Engineers have already done amazing things to solve for the sticky-cell problem in bioreactors. More and more, companies are adopting these same bioreactors to grow algae and other microbes for commercially viable applications. These organisms are some of the best synthesizers of carbon dioxide (CO2) on the planet, with efficiencies up to 1000 times that of trees. Despite this potential, bioreactors encounter multifaceted challenges such as compromised cell membranes, extended operations processes, and excessive material usage. Through inventive research, the collaborative scholarship seeks to create, operate, and maintain these systems more efficiently, cost-effectively, and sustainably.
The study, published in Science Advances, outlines how the sticky-cell problem necessitates frequent shutdowns and cleanups, sometimes as often as every two weeks. This not only disrupts routine production processes, but directly results in millions of liters of biowaste. To address all these challenges, senior author Kripa Varanasi and his team have developed a novel solution. This innovation could improve bioreactor performance across many industries and applications.
Addressing the Sticky-Cell Problem
The sticky-cell problem has historically been a major issue in bioreactor operations that has caused large inefficiencies, higher costs and other operational problems. Existing approaches make it necessary for operators to stop production entirely in order to clean the reactors, resulting in detrimental downtime.
This is why researchers have created a completely new and complementary system to address this challenge. It includes a thin glass cylinder inserted with a golden electrode. This creative approach allows for robots to easily maneuver the electrode in and out of various culture plates. This movement allows for easy and gentle detachment of cells as they expand.
Bert Vandereydt, a Ph.D. student in mechanical engineering and co-first author of the study, highlighted the core issue:
“The culprit is the anode—that’s where the sodium chloride turns to bleach.”
As the electrode starts to break down into particles, these could be removed from the system through filtration. This cooperation ensures that the independence of the overall process is protected.
Enhancing Bioreactor Efficiency
The research team’s method uses bubbles to increase the efficiency of cell detachment. Varanasi observed that they figured out how to make these bubbles on surfaces where cells shouldn’t stick.
“We realized we needed the bubbles to form on the surfaces where we don’t want these cells to stick, so when the bubbles detach, it creates a local fluid flow that creates shear stress at the interface and removes the cells,” he explained.
This approach eliminates the sticky-cell issue and guarantees that cells are viable during the entire process. Vandereydt confirmed this point:
“Mammalian cells are orders of magnitude more sensitive than algae cells, but even with those cells, we were able to detach them with no impact to the viability of the cell.”
The research team behind this new bioreactor system hopes it will have more far-reaching uses in a variety of industries, including pharmaceuticals. The technology is designed to be high-throughput and plug-and-play, where cells can attach and detach as needed.
“If we can keep these systems running without fouling and other problems, then we can make them much more economical,” Varanasi stated.
A Vision for Scalable Solutions
He mentioned that the technology is extremely scalable, so it can be used for many different processes, such as particle removal.
The pressing need for efficient CO2 capture is underscored by Varanasi’s statement:
“This has general applicability because it doesn’t rely on any specific biological or chemical treatments, but on a physical force that is system-agnostic.”
He continued to say that their current work involves collecting CO2 from various point sources and using it, mainly in the production of cement, to create profitable products.
The pressing need for efficient CO2 capture is underscored by Varanasi’s statement:
“The burning problem of our time is to somehow capture CO2 in a way that’s economically feasible.”
He added that their ongoing research focuses on capturing CO2 from diverse sources and converting it into valuable products.