Study On The Permeability Relationship Between Whey Protein Nanoparticles And Small Intestine Mucus

The mucus layer on the human gastrointestinal tract surface is a viscoelastic gel layer that can effectively capture and remove foreign particles,such as pathogens.It also limits the effective diffusion and absorption of drug delivery systems.Although the mucoadhesion nanocarriers have been reported that they can prolong their retention and release time in the gastrointestinal tract,the drug effective of delivery systems are greatly limited due to the continuous turnover of the intestinal mucus layer.Therefore,improving the nanoparticles penetrating ability in the intestinal mucus can prevent them from being quickly cleared and achieve effective delivery in the target site.Recently,nanotechnology has been used for eliminating this physiological hurdle by constantly innovate the physicochemical property of nanoparticles.In fact,most bacteria that have high mobility in mucus have a rod-like shape,indicating that the shape may help to increase the mucus penetration of the particles.In this paper,biodegradable material whey protein was used as raw materials to preparate four types of nanocarriers with different shapes and sizes.The chamber diffusion and MPT methods were taken up for studying the permeation rate of different nanoparticles in the intestinal mucus layer.Based on the Caco-2/HT29-MTX-E12 co-culture cell model,the effect of mucus on the cellular internalization and epithelial transport capacity of different nanoparticles were also evaluated.Meanwhile,this model was used to study the behavior of nanoparticles in the mucus layer and investigate the NPs ability for opening the tight junctions.The research contents of this paper are as follows:1.Explore the ability of different nanoparticles to penetrate into the intestinal mucus layer.Four kinds of nanoparticles with different particle sizes and shapes based on whey protein were prepared,namely NS(30 nm),BNS(300 nm),LNT(20×800 nm)and SNT(20×200 nm).All of them have negative charge around-20 mV.Two methods including chamber diffusion and MPT method were used to prove the effect of particle size and shape on the penetration of intestinal mucin layer.The order of the diffusion rate of the four kinds of nanoparticles was BNS<LNT<NS<SNT.Simultaneously,the faster diffusion nanoparticle SNT has a deeper distribution in the intestinal mucus layer,and the smaller-sized SNT have the potential to penetrate the intestinal mucus layer and get into the epithelial cell.2.Transport and absorption of different nanoparticles in Caco-2/E12 co-culture model.We find that the toxicity of the four nanoparticles on the co-cultured cells was very low,indicating that the whey protein nanoparticles have good biocompatibility.After removal of the mucus layer on the co-cultured cells by NAC,the uptake and transport capacity of the four nanoparticles were improved.It revealed that the mucus layer is a barrier for the absorption of nanoparticles.Compared with BNS and LNT,SNT and NS showed a good affinity with epithelial cells at the level of co-cultured cells,which enhanced the cellular uptake and enhanced its transmembrane transport capacity.It indicates that the particle size and shape have an effect on the cellular uptake and transmembrane transport ability.The smaller size of SNT has a stronger transmembrane transport capacity.At the same time,compared with spherical nanoparticles(NS and BNS),nanotubes(SNT and LNT)have a stronger ability to open the tight junctions with transiently reversible.Our study gives a new design idea for the mucosal drug delivery system and lays the foundation for the effective delivery of nanomedicines.