Chemical screening is an essential tool in early drug development, assisting in the discovery of small molecule therapeutics that would never have been drugs of interest were it not for the testing and validation of thousands of potential candidates. While some smaller labs have a modest selection of chemicals to test, others may have chemical libraries of millions of compounds, which are impossible to track without a dedicated identification system. Implementing such a system can prevent mismatches, right from the start, resulting in a lower rate of false positives and negatives.
Managing your chemical libraries
A laboratory information management system (LIMS), inventory management system, or advanced liquid handling software are strongly recommended, used in combination with barcode and/or RFID labels to track and trace chemical libraries. Most LIMS offer an all-in-one solution that can be used across the entire lab to track the location, sample type, volume, concentration, and other pertinent details for every individual microplate and well, while also monitoring the samples as they are utilized throughout workflows. Some companies, like Beckman Coulter, offer advanced software specifically to schedule and monitor liquid handler workflows, with additional data acquisition and reporting features.
Compound identification
As mentioned before, tracking chemical libraries requires an accurate and reliable method of labeling microplates. To do this, barcode and/or RFID labels are recommended. Both systems can be used together, if necessary, as nearly any label can now be outfitted with an RFID chip and printed on with a barcode using an RFID printer. While barcodes may be more advantageous for smaller libraries, RFID can benefit larger ones, as multiple plates can be scanned simultaneously without requiring a direct line-of-sight. When using barcodes for microplates, 1D barcodes are often used as they fit well on long rectangular labels; however, 2D barcodes can also be printed small enough to fit on the side of each microplate and are capable of storing more information than 1D barcodes.
The labels should be adapted to the microplate and where it is typically stored. This includes resistance to commonly used lab chemicals and solvents, such as DMSO. DMSO is a common solvent use to store compound libraries, as it considered a better solvent than water for organic molecules and resists bacterial growth when stored at 4°C or lower. For plates stored at temperatures below -20°C, freezer-grade labels are necessary. It is suggested to use thermal-transfer deep-freeze microplate labels for the sides of these microplates, ensuring the plates remain securely and accurately labeled during the entire workflow. These chemical-resistant labels should be printed with a thermal-transfer printer loaded with a resin ribbon. This printing method is always recommended as it provides optimal protection against extreme temperatures, chemical exposure, as well as abrasion and fading, all of which can lead to unreadable barcodes and, ultimately, the inability to correctly identify the contents of each library microplate.
Enhancing reproducibility and cost-effectiveness
Drug discovery is a relatively ambitious undertaking that relies on accuracy and consistency for lead discovery. Running a single assay consisting of tens to hundreds of microplates can be costly, especially if the results cannot be reproduced later. That’s why it’s crucial to ensure every component of the drug library is correctly annotated, stored, and tracked. With a single mislabeled well, additional tests may be required, and potentially effective drug candidates can be lost to experimental error. Integrating digital technology is a sure way to prevent these errors and keep data accurate, so drug validation is kept a quick, simple, and scientifically rewarding process from beginning to end.
LabTAG by GA International is a leading manufacturer of high-performance specialty labels and a supplier of identification solutions used in research and medical labs as well as healthcare institutions.
