Encapsulation And Active Regulation Of Akkermansia Muciniphila Based On Microstructure Fabrication

Akkermansia muciniphila(A.muciniphila)is a mucin degrading bacteria found in mucus layer of small intestine,and is considered as a next generation beneficial microbe.A large number of studies have shown that A.muciniphila is closely related to the health,metabolism and immunity of the host,the changes of A.muciniphila abundance are significantly associated with obesity,diabetes,hypertension and many other diseases.Therefore,the prevention or treatment of obesity and related metabolic disorders by regulating the A.muciniphila abundance in human body have become a potential therapeutic approach.At present,the regulation methods for A.muciniphila abundance in human body are mainly oral administration of A.muciniphila and the microcapsule which encapsulates A.muciniphila.However,this is a passive diffusion regulation method,and there is a great uncertainty of A.muciniphila that reach and colonize the target location.Therefore,this paper studies an encapsulation method of A.muciniphila based on microstructure fabrication technology and combine with the fabrication techniques of micromotors to realize the active regulation of A.muciniphila.This paper carry out research works in the following three aspects:(1)A high-precision microstructure fabrication system is built and tested.By using the spatial light modulation function of the digital micromirro device and the free radical polymerization reaction induced by ultraviolet(UV)irradiation,a hydrogel microstructure fabrication system integrating real-time observation is designed.The fabrication of hydrogel microstructures by this system can be completed in just a few seconds.The microstructure precision can reach below 100 microns,and arbitrary hydrogel microstructures can be fabricated,providing a much higher efficiency than existing methods,while also offering a high degree of flexibility and repeatability.Finally,the effects of different UV laser intensities,exposure time,and the concentration of hydrogel monomer on the fabrication results are investigated.(2)The encapsulation of A.muciniphila based on microstructure fabrication technology.In order to quickly detect the concentration of A.muciniphila,we fabricate a graphene-based transistor.The microstructure of poly(ethylene glycol)diacrylate(PEGDA)has the disadvantages of slow degradation and low swelling.Due to the biodegradability and easy crosslinking of sodium alginate,we combine PEGDA and Sodium Alginate to fabricate double-network hydrogel microstructures which can encapsulate A.muciniphila by first photo crosslinking of PEGDA hydrogel,and following by ionic crosslinking of Sodium Alginate.In order to simplify the experimental operating conditions,pasteurized A.muciniphila is selected to be encapsulated.Evidence from several studies suggested that the beneficial effects of A.muciniphila have not disappeared after pasteurization.The distribution of A.muciniphila inside the hydrogel microstructure is shown by fluorescence images.(3)A drivable A.muciniphila-loaded micromotor structure is designed and fabricated to realize the active regulation of A.muciniphila.Micromotors can convert chemical energy,magnetic energy,light energy and other energy into mechanical motion,and have a wide range of applications in drug delivery,biosensing,environmental management and other fields.Combined with microstructure fabrication technology,bubble propulsion is selected as the driving method which depends on the recoil mechanism of accumulated gas bubbles generated through redox reaction of platinum particles and hydrogen peroxide,and platinum particles are modified into the hydrogel microstructure to fabricate A.muciniphila-loaded micromotor structures.The movement of micromotors with different structures in hydrogen peroxide solution is studied,and the results showed that the movement speed of a single micromotor in 10% hydrogen peroxide solution could reach 109.1 μm/s,and the combined bacteria-load micromotor exhibits a speed of 26.9 μm/s.This part of the experiment is carried out in hydrogen peroxide solution in vitro conditions,which has certain limitations,but it provides an idea for the active regulation of A.muciniphila in the human physiological environment.In summary,a method based on microstructure fabrication technology is used to encapsulate A.muciniphila.In the fabrication of the hydrogel microstructure,sodium alginate is added to form a double-network hydrogel structure.We also fabricate a graphene-based transistor to quickly detect the concentration of A.muciniphila.The bacteria-encapsulated microgels are then combined with a micromotor technology to achieve certain active regulatory functions.