While companies like Organovo and Rainbow Biosciences work on 3D printing liver cells from human tissue, nano-engineers at UC San Diego are already working on their own 3D printed liver device. Only, this is no transplant, it’s meant to work outside of the body, the hepatic equivalent of a dialysis machine. Using nano particles, the device is meant to trap pore-forming toxins that hurt cellular membranes and, as a result, spur illnesses related to animal bites, stings, and bacterial infections.
From the report, published in Nature Communications: “PDA nanoparticles (green) are installed in PEGDA hydrogel matrix (grey) with liver-mimetic 3D structure fabricated by 3D printing. The nanoparticles attract, capture and sense toxins (red), while the 3D matrix with modified liver lobule structure allows toxins to be trapped efficiently.”
In the past, scientists have been able to counteract toxins in the bloodstream using nanoparticles. The only problem is that these nanoparticles can build up in the liver, causing secondary poisoning, particularly in patients already susceptible to liver failure. To bypass this concern, Professor Shaochen Chen and his nanoengineering team 3D-printed a matrix made from hydrogel to enclose the nanoparticles. The device acts similarly to the liver, sensing, attracting, and capturing toxins from the bloodstream, but it has a larger surface area to more efficiently attract and capture toxins. Though it is still in the proof-of-concept stage, the device has been tested in an in vitro study, where it demonstrated the ability to completely neutralize pore-forming toxins.
From Nature Communications: “(a) Rational design of the liver-mimetic 3D structure. The modified liver lobule topology allows toxins to enter the 3D matrix efficiently. (b) The masks that are used for printing liver-mimetic 3D structure. By alternatively using these masks in DOPsL technology, a bio-inspired detoxifier with four layers of liver-mimetic structure is created. (c) The 3D structure of the detoxifier measured by laser confocal microscopy. Incubated with melittin (50 μg ml−1, 300 μl), the red fluorescence of PDA allows the reconstruction of the microstructure of the detoxifier in 3D. (d) Scanning electron microscope image of this detoxifier. Scale bar, 50 μm. (e) Dynamic test on the neutralization efficiency with comparison between the liver-mimetic structure (3D structure) and slab control (that is, with the same total volume). After the incubation of melittin solution with detoxifier for different times, the neutralization efficiency was tested by the haemolytic assay. (f) Centrifuged RBCs after incubation with normal saline (control), melittin (5 μg ml−1), detoxifier-treated melittin or PDA nanoparticles-treated melittin. The red colour indicates the cytolysis of RBCs. (g) Neutralization efficiency of the 3D detoxifier. Equivalent amount of PDA nanoparticles is used for comparison.”
Chen believes that 3D printing will change the way doctors may detoxify the body, “The concept of using 3D printing to encapsulate functional nanoparticles in a biocompatible hydrogel is novel. This will inspire many new designs for detoxification techniques since 3D printing allows user-specific or site-specific manufacturing of highly functional products.”
The professor’s 3D bioprinting technology was previously covered on 3DPI back in 2012, when he was able to 3D print complex micro- and nanoscale biocompatible structures from hydrogel using a method called dynamic optical projection stereolithography (DOPsL). DOPsL is an interesting extension of standard stereolithography that uses a computer projection system to reflect light from controlled micromirrors onto photosensitive biopolymers. The technique is being pushed thanks to a four-year grant from the National Institute of Health for $1.5 million.
To read in greater scientific detail about the research, see the study published in Nature Communications.
Source: UCSD News
