Plastic pollution prevention has been a large focus of social and political initiatives in the last few decades. Much of this activity can be attributed to a good understanding of the immense negative aspects that such problems may pose on the planet and human health.

While the world is becoming increasingly aware of the nanoplastics pollution issue and its potential dangers, the research on these materials is still in its infancy. The main reason is our technical limitations which make detecting and tracking nanoplastics inaccessible. Moreover, capturing invisible plastic polymers in drinking water today might sound futuristic, but given the currently proposed toxicity, it could soon become a legitimate need worldwide.

Hence, for both health and research purposes, there is a large need for an easy-to-use plastic nanoparticle detection system. For this reason, we have conceptualized and engineered the NanoFind system - a toolkit for easily detecting different, frequently occurring nanoplastics. We envision this tool to be used by plastic pollution researchers, water quality analysts as well as the general public for quick water quality assessment.

To implement our Nano-Find system in the real world, we are considering making the detection kit available in two ways: a laboratory kit and a lateral flow test. The kit would be dedicated to a more precise investigation of water samples, and the simpler portable test could be used by the general public.

The research-oriented detection kit would include a specially designed 96-well glass microplate with the adjustable sheets of cellulose, our engineered peptides, and a wash solution. The proposed detection kit could determine a specific type of nanoplastic particles present in the sample and its concentration. Following a supplemented user guide, any laboratory-trained person could easily use this kit with minimal training and in a timely manner. This product would be dedicated to easing the burden of currently available methods for the research of water samples.

The currently used techniques involve stereo, fluorescence, atomic force, transmission, and scanning microscopy, which require large financial resources, specific know-how, and lots of time [1]. In contrast, the NanoFind system can be readily used with minimal training and low-to-none financial investments on expensive equipment.

The rapid lateral flow test would serve a different purpose. The aim of creating such a device is to make the detection of nanoplastics user-friendly and more accessible to non-scientists. The test will require a few drops of the water sample, and the result will be interpreted visually. While offering less precision compared to the previously described approach, this method would be much more accessible. We imagine the lateral flow test version of NanoFind to fill a gap in the future as the need for water testing will grow with the changing mindset of society, the increase in the relevance of sustainability and healthy living as well as available knowledge on the toxicity of nanoparticles.

The engineered plastic-binding peptides will be used in the NanoFind system to detect and quantify the nanoplastic in the given sample. Moreover, these peptides might also be used to capture the nanoplastic particles at scale. Furthermore, further modified cell surface display peptides may be utilized in creating a cleaning system that extracts plastic from environmental samples using bacterial chemotaxis. Finally, our engineered peptides may also be used to tackle other scientific issues which are not directly related to plastic nanoparticles. By improving molecule binding affinity, we could achieve better activity of the plastic degrading enzymes or better immobilization of required particles on the plastic plates.

Testing impure samples, such as those taken directly from the lakes or rivers, may require additional sample preparation. It is known that nanoplastic polymers in the natural environment may aggregate or undergo agglomeration with other particles [2]. In such instances, the pre-processing of the samples will be an inevitable and crucial step in experimental protocols.

Furthermore, safety is an integral part of synthetic biology. Hence, project implementations into the real world must follow the responsible design and use considerations. Therefore, we are ensuring that the parts used are neither pathogenic nor require a release beyond containment. The proposed detection kit is intended to be used in the laboratory setting. Also, users would be encouraged to manage their waste according to the waste disposal regulations. Regarding the safety of the lateral flow test, the samples are put on the cassette, and there is no need to immerse the device in water.

Even the best scientific and engineering outcomes without a good real-world implementation may never reach the true goal of helping people. For this reason, starting from the concept of the system, we aimed to have a toolkit that can be readily deployed in a real-world scenario.

We developed a proof of concept nanoplastic detection system - NanoFind - which can easily be implemented into different types of products, a detection kit and a lateral flow test targeted at separate user groups. Our detection system could be applied to test the presence of nanoplastic, helping the research on plastic pollution, toxicity, and water quality monitoring.