Understanding the cell membrane--what it's made of, what it keeps out, what it lets in--is critical to drug delivery and requires realistic cell models that act much the way natural ones would. Now, biomedical engineers at Penn State University have developed a method to mass-produce artificial cells with dynamic membrane structures to be used in the research of new delivery techniques.
The method, published in the journal Advanced Materials, could allow for more high-throughput screenings with cells that contain very realistic structures. For instance, lead researcher Sheereen Majd and her team have added proteins called multidrug-resistance pumps to their liposomes that have been blamed for the failure of chemotherapy at the surface of cancer cells. These are difficult to study in a natural setting, but using a simple model of the cell with the protein on the surface allows for much more precise research down the road.
The type of cells the researchers developed are familiar in that they are hollow, spherical liposomes made of a lipid bilayer that resembles the cell membrane. But the new models have two important modifications: One, they are a uniform size, and the other, they incorporate large proteins that would be present in a real cell and affect drug delivery, Majd told FierceDrugDelivery.
And the new process is intended to be simple, Majd said. The idea is to create lots of cells that can produce consistent results in the testing phase.
"Forming a large number of these cells with sizes as similar as possible, the hope is we would have enough to run a statistical analysis with a large sample number," Majd said. "Instead of running an experiment now and repeating a number of times, we are hoping to have multiple experiments running at the same time, with many liposomes at once."
Also, using traditional methods, she said, manufacturers produce batches of cells of diverse sizes that then require an additional step to filter out the ones of the desired size. But with a hydrogel stamping process such as the one Majd used, tiny droplets of lipid and protein are systematically placed on a sheet, where they form individual cells of exactly the same size. The process uses electroformation to cause the mixture to merge.
"We started on the surface to study membrane interactions," Majd said, "so we were seeking better models that would be simple and low-cost, and yet provide all the resolution and precision we need."