Background Info

Understanding the Invisible Threat: Why Early BPA Detection Matters

Every day, children are exposed to numerous chemicals, some of which can have profound and lasting impacts on their health. Among these, Bisphenol A (BPA) stands out as a pervasive chemical found in many everyday products, from food packaging to certain plastics. While regulatory bodies continue to assess its safety, a growing body of scientific evidence underscores the critical need for public awareness and, where possible, early detection of BPA exposure, especially in our youngest and most vulnerable populations: infants and children.

What is BPA and Why is it Concerning?

BPA is an industrial chemical primarily used to make polycarbonate plastics and epoxy resins. It can leach from these materials into food and beverages, leading to human exposure. The fundamental concern with BPA lies in its ability to mimic natural hormones in the body, particularly estrogen. This hormonal disruption can interfere with the delicate balance of a child's developing systems.

The Silent Impact: From Development to Behavior

Scientific research reveals a troubling picture of BPA's potential health effects on children:


  • Developmental Delays and Behavioral Challenges: Studies suggest a link between BPA exposure and a range of neurodevelopmental and behavioral issues. This includes increased risks of anxiety, depression, hyperactivity, inattention, and conduct problems in children. Early life, especially prenatal exposure, appears to be a particularly sensitive period, potentially affecting crucial brain development.

  • Metabolic Risks: BPA has been associated with disruptions in metabolism, increasing the likelihood of obesity and related conditions like insulin resistance and type 2 diabetes. This is a significant concern given the rising rates of childhood obesity globally.

  • Hormonal System Disruption: Beyond behavior and metabolism, BPA's endocrine-disrupting properties raise worries about its effects on reproductive development and other hormone-dependent processes.

      • The Urgency of Awareness and Action

      While BPA has been voluntarily removed from some products like baby bottles and sippy cups in many regions, it remains widespread in others. The reality is that human exposure to BPA is nearly universal, with detectable levels found in most individuals.

      Why Early Detection is Crucial:


      1. Vulnerability of Developing Systems: Infants and children are easily influenced by environmental chemicals. Their rapid growth, developing organs, and less mature detoxification systems mean they are more vulnerable to harm from even low-level exposures.


      2. Long-Term Health Consequences: The effects of BPA exposure during critical developmental windows can have lasting repercussions. Early disruptions may lay the groundwork for chronic health issues later in life.


      People can't see or taste BPA in their food or water, and most are unaware of how common it is in consumer products. Thus, the problem our team is solving is not only the health risks posed by BPA but also the lack of easy, accessible detection systems that can reveal where BPA is present.

Our Idea: BEADS

Our team’s approach to solving the BPA problem is by creating a biological detection system using yeast.
Current BPA detection methods through chemical analysis are highly accurate but require expensive equipment and trained personnel, which is impractical for widespread or community-level monitoring, especially in everyday contexts like testing baby bottles, food containers, or receipts.
By contrast, yeast is inexpensive to culture, easy to manipulate genetically, and can provide results that are directly observable. By engineering it through modified plasmids, we aim to develop a detection system that is accessible, scalable, and adaptable to different settings. Most importantly, this approach transforms BPA from an invisible contaminant into something that can be seen through the human eye or measured easily, enabling broader awareness and intervention.
A simple, accessible detection tool could be used not only by individuals but also by schools, community groups, or environmental organizations to monitor contamination in their surroundings.

Research

We invested quite a lot of time on researching methods that would help us build our ideal detection system. By using the yeast two hybrid technique, we are able to construct two plasmids, in which its interaction in the system allows us to see whether or not BPA is present.

The Yeast Two Hybrid System

Because BPA is a small molecule, it cannot directly activate a large visible signal inside yeast cells. Instead, we rely on an indirect detection method that translates the presence of BPA into a detectable reporter output. The yeast two-hybrid (Y2H) system gives us a way to convert BPA binding into a reporter signal, by making BPA trigger a protein–protein interaction inside yeast. Therefore, detecting its existence when the interaction occurs.
Normally, the Y2H system detects whether two proteins interact. It works because transcription activators in eukaryotes have two separate domains:


