What is selenium? Selenium appears on the Periodic Table of Elements, carries the symbol Se and has an atomic number of 34. Even though elemental selenium can be toxic in large amounts, it’s also an essential micronutrient for mammals, including humans. In humans, the trace nutrient functions as a cofactor in the reduction of antioxidant enzymes, such as glutathione peroxidases and certain forms of thioredoxin reductase. Put simply, the human immune system uses reactive oxygen species to ward off infection and selenium plays a part in that process.
Selenium and the Mammalian Immune System
Incorporated in the diet, the mammalian immune system integrates elemental selenium into a variety of derivatives of naturally occurring amino acids. Unlike the natural system, selenium is not the active species for warding off microbes, but acts as a catalyst to generate reactive oxygen species. These same reactive oxygen species affect vital chemical messengers in microbial communication. In excess, these reactive oxygen species undergo a complicated series of cascade reactions, including, but not limited to:
- Reactive degradation of cellular proteins, polysaccharides, and lipids, which serves to cause lesions in the membranes.
- Form longer lasting species, such as peroxide and aldehydes that can permeate the cell membrane and cause DNA damage, or even disrupt the energy producing centers within cells.
- Since proper cellular communication for the microbial life cycle requires reactive oxygen species, the excess in the environment could play a key role in disrupting quorum sensing. However, the exact role of how this may disrupt quorum sensing is the subject of many research articles in the peer-reviewed literature.
Selenium Offers New Approaches to Undermining Bacterial Communication
Our current research suggests excess reactive oxygen species in the matrix environment, of, say a medical device, results in an inhibitory effect. The net result shows microbes unable to establish a stable biofilm on many materials impregnated with our custom compounds – compounds designed after natural molecules – as observed through electron microscopy.
Other researchers are investigating biofilm dispersement techniques, but our technology’s key differentiation involves a strong focus on prevention. Most antimicrobials, currently on the market, leach from the material. This means there is a declining efficacy profile over time. Many of these antimicrobials, also called biocides, have unwanted side effects like endocrine disruption (i.e. HPA axis interruption) and an unknown environmental impact.
Approaches used by other companies use many of these same biocides to eradicate a biofilm after microbes have already established it. Our research suggests that once a biofilm is established on a medical device, it’s virtually impossible to completely eradicate. This allows recurring infections after treatment. Selenium prevents establishment of a biofilm altogether and our custom compound does not leach from the target material. Further, it is catalytic, meaning the protection should remain effective for the lifetime of the material.
Many physicians, scientists, and researchers have concerns about antimicrobials causing microbes to develop resistance to antibiotics. Since microbial growth and biofilm establishment requires reactive oxygen species, our approach will not cause microbes to develop resistance against chemical messengers that are necessary for their survival.
Emergent Believes Selenium Anti-Infectives Hold Great Potential
At Emergent, we believe this product has great potential, especially considering the current market and investment climate for anti-infectives. There’s plenty of industry skepticism in this area. In the past, some scientists hyped up their hopes a little too far and it ended up backfiring.
The skepticism and other associated flak represents a key hurdle for our selenium technology to overcome – there’s a lot of chafe in the air. Many industry-accepted practices for testing microbes deliver results skewed toward existing mechanisms of action and demonstrate a decrease of bacterial load away from the surface of the treated material. But, this result may not have anything to do with biofilm establishment. Since selenium provides a unique way to prevent biofilm formation, tests that measure free cell (planktonic) death, often aren’t the correct tests for demonstration of our product’s efficacy.
Due to this key difference, tests that current market leaders use can produce false negatives. We’re a small company and we work closely with market leaders to address these differences. While we’ve optimized and become proficient in compound preparation, compound integration, and the preparation of prototypes, the physical methods of manufacturing typically require additional modification to correctly incorporate the selenium. As a result, many of our projects require a vested industry partner for the final processing and collaboration to ensure the product meets final market specifications. What do you want to build today?