Layer-by-layer nanoencapsulation strategies for enhanced oral delivery and function of Lactobacillus plantarum B2

Abstract

Bacterial therapy based on oral delivery and intestinal colonization of probiotics has demonstrated promising effects in addressing ariboflavinosis, a deficiency of riboflavin (vitamin B₂). Nevertheless, the harsh conditions of the gastrointestinal (GI) tract, including continuous peristalsis, GI digestive fluids, high levels of reactive oxygen species (ROS), and a complex pathological environment limit the effective delivery and colonization of probiotics. This study aimed to construct a novel layer-by-layer (LBL) self-assembly strategy to enhance the oral delivery and functional benefits of Lactobacillus plantarum B2 (a riboflavin over-producing probiotic strain). The encapsulation system employs the electrostatic interaction mechanism between bacterial surface, chitosan, and mucin/sodium alginate (SA) to improve the stability and efficacy of L. plantarum B2. Various analytical techniques such as transmission electron microscope (TEM), scanning electron microscope (SEM), atomic force microscope (AFM), and laser scanning confocal microscope (LSCM) were employed to clarify the successful encapsulation and high encapsulation efficiency of probiotics. Mucin/SA-chitosan nanoencapsulated L. plantarum B2 (M/A-C-L. P. B2) was endowed with improved storage stability and enhanced resistance to simulated gastrointestinal (GI) digestive fluids or ROS. Particularly, the mucin nanolayers significantly improved the adhesion of the probiotic to simulated intestinal mucus and Caco-2 cell monolayers. In addition, M-C-L. P. B2 formulation effectively preserved the physiological activity of probiotics and significantly increased the riboflavin content of soymilk during fermentation. This nanoencapsulation strategy presents an excellent platform for enhancing the oral delivery of probiotics which can not only improve the stability and viability of probiotics in the harsh GI environment but also upgrade their functional benefits, particularly in the treatment of riboflavin deficiency.