Few pieces of laboratory equipment are as well used and essential as the pipette. Recently, a number of electronic versions have emerged on the market, among them the Eppendorf® Research Pro Electronic Pipettes.
Eppendorf® provide a full range of electronic pipettes, with 5 single channel models (from 0.5 µL to 5 ml) and a range of multichannel pipettes in both 8 and 12 channel models (from 0.5 to 300 µl). The pipettes are supplied with a built-in NiMH battery that is charged through an adaptor or a charging stand. The Research Pro pipettes have a number of liquid handling program options. To begin with, the speed at which liquids are aspirated and dispensed can be controlled separately. Other options include the ability to program volumes for quick selection, rinsing and mixing, reverse pipetting, manual pipetting (controlled by touch rather than a defined stroke), and repeated dispensation of small volumes.
The percent accuracy for the single channel pipettes is in the range of 2-3% (at the smallest volumes) which is comparable to other pipettes. The multichannel pipette accuracies are somewhat higher, from 2-6%. Of course, the pipettes are designed for use with Eppendorf tips, and other tips may not attach well, or be very hard to detach which can affect the accuracy.
The pipettes have been designed with ergonomics in mind, and despite the bulky control panel and display screen, are light and comfortable in the hand. Aspiration and dispensing are triggered by depressing a soft rubber button with the thumb, and tips are ejected by a lever which can be adjusted for left or right hand use. A good read of the manual is recommended before attempting to program the pipette as the controls are not particularly intuitive. As the electronics are contained within the body of the pipette, they cannot be taken apart for cleaning or autoclaving, and the units must be returned to the supplier for calibration or repair.
We have used Multichannel Research Pro pipettes in our laboratory for over two years and in this time a number of issues have arisen that should be considered. Our pipettes have been in action for one to several hours each day for tissue culture and 96-well plate based assays, both of which require numerous washing steps. In general, the pipettes function well, and are quite comfortable to use over longer periods of time. However, the lowest speed available for dispensing liquids is not suitable for some tissue culture situations, as weakly adherent cells can be lost. The battery life is not spectacular, requiring a charge every 1.5-2 hours of use (this is based on tissue culture work, consisting of continuous aspiration and dispensing of maximum volumes). Very little warning is given before the pipette shuts down which can be quite inconvenient if caught off guard. The tip attachments have small o-rings on them, and aside from presenting a cross contamination and sterility issue, they tend to wear quickly which results in tips not attaching properly. The tip ejector lever can also stick occasionally, requiring two hands to fix.