Drop Volume Measurement
A better quantitative Nanolitre dispensing with piezoelectric dispensers is now available for the micropipetting system Nano-PlotterTM . Basically drop-on-demand dispensing of drops smaller than one Nanolitre enables non-contact microarraying as well as assays in the Nanolitre format. However, the volume of a single droplet is often affected by sample properties like viscosity and surface tension. Variations of the droplet volume sometimes happen "silent" with non-displacement piezoelectric dispensers.
For the Nano-PlotterTM GeSiM introduced two independent and redundant real-time measurement approaches to determine flow rate and drop volume of each individual dispenser after sample aspiration.
|Flow measurement: A high sensitive MEMS based flow sensor measures the flow rate generated by the continuously working piezo dispenser.The sensor is located in the system liquid tube, it is passed by a corresponding volume of system liquid.|
|Multi-channel configurations are individually controlled by a separate sensor for each dispenser.||A flow rate of 1.7 µl/min corresponds to a drop volume of 283 Picolitre at a dispense frequency of 100 Hz.|
|Optical Measurement: The NPC16 software (from version 2.15.49) determines the drop volume of each microdispenser by measuring the drop diameter on the stroboscope image. Differences from the flow measurement may e.g. indicate mechanical damages of the piezo dispenser.|
Pipetting of accurate Nanolite Volumes with the Nano-PlotterTM