Protein pores packed in polymers make super-efficient filtration membranes

January 28, 2020

AUSTIN, Texas -- A multidisciplinary team of engineers and scientists has developed a new class of filtration membranes for a variety of applications, from water purification to small-molecule separations to contaminant-removal processes, that are faster to produce and higher performing than current technology. This could reduce energy consumption, operational costs and production time in industrial separations.

Led by Manish Kumar, associate professor in the Cockrell School of Engineering at The University of Texas at Austin, the research team describes their new high-performance membranes in a recent issue of Nature Materials.

The team's new filtration membranes demonstrate higher density of pores than that of commercial membranes and can be produced much faster -- in two hours, versus the several-day process currently used. Until now, integrating protein-based membranes into current technology used for industrial separations has been challenging because of the amount of time needed to create these membranes and the low density of proteins in resulting membranes.

This comprehensive and collaborative research effort brought together engineers, physicists, biologists and chemists from UT Austin, Penn State University, University of Kentucky, University of Notre Dame and the company Applied Biomimetic. The work presents the first end-to-end synthesis of a true protein-based separation membrane with pores between half a nanometer and 1.5 nanometers in size. A nanometer is just a few times the size of a water molecule and a hundred thousand times smaller than the width of a human hair.

The membranes created by the team are biomimetic, meaning they mimic systems or elements of nature, and imitate those that naturally occur in cell membranes for transporting water and nutrients. They recently published another paper highlighting the inspiration for their method. High-density packing of these protein channels into polymer sheets forms protein pores within the membrane, similar to those seen in human eye lenses, but within a nonbiological polymer environment.

Three different biomimetic membranes were fabricated by the team and demonstrated a sharp, unique and tunable selectivity with three different pore sizes of membrane protein channels. The methods described can be adapted with the insertion of protein channels of different pore sizes or chemistries into polymer matrices to conduct specifically designed separations.

"In the past, attempts to make biomimetic membranes fell far short of the promise of these materials, demonstrating only two to three times improvement in productivity," said Yu-Ming Tu, a UT Austin chemical engineering doctoral student and lead on the project. "Our work shows a surprising 20 to 1,000 times improvement in productivity over the commercial membranes. At the same time, we can achieve similar or better separation of small molecules, like sugars and amino acids, from larger molecules, like antibiotics, proteins and viruses."

This high productivity was made possible by the very high density of pore proteins. Approximately 45 trillion proteins can fit onto the membrane, if it were the size of a U.S. quarter; the membranes created were 10-20 times larger in area. This pore density is 10 to 100 times higher than conventional filtration membranes with similar nano-sized pores. Additionally, all the pores in these membranes are exactly the same size and shape, allowing them to better retain molecules of desired sizes.

"This is the first time that the promise of biomimetic membranes involving membrane proteins has been translated from the molecular scale to high performance at the membrane scale," Kumar said. "For so long, engineers and scientists have been trying to find solutions to problems only to find out nature has already done it and done it better. The next steps are to see if we can fabricate even larger membranes and to test whether they can be packaged into flat sheet and spiral-wound-type modules like the ones common in industry."
The research was funded by the National Science Foundation.

University of Texas at Austin

Related Engineering Articles from Brightsurf:

Re-engineering antibodies for COVID-19
Catholic University of America researcher uses 'in silico' analysis to fast-track passive immunity

Next frontier in bacterial engineering
A new technique overcomes a serious hurdle in the field of bacterial design and engineering.

COVID-19 and the role of tissue engineering
Tissue engineering has a unique set of tools and technologies for developing preventive strategies, diagnostics, and treatments that can play an important role during the ongoing COVID-19 pandemic.

Engineering the meniscus
Damage to the meniscus is common, but there remains an unmet need for improved restorative therapies that can overcome poor healing in the avascular regions.

Artificially engineering the intestine
Short bowel syndrome is a debilitating condition with few treatment options, and these treatments have limited efficacy.

Reverse engineering the fireworks of life
An interdisciplinary team of Princeton researchers has successfully reverse engineered the components and sequence of events that lead to microtubule branching.

New method for engineering metabolic pathways
Two approaches provide a faster way to create enzymes and analyze their reactions, leading to the design of more complex molecules.

Engineering for high-speed devices
A research team from the University of Delaware has developed cutting-edge technology for photonics devices that could enable faster communications between phones and computers.

Breakthrough in blood vessel engineering
Growing functional blood vessel networks is no easy task. Previously, other groups have made networks that span millimeters in size.

Next-gen batteries possible with new engineering approach
Dramatically longer-lasting, faster-charging and safer lithium metal batteries may be possible, according to Penn State research, recently published in Nature Energy.

Read More: Engineering News and Engineering Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to