired application, the chemical propelled nanomotors were successfully changed into fuel- free propelled nanomotors. Achieve the cell function like light powered nanomotor with the biomimetic technique. Therefore, this work provides theoretical basis and technical support for the design and preparation of biomimetic materials.