Automated Micro Pipetting System for Bio Chemical Fluid Handling
Our project was an undertaking aimed towards the biochemical and medicinal fields, with the development of a model that is advance and has yet not been introduced in Pakistan. Firstly, we must understand the basic idea about the project. The main goal of the project is to develop an automate
2025-06-28 16:30:23 - Adil Khan
Automated Micro Pipetting System for Bio Chemical Fluid Handling
Project Area of Specialization RoboticsProject SummaryOur project was an undertaking aimed towards the biochemical and medicinal fields, with the development of a model that is advance and has yet not been introduced in Pakistan.
Firstly, we must understand the basic idea about the project. The main goal of the project is to develop an automated pipetting system. However, an introduction to pipettes is necessary in order to understand the rest of the project. Pipettes are laboratory apparatus used to transport a measured volume of liquid. The pipette is most commonly used in genetic research, chemistry, microbiology, and drug development. With a thorough market research, it was found out that the high-tech devices using pipettes are rare or highly expensive in most Pakistan’s medicinal research departments.
The project has aimed to develop an automated micro-pipetting system with multiple nozzles designed to handle biochemical fluids for the field of medicine, and interfaced with a touchscreen LCD for user input. The base model takes inspiration from a CNC machine which dictates its type of 3 dimensional movements.
The following is a general, easy to understand, description of how the machine works. Firstly, the names and location coordinates of each chemical is firstly required to be stored by user in database using the Graphical User Interface (GUI) on the touchscreen LCD. Then the user inputs the formulas for each mixture using the appropriate chemical amounts to be stored in the database. A previously stored formula is accessed by the user to be performed and the number of times to be performed is also specified by the user. Using the chemical name(s) and amount(s), the algorithm automatically runs stepper motors for the movement of the pipette in x, y, and z axis. The pipette then aspirates the liquid and ejects the specified amount into the mixer. It is important to keep in mind that the interface continuously monitors the liquid amount and capacity using its algorithm in real-time and displays it on the screen. Finally, once the process ends, the system is ready to run another formula.
Project ObjectivesThe project aims to automate the pipetting process so that the researchers can spend more time designing experiments and analyzing data.
The following are our main objectives in this project’s undertaking:
- Designing a mechanical body capable of 3-axis movement with clearly defining the features of each and every component.
- Development of the electronic circuitry responsible for powering up the mechanical body.
- Achieving an accuracy with the pipetting system of up to 1 ?L.
- Programming of a user-friendly GUI with intelligible instructions.
- Increasing both productivity and reproducibility while maintaining integrity.
- Capability of remote operation.
The product had been classified into the following sections for successful execution:
- Mechanical System
- Electronics and Control
- Software System
The mechanical structure is assembled in such a way that 3-axis movement is achieved with the help of lead screws and supporting rods. Each axis is integrated with a stepper motor with the help of a coupler and one stepper motor was coupled to drive the piston of pipette. The automatic micropipettes were very high-priced so we had to come up with an affordable alternate technique for liquid handling. After the careful analysis, we concluded that we can use a custom-made linear actuator and drive the piston using a motor.
After construction of mechanical system, electrical system was designed. For 3-axis movement, we used NEMA-23 stepper motors. To make the stepper motors work, a stepper motor driver, namely TB6560 was integrated with the motors. NEMA-17 stepper motor was used for the movement of piston. The motors selection criteria were based on torque and speed requirement. DC power supply was purchased to power up the electrical system that could provide voltage of 24 volts and current of 9 amperes. All stepper motors required 24 volts and 2 amperes each, so the stepper motors were connected in parallel with each other. The microcontroller that we used is Raspberry Pi Model 3B+. The selection criteria of this microcontroller was based on the fact that it had its own operating system and we could store, process and manipulate data using Raspberry Pi.
The software system consisted of Front-End and Back-End programming with the feature of remote accessing. In the Front-End programming, an attractive and user friendly graphical user interface (GUI) was designed, which had number of features such as Adding, Displaying, Editing and Deleting the stored data. In the Back-End programming, motors were controlled according to the command given by the operator through GUI (graphical user interface). A hash table was developed to manipulate and store the data due to which data handling was made easier. Finally, a grid was pasted on the base so that the operator could have the option to add new chemicals to multiple locations.
Our Automated Micro Pipetting System is capable of:
- Multi-Sample Preparation
- PCR and DNA Analysis
- Multiple Drug Testing
- Auto-Cell Culture Assistance
- Cloning/Replication
These applications and features are, at this day and age, critical for the medicinal and biochemical research departments of Pakistan.
Technical Details of Final DeliverableThe final product consisted of a 3 degree of freedom machine, an electronic pipette and a pocket size computer for control.
