The outbreak of the COVID-19 pandemic demonstrated the need to rapidly develop, produce and distribute large quantities of new vaccines. A team of researchers at Purdue University and Merck & Co. Inc., known as Merck Sharp & Dohme Corp. outside of the U.S. and Canada, has now introduced a new analytical tool that could help pharmaceutical companies boost vaccine production with rapid monitoring and analysis.
The research team, led by Mohit Verma , associate professor of agricultural and biological engineering at Purdue, validated the patent-pending tool in tests that successfully measured the quality and quantity of continuously flowing viral particles.
"The current methods are more time-consuming and offline," said Shreya Athalye, a Purdue graduate student in agricultural and biological engineering. Samples need to be removed from the production line and transferred to an instrument for testing. But the new quality-control tool can operate on the production line, yielding results in 30 seconds or less. "Doing it online will save time and money in vaccine production," she said.
Athalye, Verma and their co-authors described their new analytical tool in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. They disclosed the innovation to the Purdue Innovates Office of Technology Commercialization, which has applied for a patent to protect the intellectual property. The study combined the expertise of specialists in agricultural and biological engineering, biomedical engineering, computer science, mechanical engineering, and materials science engineering. The Merck co-authors provided the samples and ensured the study's compatibility with industrial operations.
The researchers based their new tool on Raman spectroscopy, which employs a laser to obtain a sample's molecular fingerprint. "It's nondestructive in nature, and its ability to work with samples that have water makes it ideal for biological samples such as vaccines," Athalye said.
In 2022, Athalye co-authored a study from the labs of Verma and Arezoo Ardekani , professor of mechanical engineering, that applied Raman spectroscopy and machine learning to measure the concentration of viral particles in samples containing measles, mumps and other viruses.
The new study demonstrated the tool's effectiveness in detecting particles of the human cytomegalovirus (CMV), a member of the herpes family. Researchers work with viruslike particles in their efforts to develop a CMV vaccine. CMV mainly infects people with compromised immune systems, including those who receive transplants. "CMV structure and mode of action make the vaccine development challenging, but many investigational vaccines are being evaluated in clinical trials," Athalye noted.
"Process analytical technology, or PAT, holds the potential to enable rapid release of biologics," Verma said. "We have worked on this collaborative project with the Ardekani lab in mechanical engineering and with the group at Merck to enable PAT using Raman spectroscopy. By demonstrating that we're able to characterize CMV at industrially relevant concentrations and flow rates, we support easier adoption of this approach in biomanufacturing."
The research team is unaware of any previous report about a Raman spectroscopy-based tool of this type for detecting CMV particles. This type of tool, known as process analytical technology, offers improved quality control by continuously monitoring the production process.
"The point is that we want to analyze the particle as it is being produced," Athalye said. And the technology is flexible enough for application to the production of other vaccine types.
In a 2020 study , Verma and his colleagues used Raman spectroscopy to identify bacterial and fungal contaminants of concern to the pharmaceutical industry. In that project, the team developed an assay to detect bacteria 10 times larger than viruses and under static conditions. "In this study, we are moving forward with a system that allows monitoring in continuous flow," Athalye said.
Also, in 2020 , Verma and his co-authors assessed the impact of PAT on the manufacture of antibodies that work much like naturally produced human antibodies.
The researchers tested the new system under a variety of flow rates, including the industrial production flow rate and static conditions. "We wanted to make sure that we were developing a tool that can be transferred to industrial operating conditions," Athalye said. This applies specifically to continuous manufacturing, in which vaccines and other products flow nonstop from the production line.
"Continuous manufacturing is the future. It is environmentally friendly, and it saves money and resources as well," Athalye said. "The critical component of continuous manufacturing is developing a robust quality-control tool, or more specifically, a process analytical tool. That's what drives me to do this research."
In future work, the team will demonstrate the use of Raman spectroscopy for other viruses, vaccines and virus like particles. "We will also be demonstrating the potential of probe-based methods in delivering such results so that they could be integrated into continuous manufacturing unit operations," Verma said.
This work was funded by the National Institute for Innovation in Manufacturing Biopharmaceuticals, the National Institute of Standards and Technology, and the Merck Sharp & Dohme Corp.
