Project Specification

Open Source 3D-Printed ISO 8655 Compliant Multichannel Pipette

Open source multichannel pipette compliant with ISO8655 standards for precision & accuracy

Specifications

3D-printed parts Enclosure Body 1 & 2 (PLA)
Main Plunger (PLA)
Syringe Holder (PLA)
ChannelNumber: 4
Nozzle distance18 mm between the adjacent nozzles
SyringeNumber: 4
Volume: 1mL, Allegro Medical
Compression SpringNumber: 4
Material: Stainless steel, McMaster-Carr
Female adapterNumber: 4
Disposable Plastic, Cole-Parmer
Universal pipette tipsNumber: 4
Disposable Plastic
Medical tubing Size: 3/16” OD
Length: 1 foot
Material: silicon

Overview

This tech spec was submitted by Joshua Pearce as part of the University Technology Exposure Program.


Problem / Solution

Transferring small liquids in Laboratories takes too long and would require enough patience. Most of the time, measuring the necessary fluids and moving them to another multi-well plate would take several uses of a single channel pipette which is time-consuming and would sacrifice the liquid's precision. The chemical, biological and biomedical test requires precisely measured solutions, thus requiring the volume of liquids to be highly precise for the chemical being used. Today, multichannel pipettes are available that can transfer multiple samples in a single aspiration and dispensing. However, these are expensive in the market due to a lack of competition and limited production.

An open-source multichannel pipette design is an affordable and 3D-printed device priced at $24. The model is capable of handling 200 uL 4-channel pipettes. Its fabrication uses an inexpensive fused filament RepRap-class 3D printer with its custom component and interchangeable parts. The design ensures that the liquids will not be mixed and will prevent air into the liquids because the pipette will operate separate syringes with individual tips. This open-source multichannel pipette is ISO 8655 compliant for precision and accuracy, offering customization for specific parameters in the source code.

Design

The overall design of the Open-source Multichannel Pipette includes an ergonomic handle and the main plunger, which is easy to dispense liquids design for individual hand bridges. A single main plunger with a locking mechanism is used on the main pipe with four individual pipette tips. The distance between two pipette nozzles is 18mm based on the design of a multi-well plate for easier liquid retrieval and transfer.

The enclosure, syringe holder, and plunger were 3D Printed components. The plunger has a compression string mechanism to support the plunger function of the product. When the main plunger actuates the individual syringes, the spring mechanism will do the pull-back action. In addition, air displacement is the fundamental principle of the multi-channel pipette. It entails that the liquid retrieval is equal to the individual syringe being displaced.

A critical design component is the syringe holder that allows the syringe to be connected safely to the plunger. This part ensures the syringes are locked and twisted in place appropriately. The 3D-printed parts are made from the most available and easy-to-process polylactic acid (PLA) material. The other parts of the multi-channel pipette are interchangeable and readily available.

Gravimetric Testing is done for the calibration of the multi-channel pipette. Metlier Toledo XS205Du analytical scale with the resolution of 0.01mg is used to ensure precise calibration.

This multi-channel pipette has cylinders with higher volumetric capacity and appropriate pipette tips with more accurate measurement in transferring liquids than conventional pipettes. One of the concerns with the multi-channel pipette is the cross-contamination of the fluid to adjacent syringes. Unlike other multi-channel pipettes, each of this design’s cylinders has a separate piston that is not attached to the actuating base plate. Different syringes operate the nozzle tip and have no direct contact between the specimens and air.

Hence, if a human error occurs and contaminates the syringes, only replacement of the new syringes is needed, not the whole multi-channel pipette. All four channels of the pipette met ISO 8655 standard with no more than 4µL systematic error and 1.5 µL for random error.

References

A research paper describing the challenge, design, and outcome of the research.

Shubham Chinchane, Hrishikesh Kadam, Ketan Mowade, Joshua M. Pearce