Enhanced Growth of Bacterial Cells in a Smart 3D Printed Bioreactor

Abstract

In the last decade, there has been a notable advancement in diverse bioreactor types catering to various applications. However, conventional bioreactors often exhibit bulkiness and high costs, making them less accessible to many researchers and laboratory facilities. In light of these challenges, this article aims to introduce and evaluate the development of a do-it-yourself (DIY) 3D printed smart bioreactor, offering a cost-effective and user-friendly solution for the proliferation of various bioentities, including bacteria and human organoids, among others. The customized bioreactor was fabricated under an ergonomic design and assembled with 3D printed mechanical parts combined with electronic components, under 3D printed housing. The 3D printed parts were designed using SOLIDWORKS^® CAD Software (2022 SP2.0 Professional version) and fabricated via the fused filament fabrication (FFF) technique. All parts were 3D printed with acrylonitrile butadiene styrene (ABS) in order for the bioreactor to be used under sterile conditions. The printed low-cost bioreactor integrates Internet-of-things (IoT) functionalities, since it provides the operator with the ability to change its operational parameters (sampling frequency, rotor speed, and duty cycle) remotely, via a user-friendly developed mobile application and to save the user history locally on the device. Using this bioreactor, which is adjusted to a standard commercial 12-well plate, proof of concept of a successful operation of the bioreactor during a 2-day culture of Escherichia coli bacteria (Mach1 strain) is presented. This study paves the way for more in-depth investigation of bacterial and various biological-entity growth cultures, utilizing 3D printing technology to create customized low-cost bioreactors.

Keywords: 3D printing; Escherichia coli; IoT technologies; additive manufacturing; bacterial growth; bioreactor; mobile user interface.

Figure 1

Architectural diagram of the 3D printed IoT-based Bioreactor.

Figure 2

3D Printed Bioreactor.

Figure 3

(a) Gear base design; (b) Motor support base design; (c) Electronics housing; (d) Gear-propeller design; (e) Cap for protecting the motor.

Figure 4

Schematic design.

Figure 5

PCB Layout including (1) Adafruit Feather Huzzah ESP32 development board, (2) 7805-voltage regulator, (3) TIP120 NPN Darlington power transistor, (4,5,6,7) diodes, (8) Female headers and (9) terminal blocks.

Figure 6

Pulse-width modulation signal.

Figure 7

Flowchart of the usage of the Bioreactor.

Figure 8

(a) Screen when launching the app, with Bluetooth button to connect with bioreactor and buttons to create a new user or to login with credentials; (b) Main menu screen; (c) Motor speed screen to control the motor with or without timer (d) User History screen to keep track of whoever used the app in the specific device that the app is installed in.

Figure 9

Experimental Setup of the Bioreactor.

Figure 10

Data points correspond to the readings at 600 nm, while curves indicate the trendline of each experiment.