Surface Modifications for Improved Delivery and Function of Therapeutic Bacteria

Abstract

Live therapeutic bacteria (LTBs) hold promise to treat microbiome-related diseases. However, few approaches to improve the colonization of LTBs in the gastrointestinal tract exist, despite colonization being a prerequisite for efficacy of many LTBs. Here, a modular platform to rapidly modify the surface of LTBs to enable receptor-specific interactions with target surfaces is reported. Inspired by bacterial adhesins that facilitate colonization, synthetic adhesins (SAs) are developed for LTBs in the form of antibodies conjugated to their surface. The SA platform is nontoxic, does not alter LTB growth kinetics, and can be used with any antibody or bacterial strain combination. By improving adhesion, SA-modified bacteria demonstrate enhanced in vitro pathogen exclusion from cell monolayers. In vivo kinetics of SA-modified LTBs is tracked in the feces and intestines of treated mice, demonstrating that SA-modified bacteria alter short-term intestinal transit and improve LTB colonization and pharmacokinetics. This platform enables rapid formation of an intestinal niche, leading to an increased maximum concentration and a 20% improvement in total LTB exposure. This work is the first application of traditional pharmacokinetic analysis to design and evaluate LTB drug delivery systems and provides a platform toward controlling adhesion, colonization, and efficacy of LTBs.

Keywords: biomaterials; drug delivery; microbiome; probiotics; targeted delivery.