Robotic Liquid Dispensing Simplifies Lab Automation Processes

The COVID-19 pandemic has stretched clinical laboratories to the limit with the exponential increase in sample processing. Administrators are exploring new methods for processing large volumes of patient samples using robotics to address this increased demand. Hospital and clinical laboratories are ideally suited for automation equipment to carry out repetitive and hazardous tasks, freeing up technicians for more complex projects.

In the U.S., more than 7 billion clinical lab tests are performed each year according to the American Clinical Laboratory Association. Clinical laboratory testing supports early diagnosis and prevention that ultimately fosters lower costs, improved patient outcomes and better quality of life. These tests can also help clinicians provide personalized treatment plans and medication based on a patient’s unique genetic profile. Many of these routine tests were delayed during the pandemic because testing resources – both personnel and consumables – were redistributed to boost COVID-19 sample processing.

The Case for Automating Liquid Dispensing

Laboratory technicians are in high demand and lab managers are struggling to fill positions in today’s competitive job market. Coupled with higher volumes of patient samples, there is a growing need to further automate clinical laboratory systems.

Routine sample processing, such as DNA and RNA extraction, accounts for the majority of testing carried out by lab technicians. This process involves treating a blood sample with various reagents to isolate a patient’s DNA so that further testing, such as PCR analysis, can be performed. In order to transfer small volumes of liquid – even smaller than a microliter – a technician typically uses a pipette. Pipettes are capable of measuring and dispensing precise amounts of liquid. As a manual process, this can be quite repetitive, time consuming and potentially increase the probability of human errors leading to further delays in sample processing.

Automated solutions are being developed to replace manual liquid dispensing with improved throughput and accuracy. From single electronic pipettes that include a battery-powered motor to full-scale robotics solution for high volume sample processing, automated liquid handling can benefit laboratories of all sizes.

Stepping Motors Deliver Optimal Precision

How are these systems able to extract and dispense precise amounts of liquid? Many manufacturers integrate stepping motors that have a defined rotation angle making it simple to translate step angles into volumes of liquid within a pipette. For example, a standard hybrid stepping motor moves 200 steps per rotation (at 1.8° resolution). If each step equals one microliter of liquid, a single stepping motor can be programmed to extract up to 200μl of liquid in 1μl increments. If a stepper motor with a higher resolution is used – say 0.9° – the motor would be capable of extracting 0.5μl increments with the same total volume of 200μl.

Stepping motors also offer good holding torque which means once the liquid is extracted, it will stay in the pipette until the motor reverses rotation and dispenses the contents. Positional feedback is available without an additional sensor or encoder making them easy to control by the number and frequency of pulses.

Hybrid and PM stepping motors are best suited for highly repeatable tasks that require precise motion control such as liquid handling and lab automation.