Construction Of CT-developed And Enteric-targeted Dual-function Microcapsules For Oral Probiotic Delivery Was Developed

Objective:Bifidobacterium are defined as a group of living microorganism supplements which can improving intestinal flora,strengthening immunity,inhibiting tumor growth,promoting nutrient absorption and so on.However,oral exogeneous Bifidobacterium are extremely sensitive to gastric acid with low pH.When directly contact with the gastric acid in stomach,a large amount of Bifidobacterium might damage before they reach the intestine.Up to now,the main way to protect the survival rate of Bifidobacterium from gastric acid is the alginate-based encapsulation.In this study,we fabricate a chitosan-coated alginate microcapsule(CA-B microcapsule)for CT imaging and intestinal-targeted drug delivery by one-step electrostatic spraying method.Systematically characterized the basic performance about CA-B microcapsule investigated its potential applications in the improvement of the intestinal and relief of inflammatory bowel disease condition.The CA-B microcapsules provide a novel platform for efficient protection,real-time CT imaging,intestinal targeting for oral probiotics delivery.Methods:1.Using alginate and sodium sulfate mixture solution as jet fluid,barium chloride as receiving liquid,we have prepared alginate microspheres containing barium sulfate(AB microspheres)by one-step electrostatic spraying method.After chitosan coating,alginate second coating and sodium citrate liquefaction chitosan-coated alginate microcapsules(CA-B microcapsules)were successful fabricated.2.Physical properties of CA-B microcapsules were characterized by digital cameras and X-ray diffraction instrument.The pH 2.5 simulated gastric acid is chosen as the model gastric acid to investigate the protection effect of Bifidobacterium on CA-B microcapsules,AB microcapsules and free Bifidobacterium.The release of Bifidobacterium in AB microspheres and CA-B microcapsules under simulatedintestinal fluid was measured.3.Establishment of DSS induced colitis model in mice.The treatment of CA-B microcapsules encapsulated Bifidobacteriurm(the number of Bifidobacterium were ranged from 0.6,1.2,2.4 ×109 CFU)on DSS-induced colitis.The therapeutic effect of Bifidobacterizum was assessed in mice enteritis by observed the clinical symptoms,including mice weight and pathological.4.Real-time tracking of CA-B microcapsules using CT imaging in vivo.To observe the CA-B microcapsules delivery in the whole digest,0.52g CA-B microcapsules were oral administrated into mice and using CT scanned at interval time.5.The intestinal flora changes after treatment by CA-B microcapsules encapsulated Bifidobacterium was analyzed using gene sequencing methods.Fecal microbiota composition was analysised by 16S rRNA.Results:1.Uniform CA-B microcapsules were successful fabricated and their average size was 200?m.The shell of CA-B microcapsules possessed layer-by-layer structure,and internal bismuth bismuth precipitation with regular crystal structure.2.CA-B microcapsules have superior protection of Bifidobacterium in pH 2.5 simulated gastric acid and intestinal targeting release.CA-B microcapsules were not nearly degraded in simulated gastric acid but rapidly disassembled in simulated intestinal fluid.Bifidobacterium encapsulated by CA-B microcapsules exhibited intestinal-targeted and rapid released in simulated intestinal.3.The treatment of Bifidobacterium encapsulated by intestinal-targeted CA-B microcapsules could relieve DSS-induced colitis,including increasing the weight of mice,the length of the colon,intestinal inflammatory cells gradually returned to normal.4.The ability of CA-B microcapsule in CT imaging.0.52g CA-B microcapsules was oral administrated into mice and characterized using CT scanned at interval time which can detect strong CT signal.5.Analysis mice intestinal flora.Collected mice feces for 16S rRNA analysis,bifidobacterium can improve the Allobaculum and reduce the Rikenellaceae in intestinal flora.Conclusion:1.In this study,we used barium elements unique physical and chemical properties,successfully fabricated CA-B microcapsules with uniform size and contrast embedding at the same time by one-step.2.The inside barium sulfate precipitation of CA-B microcapsule has crystal structure and good effect of CT imaging.The radiopaque CA-B microcapsules provide a novel platform for non-invasive real-time monitoring and intestinal-targeted probiotic delivery.3.The encapsulation of lactic acid bacteria in the CA-B microcapsules exhibited superior resistance to gastric acid environment and intestinal-targeted Bifidobacterium delivery system.4.CA-B microcapsules mediated Bifidobacterium delivery has good treatment on DSS-induced colitis and improve the composition of intestinal flora...