New biosensor aims to help fight eternal chemicals

Per- and polyfluoroalkyl substances (PFAS) are a family of synthetic compounds used worldwide to make products that are resistant to heat, oil, stains, grease and water. The compounds break down very slowly over time and are recognized as an “emerging contaminant” with widespread concerns about their persistence, bioaccumulation, toxicity, mobility characteristics and human health impacts.

Allonnia is a company that is interested in these “eternal chemicals”. Describing themselves as a “bio-ingenuity company”, they recently announced that they had discovered a protein that could be used as a PFAS biosensor. The patent-pending protein can detect the presence of PFAS down to parts per trillion, levels as low as a single drop in an Olympic-sized swimming pool.

To learn more about the biosensor and its potential in real-world applications, we spoke to Dayal Saran, Vice President and Head of Research, Allonnia and Kent Sorenson, CTO, Allonnia.

Ash Board (AB): Can you describe what PFAS are and why they are recognized as an “emerging contaminant”?

Kent Soreson (KS): PFAS are man-made bioaccumulative toxic compounds used in various consumer and industrial products. These compounds include thousands of chemicals characterized by their carbon-fluorine bonds, the strongest chemical bond in nature. This binding strength makes PFAS very difficult to degrade and persistent in the environment; hence, these compounds are also known as “forever chemicals”. Some are complex molecules like those used to make Teflon, non-stick pans, fire-fighting foam, or stain-resistant fabric. PFAS contaminants are considered “emerging” because they are being detected, often at high levels, in more and more water sources around the world and pose a threat to human health and the environment. Recently published data has shown that PFAS are present in the blood of human and animal populations, even in the most remote places on earth.

AB: Allonnia announced that they had discovered a protein that could be used as a PFAS biosensor. Can you tell more about the protein and how it detects PFAS?

Dayal Saran (DS): At Allonnia, we selected and identified proteins from a library of approximately 1012 (one trillion) unique proteins that have high affinity and selectivity for specific PFAS compounds (perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA)). Currently, we are immobilizing these proteins on an electroactive surface which generates an electrochemical signal when these proteins recognize PFAS compounds.

When a PFAS-contaminated water or wastewater sample interacts with the protein, the detection of PFAS is captured by an electrochemical signal which is converted to a digital signal for measurement. The sensor is currently designed to detect PFOA, one of the most common PFAS, in real time at concentrations as low as a few parts per trillion in water. Allonnia’s team is working to validate the ability of the biosensor to detect other PFAS molecules.

AB: What are the advantages of using a biosensor over traditional sensors to detect PFAS contaminants? How does the sensitivity and specificity of the biosensor compare to other sensors currently on the market?

DS: There is currently no PFAS sensor on the market that can detect PFAS contaminants at these low levels in real time. Most customers send samples to off-site labs to test for PFAS contamination. Analytical methods mainly use liquid chromatography-mass spectrometry (LC-MS) in the laboratory which has the advantage of high sensitivity and low detection limits, but suffers from being expensive, time-consuming (usually three to four weeks ) and requires specialized personnel for operation.

The advantages of a biosensor include the ability to detect contaminants with high sensitivity, ease of use in a portable detection tool with high selectivity and specificity for PFAS, and greater efficiency as they provide detection immediately on site with no or minimal pre-processing and no associated shipping costs.

AB: Allonnia is working to bring the patent-pending Gen 1 protein to the field. What additional developments are needed for the protein to be commercialized?

DS: Allonnia is working with a hardware partner to field a prototype test kit solution. Our technical team is also continuing their work to increase the protein’s sensitivity and specificity to PFAS in real-world groundwater.

AB: Can you describe the usefulness of protein and what kind of industries it should benefit?

KS: The biosensor benefits groundwater, landfill leachate, and drinking water applications.

Specifically, the biosensor can be used to determine if effluent from a water treatment system meets regulatory requirements and is suitable for discharge. It can be used in a process plant to determine if process media, such as granular activated carbon or ion exchange resin, are still working properly or if they need to be changed. The sensors can also be used during field investigations to provide real-time groundwater or surface water concentrations to guide decisions about additional sampling locations and depths or to determine samples to be sent for laboratory analysis. All of these applications facilitate better decision making for risk mitigation and profitability.

AB: Nicole Richards (CEO, Allonnia) is quoted as saying, “This is just one of the first steps towards our goal of creating an optimized, sustainable and comprehensive solution for PFAS degradation.” Can we expect to see further developments from Allonnia focused on PFAS degradation and would these be achieved using other “bio-based” technologies?

KS: PFAS chemicals can take thousands of years to break down naturally, but humanity can’t wait that long. Allonnia’s goal is to work in harmony with nature, using the power of biotechnology to fast forward in time and bring nature’s future solutions to today.

Allonnia’s roadmap for resolving environmental contamination from PFAS focuses on three areas: detection, water treatment and degradation. The biosensor will help site owners and operators assess their sites and waste streams to understand if PFAS are present. We recently launched a PFAS water treatment technology, Surface Active Foam Fractionation (SAFF®) manufactured by EPOC Enviro, for which Allonnia is the exclusive North American distributor. SAFF removes over 99.9% of PFOS and PFOA from water. Finally, we are partnering with Aether Bio and UCLA to design a biological solution to degrade PFAS in soil, groundwater and drinking water.

Dayal Saran and Kent Sorenson were speaking to Dr. Ash Board, editorial director of Technology Networks.

Irene B. Bowles