3D Machine:The degrees of freedom were as follows:
- X-axis
- Y-axis
- Z-axis
These axis motions used to transport the electronic pipette to very precise and accurate locations on the grid. The motion of each axis was achieved by using a lead screw attached to a stepper motor in order to convert the rotating motion of the motor into linear motion of the screw. The lead screws were selected on the basis of level of accuracy required and the estimated weight supported on each axis. The selected lead screws were all ACME screws and single threaded. The pitch on each axis was 4 mm while the mean diameter was 16 mm. Using these values, the total torque required was calculated to be 0.383 Nm. The end fixity on 2 axes (x and y) was fixed while it was free on the z axis because of design constraints.
Using the torque calculations, the stepper motors were selected to be NEMA 23 with 2 Amps operating current rating and 24 Volts voltage rating. The stepper motors were powered through a power supply of 24V and 9A.
Electronic Pipette:The pipette was designed as a separate entity that could be mounted onto the 3D machine. It included a leadscrew, a stepper motor and an insulin syringe attached to the screw. The insulin syringe was selected because it employed the simplest mechanism available and had a very small least count. The lead screw’s design parameters included a pitch size of 1 mm and a mean diameter of 8 mm. NEMA 17 stepper motor with a step angle of 1.8 degrees was used to rotate the lead screw.
TB6560 stepper motor driver were used with the motors and because of its easier design micro stepping was achieved up to x32. Due to this very small change in the length of the insulin cavity was achieved. These techniques helped us in achieving the 1 microliter dispensing goal.
Pocket Size Computer:Raspberry Pi 3B+ was used as the brain behind the whole system. Using the TKinter library of Python a user-friendly GUI was developed. The user was required to input the chemicals and the instructions for the mixture which included the amount and the aspirate and dispense chemical names.
A data base of chemicals with its grid location and amount was maintained using file handling. Also, the instructions for the mixtures were saved on a file for repeatability. Another file was maintained to save the current location of the 3D machine for accurate movement.
Two separate hashtables were created, one for the chemicals and the other for the mixtures with different methods. Hashtables were used because of their easy and fast searching property. A class was created to simplify the implementation of the motor control code. Implementing the hashtables and motor code class in separate header files further simplified the code.
Final Deliverable of the Project HW/SW integrated systemType of Industry Medical , Others , Health Technologies Robotics, OthersSustainable Development Goals Good Health and Well-Being for People, Industry, Innovation and InfrastructureRequired Resources| Item Name | Type | No. of Units | Per Unit Cost (in Rs) | Total (in Rs) |
|---|---|---|---|---|
| Total in (Rs) | 76500 | |||
| NEMA-23 Stepper Motors | Equipment | 3 | 2400 | 7200 |
| Lead Screws (16 mm) | Equipment | 2 | 3500 | 7000 |
| Supporting Rods | Equipment | 4 | 500 | 2000 |
| 3-Axis Hardware Assembly Fabrication | Equipment | 1 | 25000 | 25000 |
| Power Supply | Equipment | 1 | 1500 | 1500 |
| TB6560 Motor Drivers | Equipment | 4 | 750 | 3000 |
| Raspberry Pi 3B+ | Equipment | 1 | 5500 | 5500 |
| Raspberry Pi Adapter | Equipment | 1 | 350 | 350 |
| Raspberry Pi Case | Equipment | 1 | 200 | 200 |
| Micro SD card for Raspberry Pi | Equipment | 1 | 750 | 750 |
| 7-Inch Touchscreen LCD | Equipment | 1 | 5800 | 5800 |
| Lead Screw (8 mm) | Equipment | 1 | 1400 | 1400 |
| Couplers | Equipment | 4 | 150 | 600 |
| NEMA-17 Stepper Motor | Equipment | 1 | 800 | 800 |
| Anti-Backlash Nut | Equipment | 1 | 250 | 250 |
| Insulin Syringes | Equipment | 8 | 25 | 200 |
| Glass Test Tubes | Equipment | 50 | 5 | 250 |
| Plastic Test Tubes | Equipment | 20 | 4 | 80 |
| Glass Beakers | Equipment | 5 | 250 | 1250 |
| Tray | Equipment | 1 | 450 | 450 |
| Spiral Wire Covers | Equipment | 3 | 100 | 300 |
| Jumper Wires | Equipment | 3 | 90 | 270 |
| Travelling Costs | Miscellaneous | 1 | 5200 | 5200 |
| Shipment Costs | Miscellaneous | 1 | 1250 | 1250 |
| Grid Printing | Miscellaneous | 1 | 400 | 400 |
| Polishing | Miscellaneous | 1 | 2000 | 2000 |
| Lead Screw (10 mm) | Equipment | 1 | 2300 | 2300 |
| Pipette System Fabrication | Equipment | 1 | 1200 | 1200 |