The new nano-head. Most noticeable from this perspective: The longer needle
We wanted to let you know about an important change to our Phoenix RE drop-setters, namely that from today onwards all Phoenix RE units will be equipped with a new protein nano-dispense head. The change might be subtle in terms of overall appearance, but the new nano-dispense head has some very distinctive advantages.
Conceptually, the biggest change is a flow through wash which improves wash speed and efficacy. A pump connected to two wash bottles allows for different wash strategies, e.g. water plus detergent or water plus buffer. The wash works by flushing fluids from behind the dispense head into the wash fountain.
The flow through design also allows for more precise aspiration and dispensing of small volumes using an isolated liquid mode where water (or any other liquid for that matter) is used as a system fluid together with an air gap. Of course the new head can also run in air backed mode which matches the dispense characteristics of the previous model dispense head.
The pump of the new nano head, together with the wash bottles. Both can be conveniently stored on a shelf mounted behind the Phoenix RE, reducing the overal footprint relative to the old style pump.
Within recommended operational parameters for the previous dispense head model, dispense accuracy is virtually identical between old and new style nano heads, yielding coefficients of variation (CV) of 3.5% for 200 nL drops. Still, the new nano-head performed very favorably at 100 nL (CV of 3.2%) and 50 nL (CV of 5.1%), both using isolated liquid mode.
The new pump also improves the overall behavior of the dispense characteristics: It eliminates bubbling during wash, allows for more protein sample to be recovered after dispensing because of reduced aerosolization, and generally samples are pushed out more gently from the dispense head. All this is thanks to a syringe driven soft purge.
Alongside the new pump comes a completely new way of defining liquid classes: Aspirate and dispense classes are now combined, simplifying definition and referencing. Also, the dependency of the liquid classes as a function of dispense volume is now modeled by a functional relationship which allows for dynamic changes for a wide range of dispense volumes.
Last but not least, the actual nano-nozzle is completely redesigned. As show in the picture on the left, the new nozzle is significantly longer and thicker. The longer needle allows for more sample to be accessed from the sample tubes and the larger diameter reduces the chances of clogging the needle, and opens as well, opportunities for exciting applications such as microseeding.
Many thanks to Matt Lundy and of course everybody at Art Robbins Instruments!
