Research teams from Zhejiang University and DE Montfort University 3D-printed a multilayer drug delivery device (DDD) capable of delivering more than one drug to different parts of the gastrointestinal system, the Bear learned on June 18, 2020.
With its unique core shell geometry, DDD can be loaded with different drugs to meet a variety of slow and fast release requirements.
The researchers believe their work could greatly help build microbial ecosystems in humans by fighting E. coli.

Good bacteria and bad bacteria
The human gut is home to a host of microbes.
These gut microbes have a profound impact on our nutrition and health.
With such a delicate balance between “good” and “bad” bacteria, a slight tilt in the balance can lead to a range of health problems, from obesity to allergies to cancer.
There is an entire industry dedicated to producing probiotics for consumption (yogurts and tablets containing live cultures of beneficial microbes) that can be eaten with main meals.
3D printing of multiple drug delivery systems
The team used an electro-hydraulic 3D printer to produce the core-shell structural fibers.
The machine allows them to precisely stack and arrange the fibres at the nanoscale to develop complex structures.
In this way, the DDD geometry can be customized according to the release curve of different patients.
The researchers printed a square, a full circle and a semicircle for the study.
In each DDD, proteoglycan was stored in the core (polyacrylate II), and kaixin fructose was stored in the shell (cellulose acetate).

The team tested DDDs in simulated gastroenteric fluid to determine their release rate and tensile strength.
The outer shell dissolves in 12 hours, but the core remains intact for 72 hours, giving enough time for DDDs to enter the bowels.
The maximum tensile strength (whole circle) is greater than 0.22mpa, which is the pressure in human stomach and intestines.
DDDs successfully increased the proliferation rate of bifidobacteria (good bacteria) to 294.2%.
In addition, DDDs was found to have a significant inhibitory effect on E. coli (not so good bacteria), up to 37%.
Given this encouraging result, the researchers believe that the core-shell structure they developed could be extremely useful in rebalancing the human gut flora.

Further details of the study could be found in the paper entitled “A core-shell Multi-drug Platform to improve the well-off Health using 3D Printing “.
The book was written by Li-Fang Zhu, Xing Chen, Zeeshan Ahmad, Yu Peng, and Ming-Wei Chang.