Automated pipetting system consists of liquid handling system that delivers precise volume of specimen and regent at high speed and accurately, motion system that moves heads with nozzles and plates and controller that controls those.
Liquid handling system
It defines the performance of the system that consists of pumps, tubes and nozzles and handles liquid.
Plunger pump is often used because it can process small amount of liquid speedy and precisely. Dispensing accuracy is expressed with AC (accuracy) and CV (coefficient of variation : the ratio of the standard deviation to the mean). AC is a indicator for absolute accuracy and CV represents repeatability. The system with only good CV may not be suited for quantitative analysis.
There are 1, 8, 12, 24, 96 and 384 channels system.
Plate handling is in only one direction, loading and ejecting, usually. There are systems without plate handlers, manual system.
Head has to move in X and Y direction in accordance with the number of channels in the head and the number of wells in the applicable plates. In addition, movement in Z direction is necessary with specific functions.
Both liquid handling and motion system are controlled by the controller. Controlling Nozzles becomes more complicated if the system has functions such as dilution, agitation and nozzle flushing as well as dispensing. Even more complex systems contain functions that can only be achieved with moving nozzles and built-in stacker.
A system with stages called Areas can replace and flush tips at each Area. There are other systems as well, that can transfer specimen to plates with different number of wells, accommodate regent reservoirs and perform Solid Phase Extraction.
Applications for automated pipetting systems
There are great many automated pipetting systems in biological, chemical and medical fields. Especially, applications for genomics, drug discovery, DNA and clinical test are most popular. Recently, demand in the system is getting greater and greater while speeding up with high throughput screening is attracted attention.
DNA sequence analysis of model organism such as mouse, drosophila, yeast fungus and nematode worm.
Genome Research from genomics to transcriptome, studying transcripts and proteome, researching proteins by a genomics.
Shotgun sequencing method
PCR (Polymerase Chain Reaction)
High throughput screening
Screening of effective microorganisms
Forensic DNA testing
Tracing biological evolution
Gene expression analysis
Laboratory tests ( blood, feces, immunity analysis and antibody response )
Tracing sources of food poisonings
Research in genetic polymorphism (SNP, single nucleotide polymorphisms) typing
Features of automated pipetting systems
Automated pipetting system can automate works that operators have done. The most significant feature of the system is that it can process a large quantity of work human can never perform at high speed. At the same time, accuracy is increased and number of operation mistakes are decreased.
Dispensing accuracy is often expressed with AC (accuracy) and CV (coefficient of variation : the ratio of the standard deviation to the mean). It varies with dispensing volume.
Capacity or performance of the system is expressed with time spending at one dispensation. It is affected with factors such as dispensing volumes and dispensing actions, for example, tip replacement.
System configuration of automated pipetting systems
In the fields of genomics, drug discovery and clinical test, automated pipetting system plays an important role, being integrated with many other system and controlling them to process jobs automatically at high efficiency rather than it is used as an isolated system. The most growing region of research and development of the system is HTS, High Throughput Screening, combining assay, one of a methodology in analyzing especially biological samples, and automated pipetting systems together.
Integration with other units such as stackers to process various operation like regent preparation and pre-process of specimen efficiently becomes more popular, comparing with those systems dedicated only for one specific purpose.
Integration with microplate readers
Microplate reader is a system that can measure reaction quantitatively, optically scanning samples mixed with regent.
It is indispensable for clinical test and drug discovery to automate the process. Although the test is automated, efficiency of the whole system does not increase unless preprocess, sample preparation is also automated. Accordingly, automated pipetting system is required to pre-process automation.
Integration with stackers
Stackers that can accommodate many well plates in stack are used to process large amount of specimen that can not be done with a single large well plate like 1536-well plate. Plates in the stacker are transferred from / to automated pipetting system. The stacker and the automated pipetting system are synchronized through signal communication.