Encapsulation of probiotic E. coli in a novel hydrogel system for individuals suffering from dysbiosis

Benjamin Matheson1, Jane C. Romero-Kotovsky1, Phuong A.H. Nguyen1, Linnea K. Ista2, Heather E. Canavan3

  1. Graduate Student in the Center for Biomedical Engineering
  2. Research Associate Professor in the Center for Biomedical Engineering
  3. Associate Professor in the Center for Biomedical Engineering

Clostridium difficile infection (CDI) is a type of dysbiosis of the large intestine that results from antibiotic therapy that disrupts the normal microbial flora. Thus, fecal microbiota transplantation (FMT), the transfer of fecal microbes from a healthy donor to a CDI patient, has emerged as an effective treatment for recurrent CDI. The risks and challenges of FMT include the transfer of pathogens/chronic infections, finding acceptable fecal transplant donors, and the use of a nasogastric tube which is considered an invasive approach. Therefore, we have developed and are exploring an alternative delivery mode of healthy fecal microbiota to people suffering from CDI, as well as other dysbioses, as a way to circumvent the current issues associated with FMT. The concept is based on a crosslinking method of chitosan, sodium alginate, and poly(ethylene glycol) (PEG) to encapsulate the probiotic E. coli strain Nissle 1917 (EcN) into spheroids. The encapsulation design is based on the well-known pH dependence of sodium alginate/chitosan gels, which has been employed extensively in drug delivery. Using fluorescent microscopy, we have studied the encapsulated EcN viability, the arrangement of EcN after encapsulation, and the structure of the encapsulation spheroids. Our aim is to find and understand a more effective way to treat people suffering from CDI, or other dysbioses, by providing insight into how specific microbial species can be introduced in the gastrointestinal tract.