Controlled Synthesis And Characteristics Study Of Prussian Blue Nanoparticles And Their Composite Hydrogels

Prussian blue nanoparticles（PBNPs）,as a kind of classical metal-organic frameworks,have potential application in the treatment of various wounds due to their unique anti-inflammatory,antioxidant and photothermal effects.In this paper,a double injection method was firstly proposed to control the size and crystallinity of PBNPs.Further,growth mechanism of PBNPs was carefully studied and their size and crystallinity-dependent physicochemical properties of were systematically summarized.Secondly,PBNPs doped polyvinyl alcohol（PVA）composite hydrogels（PVA/PBNPs）and Gelatin composite hydrogels（Gelatin/PBNPs）were developed for the hypoxia and severe inflammation characteristics in chronic wound.The production and release of dissolved oxygen based on PVA/PBNPs hydrogel and the skin temperature sensitive-solation together with reactive oxygen clearance based on Gelatin/PBNPs hydrogel were realized.Finally,the good biocompatibility of the above nanocomposite hydrogel was verified in vitro.The main findings are summarized as follows:Controlled synthesis and size and crystallinity-dependent physicochemical properties of PBNPs.Firstly,size and crystallinity of PBNPs were successfully controlled from 40nm-130nm and from amorphous to crystalline by double injection reaction and adjusting the volume of prior added ferric chloride and citric acid mixture.Secondly,growth process of PBNPs was studied and it was found that PBNPs followed the reaction rate dominated classical crystal growth process under the double injection reaction condition,rather than aggregation based growth mechanism.In addition,results showed that size and crystallinity had influence on their spectral property,enzyme-like activity and magnetic resonance imaging ability.Moreover,PBNPs with small size and low crystallinity presented wider Raman absorption peak and shorter peak wavelength in vis-NIR absorption spectrum,showed higher enzyme-like activity and stronger T₁ imaging ability.Controlled synthesis,oxygen production and release of PVA/PBNPs composite hydrogel.Firstly,PVA/PBNPs composite hydrogels were prepared by freeze-thaw method.Crystallinity,mechanical properties,water content and swelling ratio analysis revealed that the influence of added PBNPs on the structure of PVA hydrogels would change with the level of PVA content in the hydrogel structure.Secondly,an appropriate amount of H₂O₂ was loaded on the PVA hydrogel and superimposed on the PVA/PBNPs composite hydrogel.Based on catalase（CAT）like activity of PBNPs in the composite hydrogel,the multilayer hydrogel could produce and release high concentration of dissolved oxygen.Controlled synthesis and ROS scavenging ability of Gelatin/PBNPs composite hydrogel.Gelatin/PBNPs composite hydrogel were prepared by freezing method.Rheological analysis of Gelatin/PBNPs composite hydrogels revealed that the effect of doped PBNPs on the phase transformation temperature of PVA hydrogels changed with the content of Gelatin.In addition,through the dynamic light scattering test and spectral analysis,it was found that the PBNPs obtained after the temperature sensitive solation of Gelatin/PBNPs composite hydrogel presendted good stability and could scavenge H₂O₂and superoxide anion.In vitro cytotoxicity evaluation of PVA/PBNPs composite hydrogel and Gelatin/PBNPs composite hydrogel were conducted through the extract liquid method and cck8 method.The results showed that the PVA（6%）/PBNPs（3mg/m L）composite hydrogel and the Gelatin（4%）/PBNPs（<50μg/m L）composite hydrogel had no obvious cytotoxicity to several common cells at the wound microenvironment.