Micro-nano Bubbles By Magneto Induced Internal Heat Bubble Generation

Micro-nano bubbles(MNBs)refer to bubbles with particle diameters ranging from tens of nanometers to ten of microns.It shows great application prospects in biomedicine,sewage treatment,agricultural production,and mineral flotation.In recent years,the reported preparation techniques of MNBs have some limitations.According to the requirements of industrial applications,it is urgent to develop new preparation techniques for the production of uniform MNBs with ideal size distribution.In thisstudy,a novel MNBs preparation method was designed based on the magnetic internal heat technology.The size of the prepared MNBs was uniform and controllable,which could be widely used in biomedicines or other fields.The main research contents of this study were included as follows.(1)Magnetic iron oxide particles modified with citric acid were prepared by co-precipitation method using sodium citrate as a stabilizer.The effects of the operating conditions on the particle size were studied by changing the addition amount and time of sodium citrate during the reaction.The response performance,particle size and distribution,morphology characteristics,X-ray diffraction pattern,and magneto-thermal properties of the samples were investigated by a static magnetic field,dynamic light scatterer,transmission electron microscope,X-ray diffractometer,and alternating magnetic field,respectively.The study also found that the magnetic iron oxide particles with different hydraulic particle sizes(89.3±2.5,175.5±3.2,and 269.0±9.2 nm)could be prepared by adjusting the operating conditions.The PDI values of the three particleswere all below 0.3.The results indicated that the size of magnetic iron oxide nanoparticles prepared was uniform and controllable.In addition,it could be found that the water dispersion of the prepared samples was good.The appearance was black.They also had good magnetic responsiveness and magnetic thermal properties.(2)A novel green technology,namely magneto internal heat bubble generation technology(MIHBG)was developed to prepare MNBs.Magnetic MNBs were prepared by superparamagnetic iron oxide nanoparticles(SPIONs)in one step by generating local hot spots in alternating magnetic fields.In this study,Xenon was employed as the model gas.The effects of operating conditions on the MNBs properties were discussed in details.Under the optimal parameters(i.e.,magnetic current was 15 A,magnetic field frequency was 303 k Hz,SPIONs concentration was 0.01 mg/m L)the average size,the PDI value,and concentration of the prepared MNBs were 341.5±18.2 nm,0.240±0.027,and 1.5×10~9 particles/m L,respectively.The MNBs also had a high negative zeta potential(-42.4±4.2m V),and could be stable at room temperature(25℃)for 8 h.Furthermore,the preparation mechanism of MNBs was revealed.Specifically,SPIONs would form local hot spots under the alternating magnetic fields.Due to the difference solubility of gas in solution at different temperatures,bubbles could nucleate and generate MNBs around the hot spots.Meanwhile,SPIONs could be adsorbed on the surface of MNBs due to the bridging effect of bubbles,resulting in forming MNBs coated with SPIONs.The present technology need no organic solvent treatment.The process is simple and good controllability.The obtained magnetic MNBs have ordered stable structures.(3)To improve the stability of the bubbles,the phospholipid encapsulated bubbles(LBs)were prepared via the self-assembly of phospholipid and MNBs driven by temperatures based on MIHBG process.The LBs of Xenon coated with dimyristoyl phosphatidyl choline(DMPC)and distearoyl phosphoethanolamine-polyethylene glycol 2K(DSPE-PEG2K)were successfully prepared.The repair of intermittent hypoxia(IH)nerve injury cells using the prepared LBs was studied.The cell activity was detected by MTT colorimetry and the apoptosis rate was detected by TUNEL staining.It was found that the LBs could significantly reduce the IH injury of rat adrenal pheochromocytoma(PC12 cells).The results provided a foundation for the integration of diagnosis and treatment of cognitive dysfunction secondary to obstructive sleep apnea(OSA).