We ask every team to think deeply and creatively about whether their project is responsible and good for the world. Consider how the world affects your work and how your work affects the world.
How do you assess the importance of biosensors for detecting antibiotics and heavy metals in today's environment?
Overall, I see them as very valuable. Take lead in drinking water, for instance. Many households still have old lead pipes without realizing it. A home biosensor could be very helpful in detecting lead contamination in water quickly. For antibiotic detection, a key application would be in wastewater treatment, to monitor how effectively antibiotics are removed during the process. Such a system would also be beneficial for assessing antibiotic contamination in rivers and lakes to evaluate water quality. However, it ́s crucial to carefully adjust the quantification range. Every environment naturally produces antibiotics, as they are communication tools between different species. Streptomyces, some of the best antibiotic producers, are commonly found in soil and sediments, so low antibiotic concentrations are normal everywhere. Hence, the measurement range of these sensors is important. Referring to drinking water regulations can help understand the appropriate detection levels for these biosensors.
Why is it important to detect these two components, and what benefits does it bring to the environment and humans?
The benefits were partly mentioned in the first answer to the question. Being able to warn households about lead and heavy metal contamination in drinking water is crucial. Old water pipes are often made of lead, which can leach into the water if not properly treated. A system that detects these contaminants would be very useful.
Can antibiotic residues in wastewater lead to antibiotic resistance?
In general, yes. It depends on the concentration of antibiotics released into the environment. A selective pressure is needed to spread antibiotic resistance genes widely. Organisms with antibiotic resistance genes on plasmids need metabolic energy to replicate these plasmids, putting them at a disadvantage compared to those without these genes. In an environment without antibiotics, organisms with resistance genes would eventually die out. However, if antibiotics are present in high concentrations, selective pressure would allow only those organisms with resistance genes to thrive, potentially leading to new resistances. This is due to the genetic variability and diversity in microbiomes, where some organisms might survive and have a selective advantage because of random mutations in enzyme-coding genes that can degrade or detoxify antibiotics. Again, the concentration of antibiotics is key to creating selective pressure.
Do you think our biosensor can benefit society and be practically applied?
Yes, fundamentally. But we are still quite far from achieving this due to several challenges. First, the detection range of the target components is crucial. Second, the stability of the biosensors and the reproducibility of the fluorescence response over time are important—you want consistent results. The same concentration should always yield the same fluorescence. Additionally, when dealing with intracellular detection of heavy metals, it’s essential to ensure that these metals can be sensed by the cell, and in your case consistently reach the transcription factor inside the cell, and that this process is reliably reproducible.
Information: The Stadtentwässerung Hannover (Urban drainage) is the system that collects, channels and treats rainwater and wastewater in Hannover. It consists of sewers treatment plants and rainwater management to prevent flooding and ensure clean water.
Thank you for taking the time to do a short interview with us today. To start, could you briefly introduce yourself?
I'm happy to. On behalf of Stadtentwässerung Hannover, I’m Peer Lindenhayn, responsible for press and public relations for our city's drainage operations, and I’m here to help.
Great, thank you. Let's dive into our first question. Our iGEM project focuses on detecting antibiotics and heavy metals in water samples. Are there already methods used to detect these substances in wastewater?
Yes, there are various methods in instrumental analysis. Antibiotics can be detected using high-performance liquid chromatography (HPLC) coupled with mass spectrometry. We can also detect and quantify antibiotics using a competitive immunoassay called ELISA.
Is this done regularly?
We don't routinely test for antibiotics because there’s no legal requirement for it yet. However, heavy metals are routinely detected and quantified using inductively coupled plasma emission spectrometry (ICP-OES). This process involves atomizing the liquid sample and introducing the aerosol into a plasma at 6000 to 8000 Kelvin, creating ions and atoms that emit light. By analyzing the emission spectrum, we can identify the elements present.
Thanks for the information. We have another question. What challenges exist in detecting and effectively removing antibiotics and heavy metals in wastewater treatment plants?
Generally, there are no significant challenges for detecting antibiotics and heavy metals. However, quantifying these substances can be influenced by matrix effects, which affect the accuracy of results. Analysts must handle these effects in the lab. Detection and verification are only possible when the substance concentration exceeds the detection limit of the analytical method. Currently, there’s no legal requirement to monitor antibiotics in wastewater, so we don’t know the elimination rates of antibiotics in our treatment plants.
Thank you. What specific substances or pollutants are currently tested and monitored in wastewater treatment plants?
Heavy metals are routinely monitored in treatment plants. Trace substances, including antibiotics, are tested sporadically based on specific questions. In the future, legal requirements may necessitate regular monitoring of these substances.
Could you see using a biodetector like the one we developed in the future?
It’s interesting for us to know the sensitivity and selectivity of such a biosensor, and which heavy metals it can detect. However, heavy metal monitoring is regulated by law and our permits, dictating the analytical methods we use. Since our routine analyses show results well below the defined monitoring thresholds, additional monitoring with a biosensor isn’t currently necessary. However, depending on the biosensor’s specificity and sensitivity, it could potentially be used for additional antibiotic monitoring in treatment plants.
Thank you for taking the time to answer our questions.