Diana Spencer reviews the latest high throughput screening technologies used for drug discovery and how they can accelerate therapeutics to the clinic.

High-throughput screening (HTS) utilises robotics and automation to allow testing of large numbers of chemical and/or biological compounds for a specific biological target.

HTS compatible cellular assays

Robert G Lowery PhD, President & CEO at BellBrook Labs, comments: “AI and virtual screening are increasing the diversity of targets in drug discovery, but developing virtual hits still requires wet biology, using technologies developed over the last 25 years. For example, multiple RNA helicases are being targeted for cancer and viral infections before their catalytic properties are well understood. Fortunately, their unwinding activity is coupled to ATP hydrolysis, and homogenous ADP detection methods developed for kinase screening are being adapted to screen and profile helicase inhibitors. At the same time, HTS compatible cellular assays with fluorescent or luminescent readouts are readily available for most of the key immune and inflammatory pathways, and there are powerful new methods for assessing target engagement in cells.”

Bellbrook Labs produces the Transcreener and AptaFluor HTS Assays, universal HTS assays for enzymes using direct detection of nucleotides and homogenous fluorescent readouts.

HT surface plasmon resonance

In the field of antibody research, Eli Lilly and AbCellera have credited Carterra’s LSA biosensor which uses High-Throughput Surface Plasmon Resonance (HT-SPR) technology for enabling a clinical candidate in less than 90 days. In small molecule discovery, Carna Biosciences says it has achieved dramatic results using the LSAXT platform to understand kinases.

“SPR has been the gold standard for decades for characterising molecular interactions, particularly affinity, but there was always a caveat about how many samples you could or should send to the analytical team for SPR analysis. Throughput was prohibitive so the data resolution was extremely low,” says Tim Germann, Chief Commercial Officer at Carterra. “Now, with HT-SPR, researchers have the ability to screen entire antibody and small molecule libraries, along with characterising epitopes, so there is way more data available at the earliest stages of drug discovery than ever before.”

Self-assembled monolayer desorption ionisation

According to Zachary Gurard Levin, PhD, Science Director, Discovery, Charles River: “HTS assays often rely on reporter systems, including optical and fluorescent labels, to inform on enzyme activity or cellular phenotype. The prevalence of optical interference from small molecules has motivated the field to move towards label free methods such as mass spectrometry (MS).

“While advances in MS instrumentation have increased the readout speed to mirror that of optical plate readers, challenges remain. Processes to purify analytes prior to detection can be cumbersome and many researchers opt to eliminate these components altogether, which may also impact the biochemical reaction.”

Charles River’s solution is to utilise defined surface chemistries designed to specifically immobilise an analyte of interest out of a complex reaction. The technology, self-assembled monolayer desorption ionisation (SAMDI), can purify up to 1536 samples in seconds for MS detection.

Automated cell culture

“A recent study showed that 80% of the drugs that were withdrawn from the market because of serious patient adverse responses would not have been approved if organoids were used in screening,” explains Shantanu Dhamija, Vice President of Strategy and Innovation, Molecular Devices. “Innovators are leveraging advances in automation, robotics, artificial intelligence, and machine learning to alleviate the bottlenecks that have prevented broader adoption. For example, some tools combine liquid handling, incubation, and cell culture with cameras and high-content imagers to quantify the cell model development in real time, witness how it responds during the drug-screening process and make intelligent decisions along the way.”

The CellXpress.ai Automated Cell Culture System is one solution that automates the organoid culture process for prolonged, complex workflows. Machine learning informs media exchange, plating, passaging, organoid monitoring, endpoint assays, and complex image analysis, increasing productivity and reproducibility for drug screening.

High-throughput MS with automation

In 2023, SCIEX launched the Echo MS Center of Excellence, equipped with the Echo MS+ system, which delivers qualitative and quantitative results through a panel of high-throughput assays, and is compatible with automated laboratory systems, such as the Beckman Coulter Life Sciences Biomek i7 liquid handler. The company used this setup to demonstrate the ability to perform a real-time kinetic hydrolysis study. The hydrolysis of a glucuronide was measured over a one hour period where the system pipetted, incubated, and agitated the samples in a reaction plate.

“Streamlined automation in high-throughput screening accelerates discovery and enhances precision and reproducibility,” says Han Joo Lee, Sr Manager, Echo MS Excellence Team at SCIEX. “This will help speed up the process of drug discovery and reduce the potential for false positive or false negative results.”

Enzyme-linked immunosorbent assays

Abcam’s enzyme-linked immunosorbent assay (ELISA)- based tools and reagents are designed to be flexible as they can be used on multiple platforms and adapted to automatable systems and liquid handlers. The company’s SimpleStep ELISA (SSE) kits are sandwich ELISA assays developed to cover over 900 key targets across research areas, including immunology, immuno-oncology and neuroscience. The kits use the CaptSure system, a semi homogeneous system that forms the antibody-analyte sandwich complex in solution.

Polystyrene TC-treated microplates

Corning’s products for high throughput screening include plates for colourimetric, luminescent, and fluorescent based assays. The Corning 96-well Flat Clear Bottom Black Polystyrene TC-treated Microplates have bottoms that are 60% thinner than conventional polystyrene plates, designed to have lower background fluorescence and to enable readings down to 340nm. According to the company, its 384-well Flat Clear Bottom Black Polystyrene TC-treated Microplates have low background fluorescence, minimal light scatter and reduced crosstalk. The Corning 1536-well Black/Clear Bottom Low-base Polystyrene TC-treated Microplates have a low base intended to provide high bottom reader sensitivity.

Multi-mode readers

According to BMG Labtech, its PHERAstar FSX is its most sensitive multi-mode reader for high-throughput screening. The reader includes an Optic Module system, Simultaneous Dual Emission, UV/vis spectrometer, AAS System, and AlphaScreen and TRF lasers. It comes with assay optimised Optic Modules which contain application specific filters, mirrors, dichroics and/or polarisers. The PHERAstar FSX also has four matched and assay optimised photomultiplier tubes (PMTs) which are automatically selected for the relevant detection mode. Users can measure assays with two emission wavelengths at the same time with the Simultaneous Dual Emission. For HTS automation purposes, the PHERAstar FSX can be integrated into automated systems.

Protein biomarker research

Olink’s tool Explore HT for protein biomarker research is designed to allow measurement of over 5,400 proteins using 2µl of sample. According to the company, the dual-recognition, DNA-coupled technology offers high specificity, reducing the risk of wrong targets.

Explore HT is intended to be used for any scale of protein biomarker discovery, from tens to millions of samples. This is enabled by an automated workflow and a software suite that is optimised for high throughput data acquisition, says Olink. The Olink NPX Explore HT software can perform QC analysis and deliver Normalized Protein eXpression (NPX) values and raw data counts.

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