Beckman researcher Yi Lu and his collaborators, Juewen Liu and Debapriya Mazumdar, have developed a simple, easy-to-use test for drugs and other chemical agents by taking advantage of the properties found in aptamers, nanoparticles, and lateral flow technology.

Aptamers are single-stranded nucleic acids that can perform the same kind of functions antibodies do in humans due to their proficiency at binding to specific molecules. Their use in sensors has grown in recent years because, unlike antibodies used in testing, aptamers can be created in the laboratory and without using animals as part of the process.

The laboratory setting, however, prevented wider use of aptamer-based sensors because of the expertise required to perform the chemical procedures. Lu and his collaborators took lateral flow technology, common in commercial pregnancy test kits, and used it to create an aptamer-based colorimetric sensor that not only is simpler to operate than solution-based tests, but also more sensitive. The gold nanoparticles used in the test allow for detection without the need for laboratory equipment.

This simple "dipstick" test can be used to perform screenings quickly and easily, such as in an emergency room situation, to check for drugs or other chemicals. Lu said the method of targeting specific molecules with aptamers through a dipstick test could lead to other sensors with a wide range of potential applications.

"That basically opens up a whole new avenue for making sensors for all kinds of molecules," said Lu, a member of Beckman's 3-D Micro and Nanosystems group.
Lu said using aptamers for sensors has some advantages over antibodies.

"I'm not saying one is better than the other but they cover slightly different areas," Lu said. "There are some things that antibodies can do that we cannot. But there some things that nucleic acid aptamers can do that antibodies cannot. There's a strong overlap, too."

The research results are detailed in a paper by Lu and his collaborators that has been posted on the online version of Angewantde Chemie titled A Simple and Sensitive Dip Stick Test in Serum Based on Lateral Flow Separation of Aptamer-Linked Nanostructures.

To read the paper in PDF form, click here.