Liquid Handling · Bioprinting · Automated pipetting · OTTO · 2020 · Scientific Reports
Principles of computer-controlled linear motion applied to an open-source affordable liquid handler for automated micropipetting
Open-source automated liquid handler (gantry-style) for micropipetting, e.g., qPCR sample prep
Performance the paper reports
2 of 5- Motion320 µmMotion accuracy: reported
- Volume—Volumetric accuracy: not reported
- Viability—Cell viability: not reported
- UnattendedunattendedUnattended operation: reported
- Standard—Standard compliance: not reported
- Motion / positional accuracy320 µm
While this resolution is over an order of a magnitude greater than required, reversal error (U), which is a combination of backlash and hysteresis24, limits the positional accuracy (PA) of this linear actuator to 320 µm (Fig. 3B).
- Unattended operationunattended
OTTO was designed to eliminate liquid handling malfunctions that would lead to low adoption of this technology, since users would not have confidence to leave OTTO unattended.
How hard this is to adopt
3.6 of 5, higher is easierEach score is shown against the range the other 59 builds actually occupy, because no criterion uses the full 1–5 scale. These describe how reproducible the build is, not how good the science is.
Resolution
4/1–5Dispensed 5 uL with a 10 uL Eppendorf pipette at 2.5% average error against a 1.5% pipette spec, in 20 uL qPCR reactions, with 320 µm positional accuracy.
Throughput
3/2–5One micropipette forming a single channel; authors rejected automatic pipette switching so the assembly is swapped manually; fills a 96-well qPCR plate unattended but not in parallel.
Parts sourcing
4/2–4Mostly off-the-shelf or kit-based components.
Skill needed
4/2–4Build/operation described as low-skill or basic assembly.
Facilities needed
4/2–4Uses common benchtop/desktop equipment or generic consumables.
Documentation
4/2–5Open resources include several build or operation artifacts.
Validation effort
3/2–4Dye serial dilution at a single 5 uL volume (n=4), reversal-error test (n=10/axis), qPCR standard curve R2=0.998 and tip/obstruction sensing; accuracy compared to pipette spec, not an experimental benchmark.
Cycle time
3/1–496-well plate in under an hour versus 30-45 min for an experienced technician, i.e. roughly comparable to slightly slower, and tip-alignment checks can double run time.
2 further criteria are recorded but not shown
- Application Level — scored 4 (75% of records share one value), so it cannot separate one build from another.
- Build Time (scored for only 6 of 60 records), so it cannot separate one build from another.
Both remain in the published dataset.
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Record metadata
Publication data
Matched by doi · retrieved 2026-07-21
Abstract
OTTO is an open-source automated liquid handler that can be fabricated at a cost of $1,500 using off-the-shelf and 3D-printable parts as an alternative to commercial devices. Open-source approaches have been applied to build syringe pumps, centrifuges, and other laboratory equipment. These devices are affordable but generally rely on a single motor to perform simple operations and thus do not fully utilize the potential of the Maker Movement. Open-source linear actuators and microcontrollers enable the fabrication of more complex laboratory instruments that rely on 3D positioning and accurate dispensing of fluids, such as automated liquid handlers. These instruments can be built rapidly and affordably, thereby providing access to highly reproducible sample preparation for common biological assays such as qPCR. We applied the design principles of speed and accuracy, unattended automation, and open-source components to build an automated liquid handler that controls micropipetting of liquids in 3D space at speeds and positional resolutions required for qPCR. In benchmarking studies, OTTO showed accuracy and sample preparation times comparable to manual qPCR. The ability to control linear motion and liquid dispensing using affordable off-the-shelf and 3D-printable parts can facilitate the adoption of open-source automated liquid handlers for qPCR, bioplotting, and other bioinstrumentation applications.
Bibliographic details
Access and metrics
Topics and keywords
Funding
- National Science Foundation
- Vanderbilt University
Perspective and practical signals
Why it matters
Not a bioprinter, but relevant open automation tool for biofabrication/bioprinting workflows. | Canonical open-source liquid handling robot paper; good baseline against newer modular tools like digital pipette.
Limitations
lower throughput due to slow error-checking system | Lower throughput due to a slower built-in error-checking system