In response to the question “Is your assay really optimized?” the answer we hear the most is – “It’s good enough” So, if your process isn’t broken, why on earth would you consider fixing it?
But what if there were significant assay performance, cost and time benefits that could be achieved through removing bottlenecks you might not realize you have? Read on to find out more, as we delve into the process of assay development and optimization in a little more detail.
Why challenge legacy assay development?
First, let’s look at the traditional workflow. It usually involves searching the literature for similar assay conditions to reproduce, then identifying a limited number of sensible variables to tweak in iterative development cycles until adequate results are generated.
Whilst publications provide protocols, have you ever wondered how much work went into the original assay development? What was their starting point, how much subsequent optimization did they perform, were common off-the-shelf buffers used for convenience, or was time spent thoroughly evaluating different constituents and pH effects?
At first it may seem unnecessarily time consuming to consider optimizing your own buffers, especially when the number of individual variables that can be titrated per development cycle in 96-well microplates is limited to just a few, but what if more comprehensive buffer optimization led to a doubling of assay window?
Let’s ponder the ramifications of this for a second before moving on. For an enzymatic assay, you could halve the amount of enzyme and thus halve its cost per microplate, whilst still achieving the same assay window. Just consider the total cost savings that could be made across an entire screening campaign! Has that got your attention?
The bottlenecks preventing you from addressing more variables.
So, this may all sound great in principle, but where do you start? Switching to 384-well microplates sounds like an obvious next step. You can realize some cost savings associated with miniaturization and gain the ability to set up more variables and replicates in one microplate, but at this point we need to face up to the reality that we, as humans, now represent a bottleneck in the process! Whilst you might embrace the challenge of pipetting into 384-well microplates, if you get lost it is pretty hard to recover from and let’s not go there with respect to 1,536 well microplate assays and the challenges associated with them! Have you ever run out of (or wasted) reagent by miscalculating the total volume required and ruined half your experiment?
Throw a time course into the mix and you can be held to ransom at the bench for hours, with separation anxiety setting in if you can’t see your timer. Once boredom takes a hold, the temptation to multitask becomes impossible to ignore and before you know it, you have distracted yourself and missed a time point. There’s no doubt about it, assay development can be frustrating and requires a lot of patience, planning and focus.
The more complex the assay becomes the bigger the potential for human error, so it’s no wonder that “good enough” assays were traditionally considered optimized.
Have you thought about automating reagent dispensing?
Things are about to change with automation fast becoming the new best friend of assay development scientists! Liquid handling robots are helping us to extend the boundaries of assay optimization beyond what can be done by hand. They do exactly what they are programmed to do when they are asked to do it and don’t ever need a badly timed comfort break!
Before dismissing automation as an unnecessary luxury, taking the “hand” out of pipetting is not just for the privileged, nor is it a sign of defeatism, automation simply represents another tool in the box that complements your trusted pipettes to improve productivity, reduce the risk of repetitive strain injury, achieve more with your budget and focus your time on less mundane tasks. A truly valuable addition to any assay development lab, so why not give it a try? Just imagine being guided through the planning, calculation and set-up of incomprehensibly complicated multifactorial assays in just a few steps. Think about the chemical space you could explore using 10 single channel disposable tips, each set to dispense different volumes of different reagents into different wells, at different time points. Envisage the possibilities of working in 1,536 well microplates…more variables explored per plate, greater reagent savings realized and, how much smoother could the transition of optimized assays from development into screening be? So, do you think your workflow could benefit from automated assay development and are you already thinking about which additional projects you could address with all that extra budget and time?
Check back in with us next month when we will discuss what needs to be considered when making the leap from manual to automated liquid handling.
A final message to those that love their hand pipettes so much that they are labeled with your name or kept under lock and key so that they don’t wander. We can let you into a secret, we at TTP Labtech do too, and we hear you! Rest assured, we took our inspiration from the flexibility of hand pipettes so our dragonfly discovery retains all the capability you love but with an extra dimension of capacity and scale!