Low Volume Dispensing for Protein Crystallization - Genomics Solutions introduces the Honeybee 961.

Jo Butlin, Global Product Leader for Genomic Solutions' Cartesian product range talks to ProteinCrystallography.com at the MipTec conference, (9th -12th May, 2005, Basel, Switzerland).

What is the new product you have on display here at Miptec?

Our newest product within the Cartesian range is the Honeybee 961 for automation and miniaturization of protein crystallization experiments.

This will be officially launched at the American Crystallographic Association Annual Meeting (May 28 - June 2, 2005) in Orlando, Florida. We are giving people preview of this product here at Miptec.

Who is this system aimed at?

The Honeybee 961 is a high speed bench-top system for sitting drop protein crystallization experiments. Its simple experiment set up makes it ideal for multiple users. It also has a small foot print so is a great choice for labs where space is limited.

As with all our systems, the development of the 961 was driven by market needs. The general trend within the market has been the establishment of core crystallography facilities. But what we are seeing now are groups doing their own crystallization, as one of several techniques they are using, rather than looking to a core facility.

The 961 is ideal for this situation with minimal training time required. This system is designed to keep everything very straightforward for the user.

Also when a customer buys the system they will receive instrument and application training on site. These application scientists and service engineers then support the products once they are in the field.

What is the system comprised of?

Based on our market proven Cartesian dispensing technology the 961 is essentially 2 instruments in a single system so there is no need to buy a separate liquid handler to fill crystallization plates making it a very cost effective option. This system fills reservoirs as well as actually dispensing the precipitant and protein drops onto the shelves.

It is a very fast system, designed so that you can set up a full 96-well plate in less than 2 minutes so eliminating the risk of evaporation – a real problem when working with 100nL plus 100nL drops.

We have carried out studies of the evaporation rate and have found that due to the speed of our plate preparation there is no need for humidity control.

We have also developed new software optimized for protein crystallization. This software is very user friendly making the 961 suitable for even the occasional user and enables simple set up of multiple sitting drop crystallization experiments.

What volumes can this system dispense at?

We use a 96-channel head for the dispensing of the precipitant into reservoirs and onto shelves, dispensing 100µL into those reservoirs and volumes as low as 100nL onto the shelves. The 96 stainless steel pipettes are not coated as this ensures the most precise dispensing at such low volumes.

In the past others have found that using a coating, such as Teflon, could cause problems at volumes below 500nL due to the increased effect of surface tension.

For protein dispensing we use a single synQUAD channel. This non-contact dispensing is fast and precise and enables us to dispense protein volumes as low as 100nL.

In sitting drop experiments it is not only being able to dispense low volumes that is important. To get the best chance of crystallization the protein drop must be placed exactly on top of the precipitant drop and the two must be mixed together thoroughly.

The resolution of the x-y-z motors on the 961 ensure that the protein drop is placed directly on top of the precipitant, even when using100nL volumes. The fluidic inertia needed to dispense the protein drop then ensures efficient mixing of the 2 solutions, maximizing the chance of crystal growth.

What about very viscous solutions?

Dispensing viscous solutions with accuracy and precision at volumes as low as 100nL is a real problem for researchers, the 961 is an excellent system for dispensing these solutions.

We have plenty of data to support the accuracy and precision of all our systems when dispensing the more viscous solutions needed for protein crystallization e.g. 30% 8K PEG at 100nL. This is one area where we really have the advantage over a lot of our competitors in the market.

How does this system prevent sample contamination?

The 961 has a very efficient wash system that completely eliminates carry-over. This means that unlike some companies we do not need disposable tips. These tips can be expensive as well as creating another reliability variable for the user to worry about.

How does this system help to conserve valuable protein samples?

Obviously anything that conserves protein is very important because generally the proteins that are of most interest tend to be the smallest samples.

The protein is added via a single synQUAD channel from which it can be recovered after dispensing is complete. Using synQUAD technology enables us to use a very low minimum aspirate volume – ideal if you only have a small amount of your sample in the first place.

Some systems require a much larger aspirate volume while also using several channels for protein addition – this larger volume would then need to be aspirated for each channel, a process requiring more sample than you may have had to start with

Is the Honeybee 961 the only system you have for protein crystallization?

No, the 961 is one of a range of Honeybee systems including instruments capable of multiple crystallization techniques as well as higher capacity systems.

With the addition of the 961 to our range I believe Genomic Solutions now has a system to suit the requirements of any protein crystallization project.

For more information on the Honeybee 961 click here or contact Jo Butlin

Further Information: http://www.genomicsolutions.com