Methods capable of maintaining gut microbiota homeostasis to prevent bacterial translocation and infection under external threats are critical for multiple facets of human health but have been rarely reported. Here, we describe the elicitation of mucosal immunity to modulate the gut microbiota by oral delivery of living probiotics into Peyer’s patches. Probiotics are individually camouflaged within a yeast membrane, on which the embedded β-glucan can facilitate the phagocytosis of microfold cells that locate in the intestinal epithelium. The delivery of probiotics into lymphoid follicles after oral ingestion promotes robust mucosal immune responses and notably upgrades the production of secretory immunoglobulin A. The provoked immunity positively regulates the gut microflora, which, in turn, retains gut homeostasis and provides defense against environmental attacks. In two murine models of gut barrier impairment, oral administration with camouflaged probiotics effectively prevents the breakdown of intestinal barrier and evidences limited bacterial translocation and systemic inflammation.

An automated and portable microfluidic chemiluminescence immunoassay is developed for quantitative detection of biomarkers in serum samples.