Nanofiber Paper Filter Removes Virus Particles with High Efficiency
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According to a report this week by AZoNetwork UK Ltd., Cheshire, U.K., researchers at the Division of Nanotechnology and Functional Materials, Uppsala University, have developed a paper filter, which can remove virus particles with the efficiency matching or exceeding that of the best industrial virus filters. The paper filter consists of 100% high purity cellulose nanofibers, directly derived from nature.
"Viral contamination of biotechnological products is a serious challenge for production of therapeutic proteins and vaccines. Because of the small size, virus removal is a non-trivial task, and, therefore, inexpensive and robust virus removal filters are highly demanded," said Albert Mihranyan, associate professor, Division of Nanotechnology and Functional Materials, Uppsala University.
Cellulose is one of the most common materials to produce various types of filters because it is inexpensive, disposable, inert, and non-toxic. It is also mechanically strong, hydrophyllic, stable in a wide range of pH, and can withstand sterilization, e.g. by autoclaving. Normal filter paper, used for chemistry, has too large pores to remove viruses.
The team’s discovery is the result of decade long research on the properties of high surface area nanocellulose materials, which eventually enabled the scientists to tailor the pore size distribution of their paper precisely in the range desirable for virus filtration.
Previously described virus removal paper filters relied heavily on interception of viruses via electrostatic interactions, which are sensitive to pH and salt concentrations, whereas the virus removal filters made from synthetic polymers and which rely on size-exclusion are produced through tedious multistep phase-inversion processing involving hazardous solvents and rigorous pore annealing processing.
