Construction of Probiotic Double-Layered Multinucleated Microcapsules Based on Sulfhydryl-Modified Carboxymethyl Cellulose Sodium for Increased Intestinal Adhesion of Probiotics and Therapy for Intestinal Inflammation Induced by <i>Escherichia coli</i> O157:H7

Abstract

The decreased number of viable bacteria and the ability of <i>Bifidobacterium</i> to adhere to and colonize the gut in the gastrointestinal environment greatly limit their efficacy. To solve this problem, thiolated carboxymethyl cellulose sodium (CMC) probiotic double-layered multinucleated microcapsules with <i>Bifidobacterium adolescentis</i> FS2-3 in the inner layer and <i>Bacillus subtilis</i> SN15-2 embedded in the outer layers were designed. First, the viable counts and release rates of microcapsules were examined by in vitro simulated digestion assays, and it was found that microcapsules were better protected from gastrointestinal digestion than the controls. Compared with free <i>Bifidobacterium</i> strains, double-layered multinucleated microcapsules have higher viable bacterial survival rates and storage stability. Second, through in vitro rheology, tensile tests, isotherm titration calorimetry, and adhesion tests, it was observed that thiolated CMC could enhance the strong interaction of <i>Bifidobacterium</i> with intestinal mucus and significantly promote the proliferation and growth of probiotics. Finally, double-layered multinucleated microcapsules containing <i>B. adolescentis</i> FS2-3 and <i>B. subtilis</i> SN15-2 modified with sulfhydryl-modified CMC were studied in the intestine. Alleviation of <i>Escherichia coli</i> O157:H7 induced intestinal inflammation. The results showed that microencapsulation could significantly increase the colon content of <i>Bifidobacterium</i>, relieve intestinal inflammation symptoms in mice with bacterial enteritis, and repair the intestinal microbiota disorder caused by inflammation. The probiotic double-layered multinucleated microcapsules prepared in this study can improve the survival rate of probiotics and promote proliferation, adhesion, and colonization of probiotics.