Study On Preparation And Properties Of Nano/Micro-Particles In High-Gravity Field

As a powerful technical means in chemical process enhancement technology,high-gravity technology has the advantages of small equipment size and enhanced micro-mixing,and has attracted wide attention in the preparation of nano-micro particles.Therefore,this paper aims at the controllable preparation of the synthesis process of magnetic iron oxide and silk fibroin microspheres,and proposes a study on the controllable preparation of high-gravity enhanced magnetic oxide magnetic nanoparticles(Fe3O4 MNPs)and regenerated silk fibroin(RSF)microspheres.Firstly,we prepared the Fe3O4 MNPs by a high-gravity modified co-precipitation method.The high gravity environment is created by a rotating packed bed(RPB)reactor.Fe3O4 MNPs were prepared at different RPB rotation speeds(500 rpm?2000 rpm).The chemical composition and particle size distribution of Fe3O4 MNPs were analyzed by X-ray diffraction analysis(XRD),fourier infrared spectroscopy(FTIR)and dynamic light scattering(DLS)technique.Finally Fe3O4 MNPs were employed to catalyze the disruption of yeast cells.The results showed that Fe3O4 MNPs were successfully prepared under different speed conditions,and the catalyze activity was higher at 500 rpm and 1500 rpm.Then,on the basis of the understanding of the preparation of magnetic nanoparticles by high-gravity enhancement,RSF microspheres were prepared by high gravity anti-solvent precipitation method.We used RSF aqueous solution as solvent and ethanol as anti-solvent.The ethanol flow rate(0.45 mL/s?1.5 mL/s),solvent/antisolvent ratio(1:20?9:20),freezing time(0?24 h)and centrifugal effects on RSF microsphere formation,size distribution and morphology.Then we used scanning electron microscope(SEM)to observe the prepared microspheres,and the particle size and distribution were analyzed by Image J software.The results showed that RSF microspheres,with diameters of 0.1?1.6 ?m,can be prepared under high-gravity field via self-assembly of RSF molecular chains induced by ethanol and quenched by freezing and lyophilization.And the best experimental conditions were the ethanol flow rate was 0.45 mL/s,the solvent/anti-solvent ratio was 3:20,and it was frozen for 0 h without centrifugation and directly lyophilized.In addition,Rhodamine B was used as a model drug to evaluation of drug delivery capacity of the RSF microspheres.The drug-carrying rate of the microspheres prepared in a high-gravity field was significantly better than that of traditional preparation methods.The merits of this study lie in a simple low-cost apparatus with ease for scale-up and thereby potential high volume continuous production capacity,which is of practical advantages and industrial significance in preparation of Fe3O4 MNPs and protein microspheres for commercial mass production.