Mercury Bio Reports Positive Results from Preclinical Study Evaluating Novel Drug Delivery Technology Transporting Protein Cargo to the Brain

Yeast exosome-based drug delivery system achieved intracellular delivery of proteins into neurons across the blood-brain barrier

SANTA FE, N.M., Oct. 1, 2025 /PRNewswire/ -- Mercury Bio (www.mercurybio.com), a drug delivery company leveraging its novel and proprietary extracellular vesicle (EV) drug encapsulation platform (yEV™) to transport therapies directly to cells via a unique form of exosome, announced today positive results from a preclinical study that successfully utilized yEV™ to deliver proteins, in the form of nanobodies, into neurons across the blood-brain barrier. The murine model study, conducted at Vanderbilt University School of Medicine, used confocal microscopy to demonstrate abundant intracellular delivery of proteins to neurons in vivo using a customizable and scalable drug delivery system. The delivery was found to be specific to neurons, with limited distribution to microglial cells and astrocytes. Although these findings are early, they are remarkable in their specificity and the amount of delivered proteins, and have the potential to open new therapeutic pathways for treating neurological diseases like Alzheimer's and Parkinson's.

"We'd previously achieved successful delivery of mRNAs and small molecules to the brain using murine models," says Bruce McCormick, MercuryBio's Chief Executive Officer. "This FLAG-peptide nanobody experiment was our first attempt at directly delivering proteins to the brain. The data we've gathered so far has laid the groundwork for future research aimed at delivering bioactive proteins and nanobodies to address abnormal protein expression in brain cells."

The blood-brain barrier (BBB) forms a protective shield around the brain, insulating the central nervous system (CNS) from pathogens, toxins, hormones, and other substances in the blood that could disrupt brain function. This role is essential for survival but makes delivering drugs into the brain very difficult, leading to low therapeutic efficacy for many drug candidates aimed at treating brain diseases. While there have been considerable strides in developing biologic-based treatments—such as proteins, mRNA, or antibodies—for neurodegenerative disorders, most are not clinically viable because there has been no reliable, scalable means of transporting such therapies into target cells within the brain. The BBB is so selective, in fact, that it turns away 98% of small-molecule drugs and nearly 100% of biologics.

Researchers in the Simerly Lab at Vanderbilt University School of Medicine administered a dose of yEV™, loaded with FLAG-stained proteins, into mice through intravenous injection. After 48 hours, brain sections were imaged using confocal fluorescence microscopy, which showed that the proteins were widely taken up by neurons in all examined regions of the brain. This included the hippocampus, cortex, and basal forebrain—areas known to be severely impacted by Alzheimer's disease—as well as the thalamus, hypothalamus, and red nucleus, commonly affected by Parkinson's disease. "Their effectiveness in delivering proteins to neurons is striking, especially considering we can just inject them into the blood," says Dr. Richard Simerly, whose lab conducted the experiment. "Effective delivery of proteins and mRNA across the blood-brain barrier is a long-standing goal of neurological research. Although multiple strategies have been pursued, promising, non-invasive approaches are rare. In contrast, these exosomes are crossing efficiently from blood vessels and accumulating in the cytoplasm of neurons throughout the brain."

About the yEV™ platform:
Mercury Bio's yEV™ platform utilizes yeast-derived exosomes, a subtype of extracellular vesicle (EV). EVs are nanoparticles, produced by cells, that facilitate intercellular communication. They are far less immunogenic than viral vectors or synthetic nanoparticles and can be engineered to target specific cells. Extensive research over the past fifteen years has demonstrated EVs' potential to encapsulate therapeutic compounds and deliver them to cells throughout the body. However, the findings from Mercury Bio's recent testing suggest that yEV™ specifically offer an EV-based platform for regular therapeutic dosing to the brain via simple IV administration, which would open up new potential pathways for treating some of the most intractable neurological diseases.

About Mercury Bio:
Sparked by scientific breakthroughs in genomic research, Mercury Bio has developed a next-generation biomolecular drug delivery platform. The technology prioritizes safety and efficacy while reducing side effects by employing cell-specific targeting using a novel system for drug encapsulation in biological vesicles. The result is an advanced drug delivery system in a scalable, low-cost production platform that helps unlock the potential of protein therapeutics, RNA therapeutics, and small-molecule drugs.

Contact: Kaelie Barnard | Dir. Marketing, Barson Corp.
[email protected] | +1 (516) 712–6050

SOURCE Mercury Bio Inc.