Team:NTHU Taiwan/Hardware



To address the lack of accessibility to implement OD and fluorescence measurements due to the high costs and the level of knowledge required among others, our team has designed a bioreactor, a fully-equipped bioengineering device capable of automatically monitoring biosynthesizing quantum dots' process.

To ensure a functional, economical and easy-to-use design, collaboration between the hardware and the wet lab teams has been necessary throughout the development process. After several discussion with Professor YA-TANG YANG, we adopted a unique design that which can be easily transported and replicated at a cost not exceeding $60.

Figure1. The overview of BIOSQUAD bioreactor.

BIOSQUAD bioreactor is divided into three main parts dependent on each other:

1. Stirring system: A 5V DC fan with four magnets on its blade. When the fan rotates, it allows the magnet stone inside the bottle to stir and make the reactant into the homogeneous state.

2. Reaction zone: A bottle where the process of quantum dots biosynthesis in bacteria occurs.

3. Measurement zone: the bacteria are kept in conditions that allow for growth and expression while OD and fluorescence measurements are taken.

Figure2. The measurement zone of BIOSQUAD bioreactor.


OD Measurement: As for measuring the resulting bacteria we need a high precision light sensor we decided to use BIR-BM13E4G-2. This converts the magnitude of light received into voltage, which can be precisely measured. Our sensor compares the light from a laser of 940 nm that passes through the experimentation tube over time. We chose a laser for a more stable light output. Comparing the values measured to the initial values without any bacteria we can calculate the percentage of absorbance of the medium, obtaining that way a suitable measurement of the cell population.

Fluorescence Spectrometer: Similarly to our OD sensor we opted for the SUB/S530 for high precision light measuring. The only difference is that in this case the bacteria are excited with a LED of wavelength 470 nm, since it is the most suitable to excite them and obtain a fluorescent reaction from them. In front of the sensor we have put a filter that only allows light of 520 nm of wavelength to pass through. That way we obtain a result on the peak of fluorescent emission from the bacteria.

Figure 3. OD calibration curve. We have calibrated the data from the OD sensor with the OD data from the BIOSQUAD bioreactor equipment.

Once the transformed bacteria are ready, they are sent to the measurement system in order to culture them while OD and fluorescence measurements are taken. It consists of a system based on a stirring system, which has holders for the incubated tubes in which the bacteria will be stored. To those holders, there are sensors attached to monitor the growth of the bacteria and to measure the fluorescence obtained.

Overall budget

Table 1. Tools used in the dry lab part of our bioreactor. All electrical equipment used was designed to fit for assembly with Biosquad.

Part Quantity Cost per unit Total Cost
Arduino UNO Rev3 1 18.33 18.33
BRTLED 940nm LED BIR-BM13E4G-2 1 0.87 0.87
940nm Photo Transistor ST-2L2B 1 2.4 2.4
470nm LED 5mm-SUB/S530 1 1.74 11.74
520nm Photo Transistor ROHS 1 3.82 3.82
ADDA 5V DC Fan AD0405HX-G76 1 4.9 4.9
PMMA BOX 204mmx165mmx132mm 1 7.9 7.9
Breadboard Prototyping Board 80 x 60 x 10mm 1 6.32 6.32
ULN2003AN Darlington IC 1 0.68 0.68
Wireless module NRF24L01+ 2.4GHz 1 11.88 11.88


With our low-cost wireless bioreactor, users are able to introduce the culture of bacteria and monitor its growth without human interference, entitling with freedom. This device has two function, OD measurement and Fluorescence Spectrometer. All the results will be shown and stored in his library of measurements, which could be accessed at any time.

Future Work

One of the possible future work is that we would mass produce for multiple use of experiments. This means being able to run several experiments at the same time. We are limited for one reactions at one moment but we want to optimize the design of the reaction zone of the machine. We could alter this design to be able to do many more reactions at the same time for different protocols.


  1. Lin, D‐S, Lee, C‐H, Yang, Y‐T. Wireless bioreactor for anaerobic cultivation of bacteria. Biotechnol Progress. 2020; 36:e3009.