New Design of 3D ‘Organ-On-A-Chip’ Device Grows Neurons Most Affected in Parkinson’s

Scientists have designed a so-called “organ-on-a-chip” device that can grow dopaminergic neurons — the brain cells most affected in people with Parkinson’s disease — in a 3D environment where they are more like real neurons in the brain, a study shows.

The device is fully automatable and can facilitate multiple parallel experiments, which can be used to understand disease processes better and test new investigational therapies. 

The study, “Passive controlled flow for Parkinson’s disease neuronal cell culture in 3D microfluidic devices,” was published in the journal Organs-on-a-Chip.

To investigate the underlying processes in Parkinson’s disease, dopamine-producing brain cells (dopaminergic neurons) most affected by the condition need to be recreated and grown in cell culture. 

To do this, scientists have used induced pluripotent stem cells (iPSC) technology, in which any type of cell can be converted to a stem cell and then reprogrammed into many neuron types, including dopaminergic neurons. 

Cell cultures using microfluidics is a method that employs tiny chambers (chips) to grow cells in which fluid is passed through to mimic blood flow in a whole organ. 

This technique is popular among researchers as low volumes reduce costs and lower cell response times to treatments. Furthermore, large numbers of these small chambers can fit on a single device that can be automated, which increases the quantity and the quality of experiments that can be done in parallel. 

Also, evaluating new therapies with these devices can reduce animal testing and accelerate medical development. 

However, most devices currently used can generate fluid flow for only a few minutes up to an hour, which is not convenient for experiments requiring constant flow. Moreover, cells are grown in a 2D environment that does not represent a 3D organ system. 

“Cell cultures for chip devices have typically been grown in 2-D,” senior author Jens Schwamborn, PhD, of the University of Luxembourg, said in a press release. “To get closer to the real situation in the brain, the neurons need to be in a 3-D environment.”

Researchers at the University of Luxembourg, along with collaborators at  Leiden University in the Netherlands, redesigned a cell culture device called the OrganoPlate 2-lane to overcome these obstacles.  

This original device features 96 independent cell growth chambers (chips) with fluid channels and is fully compatible with automation. Each chamber has four wells: one used to load cells embedding in a gel (to maintain integrity); an input well and an output well; and one used to monitor cell quality. 

After a series of modeling steps to optimize the size of the fluid channels, the prototype device had 48 chips with six wells — one for cells, two input and two output wells, plus a well for monitoring. 

The chips’ geometric parameters were designed to yield a fluid flow rate over a 24-hour period, which was confirmed by experiment. The device also was modified to incorporate newly designed 3D microfluidic structures as well as the biological requirements for neuronal cell culture to best model the flow of blood in the brain. 

Based on this work, a new device was manufactured and validated by growing cell cultures. 

Human neural stem cells called neuroepithelial cells (NESCs) were first generated from iPSCs, which then were resuspended in gel and seeded into the new device. Fluid containing specific molecules was passed through the wells to induce differentiation — when stem cells transform into fully functioning neurons. 

After 30 days of differentiation, the analysis found the new device was able to grow not only new neurons, but also dopaminergic neurons. 

“We have created human neurons that are in an environment, more similar to the one of the human brain,” said Schwamborn. “These can help us get closer to understanding what happens in Parkinson’s disease and develop more effective treatments.”

“This technique has the potential to be applied to many cell types to generate optimum design for their culture,” the researchers wrote.