Overview
After achieving experimental results in the lab using synthetic biology, the development of Moskilla hardware helps us apply these results to real-world needs. To validate the feasibility of our Moskilla design, we deemed it essential to develop corresponding hardware devices to demonstrate Moskilla's potential in the real world.
However, to ensure our Moskilla is as effective and responsible as possible, we have iterated it based on feedback from various stakeholders we have engaged with. Starting from the 1st version design, which was inspired by Westham's ATSB, to the 2nd version design, which integrates a droplet dispenser with a household mosquito-killing device, and finally, the envisioned 3rd version Moskilla integrating with IoT based on the management needs of target end-users like general public, parks and CDC.
The ultimate aim of Moskilla is to provide a novel mosquito control solution for end-users such as households, communities, and parks. With each iteration, we've refined our approach based on stakeholder feedback, prioritizing safety, convenience, environmental impact, and economic viability. As we open-source our modules especially the droplet dispenser, we invite the next generation of innovators to join us in exploring the potential of live bacteria beyond the lab. Together, we're redefining mosquito control and shaping a healthier, more innovative future.
The 2nd version Moskilla currently implemented by AIS China provides a controllable use of GMOs beyond the lab. Our ultimate goal is to provide a new mosquito control solution for families, communities, and public spaces like parks. With each iteration, we refine our approach based on the feedbacks from stakeholders, prioritizing safety, user-friendliness, environmental sustainability, and cost-effectiveness. By open-sourcing our modules, especially the droplet dispensers, we extend an invitation to future iGEM teams and researchers to collaborate with us. Let's advance mosquito control and shape a healthier and more innovative future together!
Figure 1. Project design of Moskilla
1st version of Moskilla
Requirements
As we want to attract mosquitoes, using HMBPP, and kill them, using shRNA, we need a container of these two substances. To maximize efficiency, while shRNAs naturally degrade easily in the environment, we still want to retain the substances to the greatest extent, thus needing physical protection from threats posed by the environment. To prevent unintended ecological impacts, the active compounds should be isolated from the broader environment (i.e. Humans and beneficial insects) while still being accessible to mosquitoes. Moreover, we need a physical entity, able to shield as well as deliver useful substances, to contain HMBPP and shRNAs, thus raising the need for a hardware device. We also want to limit the target to mosquitoes only.
Design
We took inspiration from an existing ATSB device, currently under trial in Zambia as a vector control method. This device is encased in a double-layer metal enclosure, housing a reservoir with bait incorporated within it. The bait is a blend of sugary substances and chemical toxins, such as fruit syrup laced with dinotefuran, designed to eliminate mosquitoes. However, the current formulation, being solely sugar-based, has limited appeal to blood-seeking mosquitoes, which are the main vectors of mosquito-borne diseases. (Maia et al., 2018)
Notably, the upper metal layer is crafted as a porous membrane, a feature intended to enhance mosquito target specificity. The slender mouthpart of mosquitoes allows them to be the primary targets of this device. While this membrane-like top layer boosts specificity, there is a risk that non-target tiny insects may enter and be killed by the chemical insecticide within the sugary bait. (Njoroge et al., 2023)
Acknowledging the limitations of poor attractiveness to blood-seeking mosquitoes and the unintended harm to beneficial insects, we have enhanced the bait composition. Our innovation includes the addition of E. coli that produce HMBPP to improve attractiveness and the substitution of dinotefuran with specific shRNA mosquitocides. This refinement marks the debut of our first Moskilla design, offering an optimized approach to mosquito control.
Figure 2. Our first version of Moskilla referenced the attactive targeted sugar baits(ATSBs) stations currently used in Mali, Kenya, and Zambia (Maia et al., 2018)
Feedbacks
2nd version of Moskilla
A problem to solve: How to limit the usage of GMOs
Design
Our first version of Moskilla has a concerning issue: the use of live GMOs in the device without a control mechanism which effectively prevents environmental damage in the case of a leakage. Survey suggests that many people have concerns over safety when it comes to GMOs products, (check our Integrated Human Practices for more). GMOs do pose a threat to the environment as they could cause disruption to ecosystems.
