The NCKU Tainan team has been concerned with biosafety of every aspect of our project. Since the general public has many misconceptions of engineering microorganisms which can lead to the fear of the public, we realize one major responsibility of our iGEMers is to prove that our engineering bacteria are harmless to the environment and society. However, there is still much effort to do in terms of gaining widespread acceptance of synthetic biology in the general public. To achieve this goal, the NCKU Tainan team is still working hard this year to ensure the safety of lab, materials, designed devices and our team members. After all, safety is very important when it comes to doing experiments.

The iGEM NCKU Tainan team is in full compliance with the safety and security policies of the iGEM competition.

This year, our team established a new lab supported by NCKU and the Ministry of Education. With the assistance of our PIs, Prof. Ng, Prof. Wang and Prof. Hashimoto, we successfully certified our lab to BSL-1, biosafety level one. In addition, the PIs and advisors gave us some lab safety instructions and advice, ensuring that all of the members can conduct experiments safely. Before we entered the lab, all of the members received the biosafety training and got the certification through passing the exam provided by our university. And at all times, an advisor was present when work was conducted in our lab.

In order to make our contact lens safe for human use, we chose E. coli WM3064 as our chassis, which lacks the essential gene that encodes for 4-hydroxy-tetrahydrodipicolinate synthase that is critical to the production of lysine through the diaminopimelate pathway (DAP) pathway^[1]. Lysine is an essential amino acid for utilisation in protein and peptidoglycan cell wall synthesis^[2]. Hence, the bacteria will have to depend on exogenous DAP to survive. Finally, we will add DAP into our contact lens. If the bacteria escape from our contact lens, they will not survive in the environment due to the absence of exogenous DAP.

To confirm this, we did a phenotype check by streaking the bacteria on two different plates.

As shown in Fig.1, the bacteria is unable to grow without exogenous DAP.

In order to validate the function of Eye kNOw and Eye Screen, which are our designed contact lens and our device, we would need to mimic the deformation of cornea under different levels of IOP. After literature research^[3] and discussing the protocol with the ophthalmologist in the medical center, we decided to use the porcine eyes. We had filled in the check-in form about this and got approval from the official.

To explain in detail, we collected the fresh porcine eyes from a legal slaughterhouse, packed in plastic bags, and then stored at 0°C temperature in an ice-filled styrofoam container before we use them. When we conducted the experiments, the ophthalmologist in the medical center were present at all time to give us instructions. Also, an advisor in our team had a certification proving that she had completed the Laboratory animal center orientation and Ethics, Animal Welfare and the 3Rs Training Program. She joined the experiment too. Last but not least, the operators wore surgical masks, latex gloves and lab coats during the whole experiment process, and disposed porcine eyes as biomedical waste after the experiment.

In order to ensure that our bacteria in the contact lenses will not cause any harm, we chose chassis with kill switch system. We also improved binding affinity of our bacteria to the contact lenses, and used a semipermeable membrane, so that the bacteria would not escape from contact lenses.

Patients who wear our contact lenses must consult to doctor regularly to ensure the efficacy and safety of contact lenses. It cannot be purchased directly from pharmacies. This product is a daily disposable contact lens to avoid the semi-permeable membrane from rupturing due to improper cleaning of the contact lens.

Eye Screen is a portable detector providing a painless measurement of IOP using ultrasound. Rather than using ionizing radiation, Eye Screen evaluates the property of tissues based on the reflection of ultrasonic waves. Therefore, it does not have the same risks as X-rays or other imaging systems using ionizing radiation^[4]. Furthermore, the 40kHz ultrasonic transducer produces lower energy so that it has a much lower risk of bringing biological effects on the body. We conducted all the experiments for electronic components used in Eye Screen in the ultrasound research laboratory to ensure the normal function and security of Eye Screen. Besides, the material we adopted for Eye Screen is PLA, a type of biodegradable plastic that is harmless for our body^[5]. Thus, Eye Screen is a safe device for users.