Poster: KUAS_Korea

Thermopatch: What's your body temperature now? Epoch-making method for consistent temperature measurement

Presented by Team KUAS (Korea University Association of Synthetic biology) 2020

Ingeol Choi¹, Jingi Yeo², Kwangho Son², Yongjoon Jin², Woojin Kim², Kyutae Kim², Jungbin Moon², Junghyun Lee², Sungwook Lee², Kyeongmin Kim², Kyungju Shin², Yoojin Choi², Hyunkyu Han², Taehyun Eom³ Korea University, Seoul

Primary PI (Bolded member)¹ : Ingeol Choi

iGEM Student team member² : KUAS members from Korea University, Seoul

Advisor³ : Taehyun Eom

Abstract

One of the key factors to South Korea’s success in controlling COVID-19 is early detection. Aside from aggressive COVID-19 testing, South Korea also deployed temperature checks at entries of every indoor public facilities for screening purposes. However, the current screening methods such as contactless thermometers and infrared cameras are not efficient because of the high costs of resources needed for setting up screening booths and its failure to monitor temperature continuously. Our ‘Thermopatch’ is a device that complements these limitations. In the process, we utilized light-up RNA aptamer (‘Catalytic Hairpin Assembly(CHA)’ method specifically) and thermosensing RNA. We ultimately hope our ‘Thermopatch’ can help people get through these difficult times.

Introduction & Inspiration

Introduction

Inspiration

Introduction

Our team's project goal was to develop a continuous body temperature monitoring system enabled by “Thermopatch” which is a thermosensing sticker. This helps prevent the spread of infectious diseases that cause fever symptoms through relatively simple mechanism. Our team used the CHA method using thermosensing RNA to introduce a system that emits fluorescence above a specific temperature into stickers. Also, with the physical product, we aimed to create a monitoring policy that goes along with it.

Inspiration

As COVID-19 pandemic occurs, the importance of accurate temperature measurement became higher than ever. While agonizing the synthetic biological contributions toward this pandemic, we identified limitation of existing temperature measuring method in multiuse facilities.

Thermal image camera is the most frequently used temperature measuring method until the present. But it can’t deal with continuous observation, which means that people could show signs of fever after several hours. There are actual numerous examples that this weakness generated with high riskiness.

For these reasons, we decided to develop continuous temperature measuring method attaching to body directly. It could also reduce the cost for buying expensive thermal image camera and complement that method.

Engineering

Methodology

Human Practice

Methodology

'Thermopatch's capsule parts'=dried RNA parts+ buffer parts

using RNA aptamer & Broccoli

Genetically encoded light-up RNA aptamers, refer to RNA sequences that can bind with their cognate nonfluorescent fluorogens and greatly activate their fluorescence. Broccoli is an aptamer that binds to DFHBI and emits fluorescence.

using Catalytic Hairpin Assembly

:highly efficient isothermal amplification method which does not require enzymes

1. Broccoli was separated into two nonfluorescent parts, termed Broc and Coli. -> low fluorescence signal

2. Fused Broc to the 3' end of the H1 hairpin and Coli to the 5' end of the H2 hairpin.

3. The active fluorogenic form of Broccoli can only be formed upon target-driven H1 and H2 hybridization.

The target strand can be spontaneously displaced and recycled, similar to a catalyst, to induce more hairpin assembly events.

Human Practice

Interviews with many experts are very helpful in narrowing our team's theme.

Team KUAS has opened a science booth or held seminars not only for the general public but also for those who are already interested in synthetic biology.

Our team KUAS also had an academic conference with team KSA and collaboration with Korean high school team named SIS this year. Through this activity, we could share our understandings and views on iGEM and have a chance to look back on our project.

Results and Conclusion

1) Thermal conduction modeling:

Our modeling results above shows that heat transfers well into the patch. Thus, we concluded that the heat signals are sufficient for our stickers to respond.

2) Activation time

The figure shows the fluorescence over time of CHA systems with varying concentrations of C from published results (1)

Here, we compared the time constant of each graph. Time constant is an indicator of how fast the system reacts to external input and it is equivalent to the time it takes for the system to reach to 63% of final status. The table on the right, shows the values. We noticed that the time constants are very similar for 2.5 and 50 nM of the target sequence. This indicates that the step in which the fluorophore binds to H1:H2 complex is the rate determining step. If one of the steps before the binding of the fluorophore was the RDS, the time constant for 2.5 and 50nM of target sequence would differ drastically. Therefore, we can expect our system to emit sufficient fluorescence within half an hour.

3) Predicted activation temperature for each modified sequence.

This is the graph that shows the concentration of C:H1 complex at each temperature according to Mfold. From previous studies, it is known that at 22 degrees, the CHA system is activated. Therefore, from this graph, we selected the concentration of C:H1 complex at 22 degrees to be the threshold concentration for activation. The threshold value is 3.87569e-13M

With Mfold, we also modeled the behavior of the modified sequences. at each temperature. The chart below shows the temperature at which the threshold concentration is achieved.

None of our modified target sequences are activated around 37.5 degrees according to the modeling. However, since this is only a modeling heavily based on assumptions, some of the sequences may actually activate the system at 37.5 degrees. In the future, we will have to design new sequences and test their behavior through wet lab experiments.

4) Visibility modeling

This section shows the result of our light intensity modeling. Through a series of calculations, we wanted to acquire the concentrations required to reach a certain light intensity. The following chart shows the required concentration of each component required to achieve light intensity of 0.1lux.

References and Acknowledgements

(1) Karunanayake Mudiyanselage, A. P., Yu, Q., Leon-Duque, M. A., Zhao, B., Wu, R., & You, M. (2018). Genetically encoded catalytic hairpin assembly for sensitive RNA imaging in live cells. Journal of the American Chemical Society, 140(28), 8739-8745.

(2) Genetically Encoded Catalytic Hairpin Assembly for Sensitive RNA Imaging in Live Cells, Aruni P. K. K. Karunanayake Mudiyanselage et al., J. Am. Chem. Soc. 2018.