MIT chemical engineers have discovered that arrays of billions of nanoscale
sensors2 have unique properties that could help
pharmaceutical3 companies produce drugs -- especially those based on antibodies -- more safely and
efficiently4. Using these sensors, the researchers were able to characterize variations in the
binding5 strength of antibody drugs, which hold promise for treating cancer and other diseases. They also used the sensors to monitor the structure of antibody
molecules7, including whether they contain a chain of sugars that
interferes9 with proper function.
"This could help pharmaceutical companies figure out why certain drug formulations work better than others, and may help improve their effectiveness," says Michael Strano, an MIT professor of chemical engineering and senior author of a recent paper describing the sensors in the journal ACS Nano.
The team also demonstrated how nanosensor arrays could be used to determine which cells in a population of
genetically10 engineered, drug-producing cells are the most productive or desirable, Strano says.
Lead author of the paper is Nigel Reuel, a graduate student in Strano's lab. The labs of MIT
faculty11 members Krystyn Van Vliet, Christopher Love and Dane Wittrup also contributed, along with scientists from Novartis.
Testing drug strength
Strano and other scientists have
previously12 shown that tiny, nanometer-sized sensors, such as carbon nanotubes, offer a powerful way to detect minute quantities of a substance. Carbon nanotubes are 50,000 times thinner than a human hair, and they can
bind6 to proteins that recognize a specific target
molecule8. When the target is present, it alters the
fluorescent13(荧光的) signal produced by the nanotube in a way that scientists can detect.
Some researchers are trying to exploit large arrays of nanosensors, such as carbon nanotubes or semiconducting nanowires, each customized for a different target molecule, to detect many different targets at once. In the new study, Strano and his colleagues wanted to explore unique properties that emerge from large arrays of sensors that all detect the same thing.
The first feature they discovered, through mathematical modeling and
experimentation14, is that uniform arrays can measure the distribution in binding strength of complex proteins such as antibodies. Antibodies are naturally occurring molecules that play a key role in the body's ability to recognize and defend against foreign
invaders15. In recent years, scientists have been developing antibodies to treat disease, particularly cancer. When those antibodies bind to proteins found on cancer cells, they
stimulate16 the body's own immune system to attack the
tumor17.
For antibody drugs to be effective, they must strongly bind their target. However, the manufacturing process, which relies on nonhuman, engineered cells, does not always generate consistent, uniformly binding
batches18 of antibodies.
Currently, drug companies use time-consuming and expensive
analytical20 processes to test each
batch19 and make sure it meets the regulatory standards for effectiveness. However, the new MIT
sensor1 could make this process much faster, allowing researchers to not only better monitor and control production, but also to fine-tune the manufacturing process to generate a more consistent product.
"You could use the technology to reject batches, but ideally you'd want to use it in your upstream process development to better define culture conditions, so then you wouldn't produce spurious lots," Reuel says.