Simple, Inexpensive, Fast and Accurate Nano-Sensors Pinpoint Infectious Diseases Like SARS CoV-2

The technology, developed by researchers at Arizona State University (Tempe, AZ, USA) and the University of Washington Seattle (Seattle, WA, USA), represents a significant advance in the fight against infectious diseases. It can be developed and produced at very low cost, deployed within weeks or days after an outbreak, and made available for around one cent per test.

In recent years, deadly infectious diseases, including Ebola and COVID-19, have emerged to cause widespread human devastation. Although researchers have developed a range of sophisticated methods to detect such infections, existing diagnostics face many limitations. The new technique, known as Nano2RED, is a clever twist on conventional high-accuracy tests relying on complex testing protocols and expensive readout systems. The in-solution nano-sensors (“Nano2” in the name) serve to detect disease antigens in a sample by simple mixing. The innovative Rapid and Electronic Readout process (“RED”) developed by the researchers delivers test results, which are detectable as a color change in the sample solution, and record the data through inexpensive semiconductor elements such as LEDs and photodetectors.

Compared with widely used high-accuracy lab tests, such as ELISA, Nano2RED is much easier to use. It does not require surface incubation or washing, dye labeling, or amplification, yet still provides about 10 times better sensitivity than ELISA. In addition, the use of semiconductor devices supports a highly portable digital readout system, which can be developed and produced at a cost as low as a few dollars, making it ideal not only for lab use but for clinics, home use, and remote or resource-strained locations. This approach is based on modular designs, and could potentially be used to test for any pathogen.

As a proof of concept, the researchers conducted a study to apply their innovative method to test for two prominent diseases, Ebola virus (EBOV) and SARS CoV-2. The new technology can identify secreted glycoprotein (sGP), a telltale fingerprint of Ebola virus disease and the SARS-CoV-2 spike protein receptor binding domain (RBD). Similar to ELISA, Nano2RED also relies on binding affinity for positive diagnosis but instead uses floating gold nanoparticles for readout. Unlike ELISA, Nano2RED can be developed from scratch in roughly 10 days and theoretically applicable for any pathogen, providing vitally important early surveillance in the case of a disease outbreak. It can deliver test results in 15-20 minutes and may be administered at an estimated cost of a penny per test. In the current study, the new test was shown to detect Ebola’s sGP in serum with a sensitivity roughly 10 times better than ELISA.

“This technology works not because it is complex but because it is simple,” said Chao Wang, a researcher at Arizona State University’s Biodesign Institute and School of Electrical, Computer & Energy Engineering. “Another unique feature is the multidisciplinary nature of biosensing. A fundamental understanding of biochemistry, fluidics, and optoelectronics helped us come up with something this ‘simple’.”

Related Links:
Arizona State University 
University of Washington Seattle