July 25, 2019 -- Researchers at Tufts University have designed an ingestible, biocompatible, battery-less, 3D-printed micro-engineered pill that will enable them to non-invasively profile bacterial species that could provide new insights into many gastrointestinal diseases. All scientists studying human diseases and the microbiome will find this new research of interest.
The research was published in Advanced Intelligent Systems on July 19th, 2019 and represent an entirely novel approach to sampling the microbiome. Current methods of sampling the human gut microbiome involve analysis of fecal DNA and metabolites, which provides little information about the microbial populations above the colon. From research in animal models and clinical trials, scientists know that the microbiome is vastly different in the various components of the gastrointestinal tract which uniquely and significantly impact the health of host organisms.
This system, which has been tested using in vivo models in pigs and primates, uses integrated osmotic sampler and microfluidic channels for in vivo sampling of the gut lumen and microbiome upstream of the colon. Clinical trials are still needed to determine if the pill is a viable tool for human patients.
The pill is designed to sample the GI tract at different stages as it passes through utilizing microfluidic channels. The surface of the pill is covered with a pH sensitive coating, so that it does not absorb any samples until it enters the small intestine (bypassing the stomach) where the coating dissolves. A semi-permeable membrane separates two chambers in the pill – one containing helical channels that take up the bacteria and the other containing a calcium salt-filled chamber. The salt chamber helps create an osmotic flow across the membrane which pulls the bacteria into the helical channels. A small magnet in the pill enables one to hold it at certain locations in the gut for more spatially targeted sampling using a magnet outside the body. A fluorescent dye in the salt chamber helps locate the pill after it exits the GI tract.
“We have advanced technologies to analyze bacterial populations using DNA sequencing, but until now have not had a way to sample bacteria throughout the GI tract in a way that is not invasive,” said Hojatollah Rezaei Nejad, a post-doctoral fellow studying novel applications of 3D printing at Tufts and lead author of the study. The researchers believe that such lab‐on‐a‐pill devices will revolutionize our understanding of the spatial diversity of the gut microbiome and its response to medical conditions and treatments.
This research was supported by the Office of Naval Research (#N0014-16-1-2550), the National Institute of Allergy and Infectious Diseases (#5R21AI125891), and the National Science Foundation (CBET1511340, CAREER-1554095).
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