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High Throughput Screening
With over 20 years of screening experience we are adept at designing screening assays and screening 100,000 to 1 million compounds in 384 well and 1536 well plates.
We have screened up to one million compounds in both cell and biochemical assays using a number of read outs including FLIPR, FMAT, FI, FRET, chemiluminescence, luminescence and label-free formats.
We have extensive experience of cell-based assays in HTS where we have used either cell lines expressing the target in a recombinant manner, Bacmam transient expression and cryopreserved cells.
For human primary cell screening we have used either cryopreserved or freshly isolated cells such as PBMC’s and neutrophils. We understand the importance of delivering robust, reproducible assays with excellent quality control statistics for use in high throughput screening.
We are able to use our experience to assist your drug discovery projects in a number of ways:
- we can validate your in-house assay for high throughput screening on our systems
- we can adapt your assay for high throughput screening e.g. miniaturisation
- we can develop a specific assay for your target, suitable for screening large numbers of compounds
- we can run proof of concept or “tool” compound identification assays
Screening densities will be utilised which are consistent with the assay format and the number of compounds to be screened.
Initially after developing an assay for compound screening, we would run a set of compounds through the assay under screening conditions to validate the approach and the equipment. This would be performed using the same compounds on consecutive days and correlated to determine consistency.
In general, our initial screening is performed at one compound per well at a single concentration. Compounds are then ranked using either percent inhibition (or activation) versus on-plate controls or using B-score, a statistical method that does not rely on on-plate controls but uses an iterative median polish of data.
Retest Confirmation and XC50 Determination
After discussion with the client, an appropriate cut-off is selected and compounds are retested in triplicate for confirmation.
If compounds achieve a pre-determined level in at least two out of three replicates then these can be taken forward for XC50 testing.
While this is our “typical” screening cascade, we are flexible and will adapt our approaches to suit the needs of the client, such as re-designing assays to identify agonists, antagonists, inverse agonists etc.
We have recently added an Envision 2100 with stacker unit to our laboratory, with the support of an ERDF grant. The Envision with stacker is capable of performing multiple assay types in a high throughput 384 well plate format. This facilitates automated analysis of a wider range of screen types.