Background and introduction of Programmable Probiotic Nanocoating

Capsular Polysaccharides
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Microbe Engineering
Microbe colonization
The first stage of microbial infection is by colonization, where an establishment of a pathogen is made at an appropriate portal entry. The host tissues in contact with the external environment are usually colonized by the pathogens. Pathogens normally enter the host through; urogenital tract, respiratory tract, digestive tract, and conjunctiva. Organisms affecting these regions develop tissue adherence mechanisms to withstand pressure from the host defenses at the surface. One of the adherence factors is a capsule, a detectable layer of polysaccharide on the surface of a bacterial cell that meditates specific or nonspecific attachment (Todar, 2004).
Microbes have been linked with approximately 10 to 20 percent of human cancers. They contribute to cancer by modifying DNA in somatic cells, thus altering cell cycle controls, accelerating cell proliferation, and disrupting normal programs that protect the body from aberrant cells. Cancer cells evolve in an ecosystem of the body and create a microenvironment around the tumor, thus facilitating their growth. However, the microenvironment in the early stages can be significant in suppressing cancer. Tumor microenvironments may include microbes living in or near the tumor, which can alter the microenvironment by producing factors influencing cancer cells. An instance is the strains of E. coli, mostly in the mucosa of individuals with colorectal cancer (Whisner & Athena Aktipis, 2019).
Efficacy and Safety: Host Immune Obstacles
For an optimal host defense, the quick removal of microbes from the bloodstream together with the ability to mount an adaptive immune response is hugely significant. Kupffer cells are usually strategically placed in liver sinusoids to efficiently capture circulating microbes from the hepatic artery and portal vein, thereby preventing bacterial dissemination. The complement receptor of the immunoglobin superfamily (CRIg) in Vivo and Vitro studies have proved to be important in pathogen recognition and clearance (van Lookeren Campagne & Verschoor, 2018). An analysis of complemented-mediated phagocytosis by Zaragoza et al., (2003) revealed an inverse correlation between the phagocytic index and capsule volume. An increase in capsule volume leads to the decreased efficacy in complement-mediated phagocytosis. Specific antibodies are often absent thus leading to activation of complement on the alternative pathway.
The complement system is one of the main mechanisms by which pathogen recognition is converted to effective host defense against initial infection. It contains a system of plasma proteins which can be activated directly by pathogens or indirectly through pathogen bound antibody. There are three pathways of complement activation. The classical pathway is triggered directly by a pathogen, while the MB-lectin pathogen is triggered indirectly by an antibody. However, it’s the alternative that is more effective, as it amplifies the loop for the two pathways. A large active fragment, C5b, creates a sequence of polymerization in which complement components react to form a membrane attack complex that creates pores in cell membranes,...