A novel method to sort stem cells that could prove quicker, easier and more cost effect than existing methods has been discovered by Scientists at the University Of California, Irvine. This technique may help speed up the future stem cell therapies.
This technique, called dielectrophoresis, can be beneficial in future to develop therapies for people with conditions ranging from brain and spinal cord damage to Alzheimer's and Parkinson's diseases.
The study was led by Lisa Flanagan, a stem cell biologist at UCI.
This technique makes use of electrodes on a tiny, inch-long glass slide to sort cells according to their electric charges and has been used in cancer research.
There's a lack of tools for identifying and sorting cells in the stem cell field.
This can prove to be a significant discovery as it could add a new tool to current sorting methods, which generally involve expensive, bulky equipment.
"For therapeutic purposes, we want stem cells to turn into specific cell types once they have been transplanted. The trick to doing this is identifying beforehand which cells will become the desired cell type, such as a neuron," said Lisa.
She added: "We have discovered a new, potentially better way to do this by focusing on the electric properties of the cells."
Dielectrophoresis relies on the fact that different types of cells have different electric properties. For example, the stem cells meant to become neurons, have a different electric charge than stem cells that will become astrocytes, another type of brain cell.
It was revealed that the cells respond differently when electric fields are applied. While, at one frequency, a neuron will be attracted to an electrode but an astrocyte will not, and at a different frequency, an astrocyte will be attracted but a neuron will not.
It is important to identify and sort stem cells while creating stem cell-based therapies. Stem cell transplantations can cause tumors or be rejected by the body's immune system, if a purification process is not there.
The scientists wanted to identify and collect stem cells that were destined to become neurons, which are cells in the brain and spinal cord that process and transmit information.
However, neurons that die as a result of injury or disease do not regenerate, which is why people with loss of neurons experience problems like paralysis and memory loss.
The scientists thought that stem cell transplantations might be able to restore part of the lost function.
UCI engineers made a tiny device using a glass slide to perform the dielectrophoresis in order to identify future neurons,
Firstly, scientists positioned unsorted mouse stem cells on one side of the device. The cells then float in sugar water through a tiny channel past electrodes set to a particular frequency.
At a definite frequency, stem cells intended to become neurons will stick to the electrodes while other cells pass by. The cells that stick then can be removed and grouped together, potentially for use in a therapy.
At present, stem cells are usually separated using a machine called a fluorescence-activated cell sorter (FACS).
FACS machines use lasers to detect the light scattering and fluorescent characteristics of the cells, can weigh hundreds of pounds and cost 500,000 dollars or more.
The UCI-designed dielectrophoresis device is just a part of the size and cost. The two devices could be used to complement each other in order to create ultra pure stem cell populations.
"Once the mold is created, these sorts of devices can cost just pennies to make," said Ed Monuki, senior author and UCI developmental biologist.
He added: "You could have many for every member of your lab and it wouldn't be prohibitively expensive."
This study appeared online in the journal Stem Cells.