Preparation Of Polyelectrolyte Microcapsule And Its Influences With Cells

With the rapid development of nanotechnology and biotechnology,microcapsule has been widely used in the biomedical field,including drug delivery,gene therapy,disease diagnosis and bioimaging.However,the interaction between microcapsule and cells should not be neglected.On one hand,many biological applications,such as intracellular drug and gene delivery,rely on the cellular uptake of microcapsules;On the other hand,some side-effects,such as cell toxicity and the influences on cell functions,occurred due to the endocytosis.In either case,the microcapsules must be introduced into the cells in the physiological environment.It is of paramount importance to investigate the relationship between the chemical and physical properties of microcapsules and the responses of cells,including uptake kinetics and pathways,intracellular distribution and the changes in cellular functions.It is known that the physicochemical properties of microcapsules,such as size,shape,mechanical property and surface charge,are of great influences on cellular uptake process.However,the influence of microcapsules with different stiffness on the endocytosis was rarely studied.?1?Microcapsules with variable mechanical strength were fabricated via layer-bylayer?LBL?assembly based on CaCO₃ templates.Poly?allylamine hydrochloride??PAH?was selected as the major component of the wall material.SEM,FITR,XRD,TEM and CLSM were used to characterize the basic physical and chemical properties of the microcapsules.Besides,their interaction with human Hep-G2 cells was further investigated.The microcapsules with less mechanical strength were well dispersed in water and had a spherical form with a uniform size of 3-4 ?m.These microcapsules may collapse in dry state and would recover the hollow spherical form when they were dispersed in water.FTIR results suggest that the microcapsules had a stable wall structure.The microcapsules have suitable size and good biocompatibility,which is very important for the further application in biological field.?2?The microcapsules were further co-incubated with Hep-G2 cells and the interaction between them was investigated.The elasticity modulus of the two microcapsules was measured to be 1243.3 and 3309.5 MPa,respectively.With the prolongation of incubation time,the uptake amount of microcapsules increased and then reached a stable value.It is easier to uptake the microcapsules with less elasticity modulus.Since the cell viability was not obviously impaired by endocytosis,it can be considered that the microcapsules were nonhazardous to the cell.?3??PAH/DPA?₄ microcapsules cross-linked by disulfide bond were prepared via layer-by-layer?LBL?assembly based on MnCO₃ templates.All of the microcapsules had an average size of 3 ?m and a wall thickness of 55.25 nm,and were well dispersed in water.Moreover,a reversible elastic deformation of the microcapsules with certain mechanical strength was observed in the PSS solution with high concentrations.FTIR results also show that the microcapsules had stable wall structures.In consideration the above advantages of the microcapsules,they may have wide potential applications in the biomedical field.