Microfluidic Fabrication Of Anisotropic Microcarriers

Microfluidics is the science and technology of systems that manipulate small amounts of fluids with the use of microscale channels.As a new interdisciplinary technology which has a close relationship with chemical analysis,fluid dynamics and biological analysis,microfluidics offer a number of advantages: redeuced quantities of samples and reagents,high resolution,high precision and fast analysis.Apart from its merits in seperation,detection and analysis fields,Microfluidics' s ability to precisely control submicron scale fluids turns it into an ideal preparation technology of microscale materials,exhbiting the potential to influence the fabrication of functional and structural microcarriers.There are mainly two kinds of microcarriers: microparticles and microfibers,both of which are important biomedical materials and have significant value in areas of antibody setection,tissue engineering,biosensors,targeted drug delivery and molecular recognitions.Research about microcarriers have been reported recently,however,few of them focus onthe fabrication of anisotropic microcarriers.In fact,anisotropic microcarriers with different shapes have distinct physio-chemical and optical properties,and can behave differently in the same fluid dynamic,elctrical and magnetic environment,which greatly widen the range of applicaiton of microcarriers.Compared with classical preperation,microfluidics provides the microcarriers with elaborate micro-structures and highly controllable preperation process,which makes it possible to fabricate microcarriers as required.Herein,we used a microfluidic emulsification and spinning collaborative technology to fabricate a series of microcarriers with special morphologies and studied the relationship between tension and their morphologies.The detail works are as follow:(1)Co-flow capillary microfluidic devices used for generating droplets and fibers were designed and constructed,respectively.A microfluidic emulsification and spinning collaborative technology was used to fabricate droplets which were encapsulated by fibers.(2)Based on the above mentioned microfluidic devices,the Graphene Oxide/Alginate fibers which contained droplets were fabricated.After the solidification,dehydration and reduction process,the biomimetic spindle-knotted graphene microfibers were obtained.By adjusting the tension,the shape of the spindle knots were highly controllable.There fibers were characterized by the optical microscope and the SEM microscope,and their wettabilities,mechanical properties and detailed structures were also investigated.The fiber's ability to absorb oil is examined,and magnetic fibers were prepared to investigate their manetic control effect.(3)The above mentioned microfluidic devices were modified for the generation of droplets(single and double emulsion droplets)which were encapsulated by the fibers.The elastic fibers were stretched to induce the deformation of droplets,so that nonspherical anisotropic microparticles were fabricated.The relationship between the tension and the particle shape were investigated,and how the tension influenced the arrange of inner cores in the particles were also studied.Magnetic nonspherical anisotropic microcapsules were fabricated to investigate their performance in a rotating magnetic field.