Harvesting proteins to find a vaccine for COVID-19

For many years, vaccines have been developed using inactivated viruses. Weakened viruses, when given to a patient, stimulate an immune response in the body to protect against future infections from that virus. This approach is still effectively used for influenza, chickenpox, measles and mumps, to name a few examples. It requires scientists to grow viruses in a lab, which can take months.

In recent years, researchers have developed vaccines using purified proteins to prevent the virus from attaching to and entering into human cells. These vaccines can be developed more quickly without the inherent risks associated with the use of a live virus. Protein-based vaccines include HPV, shingles and hepatitis B.

With any vaccine or therapeutic, the process of developing a new drug requires multiple steps. Scientists continue to find new ways to shorten the timeline – which is especially important now – using newly discovered techniques and technologies.

3M is helping in the fight against the pandemic from multiple angles, including working alongside biopharmaceutical companies as they develop and manufacture protein-based vaccines and therapeutics.

We talked to Jonathan Hester, Ph.D., a research scientist on 3M’s Biopharmaceutical Purification team, to get his insight on how new technology is being used to develop vaccines and therapeutics.

Hester: Some of the most promising therapeutics right now are protein-based drugs, where the drug is a protein. Pharmaceutical companies make protein drugs by genetically engineering a cell – usually a mammalian cell – to make the protein.

The engineered cells are grown in a culture for 48 or 72 hours. After that time, they will have a fluid that contains the protein drug the cells have made, but it also contains the cells, debris from broken cells, and all sorts of other proteins that have been produced by the cells. Once they harvest the fluid, they have to isolate the drug protein from cell fragments, from other proteins the cells have made, and also from DNA and other contaminants. It’s typically a 15- to 20-step process to isolate the drug protein in a pure form.

Hester: There are a lot of reasons that developing new pharmaceuticals takes a long time. One is that a huge amount of research and development goes into developing and studying treatments. For every successful drug, hundreds or thousands have been tried and failed because they were either insufficiently safe or effective or too difficult to manufacture and distribute at scale.

Another reason is that a lot of time and effort go into developing the purification processes for drug candidates. To get to Phase 1 clinical trials, before you test it on humans, you have to develop a very good purification process. And the isolation process required varies by drug molecule. So you are developing and building that entire purification process even for products that fail.

Hester: Yes. Our objective is to condense the process for our customers – to simplify and reduce the number of steps and help them to get more quickly through clinical trials and, ultimately, to have more economical and productive manufacturing processes for the successful drugs. Our goal is to use smart materials to reduce the number of steps and make purification steps that are more reliable so they work the same way from drug molecule to drug molecule. By doing that, we can help pharmaceutical companies spend less time doing the purification process development work.

One product, the 3M™ Emphaze™ AEX Hybrid Purifier, is currently being used for COVID-19 treatments and vaccines. This product was developed to replace a simple filter that takes out chunks of cells and cell debris. When we started the early development work in the Corporate Research Labs, our hypothesis was that we could remove soluble contaminants, too, and make one device that does two things at once. Two process steps are now one with this purifier.

Nonwovens, one of our basic 3M technologies, are key to this technology. In simple terms, nonwovens are a mat of fibers. We adapted this technology for a purifying application by grafting positively charged polymers to a nonwoven to make a material that acts like a filter but also binds negatively charged molecules. The proteins we want to keep are usually positively charged and most contaminants are negatively charged. So the protein product goes through the filter and the negatively charged contaminants, both cell chunks and dissolved contaminants like DNA, stick to it. This helps generate a purer product at the front end and enables more consistent fluid quality throughout the entire process.

When we started testing this product, we also found we were able to work with our customers to learn how its removal of DNA earlier in the purification process makes a subsequent separation process much more effective. For many customers, this further condenses downstream steps and also increases yield of the drug product.