The purpose of this investigation was to develop Pluronic F-127 coated N-trimethyl chitosan nanoparticles(F-S NPs)of insulin as the model drug and asses their penetration of the mucosal barriers. Single factor screening was used to optimize the formulations of nanoparticles and the nanoparticles were characterized. Their particle size, Zeta potential, encapsulation efficiencies and drug loading were assayed to be(240. 6±6. 51)nm, (10. 42±1. 60)mV, (43. 39±2. 83)% and(3. 39±0. 57)%, respectively. The impact of PF-127 on mucin binding in vitro and nanoparticles′s transport in freshly obtained mucus were also evaluated. The mucin affinity of F-S NPs was significantly reduced when compared to that of the N-trimethyl chitosan nanoparticles(S NPs), i. e. , 28% of the latter. And F-S NPs was found to have an improved mucosal penetrating capability. Mucus-secreting HT29-MTX-E12(E12)cell monolayer was selected to investigate their cellular uptake. F-S NPs exhibited higher penetration coefficient than both free insulin and S NPs in mucus-secreting epithelium cells, i. e. , 16-fold and 1. 4-fold, respectively. Data suggest that F-S NPs be potential carriers to cross mucosal barriers and enhance the cellular uptake of insulin.

Protein corona (PC) has been identified to impede the transportation of intravenously injected nanoparticles (NPs) from blood circulation to their targeted sites. However, how intestinal PC (IPC) affects the delivery of orally administered NPs are still needed to be elucidated. Here, we found that IPC exerted "positive effect" or "negative effect" depending on different pathological conditions in the gastrointestinal tract. We prepared polystyrene nanoparticles (PS) adsorbed with different IPC derived from the intestinal tract of healthy, diabetic, and colitis rats (H-IPC@PS, D-IPC@PS, C-IPC@PS). Proteomics analysis revealed that, compared with healthy IPC, the two disease-specific IPC consisted of a higher proportion of proteins that were closely correlated with transepithelial transport across the intestine. Consequently, both D-IPC@PS and C-IPC@PS mainly exploited the recycling endosome and ER-Golgi mediated secretory routes for intracellular trafficking, which increased the transcytosis from the epithelium. Together, disease-specific IPC endowed NPs with higher intestinal absorption. D-IPC@PS posed "positive effect" on intestinal absorption into blood circulation for diabetic therapy. Conversely, C-IPC@PS had "negative effect" on colitis treatment because of unfavorable absorption in the intestine before arriving colon. These results imply that different or even opposite strategies to modulate the disease-specific IPC need to be adopted for oral nanomedicine in the treatment of variable diseases.