This year Vilnius-Lithuania iGEM team decided to characterize and implement a part, which was first used by the iGEM 2018 NDC-HighRiverAB team (BBa_K2694001), encoding a bacterial surface EstA protein from Pseudomonas aeruginosa. Hopefully, new literature analysis, experimental characterization and usage of this part will encourage future iGEM teams to work with cell surface display systems.

We were able to design, produce and test 13 basic parts, 9 composite parts, adding up to iGEM's part collection registry with thorough documentation and usage analysis.

To fulfill our goal of developing a rapid and easy nanoplastic detection system, we decided to design and produce an unconventional microplate model, which was specifically tailored to complement the anticipated function.

Compared to the standard 96-well plates, the 3D microplate model is unique in its detachable parts. Our envisioned hardware contains three parts - a bottom plate with raised knobs, a cellulose sheet in the middle, and a top plate with projected wells. Complementarity of the top and bottom plates as well as two clamps on the sides enables the tight instalment of the cellulose membrane.

In our nanoplastics detection tool, a fusion peptide with cellulose binding domain is immobilized on a cellulose membrane. Our model is designed to facilitate a more uniform cellulose coverage with peptides. When sample is loaded and washed with buffer, another plastic-binding peptide, giving a fluorescent signal, is added and incubated. After this, the peptide is washed with a contained buffer and fluorescence is measured with a microplate reader using a compatible plate. In the case of our 3D model, the microplate is tailored to fit the fluoresence reader.

Even though our current 3D model could only be used as a mock-up model, we envision this design to be based on glass material. As we are working with molecules with a high affinity for plastic surfaces, the proposed microplate design should be used as an alternative to the plastic microplates. Not only would it solve some challenges related to the nanoplastic research but also offer a reusable and sustainable hardware.

Since our project contained peptides, which have a high affinity for plastic material, many ideas and project protocols required troubleshooting and rethinking of the most commonly used laboratory plasticware. Our adjustments included applying small glass bottles for protein and nanoplastic storage, using glass microplates for specific nanoplastic binding experiments, and even inventing a glass-based column for peptide-plastic binding experiments. (Shown in picture gallery).

Our experiments required a lot of repetition, ingenuity, and fidelity in order to show only the best and most repetitive results. Therefore, our small hardware laboratory equipment can be a building block for teams who try to work with similar topics or who will try to make a small hardware device similar to ours.

Human exposure to nanoplastics through inhalation and ingestion raises concerns about their potential adverse health effects. The toxicity of nanoplastic particles is not well characterized in part due to their small size and chemical inactivity and, consequently, to difficulties in detection. However, it is recommended to handle them as potentially hazardous material.

For this, with the help of experts in nanomaterials, we analyzed and created safety rules for the safely handling of nanoplastics. We believe that these guidelines will set a standard for future iGEM teams working with small plastic particles in their future projects.