Northwestern University chemists have developed ultra-sensitive technology based on gold nanoparticles and DNA that is easier to use, considerably faster, more accurate, and less expensive than PCR, making it a leading candidate for use in point-of-care diagnostics.

The method, called bio-bar-code amplification (BCA), can test a small sample and quickly deliver an accurate result. BCA also can scan a sample for many different disease targets simultaneously.

The team used a magnetic microparticle and a gold nanoparticle each with a different oligonucleotide, a single strand of DNA that is complementary to the target DNA. When in solution, the oligonucleotides “recognize” and bind to the DNA, sandwiching the DNA between the two particles.

Attached to each 30-nm gold nanoparticle are hundreds to thousands of identical strands of “bar-code DNA,” so called because they are designed as a unique label specific to the DNA target. After the “particle-DNA-particle” sandwich is removed magnetically from solution, the bar-code DNA is removed from the sandwich and read using standard DNA detection methodologies.

Northwestern University news release