  1. DNA-Binding Domain (BD): attaches to reporter gene promoter

  2. Activation Domain (AD): recruits RNA polymerase to turn the reporter on


transcription activator

as shown in the photo above


Once these two domains are brought together, the reporter gene turns on, demonstrating interaction.
The experiment engineers two fusion proteins: Bait and Prey. Bait is a protein domain that binds with BPA fused to the binding domain. The prey is a coactivator protein fragment fused to the activation domain. When BPA is absent, the bait and prey remain separate, and the BD and AD cannot work together, so no transcription occurs. However, when BPA binds to the bait protein, it changes the protein’s conformation so that it can now interact with the prey protein. This interaction physically brings the BD and AD together on the reporter gene promoter. Once the Bait and Prey protein are fused together, transcription of the reporter gene is activated, producing a signal.


as shown in the photo above

Plasmid Construction

We used pGilda as the bait vector and pB42AD as the prey vector, inserting the ESR1 gene into both. Estrogen is structurally similar to BPA, so we inserted the ESR1 gene that produces ERα, the estrogen receptor. When BPA binds to ERα, the prey and bait proteins will interact and fuse.
By doing so, when the fusion occurs, we can connect it to a reporter gene and visually see the output.

Applications

Our target audience is the the public in general, specifically, can be divided to three groups:


  1. Households, which are parents and caretakers who want a yes/no check on plastics at home. It provides a clear instruction, no special tools, low cost, and a visible output which they can interpret without jargon.
  2. Schools, especially with teachers who want a hands-on lab that fits in a short period, and can see the result within a day. What they need would be a safe yeast that has reliable controls and could be curriculum tie-in.
  3. Community & environmental groups, for people testing local water or soil. They need simple sample prep (filtration or dilution), quantifiable readouts (photo or color scale), metadata templates and most importantly affordable per-test costs so they can have a great sample over time

Our plasmid set is built so others can plug these user needs into a fieldable kit for further uses.

Results

Our engineered yeast sensor reliably produced a visible, same-day response to BPA while keeping background low. In side-by-side tests with standard controls, the BPA condition turned the reporter on clearly within a few hours, whereas the no-ligand and blank tubes stayed near baseline and estradiol produced only a minor response under the same timing. A matching full-length ESR1 version confirmed the sensing logic but required longer incubation and showed more off-target color. Overall, the truncated, BPA-biased design delivered the outcome we aimed for: a rapid, easy-to-read signal suitable for home, classroom, and community use.

References

  • Wang, H., Peters, G. A., Zeng, X., Tang, M., Ip, W., & Khan, S. A. (1995, October 6). Yeast Two-hybrid System Demonstrates That Estrogen Receptor Dimerization Is Ligand-dependent in Vivo. J. Biol. Chem., 270(40), 23322–23329. Link
  • Arao, Y., & Korach, K. S. (2018). Detecting the Ligand-binding Domain Dimerization Activity of Estrogen Receptor Alpha Using the Mammalian Two-Hybrid Assay. Link
  • Acconcia, F., Pallottini, V., & Marino, M. (2015). Molecular Mechanisms of Action of BPA. Dose-Response, 13(4), 1–9. Link
  • Braun, J. M., & Hauser, R. (2011, April). Bisphenol A and children’s health. Current Opinion in Pediatrics, 23(2), 233–239. Link
  • Morgan, M., Deoraj, A., Felty, Q., & Roy, D. (2017, December 5). Environmental estrogen-like endocrine disrupting chemicals and breast cancer. Molecular and Cellular Endocrinology, 457, 89–102. Link
  • Marmugi, A., Lasserre, F., Beuzelin, D., Ducheix, S., Huc, L., Polizzi, A., Chetivaux, M., Pineau, T., Martin, P., Guillou, H., & Mselli-Lakhal, L. (2014). Adverse effects of long-term exposure to bisphenol A during adulthood leading to hyperglycaemia and hypercholesterolemia in mice. Toxicology, 324, 92–102. Link
  • Naomi, R., Yazid, M. D., Bahari, H., Keong, Y. Y., Rajandram, R., Embong, H., Teoh, S. H., Halim, S., & Othman, F. (2022, March 9). Bisphenol A (BPA) Leading to Obesity and Cardiovascular Complications: A Compilation of Current In Vivo Study. International Journal of Molecular Sciences, 23(6), 2969. Link