The construction of nasal cavity-mimic M-cell model, design of M cell-targeting nanoparticles and evaluation of mucosal vaccination by nasal administration.

In order to better evaluate the transport effect of nanoparticles through the nasal mucosa, an nasal cavity-mimic model was designed based on M cells. The differentiation of M cells was induced by co-culture of Calu-3 and Raji cells in invert model. The ZO-1 protein staining and the transport of fluorescein sodium and dexamethasone showed that the inverted co-culture model formed a dense monolayer and possessed the transport ability. The differentiation of M cells was observed by up-regulated expression of Sialyl Lewis A antigen (SLAA) and integrin 1, and down-regulated activity of alkaline phosphatase. After targeting M cells with iRGD peptide (cRGDKGPDC), the transport of nanoparticles increased. , the co-administration of iRGD could result in the increase of nanoparticles transported to the brain through the nasal cavity after intranasal administration. In the evaluation of immune effect , the nasal administration of OVA-PLGA/iRGD led to more release of IgG, IFN-, IL-2 and secretory IgA (sIgA) compared with OVA@PLGA group. Collectively, the study constructed M cell model, and proved the enhanced effect of targeting towards M cell with iRGD on improving nasal immunity.