Metal ion-induced multi-layer coatings improves gastrointestinal resistance of Lactiplantibacillus plantarum and biosafety evaluation

Probiotics provide numerous health benefits; however, their low survival rate in gastric acid and short retention time in the intestine are major obstacles to their effective utilization. Here, a simple yet effective novel probiotic multilayer coating consisting of Fe 3+ -protocatechuic acid (PCA) crosslinked network and Ca 2+ -induced sodium alginate (SA) for arming Lactiplantibacillus plantarum (LP) was developed. The Fe 3+ -PCA and SA coating process did not affect the normal growth of probiotics. Electron microscopy experiments confirmed the feasibility of this coating strategy. In vitro simulations of gastric acid and bile salt environments demonstrated that SA-PCA coating could enhance probiotics' resistance to gastrointestinal digestion and protect against damage from ethanol and antibiotics. In vivo survival experiments further showed that SA-PCA coating improved the probiotic survival rates. Biosafety experiments indicated that this coating strategy exhibited good biosafety. This study introduces a novel conservation strategy in probiotic delivery, providing effective protection for probiotics and offering theoretical references for developing innovative approaches to alleviate related diseases.