LIGHTSABR - a cheap, portable drug-discovery system

Screening large "libraries" of compounds to find those with a desired biological activity is a powerful method for discovering new drugs, but requires a large, expensive and dedicated facility. Now, scientists at the Florida campus of The Scripps Research Institute (TSRI) have devised the central component of a screening system that would be orders of magnitude smaller and cheaper.

"We've developed a device that can do the functional equivalent of high-throughput compound screening on an ultra-miniaturized scale," said the study's principal investigator Brian M. Paegel, an associate professor at TSRI.

The advance, published recently online ahead of print in Analytical Chemistry, follows a previous study from the Paegel laboratory in ACS Combinatorial Science that described the synthesis of miniaturized DNA-encoded compound libraries. The new screening device is designed to work with the new type of library.

One-bead, one-compound
Current high-throughput screening systems typically occupy 10,000 square feet of space or more and cost millions of dollars. They rely heavily on robotic devices that retrieve compounds from the library, place each compound into a separate small well in an "assay microplate" and measure each compound's biological activity--for example, whether the compound inhibits a particular enzyme involved in viral replication.

Being almost entirely automated and relatively quick, such systems can rapidly screen the tens or hundreds of thousands of compounds in a typical library. But the great cost of these high-throughput screening systems limits their use to locations at pharmaceutical companies and large research institutions. The Scripps Florida campus houses one of the most active high-throughput screening facilities outside the pharmaceutical industry.

The new approach starts with the use of "one-bead-one-compound" (OBOC) libraries, in which individual compounds are chemically attached to microscopic beads. Over the past two decades, many laboratories have begun to work with OBOC libraries of one type or another, which are so quickly and cheaply prepared and are so compact that such libraries are essentially laboratory consumables. "It is possible to generate an OBOC library of millions of compounds in a week for about $500," said Alexander K. Price, a senior research associate in the Paegel laboratory and lead author of the new study.

LIGHTSABR
There are considerable technical challenges involved in putting bead-borne compounds through miniature screening devices. But, as they report in their new paper, Paegel and Price were able to engineer a benchtop-scale device that meets these challenges and can screen OBOC libraries.

The device is built on the microfluidics principles that also underlie inkjet printer technology. Using a "suspension hopper," which Paegel and Price described in a 2014 Analytical Chemistry paper, the device introduces OBOC library beads into tiny liquid droplets that contain the assay of interest, such as an enzymatic activity assay. The volume of these assay droplets is about 100,000 times less than the volumes used for high-throughput screening assays.

The device then frees each compound from its bead with a photochemical reaction induced by ultraviolet (UV) light and, after an appropriate period of incubation, records the result in each droplet.

Dubbed LIGHTSABR (Light-Induced and Graduated High-Throughput Screening After Bead Release) for its light-based cleavage of compounds from their carrier beads, the device overcomes significant technical hurdles concerning the smooth flow of droplets, the absorption of stray UV irradiation and calibration of the UV waveguide.

A key innovation is that the technique allows users to vary the UV illumination to adjust the amount of a compound cleaved from its bead--and thus adjust the dose of the compound being tested. The team successfully demonstrated this dosing function using an assay designed to find inhibitors of HIV-1 protease, a key enzyme involved in the replication of the virus that causes AIDS.

The next step for Paegel and Price is to apply the microfluidic LIGHTSABR and the laboratory's DNA-encoded OBOC libraries. "In addition to antiviral compounds, we are also pursuing new antibiotics and other drug classes that address the emergence of resistance in rapidly evolving pathogens," said Paegel.

"Hundreds of laboratories around the world could operate their own miniaturized screening facilities, using their own assays to go after targets that are of most interest to them," said Price.

In addition to Paegel and Price, the study, "hνSABR: Photochemical Dose-Response Bead Screening in Droplets," was authored by Andrew B. MacConnell of TSRI.

Funding for the research was provided by a Director's New Innovator Award from the National Institutes of Health (OD008535) and the Defense Advanced Research Projects Agency (N66001-14-2-4057). To view the paper, see http://pubs.acs.org/doi/abs/10.1021/acs.analchem.5b04811

Most Popular Now

Pfizer and BioNTech complete submission to Europea…

Pfizer Inc. (NYSE: PFE) and BioNTech SE (Nasdaq: BNTX) today announced they have completed a submission to the European Medicines Agency (EMA) for an Omicron-adapted biva...

AstraZeneca to acquire TeneoTwo and its clinical-s…

AstraZeneca announced an agreement to acquire TeneoTwo, Inc. (TeneoTwo)i, including its Phase I clinical-stage CD19/CD3 T-cell engager, TNB-486, currently under evaluatio...

Lilly will supply an additional 150,000 doses of b…

Eli Lilly and Company (NYSE: LLY) announced a modified purchase agreement with the U.S. government to supply an additional 150,000 doses of bebtelovimab for approximately...

Bayer to sell men's health product Nebido™ to Grün…

Bayer and Grünenthal have entered into a definitive agreement regarding the sale of Bayer's men's health product Nebido™ (testosterone undecanoate), for a purchase price ...

Demonstration of a potent, universal coronavirus m…

The SARS-CoV-2 that causes COVID-19 has killed 6.3 million people worldwide since 2019, painfully highlighting the vulnerability of humanity to novel coronaviruses. Re...

Vaccine protection against COVID-19 short-lived, b…

Since COVID-19 vaccines first became available to protect against infection and severe illness, there has been much uncertainty about how long the protection lasts, and w...

SARS-CoV-2 hijacks nanotubes between neurons to in…

COVID-19 often leads to neurological symptoms, such as a loss of taste or smell, or cognitive impairments (including memory loss and concentration difficulties), both dur...

Anti-inflammatory compound shows potential in trea…

An anti-inflammatory compound may have the potential to treat systemic inflammation and brain injury in patients with severe COVID-19 and significantly reduce their chanc...

Pfizer and BioNTech advance COVID-19 vaccine strat…

Pfizer Inc. (NYSE: PFE) and BioNTech SE (Nasdaq: BNTX) today announced that the companies have initiated a randomized, active-controlled, observer-blind, Phase 2 study to...

Vaccine-induced immune response to omicron wanes s…

Although COVID-19 booster vaccinations in adults elicit high levels of neutralizing antibodies against the Omicron variant of SARS-CoV-2, antibody levels decrease substan...

Scientists develop new biomimetic formulation for …

Glioblastoma multiforme (GBM) is an aggressive brain cancer with a poor prognosis and few treatment options. New and effective approaches for GBM treatment are therefore ...

New needle-free nasal vaccine shows promise for CO…

New research shows that a needle-free mucosal bacteriophage (phage) T4-based COVID-19 vaccine is effective against SARS-CoV-2 infection. The findings were published in mB...