We designed the second version of Moskilla with the goal of eliminating any potential environmental threats from GMOs in our devices. The second version of Moskilla comprises 3 key components:
· The Upper section containing UV light and air tunnel to attract mosquitoes into the device;
· The Body section housing the fan and kill-switch mechanism;
· The Base section responsible for air exhaust and storing the ATSB to feed the mosquitoes.
Figure 3. The Upper Section of Moskilla Version 2
Figure 4. The Body Section of Moskilla Version 2
Figure 5. The Base Section of Moskilla Version 2
Figure 6. 3D-Printed Moskilla Version 2 Prototype
Device Parts
Droplet dispenser for kill switch
We have achieved a significant milestone by engineering and validating an inducible kill switch mechanism in E. coli (Check our X174E inducible expression system Engineering Page for more). By introducing an inducer solution to the modified E. coli, we can trigger a response that leads to the bacteria's demise over time. This innovative mechanism is pivotal for mitigating environmental risks associated with the leakage or uncontrolled proliferation of genetically modified organisms.
For the enclosure design, we have ensured the confinement of GMOs within the device. To operationalize the kill switch mechanism in real-world application, we are integrating an automatic and controllable droplet dispenser module. This module will be activated by the user through the hardware interface. Upon activation of the stop switch, the microcontroller generates a pulse width modulation (PWM) signal to the H-bridge motor driver, which in turn manages the screw motor, effectively dispensing the inducer solution to enact the kill switch.
Figure 7. Motor Driver Connection Guide
Figure 8. Screw Motor Component which is used to control the syringe pulling and pushing of inducible solution from the replacable serum tubes (test tubes with rubber top).
Figure 9. Integration of Screw Motor, Syringe, and Serum tube
When the motor turns clockwise, the syringe pulls liquids from serum tubes and stores it in the barrel. After a set time, the motor turns anticlockwise and the syringe starts to push back. However, the barrel wall contains a small hole, so the death-inducing liquid will drop from the hole and down into the plate of GMOs. The time of rotation determines the amount of liquids dropped.
The kill switch mechanism in our device offers a unique and innovative solution of managing the use of live (and genetically modified) bacteria in external environments with a reliable safety control system. By implementing our kill switch mechanism, future iGEM Teams and stakeholders can adopt a safer and more responsible approach to microbial management, enhancing environmental safety. More information regarding our killswitch mechanism can be found in the Moskilla: User Assembly Manual document in the Supplementary section.
Figure 10. Holder for motor, syringe, and serum tube
Mosquito Attraction Module
Apart from ATSB and HMBPP, from the perspective of hardware, UV light is also used to attract mosquitos. Mosquitoes are particularly attracted to UV light in the range of 350-400 nm. These wavelengths stimulate their visual receptors, making them more likely to approach these light sources.
During our participation in the CCIC conference, we received valuable insights that UV lamps, while effective in attracting mosquitoes, could adversely impact the growth of our engineered E. coli within the closed device. To address this potential risk, we strategically positioned a mosquito-collecting fan between the UV lamp and the bait compartment. We chose fan blades with a diameter similar to that of the device itself, utilizing their rotation to substantially block UV light from reaching the engineered E. coli. This design modification ensures the viability of our bacteria while maintaining the mosquito attraction capability of the device. (Check our gains at CCIC conference in Integrated Human Practices for more)
Figure 11. UV Light Component Integration Diagram
Exit Mechanism
Under the attraction of UV light and our baits, a fan is used to pull the mosquito into the body of Moskilla. Furthermore, as it is mentioned above, the mosquito-collecting fan is strategically positioned between the UV lamp and the bait compartment. And the fan was chosen for its fan blades that closely match the device's diameter, effectively using their rotational motion to shield the E. coli from direct UV exposure. This design ensures that the bacteria remain unharmed while still allowing the device to attract and collect mosquitoes effectively.
Figure 12. Mosquito-collecting fan Component Integration Diagram
Air leaves the device from the base. A filtering net is used to keep mosquitoes inside. The opening has a special wind flue pointing upwards that blows the scent of HMBPP towards the entrance of Moskilla instead of spreading it widely to maximise the effect of HMBPP.
