Vaxiion's Bacterial Minicells


Vaxiion's proprietary bacterial strains are each designed with inducible minicell-production phenotypes to ensure reliable and reproducible  production.

Bacterial minicells (BMCs), the underpinning of Vaxiion's technology and asset base, were originally discovered by microbial geneticists studying cell division in Gram-negative bacteria over 40 years ago. Since then, BMCs have been used to study other aspects of microbial genetics and physiology as well as phage transduction, protein synthesis, and plasmid biology. After 1990, minicells were seldom reported in the literature outside of the context of plasmid-borne protein synthesis or cell division gene studies.  Major advances in molecular biology, microbial genetics, cancer biology, and genomics - along with the efforts of Vaxiion - have resurrected BMCs as a viable and highly flexible targeted delivery platform. 

Bacterial minicells (BMCs) are small, spherical, bacterial nano-particles (shown at the right are BMCs budding off of the polar region of a parental E. coli cell, middle panel).  BMCs are unique in that they contain all of the components of the parental bacteria, except the chromosome.  Without chromosomes, BMCs cannot divide and are non-infectious, making them highly suitable for development as  in vivo targeted delivery products.   

Vaxiion has generated a panel of stable inducible minicell-producing bacterial strains containing key genetic modifications that combine to make manufacturing of our BMC products reliable, reproducible and scalable.  Our proprietary strains are engineered so that they cannot grow outside of the laboratory and production facility yet are capable of generating consistently high yields of BMCs when grown in permissive conditions, allowing for well-controlled upstream and downstream GMP production processes.  In addition, genetic safeguards that de-toxify the endotoxin component of the BMC cell wall have been introduced to ensure safety for use in humans and animals, all while maintaining product stability.

​From the perspective of discovery and product development, Vaxiion's BMCs are as amenable to recombinant engineering as any common ​bacterial expression strain.  Because BMCs incorporate anything present in the parental bacterial strain with the exception of the chromosome, they can be easily modified to include recombinant proteins (including protein toxin payloads and BMC-surface localized cancer cell targeting molecules), expression plasmids, and various silencing RNA molecules - making for a highly versatile "self assembling" delivery technology.  Adding to these capabilities, Vaxiion's BMCs can be loaded with high concentrations of small molecule drugs following purification.  ​​

History of Bacterial Minicells