Research On Preparation And Properties Of Stimuli-responsive Composite Microspheres Of Biopolymer/Nanoparticle

Chitosan, agar and gelatin which are abundant in nature have been used widely in biomedical fields as polysaccharide or protein materials with excellent biocompatibility, extensive sources and low cost. At the same time nanoparticles also play a crucial role in many aspects such as disease diagnosis and treatment, drug delivery, chemical analysis due to their unique physical and chemical properties. Therefore we can composite these nanoparticles with natural polymer materials to improve their biocompatibility, offering convenience for their further applications. It's worth noting that, the unique stimuli-responsive properties of natural polymers are of great importance. Especially, stimuli-responsive natural polymer/nanoparticles composite microspheres as the carriers of nanoparticles, which have potential applications in a wide range of areas such as medical diagnostics, multicomponent biological detection, drug screening has attracted attention of researchers. This will play a significant role in analysis of chemical and biological engineering.In this work aqueous Zn S quantum dots are first synthesized, and then Zn S quantum dots/chitosan composite are prepared by blending Zn S quantum dots and chitosan, which has the properties such as biocompatibility, biodegradability and non-toxic under appropriate conditions. Then we assemble a microfluidic channel for controllable preparation of p H-responsive Zn S quantum dots/chitosan composite microspheres. We hope to obtain microspheres with excellent combination properties, which possess both stimuli-responsive sol-gel transition and favourable fluorescent by researching the property of the system. Zn S quantum dots and Zn S quantum dots/chitosan composite are characterized utilizing the appropriate test methods, and the results demonstrate that Zn S quantum dots are monodispersed with an average particle size of about 6 nm. Zn S quantum dots and Zn S quantum/chitosan composite both show obvious blue fluorescence. The controlled preparation and release of Zn S quantum dots/chitosan composite microspheres can be realized by using gas-liquid microfluidic channel technology and p H-responsive property of the composite.Magnetic Fe3O4 nanoparticles are synthesized by chemical co-precipitation method. Then Fe3O4 nanoparticles are employed to composite with agar and gelatin to obtain magnetic Fe3O4 nanoparticles/agar/gelatin “babyships/motherships” microspheres by thermo-responsive method. First we obtain magnetic Fe3O4/agar microspheres due to the thermo-responsive property of agar. And then the prepared magnetic Fe3O4/agar microspheres are blended with gelatin sol to obtain magnetic Fe3O4/agar/gelatin “babyships/motherships” microspheres on the basis of the sol-gel transition property of gelatin. We hope to obtain microspheres with excellent combination properties such as stimuli-responsive sol-gel transition and favourable magnetic by researching the properties of the system. Properties of Fe3O4 nanoparticles, Fe3O4/agar microspheres and magnetic Fe3O4/gelatin/agar “babyships/motherships” microspheres are characterized and analyzed using the appropriate measures. The results reveal that Fe3O4 nanoparticles show an average size of 95.6 nm, and after blending with agar the Fe3O4/agar microspheres retain excellent magnetic property. And magnetic Fe3O4/agar/gelatin “babyships/motherships” microspheres can offer controlled-release property as proposed due to the thermo-responsive property.This work will provide new ideas and methods of applications for the combination of nanoparticles and natural polymer materials. For instance, the composite systems are beneficial for broad applications in fluorescent biological labels, smart drug delivery systems, disease diagnosis and treatment.