Figure 13. Air Outlet design (a) and Cyclic Airflow (b) Diagram
User-Interaction: Button
To allow the user to interact with mosklilla, we've incorporated a straightforward and accessible design feature: a single button. A simple tap toggles the mosquito-collecting fan, allowing users the flexibility to switch it on or off as users might want to minimize noise at night. Pressing and holding the button activates the droplet dispenser, ensuring a seamless interaction with the device.To allow the user to interact with mosklilla, we've incorporated a straightforward and accessible design feature: a single button. A simple tap toggles the mosquito-collecting fan, allowing users the flexibility to switch it on or off as users might want to minimize noise at night. Pressing and holding the button activates the droplet dispenser, ensuring a seamless interaction with the device.
Figure 14. Button and USB-C power components Diagram
Cost
Table 1. Cost sheet for Moskilla Device.
Demonstration Video
Feedback
After constructing the Version 2 of Moskilla, we revisited park administrators we had previously interviewed and also collected opinions from randomly selected passersby in the local community to further optimize our hardware according to user needs. During the introduction, no engineered E. coli was placed in the hardware, and it has never been in contact with GMOs or other experimental materials.
We clearly received positive feedback, and they are all willing to try Moskilla's new technology. However, the insights they provided reflect that home use and open environments like parks are two different application scenarios, thus having different needs.
For home use scenarios, the general public needs more aesthetic and compact devices. However, park administrators did not express any negative views on the size of our current devices.
Later, in the communication process with Jing Wu, a PhD candidate from Professor Chen Xiaoguang's team, her professional insights gave Moskilla's product an unexpected development direction, which is to create a mosquito monitor.
However, whether it is the general public, park property managers, or researchers in this field, they all expressed a demand for functions that combine smart control on mobile or web ends. After seeking advice from embedded engineer, Mr. Gao, he gave us suggestions on combining the Internet of Things engineering (IoE) and technical reference documents, which also laid the foundation for the design ideas of our future third version.After constructing the Version 2 of Moskilla, we revisited park administrators we had previously interviewed and also collected opinions from randomly selected passersby in the local community to further optimize our hardware according to user needs. During the introduction, no engineered E. coli was placed in the hardware, and it has never been in contact with GMOs or other experimental materials.
Further optimization - 3rd version
We concluded that a online management system of Moskilla would be more convinient, efficient, manageable, and user-friendly. We will develop an system that allows the user to connect Moskilla to their phone app. The app will remind the user to resupply the seum tube or the base plate. With AI vision, we could give reports on the amount of mosquitos caught.
After the basic functionality is implemented, the next step is the advanced phase. The IoE is a trend in industrial development, where products can be intelligently connected and controlled in real time, giving them a significant market advantage. For our mMosquito killer lamp to further upgrade, it needs to connect to the cloud. The benefit of cloud connectivity for home users is that they can control the UV light, fan, and self-destruction mechanism of the mosquito killer lamp anytime and anywhere, as well as set up timed tasks. For government or corporate users, in addition to the home features, they can also view the working status of all deployed mosquito killer lamps on a web dashboard in real time. Before replacing the bait, they can remotely activate the self-destruction mechanism and then notify local maintenance personnel to perform the replacement, among other features.
Figure 16. The envisioned User Interface of Moskilla
Supplementary
You can implement our hardware based on the manual below!
For the further optimization, Mr. Gao, the embedded engineer we engaged with provided us the IoT Development Guide below!
Reference
- Maia, Marta Ferreira, et al. Attractive Toxic Sugar Baits for Controlling Mosquitoes: A Qualitative Study in Bagamoyo, Tanzania. Malaria Journal. 2018, 17(1): 22. https://doi.org/10.1186/s12936-018-2171-2
- Njoroge, Teresia Muthoni, et al. Maximizing the Potential of Attractive Targeted Sugar Baits (ATSBs) for Integrated Vector Management. Insects. 2023, 14(7): 585. https://doi.org/10.3390/insects14070585
- https://www.ivcc.com/large-scale-epidemiological-studies-begin-for-attractive-targeted-sugar-baits-atsb/
- https://blog.csdn.net/2301_78772787/article/details/138091292
- https://www.perplexity.ai/search/is-mosquito-attracted-by-light-fmxBGg5PTE.U8uAcfs0SUg