Mochly-Rosen began looking for antibodies against SARS-CoV-2 from the eggs of immunized hens in mid-2020. A trial in Australia found the nose drops to be safe.
In June 2021, Mochly-Rosen and his team followed that up with a review paper Posted in Frontiers in immunology detailing the many potential uses of chicken IgY to safely detect, prevent and treat animal and human infections and infectious diseases, including hepatitis B, Zika virus and dengue fever.
But all of this led to a burning question for Mochly-Rosen: Was there an inexpensive way to extract IgY antibodies from eggs, one that could be used in areas without a commercial lab?
Mochly-Rosen posed the question to a group of Stanford freshmen, who signed up for the research by Stanford students in Biodesign and Biopharmaa club for those interested in medical technology.
“All of those students were smart cookies,” she said. “We met [online] every Monday at 9 p.m. PT … and discussed how to crack eggs, isolate antibodies using household ingredients, and adapt household equipment.
Because their research was primarily conducted last year, when COVID-19 restrictions limited on-campus gatherings, the students worked in their homes and dorms. They used ordinary household materials, such as baking soda and vinegar, and kitchen equipment, such as a food processor.
The research “was an incredible opportunity, and it aligned with my goal of equity and accessibility for COVID protection around the world,” Allison Jia said. She and a fellow researcher “were locked in her dorm cracking eggs to figure out the best way to extract the yolk. We accidentally stank the women’s bathroom while disposing of the eggs.
They tested the pH levels of various ingredients, such as grapefruit and lemon juice, to find the best substitute for commercial chemicals. The team chose vinegar, in part because it’s more widely available than fresh fruit in many places, said Jia, now a sophomore.
Other students were tasked with finding household products that would spin at high speed to simulate a centrifuge. They tried an electric shaver and a blender before settling on a food processor modified to hold test tubes, Mochly-Rosen said.
How to make antiviral nose drops
The students worked with eggs purchased from grocery stores, online grocery delivery services or other sources, so the eggs lacked antibodies against viruses such as SARS-CoV-2. However, the eggs contained other antibodies, which the students were able to isolate. The isolation process is the same for all antibodies.
Here, in brief, is the recipe they came up with: Separate the yolk from the white, then dilute the egg yolk in water. Add the vinegar, swirl gently, then freeze until solid. Thaw and strain the mixture to remove the fat. Add salt and place the solution in test tubes in a commercial or makeshift centrifuge, where gravitational forces cause soft beads to form at the bottom of the tubes. Dissolve the pearls in water, neutralize them with baking soda and place the solution in a dropper.
Lab analyzes confirmed that the protocols worked as well as, if not better than, commercial processes, Mochly-Rosen said. According to the students’ method, each egg produced about 90 milligrams of IgY antibodies, or about 25 doses. Purified IgY solution is stable at room temperature for up to two weeks and much longer if prepared under sterile conditions and refrigerated.
The researchers also developed a kit that includes everything needed for the whole process – including an egg yolk separator, gloves, bottles, salt, pH strips and pipettes. There are two versions of the kit: one with a makeshift centrifuge (a food processor with instructions to turn it into a centrifuge using a 3D printer) and one without (for labs that have a commercial centrifuge).
All kit materials except the food processor fit in a 15 inch box.
A dissemination plan
According to the researchers, an industrial or university laboratory could produce a COVID-19 antigen or an antigen from another virus and send it to chicken farmers to inject into their hens. Farmers could then distribute the antibody laying hens or their eggs.
Mochly-Rosen hopes food processor makers would be willing to make an improvised juicer at cost for rural areas that don’t have access to commercial juicers.
Their price analysis suggests that a dose using the kit would cost as little as 20 cents versus $5.40 in a commercial setting.
“It could be an effective and cheap solution,” Mochly-Rosen said. “If we’re trying to deal with an epidemic or a pandemic properly, we have to make sure that a solution is available quickly and everywhere in the world.”
Other Stanford co-authors on the study are Ravinder Pamnani, an instructor at the Stanford Byers Center for Biodesign; undergraduate students Carrie Chen, Anna Hudson, Caitlin Kunchur, Andrew Song and Edward Tran; graduate students Chris Fisher Davide Zanchi, PhD; life science researcher Lucia Lee; and former postdoctoral researcher Ana Koperniku, PhD; Stephen Kargotich, Executive Director of SPARK Global; and Mary Romeoscientific writer and communication at SPARK Global.
The research was funded by SPARK at the Stanford Translational Research Program and the Stanford Byers Center for Biodesign.